To see the other types of publications on this topic, follow the link: Steel Slag.
Dissertations / Theses on the topic 'Steel Slag'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Steel Slag.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Berryman, Eleanor. "Carbonation of steel slag." Thesis, McGill University, 2012. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=110434.
Full textAbstract:
Iron and steel production is a rapidly growing industry with global outputs increasing 65% over the last ten years (World Steel Association, 2012). Unfortunately, it is also the largest industrial source of atmospheric CO2, accounting for a quarter of the CO2 emissions from industrial sources (International Energy Agency (IEA), 2007).Mineral carbonation provides a robust method for permanent sequestration of CO2 that is environmentally inert. Larnite (Ca2SiO4), the major constituent of steel slag, reacts readily with aqueous CO2 (Santos et al., 2009). Consequently, its carbonation offers an important opportunity to reduce CO2 emissions at source. A potential added benefit is that this treatment may render steel slag suitable for recycling. This study investigates the impact of temperature, fluid flux and reaction gradient on the dissolution and carbonation of steel slag, and is part of a larger study designed to determine the conditions under which conversion of larnite, and other calcium silicates, to calcite is optimized. Experiments were conducted on 2 – 3 mm diameter steel slag grains supplied by Tata Steel RD&T. A CO2-H2O mixture was pumped through a steel flow-through reactor containing these grains. For a given experiment, temperature was fixed at a value between 120°C and 200°C, pressure was 250 bar, and the fluid flux was fixed at 0.8 mL/cm2min or 6 mL/cm2min. Reactions were also carried out in a batch reactor at 180°C and 250 bar, corresponding to a condition of zero flux. The duration of experiments ranged from 3 to 7 days. The CO2-H2O fluid reacted with the steel slag grains to form phosphorus-bearing Ca-carbonate phases. At high fluid flux, 6 mL/cm2min, these phases dissolved at the edges of slag grains, leaving behind a porous rind of aluminum and iron oxides. Increasing temperature increased the rate of this reaction. At low fluid flux, 0.8 mL/cm2min, the extent of carbonation was increased. At the edge of grains, instead of being transformed to porous rinds, primary Ca minerals were replaced by phosphorus-bearing Ca-carbonate phases. As a result of the greater length of reactor used in these experiments, a reaction gradient was observed along which the fluid remained supersaturated with respect to the calcium carbonate, coating the surfaces of the slag grains. Steel slag exposed to the CO2-H2O fluid in the batch reactor was less carbonated; incongruent dissolution of the slag followed by surface coating of the grains by calcium carbonate inhibited further interaction of the slag with the fluid, limiting the extent of possible carbonation.The results of this study show that carbonation of steel slag by aqueous CO2 is feasible using relatively large grains, and that it can be optimised by varying fluid flux. Experiments of the type described above will contribute to the eventual global reduction of industrial CO2 emissions.L'industrie du fer et de l'acier est en pleine croissance et sa production mondiale a augmenté de 65% au cours des dix dernières années (World Steel Association, 2012). Malheureusement, elle est également responsable d'un quart des émissions industrielles de CO2 ce qui en fait la plus importante source industrielle de CO2 atmosphérique (International Energy Agency (IEA), 2007).La carbonatation minérale fournit une méthode robuste pour la séquestration permanente du CO2 sous une forme écologiquement inerte. La larnite (Ca2SiO4), constituant principal des scories d'acier, réagit aisément avec le CO2 aqueux (Santos et al., 2009). Par conséquent, sa carbonatation offre une importante occasion de réduire à la source les émissions de CO2. Un avantage potentiel supplémentaire de ce traitement est de rendre les scories d'acier convenables pour le recyclage. Cette étude examine l'impact de la température, le flux molaire surfacique du fluide carbonaté, et d'un gradient de réaction sur la dissolution et la carbonatation des scories d'acier. Elle s'inscrit dans une étude plus large visant à déterminer les conditions optimisant la conversion de la larnite, et d'autres silicates de calcium, à la calcite.Des expériences ont été menées sur des grains de scories d'acier d'un diamètre de 2 à 3 mm fournis par Tata Steel RD&T. Un mélange de CO2-H2O a été pompé à travers un réacteur continu contenant ces grains et maintenu à une température entre 120°C et 200°C, une pression de 250 bar et à des flux molaires surfaciques de 0.8 à 6 mmol/cm2min. Chaque expérience a duré de 3 à 7 jours. Le fluide CO2-H2O a réagi avec les grains de scories d'acier et a formé des minéraux de carbonate de calcium contenant du phosphore. À flux molaire surfacique élevé, soit 6 mL/cm2min, ces phases sont dissoutes aux bords des grains, laissant place à une bordure poreuse d'oxydes d'aluminum et de fer. Une augmentation de la température a augmenté la vitesse de cette réaction. A valeur intermédaire de flux molaire surfacique, 0.8 mL/cm2min, le degré de carbonatation a augmenté. Au lieu laisser des bordures poreuses d'oxydes, les minéraux de calcium primaires en marge des grains ont plutôt été remplacés par des phases de calcium carbonate contenant du phosphore. En plus, l'usage d'un réacteur plus long a créé un gradient de réaction et maintenu la supersaturation du fluide relative au carbonate de calcium qui a enrobé les grains. Les scories d'acier exposées au fluide dans un réacteur discontinu (sans flux de fluide) ont été moins carbonatées; la dissolution non-congruente de la scorie a pris place suivie par l'enrobage des grains de scories par le carbonate, et ce dernier a réduit la surface de réaction de la scorie avec le fluide.Les résultats de cette étude démontrent que la carbonatation par le CO2 aqueux des scories d'acier à granulométrie relativement grossière est possible et qu'elle peut être optimisée en variant le flux molaire surfacique du fluide. Les expériences de ce type contribueront à la réduction éventuelle des émissions industrielles globales de CO2.
2
Kombathula, Sushanth. "Sequestration of carbon dioxide in steel slag." Thesis, KTH, Materialvetenskap, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-280716.
Full textAbstract:
Although Iron and steel industry is essential for the development of society, the industry is responsible for a large portion of CO2 emissions. The industry also produces by-products like metallurgical slag in orders of million tons. The slag is alkaline in nature and rich in Ca and Mg oxides. Upon use the oxide interact with atmospheric CO2 and form carbonates, making them unstable. Storing CO2 in the slag would make it more stable, enhances its life cycle and promotes further usage in various applications. CO2 sequestration can be done through carbonation of steel slag. Carbonation of slag can be achieved through direct and indirect carbonation. Direct carbonation is performed either in a gaseous or an aqueous state in a single step. Indirect carbonation involves multiple steps as it activates the Ca/Mg ions in the slag before they interact with CO2. For an industrial process the direct route would be more viable as it involves lesser steps, easier to scale up. Since there are no solvents to activate the Ca/ Mg the cost involved is also less. This thesis focuses on developing an industrial process to sequester CO2 in metallurgical slag. Sequestration through a combination of gaseous and aqueous has been attempted while studying the effect of carbonation time, carbonation temperature and shape of slag used. Carbonation of the slag is performed using CO2 and steam. The results show that carbonation yield increases with carbonation time and decreases with increase in temperature. The effect of the shape of slag used for carbonation was studied by performing carbonation test in a slag pellet. Diffusion plays a significant role in carbonation process. Powdered slag showed higher carbonation yield compared to the pellet. CO2 uptake as high as 53g of CO2/kg of slag at 200 oC for 6 hr has been achieved. The results indicate the possibility for an industrial carbonation process.Även om järn- och stålindustrin är avgörande för samhällets utveckling, är industrin ansvarigför en stor del av koldioxidutsläppen. Industrin producerar också biprodukter som metallurgisk slagg i order på miljoner ton. Slaggen är alkalisk till sin natur och rik på Ca- och Mg-oxider. Vid användning interagerar oxiden med atmosfärisk CO2 och bildar karbonater, vilket gör dem instabila. Att lagra koldioxid i slaggen skulle göra den mer stabil, förbättra livscykeln och främja ytterligare användning i olika applikationer. CO2-bindning kan göras genom kolsyrning av stålslagg. Kolsyrning av slagg kan uppnås genom direkt och indirekt karbonatisering. Direkt karbonatisering utförs antingen i ett gasformigt eller vattenhaltigt tillstånd i ett enda steg. Indirekt kolsyrning involverar flera steg eftersom den aktiverar Ca/Mg-jonerna i slaggen innan de interagerar med CO2. För en industriell process skulle den direkta vägen vara mer livskraftig eftersom den innebär mindre steg, lättare att skala upp. Eftersom det inte finns några lösningsmedel för att aktivera Ca/Mg är kostnaden också mindre. Denna avhandling fokuserar på att utveckla en industriell process för att binda koldioxid i metallurgisk slagg. Sekvestrering genom en kombination av gasformig och vattenhaltig har försökt under undersökning av effekten av kolsyratid, kolsyratemperatur och form av den använda slaggen. Kolsyringen av slaggen utförs med CO2 och ånga. Resultaten visar att karbonatiseringsutbytet ökar med kolsyratiden och minskar med temperaturökningen. Effekten av formen på slagg som användes för karbonatisering studerades genom att utföra karbonatiseringstest i en slaggpellet. Diffusion spelar en viktig roll i karbonatiseringsprocessen. Pulveriserad slagg visade högre karbonatiseringsutbyte jämfört med pelleten. CO2-upptag så högt som 53 g CO2/kg slagg vid 200 oC under 6 timmar har uppnåtts. Resultaten indikerar möjligheten för en industriell karbonatiseringsprocess.
3
Skagerkvist, Mio. "Adsorption of anionic elements to steel slag." Thesis, Örebro universitet, Institutionen för naturvetenskap och teknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-71048.
Full textAbstract:
Steel slag is a by-product from steel production and has potential to act as a sorbent for several contaminants. Contaminated water is a global problem and cheap and simple remediation solutions are often sought. The potentials are many to use an industrial residue for water purification purposes e.g. low cost. The absorption efficiency was evaluated for two different steel slags further divided into two grain sizes, <0.9 mm and 0.9-2 mm. Laboratory experiments was conducted for three anionic elements; bromine, chromate and molybdate. Controlled parameters were; time, sorbent amount and sorbate concentration. The sorption was primarily dependent on the grain size and the smaller grain size had a higher sorption of all three tested anionic species. Unfortunately the results are partially affected by the release of the tested elements from the sorbent itself.
4
Jansson, Sune. "A study on molten steel/slag/refractory reactions during ladle steel refining." Licentiate thesis, Stockholm, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-312.
Full text
5
Kjellqvist, Lina. "Studies of Steel/Slag Equilibria using Computational Thermodynamics." Licentiate thesis, Stockholm Stockholm : Materialvetenskap, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3914.
Full text
6
Holloway, Mark. "Corrosion of steel reinforcement in slag-based concrete." Thesis, University of Oxford, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.365811.
Full text
7
Ekengård, Johan. "Slag/Metal Metallurgy in Iron and Steel Melts." Doctoral thesis, KTH, Tillämpad processmetallurgi, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-187228.
Full textAbstract:
In this work, the metal and slag phase mixing in three steps of a ladle refining operation of steel melts and for an oxygen balance during cooling of cast iron melts have been studied at two Swedish steel plants and at two Swedish cast iron foundries, respectively. In order to predict the oxygen activity in the steel bulk in equilibrium with the top slag as well as in metal droplets in the top slag in equilibrium with the top slag, three slag models were used. In addition, the assumptions of a sulphur-oxygen equilibrium between steel and slag and the dilute solution model for the liquid steel phase were utilized in the calculations. Measured oxygen activities in steel bulk, which varied between 3.5-6 ppm, were compared to predicted oxygen activities. The differences between the predicted and measured oxygen activities were found to be significant (0-500%) and the reasons for the differences are discussed in the thesis. Slag samples have been evaluated to determine the distribution of the metal droplets. The results show that the relatively largest numbers of metal droplets are present in the slag samples taken before vacuum degassing. Also, the projected interfacial area between steel bulk and top slag has been compared to the interfacial area between the metal droplets and slag. The results show that the droplet-slag interfacial area is 3 to 14 times larger than the flat projected interfacial area between the steel and top slag. Furthermore, the effect of the reactions between top slag and steel and the slag viscosity on the metal droplet formation is discussed. The results show significant differences between the steel bulk and steel droplet compositions and the reasons for the differences are discussed in the thesis. The oxygen activity in different cast irons was studied. Plant trials were performed at three occasions for lamellar, compacted and nodular iron melts. The results show that at temperatures close to the liquidus temperature the oxygen activities were 0.03-0.1 ppm for LGI, around 0.02 ppm for CGI, and 0.001ppm for SGI. In addition, it was found that as the oxygen activities increased with time after an Mg treatment, the ability to form a compact graphite or a nodular graphite in Mg-treated iron melts was decreased. Also, extrapolated oxygen activity differences up to 0.07 ppm were found for different hypoeutectic iron compositions for lamellar graphite iron at the liquidus temperature. Overall, the observed differences in the dissolved oxygen levels were believed to influence how graphite particles are incorporated into the austenite matrix and how the graphite morphology will be in the cast product.QC 20160518
8
Patel, Jigar P. "Broader Use of Steel Slag Aggregates in Concrete." Cleveland State University / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=csu1229627352.
Full text
9
Oty, Uchenna Victor. "Steel slag leachates : environmental risks and metal recovery opportunities." Thesis, University of Hull, 2015. http://hydra.hull.ac.uk/resources/hull:13632.
Full textAbstract:
Steel slag wastes are large volume residues generated in increasing quantities globally during steel production. While there are many afteruses for slag, roughly a quarter produced globally is stockpiled or landfilled where it may pose environmental risks. Furthermore as resource pressures increase there is a growing interest in recovering valuable metals from industrial by-products. Given the uncertainties in environmental risks and opportunities for further valorisation of wastes, an improved understanding of leaching processes from steel slag would help inform long term management of these industrial by-products. This thesis aims to investigate a series of alkaline disposal sites (both steel slag and limespoil) to improve our understanding of the geochemical nature and fate of notable contaminants, as well as valuable metals of interest, in highly alkaline settings. The results of the field investigations show that leachates are characterised by high pH ( > 11) and negative redox potential, excess deposition of secondary precipitates, and increased mobility of lithium ( > 800 ppb), strontium ( > 2500 ppb) and vanadium ( > 50 ppb), present in concentrations greater than those typically encountered in natural surface waters. Furthermore, these slag deposits were enriched with less mobile elements such as molybdenum (60 ppb) and nickel (61 ppb) with associated low environmental concern, but high resource value. Laboratory batch tests showed that acid leaching promotes the leaching of the elements of interest particularly vanadium. However, such approach may not be viable at legacy sites due to cost. On the other hand, compost amendment of slag enhanced the leaching of molybdenum and vanadium by a factor of 3.6 and 2.5 respectively above water leaching alone. Column experiments reinforced these patterns in showing enhanced leaching of vanadium, molybdenum, and lithium when organic amendment is in contact with hyperalkaline leachate under aerobic conditions. This is most likely due to alkaline hydrolysis of organics within the system and subsequent metal complexation. Analysis of secondary precipitates (notably calcium and magnesium carbonates) forming around the slag suggest these are key in controlling solubility of contaminants and metals of potential resource value (e.g. Ni).
10
Wang, George Chenggong. "Properties and utilization of steel slag in engineering applications." Online version, 1992. http://bibpurl.oclc.org/web/23804.
Full text
11
El-Baghdadi, Ahmed. "Carbon dioxide activated steel slag as a cementing material." Thesis, McGill University, 2012. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=107748.
Full textAbstract:
Steel slag is a major by-product of the steel industry, with a production of nearly 300 kg for every tonne of steel produced. It has been conventionally used as an aggregate in road base construction, but this use has been limited due to the high free lime content, which causes volume expansion problems. This thesis explores the feasibility of using CO2 activation to eliminate free lime and develop strength for a steel slag-based building product. The CO2 activated steel slag has the potential to be used as cementing material to replace Ordinary Portland Cement (OPC) and to sequester carbon dioxide through activation. The technology can show numerous technical and environmental benefits, while minimizing the embodied energy in the final products.Compressive strength and carbon uptake of compacts made of KOBM1, KOBM2, ladle and GGBF slag were evaluated in comparison with counterpart OPC compacts. KOBM slag showed the greatest potential, with compressive strength and carbon uptake values comparable to OPC. The microstructural change of carbon dioxide activated KOBM slag was assessed in detail by X-ray diffraction (XRD), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). Its durability was also measured by the means of an accelerated water softening test. The wallboard made of KOBM slag bonded with sawdust was fabricated, and its mechanical performance was found to be competitive to commercial cement-based wall-boards. The research demonstrates that certain types of steel slags can be successfully activated by carbon dioxide in the production of commercial products to replace OPC.Le laitier d'acier est un important coproduit de l'industrie de l'acier ayant une production près de 300 kilogrammes pour chaque tonne d'acier produite. Il est traditionnellement utilisé pour la construction d'infrastructure routière, étant ajouté comme additif dans le ciment et les agrégats. Cependant la forte présence de chaux libre dans les résidus de métallurgie cause une expansion de volume lors de son utilisation comme matériau de construction, ce qui limite son application dans l'industrie.Cette thèse explore la possibilité d'éliminer la chaux libre par l'activation de la réaction chimique du CO2 ainsi développer la résistance pour un produit de construction à base de laitier d'acier. L'activation du dyoxide de carbone présent dans le laitier d'acier a le potentiel d'être utilisé comme matériau cimentière au lieu du ciment Portland ordinaire en plus de séquestrer le CO2 grâce à son activation. Cette technologie peut démontrer de nombreux avantages techniques et environnementaux, tout en minimisant l'énergie intrinsèque des produits finaux.Des essais pour quatre différents types de scories compactes, formées à partir de KOBM1, KOBM2, et de scories de GGBF ont été realisés afin de tester leur capacité d'absorption de carbone et leur résistance à la compression. Les résultats ont été comparés avec des spécimens homologues produits avec du ciment Portland ordinaire. Le changement microstructurel du laitier KOBM avec CO2 activé a été évalué en détail par diffraction des rayons X, TGA et SEM. Sa durabilité, par un essai de résistance à l'eau a également été mesurée. Des plaques de plâtre à base de laitier d'acier KOBM liés avec de la sciure de bois ont été fabriquées, leur performance mécanique s'est avérée tout à fait comparable à celle des plaque de plâtres en ciment offertes sur le marché. Finalement, la recherche conclut que l'activation du dioxyde de carbone de certains produits commerciaux, faits à base de laitier d'acier, peuvent être utilisés et permette l'emploi du laitier d'acier pour remplacer le ciment Portland ordinaire dans certains produits commerciaux.
12
Chaudhary, Zia-Ul-Hasan. "Pitting corrosion of austenitic stainless steel in slag cement." Thesis, University of Oxford, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.291082.
Full text
13
Jesic, James John. "The utilisation of reclaimed asphalt and steel slag fines." Thesis, University of Birmingham, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.403088.
Full text
14
De, Oliveira Campos Leandro Dijon. "Mass transfer coefficients across dynamic liquid steel/slag interface." Thesis, Bordeaux, 2017. http://www.theses.fr/2017BORD0554/document.
Full textAbstract:
Afin de prédire l’évolution de la composition chimique du laitier dans différents procédés sidérurgiques, un modèle CFD a été développé. Les coefficients de transfert de masse sont estimés à partir des modèles basés sur les paramètres physico-chimiques et hydrodynamiques, comme par exemple la diffusivité des espèces chimiques et la divergence de l’interface. Ces modèles ont été développé pour la prédiction du transfert gaz-liquide où le les nombres de Schmidt (Sc=ν⁄D) sont relativement faible (Sc≈200). Par contre, les procédés industriels ont un nombre de Sc considérablement plus importante, de l’ordre de 103 à 104. Pour évaluer la pertinence de ces modèles, l’hydrodynamique au voisinage d’une interface liquide-liquide a été étudiée. Un modèle CFD et des mesures par l’anémométrie laser (LDA) ont été utilisés pour calculer et valider les champs de vitesse d’une maquette à eau d’une lingotière de coulée continue (CC).Le modèle de transfert de masse d’une lingotière de coulée continu industriel nous a montré que les coefficients de transfert de masse ne sont pas distribués de manière homogène, et les propriétés physiques du laitier ne doivent pas y être non plus. Cette distribution non-homogène a été confirmée par des essais physiques. Les écoulements calculés numériquement ont été utilisé pour prédire les coefficients de transfert de masse entre les deux phases liquide. Ces paramètres seront utilisés comme donnée d’entré pour un modèle de thermodynamique afin de prédire l’évolution de la composition chimique du laitierIn order to characterize the mass transfer coefficients (MTC) of different species across liquid steel/slag interface, a multiphase Computational Fluid Dynamic (CFD) model was developed. MTC’s are estimated from models based on physicochemical and hydrodynamic parameters, such as mass diffusivity, interface shear and divergence strength. These models were developed for gas-liquid interactions with relative low Schmidt (Sc=ν⁄D) numbers (Sc≈200). However, the industrial processes involve mass transfer of chemical species with Sc number ranging from 103 to 104. To evaluate the applicability of these existing models, the fluid flow in the vicinity of a liquid/liquid interface is investigated. Computational Fluid Dynamic (CFD) and Laser Doppler Anemometry (LDA) were used to calculate and measure the velocity field on a continuous casting (CC) water model configuration. The work provides new insights and original measures to understand the fluid flow near liquid-liquid interfaces.The mass transfer model of an industrial continuous casting mold showed that the mass transfer coefficients are not homogeneously distributed, and slag properties should follow this trend. This non-homogeneity was confirmed by physical experiments performed with a water model of a CC configuration and its CFD representation. The calculated flow was used to predict the MTC and the interface area between phases, since the interface is constantly moving. These parameters will be the input of thermodynamic models to predict slag composition and viscosity. This methodology is currently under validation, and it will also be applied to improve steel plant performance in the desulphurization process
15
Talefirouz, Davood. "Use Of Granulated Blast Furnace Slag, Steel Slag And Fly Ash In Cement-bentonite Slurry Wall Construction." Master's thesis, METU, 2013. http://etd.lib.metu.edu.tr/upload/12615432/index.pdf.
Full textAbstract:
Slurry walls have been widely used for more than 25 years to control the migration of contaminants in the subsurface. In the USA, vertical barriers are mostly constructed of soil-bentonite using the slurry trench method of construction. In this method, sodium bentonite is mixed with water to form a viscous slurry that is pumped into a trench during excavation to maintain the trench stability. The stable trench is then backfilled with a mixture of soil and slurry having a consistency of high slump concrete. These barriers have been designed primarily for low permeability, generally less than 10&minus9 m/s. Some investigations have pointed toward improved performance using admixtures that would provide low permeability. In this study, Soma thermal power plant fly ash, granulated blast furnace slag, lime, and steel slag are used as admixture to improve the performance of slurry walls. Permeability, compressive strength, slump, compressibility properties of the mixtures were found and checked for the minimum requirements. According to the findings of this study, granulated blast furnace slag (GGBS), fly ash and steel slag can be used at certain percentages and curing periods as additive in cement-bentonite barrier wall construction. Permeability of specimens having fly ash decreases by increasing fly ash content. Mixtures having 50 % of GGBS type I with 5 % of lime and 9% bentonite content gave acceptable results in 28 days of curing time. Specimens including 50 % of GGBS type II with 5 % of lime and 9% bentonite content gave the higher permeability value in 28 days of curing time with respect to GGBS type I. In addition, most of the mixtures prepared by steel slag gave the acceptable permeability values in 28 days of curing period. Unconfined compressive strength of all mixtures increase by increasing curing time. Cc, Cr, Cv, kcon values were found from consolidation test results. Permeability values found from consolidation tests are 10 times to 100 times higher than flexible wall k results for the same effective stress of 150 kPa. Generally, mv values are decreasing with increasing curing time. As mv decreases, D increases.
16
Björklund, Johan. "A study of slag-steel-inclusion interaction during Ladle treatment." Licentiate thesis, KTH, Materials Science and Engineering, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4018.
Full textAbstract:
The thesis is based on two supplements with two major objectives. In the first supplement equilibrium top slag-steel bulk and inclusions-steel bulk were investigated by comparison between calculated and measured oxygen activity values. This was done by applying different oxide activity models for slags combined with thermodynamic calculations. In the second supplement the inclusion composition is studied during the ladle refining process. The inclusion composition is related to top slag composition and other parameters during ladle
treatment.
The work was carried out by collecting data during well controlled sampling procedures at two different steel plants. Extensive inclusion analyses in Scanning Electron Microscope, SEM, were done. The data was used together with thermodynamics for a description of the interaction between slag-steel-inclusion interaction during ladle treatment.
Evaluation of inclusion composition during the ladle refining have revealed that the majority of the inclusions belonged to the system Al2O3-CaO-MgO-SiO2 and showed a continuous composition change throughout the ladle refining process, from high Al2O3, via MgO-spinel to finally complex types rich in CaO and Al2O3. The final composition after vacuum treatment was found to be close to the top slag composition. Small process parameter changes and practical variations during ladle refining were proven to give large differences of the inclusion composition.
Finally, it was concluded that equilibrium does not exist between top slag and steel bulk, with respect to oxygen, for the studied conditions. However, the equilibrium does exist between the steel bulk and inclusion.
17
Björklund, Johan. "A study of slag-steel-inclusion interaction during ladle treatment /." Stockholm, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4018.
Full text
18
Bathy, Vodeyar Math Kailash. "Optimization of steel production: ladle furnace slag and caster productivity." Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=117152.
Full textAbstract:
A slag optimization model is the first objective of this thesis. The importance of slag has been very well understood by the steelmaking industry to produce cost effective, quality steel, where the slag phase has become an essential part of steel making process. The composition and properties of slag play an important role in protecting furnace refractories. The research focused on the development of a slag model to have optimum slag saturated with MgO for better refractory life. A computer model was developed to calculate minimum MgO required during the ladle refining process. The effect of the desulfurization process on optical basicity and MgO requirement is discussed. The plant data at Arcelormittal Contrecoeur West were used to compare the results generated by the model for usage of MgO and CaO. The application of the slag model at the ladle metallurgical facility can increase the life of the refractory and can result in reduced usage of additives to generate sufficient MgO and CaO. The second objective of the thesis is to increase the casting throughput of a continuous caster to improve the factory throughput. An experimental investigation of heat flow during the production of steel billets was undertaken. This research measured the cooling rate of the molten steel at the casting facility by systematic measurement of the steel temperature at several points during the casting process by the use of a pyrometer. A 2D steady state heat transfer simulation model was developed to produce data on temperature and phase distributions for different casting rates. The model data for billet surface temperatures were compared to measured surface temperatures. The comparison between measured and calculated surface temperatures was reasonable and the two sets of data were within ± 30-40 °C. The model data can be used to predict optimum casting speed based on the liquid well closure position and its corresponding surface temperature. This predicted parameter can be monitored by using sensors, and the casting rate can be controlled through a feedback system.Un modèle d'optimisation de laitier est le premier objectif de cette thèse. L'importance de laitier dans la qualité et la rentabilité de l'acier a été très bien comprise par l'industrie sidérurgique. En effet, la phase de laitier est devenue une partie essentielle du processus de production d'acier. La composition et les propriétés du laitier jouent un rôle important dans la protection des réfractaires de four. La recherche s'est portée sur le développement d'un modèle de laitier afin d'avoir le laitier optimal, saturé en MgO, pour allonger la vie de réfractaire. Un modèle informatique a été développé pour calculer la quantité de MgO minimale requise lors du processus de l'affinage en poche. L'effet de la désulfuration sur la basicité optique et l'exigence de MgO est discuté. Les données de l'usine Arcelormittal Contrecoeur-Ouest ont été utilisées pour comparer les résultats générés par le modèle pour l'utilisation de MgO et CaO. L'application du modèle de laitier dans l'installation de métallurgie en poche peut augmenter la durée de vie du réfractaire et peut réduire la quantité d'additifs utilisée pour générer suffisamment de MgO et de CaO.Le deuxième objectif de la thèse est d'augmenter le débit de coulée d'une machine de coulée continue afin d'améliorer la capacité de production de l'usine. Une étude expérimentale du flux de chaleur lors de la production de billettes d'acier a été entreprise. Cette recherche a mesuré la vitesse de refroidissement de l'acier en fusion dans l'installation de coulée par la mesure systématique de la température de l'acier à travers un pyromètre sur plusieurs points pendant le processus de coulée. Un modèle de simulation à 2D de transfert de chaleur à l'état d'équilibre thermique a été développé pour produire des données sur la répartition de la température de phase à des vitesses de coulée différentes. Les données de modèle concernant la température de surface de la billette a été comparée à la température de surface mesurée. La comparaison entre les températures de surface mesurées et calculées était raisonnable et les deux ensembles de données ont été à l'intérieur de ± 30-40 ° C. Les données modèles peuvent être utilisées pour prédire la vitesse de coulée optimale en fonction de la position de fermeture du puits et sa température de surface correspondante. Ce paramètre prédit peut être suivi en utilisant des capteurs et la vitesse de coulée peut être contrôlée par un système de rétroaction.
19
Georgakopoulos, Evangelos D. "Iron and steel slag valorization through carbonation and supplementary processes." Thesis, Cranfield University, 2016. http://dspace.lib.cranfield.ac.uk/handle/1826/12323.
Full textAbstract:
Alkaline industrial wastes are considered potential resources for the mitigation of CO2 emissions by simultaneously capturing and sequestering CO2 through mineralization. Mineralization safely and permanently stores CO2 through its reaction with alkaline earth metals. Apart from natural formations, these elements can also be found in a variety of abundantly available industrial wastes that have high reactivity with CO2, and that are generated close to the emission point-sources. Apparently, it is the applicability and marketability of the carbonated products that define to a great extent the efficiency and viability of the particular process as a point source CO2 mitigation measure. This project investigates the valorization of iron- and steel-making slags through methods incorporating the carbonation of the material, in order to achieve the sequestration of sufficient amounts of CO2 in parallel with the formation of valuable and marketable products. Iron- and steel-manufacturing slags were selected as the most suitable industrial byproducts for the purposes of this research, due to their high production amounts and notable carbonation capacities. The same criteria (production amount and carbonation capacity) were also used for the selection of the iron- and steel-making slag types that are more suitable to the scope of this work. Specifically for the determination of the slag types with the most promising carbonation capacities, the maximum carbonation conversions resulting from recent publications related to the influence of process parameters on the conversion extent of iron- and steel-manufacturing slags, were directly compared to each other using a new index, the Carbonation Weathering Rate, which normalizes the results based on particle size and reaction duration. Among the several iron- and steel-manufacturing slags, basic oxygen furnace (BOF) and blast furnace (BF) slags were found to combine both high production volumes and significant affinity to carbonation. In the context of this research, two different procedures aiming to the formation of value added materials with satisfactory CO2 uptakes were investigated as potential BF and BOF slags valorization methods. In them, carbonation was combined either with granulation and alkali activation (BOF slag), or with hydrothermal conversion (BF slag). Both treatments seemed to be effective and returned encouraging results by managing to store sufficient amounts of CO2 and generating materials with promising qualities. In particular, the performance of the granulation-carbonation of BOF slag as a method leading to the production of secondary aggregates and the sequestration of notable amounts of CO2 in a solid and stable form, was evaluated in this work. For comparison purposes, the material was also subjected to single granulation tests under ambient conditions. In an effort to improve the mechanical properties of the finally synthesized products, apart from water, a mixture of sodium hydroxide and sodium silicate was also tested as a binding agent in both of the employed processes. According to the results, the granules produced after the alkali activation of the material were characterized by remarkably greater particle sizes (from 1 to 5 mm) compared to that of the as received material (0.2 mm), and by enhanced mechanical properties, which in some cases appeared to be adequate for their use as aggregates in construction applications. The maximum CO2 uptake was 40 g CO2/kg of slag and it was achieved after 60 minutes of the combined treatment of alkali activated BOF slag. Regarding the environmental behavior of the synthesized granules, increased levels of Cr and V leaching were noticed from the granules generated by the combination of granulation-carbonation with alkali activation. Nevertheless, the combination of granulation with alkali activation or that of granulation with carbonation were found not to worsen, if not to improve, the leaching behaviour of the granules with regards to the untreated BOF slag. The formation of a zeolitic material with notable heavy metal adsorption capacity, through the hydrothermal conversion of the solid residues resulting from the calcium- extraction stage of the indirect carbonation of BF slag, was also investigated in this project. To this end, calcium was selectively extracted from the slag by leaching, using acetic acid of specific concentration (2 M) as the extraction agent. The residual solids resulting from the filtration of the generated slurry were subsequently subjected to hydrothermal conversion in caustic solution of two different compositions (NaOH of 0.5 M and 2 M). Due to the presence of calcium acetate in the composition of the solid residues, as a result of their inadequate washing, only the hydrothermal conversion attempted using the sodium hydroxide solution of higher concentration (2 M) managed to turn the amorphous slag into a crystalline material, mainly composed by a zeolitic mineral phase (detected by XRD), namely, analcime (NaAlSi2O6·H2O), and tobermorite (Ca5(OH)2Si6O16·4H2O). Finally, the heavy metal adsorption capacity of the particular material was assessed using Ni2+ as the metal for investigation. Three different adsorption models were used for the characterization of the adsorption process, namely Langmuir, Freundlich and Temkin models. Langmuir and Temkin isotherms were found to better describe the process, compared to Freundlich model. Based on the ability of the particular material to adsorb Ni2+ as reported from batch adsorption experiments and ICP-OES analysis, and the maximum monolayer adsorption capacity (Q0 = 11.51 mg/g) as determined by the Langmuir model, the finally synthesized product can potentially be used in wastewater treatment or environmental remediation applications.
20
Swinnerton, Mark. "The influence of slag evolution on BOF dephosphorisation." School of Mechanical, Materials & Mechatronic Engineering - Faculty of Engineering, 2005. http://ro.uow.edu.au/theses/282.
Full textAbstract:
A study has been conducted to examine the influence of slag evolution on BOF dephosphorisation. An experimental technique was developed where slag/metal emulsion samples were obtained from the BOF during processing. The observed evolution of slag composition was consistent with many previous studies, where in the first half of the blow slags high in (%SiO2) and low in (%FeO) are generated. During the second half of the oxygen blow, (FeO) generation and lime dissolution improve the slag basicity and contribute to the transfer of phosphorus from metal to slag. Poor levels of phosphorus removal during the centre region of the blow were found to coincide with a minimum in the (%FeO) composition. By the end of blow, 70% of the mass of phosphorus in the furnace is present in the slag, and the extent of phosphorus removal is proportional to the slag basicity and the (%FeO) concentration in the slag. By utilizing mass balance calculations to estimate the mass of slag in the furnace, it was shown that at tap, approximately 30% of lime and 50% of magnesia remain undissolved in a liquid slag saturated in both components. It was concluded that the mass of lime added to the furnace could be reduced without influencing the dissolved concentration of (%CaO), and therefore without deteriorating the extent of dephosphorisation.
21
Tanaka, Shigenori. "Modelling inclusion behaviour and slag entrainment in liquid steel processing vessels." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1986. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/NQ44661.pdf.
Full text
22
Fronek, Brad A. "Feasibility of Expanding the use of Steel Slag as a Concrete Pavement Aggregate." Cleveland State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=csu1344208168.
Full text
23
Seshadri, Prashant. "Treatment of acid mine drainage with Weirton steel slags." Morgantown, W. Va. : [West Virginia University Libraries], 2000. http://etd.wvu.edu/templates/showETD.cfm?recnum=1730.
Full textAbstract:
Thesis (M.S.)--West Virginia University, 2000.Title from document title page. Document formatted into pages; contains vii, 38 p. : ill. Includes abstract. Includes bibliographical references (p. 29-30).
24
Mäkikyrö, M. (Marko). "Converting raw materials into the products–Road base material stabilized with slag-based binders." Doctoral thesis, University of Oulu, 2004. http://urn.fi/urn:isbn:9514272528.
Full textAbstract:
Abstract
A procedure is defined for commercializing slags arising as by-products of steelmaking, and this is used to develop certain products. The outcome of the present work comprised three products or groups of products: 1) slag-based binding agents, 2) a road structure improved by means of stabilization with such binding agents, and 3) a procedure for designing stabilized structures. The commercialization procedure was drawn up by examining the technical properties of the initial materials, excluding environmental acceptability and the mechanisms of their chemical reactions.
The research proceeded in stages, of which the first was a reconsideration of the results presented in the author's licentiate thesis concerning factors affecting the stabilization of road construction aggregates with blast-furnace slag-based binding agents and their significance. This was followed by a series of experiments designed to test the validity of these results. At the third stage the selection of slag-based binding agents was extended to include LD steel slag products, while the final stage consisted of the implementation of a set of test structures and associated preliminary experiments and monitoring measurements.
The binding properties of three blast-furnace slag products and three LD steel slag products, used separately or in various combinations, were examined in the course of this work, taking cement as a reference material. Materials were then eliminated as the research proceeded, either on account of their poor binding properties or on economic grounds. The final construction experiments were performed with three combinations: cement-activated granulated blast-furnace slag, LD steel slag-activated granulated blast-furnace slag and a mixture of ground granulated blast-furnace slag and cement.
The actual novel product among the slag-based binding agents to be introduced here is LD steel slag-activated granulated blast-furnace slag, which was found to be similar in its technical properties to cement-activated granulated blast-furnace slag. Structural layers stabilized with these two binding agents showed very similar bearing capacities, although the former did not reach the same compression strengths at an age of 91 days. The reasons for these similarities lay in a larger amount of binding agent used when activated with LD steel slag and the greater thickness of the stabilized layer, factors which both tended to compensate for the poorer compression strength.
The new information gained on the properties of cement-activated granulated blast-furnace slag and the mixture of ground granulated blast-furnace slag and cement opens up fresh opportunities for selecting binding agents and designing road structures. Formulae were developed here for predicting the uniaxial compression strength at 91 days, used as a stabilization criterion, from the value for a sample taken at 28 days, a technique which will speed up the assessment of stabilization results, especially when using slowly reacting slag-based binding agents.
25
Haji, Amini Shahriar School of Chemical Engineering & Industrial Chemistry UNSW. "Dissolution rate and diffusivity of lime in steelmaking slag and development of fluoride-free fluxes." Awarded by:University of New South Wales. School of Chemical Engineering and Industrial Chemistry, 2005. http://handle.unsw.edu.au/1959.4/22469.
Full textAbstract:
A rotating disk technique was used to determine the dissolution rate and diffusivity of CaO and MgO in slags. The dissolution rate was deduced from the measured changes in concentration of oxides in slag with respect to reaction time. The experimental set- up was initially tested with dissolution of magnesia in the CaO ??? 55 wt% Al2O3 slag at 1430 ??C and a measured rate of 2.7 ??10 -5 g/cm2.s was obtained. The dissolution rate was increased by slag chemistry and ranged from 6.5??10-5 to 2.1??10-4 g/cm2.s. The dissolution rate of CaO was measured in CaO ??? 42 wt% Al2O3 ??? 8% SiO2 based slag. The measured dissolution rates were found to be strongly dependent on the slag chemistry and temperature and ranged from 5.03??10 -5 to 3.3??10 -4 g/cm2.s. The dissolution rates were strongly dependent on the rotation speed and results indicate mass transfer in the slag phase to be rate- limiting step. The diffusivity of MgO / CaO was calculated from the dissolution rate and solubility data, using known mass transfer correlations. The diffusivity of MgO in the calcium aluminate slag at 1430 ??C was found to be about 1.1??10-5 cm2/s. Additions of 5 and 10 wt% Fe2O3 increased the diffusivity by a factor ~ 1.5 to 3, respectively. However, with introduction of (CaF2 5 wt% + Fe2O3 5 wt%) and (CaF2 5 wt% + Fe2O3 10 wt%) in the slag, the diffusivity increased considerably by a factor of about 29 and 11, respectively. The diffusivity of CaO in calcium aluminosilicate was measured to be in the order of 10-6 to 10-5 over a temperature range of 1430 ??? 1600 ??C. CaF2 increased the diffusivity by a factor of 3 to 5 while MnOx and FeOx, ilmenite and TiO 2 increased the diffusivity substantially and SiO2 had an opposite effect. The measured diffusivities are in accord with published data on comparable systems and are discussed with reference to Eyring theory. It was concluded that MnOx, FeOx and ilmenite in the slag increase the dissolution rate and diffusivity of lime, showing comparable results with respect to CaF2.
26
Adolfi, Sofia. "Slag inclusion formation during solidification of steel alloys and in cast iron." Licentiate thesis, Stockholm : Materialvetenskap, Kungliga Tekniska högskolan, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4371.
Full text
27
Barca, Cristian. "Steel slag filters to upgrade phosphorus removal in small wastewater treatment plants." Thesis, Nantes, Ecole des Mines, 2012. http://www.theses.fr/2012EMNA0045/document.
Full textAbstract:
L’objectif de ce travail est la mise au point de filtres garnis de laitiers d’aciéries destinés au traitement du phosphore (P) des eaux usées au sein de petites installations. Deux types de laitiers on été testés: laitiers de four à arc électrique (EAF), et laitiers d'aciérie de conversion (BOF). Une approche intégrée a été suivie, avec investigations à différentes échelles: (i) Des expériences en flacons ont été réalisées pour établir les capacités de rétention du P de laitiers produits en Europe, et ainsi sélectionner les échantillons les plus adaptés pour l’élimination du P; (ii)Des expériences en colonnes ont été menées pour étudier l'effet de divers paramètres, notamment la taille et la composition du laitier, sur les performances hydrauliques et épuratoires des filtres; (iii) Enfin, des expériences sur terrain ont été conduites afin d’évaluer les performances hydrauliques et épuratoires de deux unités démonstration conçues pour le traitement du P au sein d’un marais artificiel. Les résultats expérimentaux ont indiqué que le principal mécanisme d'élimination du P est lié à la dissolution du CaO des laitiers, suivie de la précipitation de phosphate de Ca et recristallisation en hydroxyapatite (HAP). Après 100 semaines d'alimentation avec une solution de P (concentration moyenne de P totale 10,2 mgP/L), les colonnes remplies de laitiers de petite taille (BOF6-12 mm et EAF 5-16 mm) ont retenu >98% du P total en entrée, tandis que les colonnes remplies de laitiers de grande taille (BOF 20-50 mm et EAF 20-40) ont retenu 56et 86% du P total en entrée, respectivement. Il apparaît que, plus la taille des laitiers est petite, plus la surface spécifique disponible pour la dissolution du CaO et pour l’adsorption des phosphates de Ca est grande. Les expériences sur terrain ont confirmé que les laitiers sont efficaces pour le traitement du P de l'effluent d'un marais artificiel (concentration moyenne du P totale 8,3 mg P/L). Sur une période de 85 semaines d'opération, de laitiers EAF ont retenu le 36% du P total en entrée, tandis que les laitiers BOF ont retenu le 59% du P total en entrée.L’efficacité de rétention du P apparaît augmenter avec la température et le temps de rétention hydraulique (HRT),très probablement parce que l'augmentation de la température et du HRT a favorisé la dissolution de la CaO et la précipitation de phosphate de Ca. Toutefois, il a été constaté que HRT >3 jours peuvent produire des pH élevés (>9), à la suite d’une excessive dissolution de CaO.Cependant, les résultats des unités démonstration ont montré que, à HRT de 1-2 jours, les filtres produisent des pH élevés seulement pendant les 5 premières semaines de fonctionnement, puis les pH se stabilisent en dessous de 9. Enfin, une équation de dimensionnement sur la base des résultats expérimentaux a été proposéeThis thesis aimed at developing the use of electric arc furnace steel slag (EAF-slag) and basic oxygen furnace steel slag (BOF-slag) in filters designed to upgrade phosphorus (P) removal in small wastewater treatment plants. An integrated approach was followed, with investigation at different scales: (i) Batch experiments were performed to establish an overview of the P removal capacities of steel slag produced in Europe, and then to select the most suitable samples for P removal; (ii)Continuous flow column experiments were performed to investigate the effect of various parameters including slag size and composition, and column design on treatment and hydraulic performances of lab-scale slag filters; (iii)Finally, field experiments were performed to investigate hydraulic and treatment performances of demonstration scale slag filters designed to remove P from the effluent of a constructed wetland. The experimental results indicated that the major mechanism of P removal was related toCaO-slag dissolution followed by precipitation of Caphosphate and recrystallisation into hydroxyapatite (HAP).Over 100 weeks of continuous feeding of a synthetic Psolution (mean inlet total P 10.2 mg P/L), columns filled with small-size slag (6-12 mm BOF-slag; 5-16 mm EAFslag)removed >98% of inlet total P, whereas columnsfilled with big-size slag (20-50 mm BOF-slag and 20-40mm EAF-slag) removed 56 and 86% of inlet total P,respectively. Most probably, the smaller was the size ofslag, the greater was the specific surface for CaO-slagdissolution and adsorption of Ca phosphate precipitates.Field experiments confirmed that EAF-slag and BOF-slagare efficient substrate for P removal from the effluent of aconstructed wetland (mean inlet total P 8.3 mg P/L). Overa period of 85 weeks of operation, EAF-slag removed 36%of inlet total P, whereas BOF-slag removed 59% of inlettotal P. P removal efficiencies increased with increasing temperature and void hydraulic retention time (HRTv),most probably because the increase in temperature and HRTv affected the rate of CaO dissolution and Caphosphate precipitation. However, it was found that longHRTv (>3 days) may produce high pH of the effluents(>9), as the result of excessive CaO-slag dissolution. However, the results of field experiments demonstrated that at shorter HRTv (1-2 days), slag filters produced pH that were elevated only during the first 5 weeks of operation, and then stabilized below a pH of 9. Finally, a dimensioning equation based on the experimental results was proposed
28
Muntasser, Tarek Ziad. "Properties and durability of slag based cement concrete in the Mediterranean environment." Thesis, University of Surrey, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.247994.
Full text
29
Wikström, Jenny. "A Mathematical and Experimental Study of Inclusion Behaviour at a Steel-Slag Interface." Doctoral thesis, KTH, Materialvetenskap, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4574.
Full textAbstract:
The aim of this thesis work is to increase the knowledge of inclusion behavior at the steel-slag interface by mathematical modeling and in-situ Confocal Scanning Laser Microscope experiments. Mathematical models based on the equation of motion predicting liquid and solid inclusion behavior was first investigated. Four main forces, the buoyancy force, the added mass force, the rebound force and the drag force, act on the inclusion as it crosses the interface. There are three types of behavior an inclusion at the steel-slag interface can adopt. These are a) pass, which means that the inclusion is separated to the slag, b) remain, where the inclusion stays at the interface without being fully transferred to the slag or c) oscillate, and the inclusion rises and descends at the interface until the motion is dampened out by the interfacial forces. The studies showed the importance of accurate experimental physical property data. Application of the models to industrial conditions illustrated that useful plots could be made showing the industry how to optimize their interfacial properties in the ladle and tundish to obtain maximum inclusion separation. In-situ Confocal Scanning Laser Microscope (CSLM) experiments were carried out in order to study agglomeration of liquid and semi liquid inclusions at the steel-gas and steel-slag interfaces and in the slag. Liquid-liquid inclusion agglomeration at steel-gas and steel-slag interfaces was seen to not occur without using force. However, when already transferred to the slag the inclusions agglomerated freely due to a higher free energy force. Comparison of experimental and theoretical agglomeration force showed good agreement between experiments and theory. The main conclusion of this work is that inclusion separation is a complex field of study and there exist no model that takes everything into account. Here the tendency for inclusion transfer and how to manipulate the physical properties for inclusion separation together with agglomeration experiments have been studied. For the future maybe coupling of models for computational fluid dynamics, agglomeration, inclusion separation, dissolution and slag entrainment in addition with experimental physical property data can provide a better overview and understanding.QC 20100823
30
Strandh, Jenny. "A study of solid and liquid inclusion separation at the steel-slag interface." Licentiate thesis, Stockholm, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-307.
Full text
31
Wikström, Jenny. "A mathematical and experimental study of inclusion behavior at a steel-slag interface /." Stockholm : Royal Institute of Technology, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4574.
Full text
32
Jansson, Sune. "A Study on the Influence of Steel, Slag or Gas on Refractory Reactions." Doctoral thesis, Stockholm : Materialvetenskap, Materials Science and Engineering, Kungliga Tekniska högskolan, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4764.
Full text
33
Zeng, Fengzhencheng. "Phosphorus Retention and Regeneration of EAF Steel Slag and a Synthetic Iron Oxyhydroxide." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1512067344406673.
Full text
34
Rawlins, Charles Henry. "Geological sequestration of carbon dioxide by hydrous carbonate formation in steelmaking slag." Diss., Rolla, Mo. : Missouri University of Science and Technology, 2008. http://scholarsmine.mst.edu/thesis/pdf/Rawlins_09007dcc804d4f95.pdf.
Full textAbstract:
Thesis (Ph. D.)--Missouri University of Science and Technology, 2008.Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed April 18, 2008) Includes bibliographical references.
35
Steinberg, W. S. "Development of a control strategy for the open slag bath furnaces at Highveld Steel and Vanadium Corporation Ltd." Pretoria : [s.n.], 2009. http://upetd.up.ac.za/thesis/available/etd-07062009-115433.
Full text
36
Dahlin, Anders. "Influence of Ladle-slag Additions on BOF-Process Parameters." Licentiate thesis, KTH, Tillämpad processmetallurgi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-33270.
Full textAbstract:
The influence of ladle-slag additions on the BOF-process performance were investigated in plant trials. The aim of the study was to recycle ladle slag from secondary steelmaking to the LD-converter to save lime and improve the slag formation. More specifically, two plant trial campaigns covering in total 83 heats, whereof 47 with ladle-slag additions and 36 without ladle-slag additions, were performed. Slag and steel sampling of the process were performed at tapping as well as during blowing at 15, 35, and 65% of the total blowing time. During the first campaign, ladle slag was added through the chute and lime reductions were made manually to correct for the ladle-slag addition. In the second campaign, a development of the approach was made to suite a normal production practice. More specifically, the ladle slag was added through the weight-hopper system and implemented in the process-control system. In this way, the lime additions were reduced automatically by approximately 260 kg per heat. Moreover, the heat balance was compensated with a reduction in the iron-ore consumption. Additionally, the lance program was modified and the lance was lowered in the initial stages of the blow. On the positive side, it was found that no demerits in the metallurgical performance of the process occur when ladle slag is recycled to the BOF-process. Furthermore, only slight affections on the slag composition were found, mainly with respect to the Al2O3 and FeO-content. In addition, the ladle slag was shown to melt during the initial stages of the blow. This contributed to an increased slag weight both during the blow and at tapping. However, a negative effect on the blowing time was experienced during the trials. Although, this effect was more pronounced during the first campaign and could be reduced with a controlled heat balance during the second campaign.QC 20110503
37
Riyahimalayeri, Kamrooz. "Slag, Steel, Ladle and Non-metallic Inclusions Equilibria in an ASEA-SKF Ladle Furnace." Doctoral thesis, KTH, Termodynamisk modellering, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-102149.
Full textAbstract:
This study explores the possibility of prediction and modification of some of the physicochemical properties of non-metallic inclusions by considering top slag-steel-ladle equilibria in an ASEA-SKF ladle furnace. To test the reliability of an available computational thermodynamic computer program, the first sub project was done. It was concluded that LiMeS, an interface for Thermo-Calc, is a useful tool for slag-steel equilibrium calculations. The second sub project was set out to find some model/s that could calculate the most accurate oxygen activity of molten steel compared to the measured one. This study concluded that both Wagner’s and Turkdogan's equations are useful. It was further seen that increasing the Al contents in the molten steel, increasing the CaO/Al2O3 ratio in the top slag, and reducing the temperature, resulted in reduction of the oxygen activity of the molten steel. In the third sub project a comparison was made between measured CaO and Al2O3 (normalised to CaO-Al2O3) in top slag, calcium aluminate inclusions, and the results of theoretical calculations. The average contents of CaO and Al2O3 in all inclusions were close to the composition of the phase Ca12Al14O33 and the contents of CaO and Al2O3 in the slags were close to the composition of the phase Ca3Al2O6 in the binary phase diagram of CaO-Al2O3. The forth sub project set out to study the effect of vacuum degassing time on non-metallic inclusions. It was concluded that during the vacuum degassing process the share of calcium aluminates compared to spinels, Ca content of the oxides, and the average equivalent circle diameters of the oxides were increasing, and oxides tended to form spherical shapes. Finally, based on the preceding four sub projects, the fifth sub project aimed to optimize the steel treatment in an ASEA-SKF ladle furnace. The final results showed that by adding 200 kg fluorite to the top slag of 1200 kg, it was possible to achieve a sulphur content of less than 10 ppm in the steel and a sulphur ratio between slag and steel of 1570, and at the same time reduce the oxygen activity of the molten steel and the degassing time.QC 20120917
38
Kasimagwa, Ismail. "A study of slag corrosion of oxides and oxide-carbon refractories during steel refining." Licentiate thesis, KTH, Tillämpad processmetallurgi, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-25221.
Full textAbstract:
The use of ceramic material as refractories in the manufacturing industry is a common practice worldwide. During usage, for example in the production of steel, these materials do experience severe working conditions including high temperatures, low pressures and corrosive environments. This results in lowered service lives and high consumptions of these materials. This, in turn, affects the productivity of the whole steel plant and thereby the cost. In order to investigate how the service life can be improved, studies have been carried out for refractories used in the inner lining of the steel ladles. More specifically, from the slag zone, where the corrosion is most severe. By combining thermodynamic simulations, plant trails and post-mortem studies of the refractories after service, vital information about the behaviour of the slagline refractories during steel refining and the causes of the accelerated wear in this ladle area has been achieved. The results from these studies show that the wear of the slagline refractories of the ladle is initiated at the preheating station, through reduction-oxidation reactions. The degree of the decarburization process is mostly dependent on the preheating fuel or the environment. For refractories without antioxidants, refractory decarburization is slower when coal gas is used in ladle preheating than when a mixture of oil and air is used. In addition, ladle preheating of the refractories without antioxidants leads to direct wear of the slagline refractories. This is due to the total loss of the matrix strength, which results in a sand-like product. Thermal chemical changes that take place in the slagline refractories are due to the MgO-C reaction as well as the formation of liquid phases from impurity oxides. In addition, the decrease in the system pressure during steel refining makes the MgO-C reaction take place at the steel refining temperatures. This reduces the refractory’s resistance to corrosion. This is a serious problem for both the magnesia-carbon and dolomite-carbon refractories. The studies of the reactions between the slagline refractories and the different slag compositions showed that slags rich in iron oxide lead mostly to the oxidation of carbon/graphite in the carbon-containing refractories. This leads to an increased porosity and wettability and therefore an enhanced penetration of slag into the refractory structure. If the slag contains high contents of alumina and or silica (such as the steel refining slag), reactions between the slag components and the dolomite-carbon refractory are promoted. This leads to the formation of low-temperature melting phases such as calcium-aluminates and silicates. The state of these reaction products during steel refining leads to an accelerated wear of the dolomite-carbon refractory. The main products of the reactions between the magnesia-carbon refractory and the steel refining slag are MgAl2O4 spinels, and calcium-aluminates, and silicates. Due to the good refractory properties of MgAl2O4 spinels, the slag corrosion resistance of the magnesiacarbon refractory is promoted.QC 20101013
39
Krishnapisharody, Krishnakumar Irons Gordon A. "Model studies of fluid mechanic interactions between steel and slag in gas-stirred ladles." *McMaster only, 2006.
Find full text
40
Simon, Hellgren. "Secondary Steel Metallurgy Slag Design and MgO-C Refractory Implications : Theoretical and Practical Considerations." Thesis, Luleå tekniska universitet, Industriell miljö- och processteknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-76339.
Full textAbstract:
MgO-C based refractory materials, often used in secondary steel making, are exposed to variouswear mechanisms in its application. The wear could be divided into oxidative, chemical andabrasive categories, all behaving differently and all being influenced by different factors. Dueto the importance of minimizing material loss and to the environmental challenges to run asustainable industry, it is of interest to gain more knowledge of the behavior of the refractorymaterial in use. The present thesis work specifically investigated slag designed of the CaOSiO2-Al2O3-MgO (CSAM) system as well as the chemical and oxidative wear mechanisms ofthree different MgO-C based refractory materials from Höganäs AB, Halmstadverken, whichcontained 5, 10 and 12 wt% carbon (labeled T05, T10 and T12). Different CSAM slags weredesigned to meet certain process criteria such as MgO and CaO saturations and wereinvestigated through thermodynamic calculations using the FactSage software and throughlaboratory scaled slag smelting experiments. The oxidation effect on the refractory material wasalso studied through pre-heating simulations in chamber furnaces, similar to the pre-heating ofa re-built ladle furnace.The thermodynamic calculations made in FactSage 7.0, using the FactPS and FToxid databases, resulted in a few different slag designs with different properties. A few different slagsfulfilled the CaO and MgO saturation limits proposed by Höganäs AB and could be consideredto test experimentally for further evaluation. The simulations also showed trends on how theliquid viscosity behaved with different slag compositions and how the solids content changedwith temperature.The oxidation experiments were performed on the different MgO-C refractory types, where thebricks with 10% carbon also contained Al2O3 antioxidants. The experiments showed that themass loss during the pre-heating is greater for refractory with higher carbon content, withexception to T10, where the mass losses were measured to 3.76 – 4.01%, 1.06 – 1.28% and6.28 – 6.33% for T05, T10 and T12 respectively. Further, the oxidation depth of each materialwas measured to 9-10 mm, 2-3 mm and 2-5 mm for the T05, T10 and T12. The experimentsalso showed that T12 refractory in particular was very susceptible to abrasive wear after beingoxidized.The slag smelting experiments were carried out through two different methods, by melting slagin MgO-C crucibles and by melting pressed slag briquettes on top of refractory bricks. Theformer tests mainly showed that the methodology was not suitable for this type of refractorymaterial due to the crucibles cracking during the experiments. The latter experiments showedsome general behaviour of the different components in the slag, where Ca, Al and Fe stayednear the surface, and Si and Mg penetrated deeper. The spinel formation at the refractory surfacewas then concluded to be the reason for Al not penetrating deeper. Further it was concludedthat no significant difference in refractory dissolution was seen between slags with- and withoutMgO, other than possibly a small increase in refractory dissolution for the latter.
41
MORONE, MILENA. "Valorization of BOF steel slag and gasification ashes through suitable treatments aimed at reuse." Doctoral thesis, Università degli Studi di Roma "Tor Vergata", 2013. http://hdl.handle.net/2108/203347.
Full textAbstract:
La gestione dei rifiuti solidi e gassosi derivanti da processi termici è una delle principali criticità da affrontare per i diversi settori industriali coinvolti. Le proprietà fisiche, chimiche e ambientali di tali residui non li rendono spesso adatti per il riutilizzo, generalmente provocandone lo smaltimento in discarica o eventualmente l’impiego in applicazioni di scarso valore. Ne risulta la necessità di sviluppare trattamenti idonei a valorizzare il potenziale di questi sottoprodotti, al fine di ridurne lo smaltimento in discarica e produrre prodotti finali in grado di sostituire materie prime vergini.
L'obiettivo principale di questa tesi di dottorato è stato pertanto quello di indagare nuovi trattamenti per la valorizzazione di residui industriali prodotti da diversi processi termici.La prima e più rilevante parte di questo lavoro ha riguardato lo studio di scorie provenienti da impianti per la produzione dell’acciaio. In particolare, le scorie BOF sono state trattate con un processo di granulazione e di granulazione/carbonatazione, con l'obiettivo di produrre aggregati secondari idonei al riutilizzo in applicazioni di ingegneria civile e di stoccare CO2 in forma solida e termodinamicamente stabile, contribuendo in questo modo, seppur parzialmente, alla riduzione delle emissioni di CO2 dell’acciaieria. I risultati dei test, condotti su scala di laboratorio in un reattore a tamburo rotante dotato di un coperchio e di un sistema per l’alimentazione della CO2 e miscelando le scorie con acqua, hanno mostrato che la dimensione delle particelle aumenta progressivamente con il tempo di reazione e valori significativi di CO2 uptake (tra 120 e 150 g CO2/kg) sono stati misurati anche dopo tempi di reazione brevi (30 minuti). Il comportamento alla lisciviazione dei granuli ottenuti rispetta i limiti previsti per il riutilizzo fissato dalla normativa italiana. Tuttavia, le prestazioni meccaniche dei granuli non sono risultate adatte per permetterne il riutilizzo in applicazioni dell’ ingegneria civile. Quindi, con l'obiettivo di migliorare le proprietà meccaniche degli aggregati, i trattamenti di granulazione e granulazione-carbonatazione sono stati applicati ad una miscela scorie-cemento, sostituendo il 10% e 20% in peso di scorie con cemento. In questo caso, si è osservato che le prestazioni meccaniche migliorano, indipendentemente alla quantità di cemento nella miscela, raggiungendo valori di ACV simili a quelli riportato nel British Standard per rocce ignee, ossia 16%. Inoltre, è risultato che la carbonatazione non influenza le proprietà meccaniche dei granuli ottenuti, per tutte le miscele testate. Ciononostante, al di là del cemento cui sono associati alti impatti ambientali, sono state valutate altre opzioni alternative e più sostenibili in grado di migliorare le performances dei granuli prodotti. Al fine di accelerare le originali latenti proprietà idrauliche delle scorie BOF, è stato sfruttato il processo di attivazione alcalina utilizzando due diverse soluzioni alcaline (una miscela di idrossido di sodio/silicato di sodio e idrossido di sodio/carbonato di sodio). Si è osservato che la resistenza meccanica è risultata maggiore per i campioni di scorie miscelati con la soluzione di idrossido e silicato di sodio. Quindi, sulla base di questi risultati, tale soluzione alcalina è stata utilizzata per studiare l'effetto del processo in combinazione con il trattamento di granulazione-carbonatazione, con l’obiettivo di migliorare le proprietà meccaniche degli aggregati. I risultati dei test hanno mostrato che il diametro medio massimo raggiunto dai granuli era pari a 13 mm e che il valore massimo di stoccaggio della CO2 dei granuli contenti l’attivatore alcalino è risultato pari a 40 gCO2/kg di scoria. Quanto al comportamento ambientale del materiale trattato, sono state osservate differenze tra le prove di lisciviazione effettuate con granuli attivati frantumati e non frantumati, ma in entrambi i casi le concentrazioni di Cr e V sono risultate superiori al limite imposto per il riutilizzo dalla normativa italiana. Inoltre, l’utilizzo dell’attivatore influenza la resistenza dei granuli che dopo entrambi i trattamenti, hanno fornito valori di ACV confrontabili o inferiori di quelli ottenuti per la ghiaia naturale (20%). La seconda parte del lavoro ha riguardato la caratterizzazione e l’applicazione di processi per la valorizzazione di ceneri prodotte dalla piattaforma Zecomix, i cui residui solidi sono stati raccolti dal letto solido del gassificatore e dal ciclone posto a valle dello stesso. Si è osservato che le ceneri sono costituite principalmente da Mg, Si e Fe, tipici elementi dell’olivina utilizzata nel letto fluido. Il contenuto di carbonio organico totale è risultato maggiore nel campione di ceneri dal ciclone (27% in peso) rispetto a quello ottenuto nel campione di ceneri pesanti (5% in peso). Dopo la caratterizzazione, i campioni sono stati sottoposti ad un procedura di separazione per vagliatura e per densità, con l’obiettivo di valutare le più idonee applicazioni per ciascun residuo ottenuto.The management of the great amount of solid residues and gaseous emissions resulting from thermal and industrial processes is one of the major critical issues to be dealt with by the different sectors involved. The physical, chemical and environmental properties of the solid streams are, in some cases, not suitable for their reuse and a relevant fraction is directly landfilled or limitedly reused for low-end applications. Hence, suitable treatments are needed to exploit and to valorize the potential of these by-products in order to reduce their landfilling and produce valuable products able to replace virgin raw materials. The main objective of this doctoral thesis was to investigate new process routes for the valorization of two types of industrial residues, i.e. Basic Oxygen Furnace (BOF) steel slag and coal gasification ash. The first and most relevant part of this work was addressed to slags generated from steel production, which generates high emissions of CO2, making it one of the main industrial sources of greenhouse gases (GHG). In particular, the BOF steel slags were treated with a granulation and granulation/carbonation process, with the aim of producing secondary aggregates suitable for reuse in civil engineering applications and of storing CO2 in a solid and thermodynamically stable form, thus at least partially contributing to the reduction of GHG emissions from steelmaking plants. The results of the tests, carried out in a rotary drum granulator and by mixing the slag with water, indicated that the particle size of the slag increased progressively with reaction time and significant CO2 uptake values (between 120 and 150 g CO2/kg) were measured even after short reaction times (30 or 60 minutes). The leaching behavior of the obtained granules showed to comply with the limits for reuse set by the Italian legislation. However, the mechanical performance of the granules, evaluated by applying the Aggregate Crushing Value (ACV) test, resulted far from that achieved by natural gravel. The mechanical properties of the artificial aggregates were improved by applying both treatments to slag-cement mixtures, by replacing 10% and 20% by wt. of slag with cement. In this case, the mechanical performance was improved regardless the amount of cement employed, reaching ACV similar to those reported in the British Standard for igneous rock, i.e. 16%. Nevertheless, as the production of cement is related to high environmental impacts, an alternative and more sustainable option was evaluated with the aim to increase the mechanical performance of the granules. Indeed, in order to accelerate the original latent hydraulic properties of the slag, the alkali activation process was exploited by using two different alkali solutions, i.e. a mixture of sodium hydroxide/sodium silicate and sodium hydroxide/sodium carbonate. It was found that the BOF slag mortars activated with the sodium hydroxide/sodium silicate solution and cured under a continuous flux of CO2 at 50 °C, showed the highest mechanical strength. So, this alkaline solution was used as binder in the granulation-carbonation treatment, with the aim of enhancing the mechanical properties of the obtained aggregates. The results of the tests showed that the maximum mean diameter achieved for the activated granules was 13 mm, with maximum CO2 uptake of the activated granules resulted equal to 40 gCO2/kg steel slag. As for the environmental behavior of the treated material, only the release of Cr and V of the activated granules exceeded the Italian limit for reuse. More important, the use of alkalis showed to exert a relevant influence on the strength of the granules, that after both the granulation and granulation-carbonation treatments showed an ACV comparable or even lower than that of natural gravel (20 %). The second part of this work was addressed at the characterization and valorization of the ashes produced by the Zecomix (Zero Emission COal MIXed technology) platform, collected both directly from the solid bed (bed ash) and from the cyclone installed downstream the coal gasifier (fly ash). Both ashes were composed mainly by Mg, Si and Fe, typical of the olivine that made up the bed of the gasifier, whereas the total organic carbon was 5% in the bed ash and 27% in the the fly ash. Both gasification residues underwent a particle size and density separation procedure, allowing to obtain an organic and an inorganic fraction, which could then be separately reused.
42
Larsson, Jesper. "Acid neutralization using steel slags : Adsorption of fluorides in solutions using AOD slags." Thesis, KTH, Materialvetenskap, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-171235.
Full textAbstract:
Surface treatment processes of stainless steel, such as pickling, produces acidic waste water consisting of Na⁺, Cl⁻, F⁻, NO⁻3, SO42-, PO43-, Fe3+, Cr6+ and Ni2+. At Sandvik ABs steel works in Sandviken, this waste water is treated and neutralized using slaked lime before being released into the lake Storsjön. The aim of this report was to make a literary review of previous work in using slag as a neutralizing agent for acidic waste water. Furthermore, to see if it’s possible to replace some or all of the slaked lime in the neutralization process with slag and to study what slag that might be suitable to use. Since the waste water contains HF acid, the focus of this report was on different materials used for fluoride adsorptions. The literary study showed that the fluoride adsorption process with BOF slag, quick lime and magnesium oxide as adsorbents were endothermic. Therefore, it benefitted from an increased temperature. Furthermore, the literature study showed that many materials follow a pseudo-second-order kinetic model as well as a Langmuir or Freundlich isotherm for a fluoride adsorption. A previous experiment showed that a mixture of BF slag and slaked lime had the best HF acid neutralization among the tested materials. A fluoride adsorption experiment was made at different temperatures (25 – 55 °C) by using a slag from an aluminium reduced steel melt and a slag from a silicon reduced steel melt from the AOD converter in Sandviken. The silicon reduced steel melt slag showed an increase of fluorides in the solution, due to the presence of calcium fluoride in the slag. This was observed for all temperatures. The aluminium reduced steel melt slag also increased the fluoride content in the solution at 25 and 30 °C. At higher temperatures the fluoride content in the solution decreased with 93.6 to 94.9 %. Na⁺, Cl⁻, F⁻, NO⁻3, SO42-, PO43-, Fe3+, Cr6+, and Ni2+
43
Ghasemi, Sara. "Comparative Life-Cycle Assessment of Slurry vs. Wet Carbonationof BOF Slag." Thesis, KTH, Skolan för kemivetenskap (CHE), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-180552.
Full textAbstract:
Accelerated carbonation is a new C02 storage method under development as a solutionfor climatechangecausedbyanthropogenicactivities.Inacceleratedcarbonationanalkalinesourcesuch as minerals or industrial resid ues react with carbon dioxide in a presence of slightly acidicsolution to produce stable solid carbonates. There are varieties of accelerated carbonation routes,which differ in process condition. The aim of this study was to evaluate and compare the potential of a slurry route process and a wet route process for the carbonation of basicoxygenfurnace slag using the C02 emitted by a conventional natural gas power plant. For this pmpose alife cycle assessment (LCA) study was performed based on principles and guidelines provided byISO 14040:2006 and routines and data provided by the SimaPro V8 software package.Thematerial and energy requirements for each of the steps involved in the carbonation process, i.e.pre-treatment of raw material, C02 compression, transportation, carbonation step, after-treatmentand landfill, were calculated and included in the LCA study. The slurry and wet route resulted innet C02 reduction of 87.4% and 72.3% respectively. However, a positive contribution to otherenvironmental issues was observed with the wet route leading to higher impact mainly due tohigh heating requirement. An exception was the contribution of the slurry route to abioticresource depletion, which was higher for the slurry route due to high water requirement. Ageneral conclusion was that the electricity consumption is the main cause ofenvironmentalissues. Sensitivity analyses showed that the environmental impacts are dependent on thetransp01iation distance and electricity source, while no dependence was observed with respect toconstruction of the carbonation plant.
44
Elmroth, Edvin. "Adsorption of Zn, Cd, V, Ba, Cu, Mo, Ni, Cr, Li and Pb to silicon and aluminium reduced AOD-slag." Thesis, Örebro universitet, Institutionen för naturvetenskap och teknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-68989.
Full textAbstract:
During production of steel, slag is formed as a by-product. The process of steelmaking involves usage of additives such as chromium or vanadium as reactants to optimize and produce high quality steel. Vast amounts of slag are formed and there is a continuous search for applications that can make good use of the slag. Currently the use of slag in cleaning of metal polluted waters is researched and promising results has been found for many different types of slags. In this work two different AOD-slags has been used as sorbents for some selected elements (Zn, V, Cr, Mo, Pb, Li, Cd, Ba, Cu, Ni). The main difference between the two slags is the reducing agent that has been used, aluminium and silicon. This results in slags with different adsorption properties. The aluminium reduced slag show tendency for better adsorption capacities in general for the tested elements (Zn, V, Cr, Mo, Pb, Li, Cd, Ba, Cu, Ni), with a few exceptions. The buffering capacity of the materials were high, shown by the fact that final pH reached nearly 11.5 independent of the start pH (varied between 2 and 8). The adsorption process was rather quick and 24 minutes contact time was in most cases sufficient to reach equilibrium. For several of the elements e.g. Lithium, the maximum capacity of the slags was not reached even though a load of 3,07 mg Lithium was added per gram of slag.
45
Puthucode, Rahul. "Neutralization of acidic wastewaters with the use of landfilled Electric Arc Furnace (EAF) high-alloyed stainless-steel slag : An upscale trial of the NEUTRALSYRA project." Thesis, KTH, Materialvetenskap, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-258901.
Full textAbstract:
The landfilling of slag obtained from the high alloyed Electric Arc Furnace (EAF) steel making process, constitutes an environmental treat for society as well as an economical problem for the companies producing it, due to the costs related to waste management practices. Conventional methods of slag recycling are abundantly used among the steelmaking business, but due to their particular physical properties, high- alloyed EAF slags cannot be properly valorized. Moreover, the pickling process that high-alloyed EAF steels undergo to, generates acidic wastewaters, that need to be collected and neutralized, before they can be recirculated into the natural water streams. For such a task, steel mills currently utilize slaked lime (a Ca rich mineral) to raise the pH and to remove any metal particles dissolved into the wastewaters. Slag contains high amount of Ca; therefore, it has already been tested as a slaked lime replacement. In fact, previous studies conducted at the Material Science and Engineering department at KTH Royal Institute of Technology showed, on a laboratory scale, that slag has the potential to replace lime for the neutralization and purification of the acidic wastewaters. This Master’s thesis project aims at upscaling the volumes of wastewaters to be tested, about 70 to 90 folds of the one from previous research, bridging the gap between laboratory tests and the industrial scale. The thesis is divided into three tranches, a first part where a water-salt solution conductivity trials were carried out, to model the behavior or slag dispersion in the acidic wastewaters. After the results obtained from the conductivity trials, neutralization trials with slag and the lime product currently in use by the company, were carried out at the neutralization plant in Outokumpu Stainless, Avesta (Sweden). The neutralization trials were carried out with 70 and 90 liters of acidic wastewaters and in order to perform the trials on site, the slag sample was dried and later sieved to a particle size of less than 350μm. Moreover, data was analyzed and compared to previous studies in order to have a clearer understanding regarding the neutralization efficiency of the slag, especially whether or not the technology would had worked on upscaled volumes. Additionally, the project checked if it was possible to find a generalized relationship between the mass of slag and volume of wastewaters required for the neutralization process. Slag demonstrated to be able to buffer the pH to the target values of 9, while also showing an almost linear trend compared to previous studies. The reaction progress between slag, lime, and the acidic wastewaters was also analyzed.Deponering av slagg som erhållits från den höglegerade ljusbågsugn (EAF) stålframställningsprocessen utgör en miljömässig behandling för samhället och ettekonomiskt problem för de företag som producerar den på grund av kostnaderna för avfallshantering. Konventionella metoder för återvinning av slagg används i storutsträckning bland stålindustrin, men på grund av deras speciella fysiska egenskaper kan höglegerade EAF-slaggen inte värderas ordentligt. Dessutom produceras sura avloppsvatten av betningsprocessen som höglegerade EAF-stål genomgår som sedan måste samlas in och neutraliseras innan de kan återcirkuleras i det naturliga vattnet. För en sådan uppgift använder stålfabriker för närvarande släckt kalk (ett Ca-rikt mineral) för att höja pH-värdet och för att avlägsna alla metallpartiklar som löses upp i avloppsvattnet. Slaggen innehåller hög mängd Ca och därför har den testats som en ersättning till släckt kalk. Tidigare studier utförda vid avdelningen materialvetenskap och teknik vid Kungliga Tekniska Högskola visade på laboratorieskala att slagg har potential att ersätta kalk för neutralisering och rening av sura avloppsvatten. Detta examensarbete syftar till att skala upp volymerna av avloppsvattnet som ska testas till cirka 70–90 gånger av den från tidigare forskning, och därav fylla ut bryggan mellan laboratorietester och industriell skala. Avhandlingen är uppdelad i tre delar, Första delen innehåller försök på ledningsförmåga i en vatten-saltlösning som genomfördes för att modellera beteende eller slaggspridning i sura avloppsvatten. Efter de resultat som erhållits från konduktivitetsmätningarna genomfördes neutraliseringsförsök med slagg och kalk som för närvarande används av företaget vid neutraliseringsanläggningen i Outokumpu Stainless, Avesta (Sverige). Neutraliseringsförsöken genomfördes med 70 och 90 liter sura avloppsvatten och för att utföra experimenten på plats torkades slagg provet och siktades senare till en partikelstorlek på mindre än 350 μm. Dessutom analyserades data och jämfördes med tidigare studier för att få en tydligare förståelse för slaggens neutraliseringseffektivitet, särskilt huruvida tekniken skulle ha fungerat på större volymer, och även om det också var möjligt att hitta ett generaliserat samband mellan mängden slagg och volym avloppsvatten som krävs för neutraliseringsprocessen. Slagget visade sig kunna buffra pH till målvärdena 9, samtidigt som den visade en nästan linjär trend jämfört med tidigare studier. Reaktionsförloppet mellan slaggkalk och de sura avloppsvattnen analyserades också.
46
Doostmohammadi, Hamid. "A Study of Slag/Metal Equilibrium and Inclusion Characteristics during Ladle Treatment and after Ingot Casting." Doctoral thesis, KTH, Materialvetenskap, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-11596.
Full textAbstract:
Today, there is a high demand on clean steel for high performance materialproperties. Thus, steel producers try to deliver a steel product with the highestquality and cleanliness to the market. The number of parameters that affect thesteel cleanliness may vary depending on the required material properties of thefinal product. However, the non-metallic inclusion characteristics represent one ofthe most important parameters. More specifically, the composition, size, numberand morphology affect steel cleanliness. In this work, selected parameters affectingthe inclusion characteristics were studied using the following methods: i)thermodynamic calculations (including computational thermodynamiccalculations), ii) inclusion determinations using a cross sectional (CS) method (2Dinvestigations) and iii) inclusion determinations using an electrolytic extraction(EE) method (3D investigations). The computational thermodynamic calculations of the slag-steel and inclusion-steelequilibriums were carried out using the Thermo-Calc software. With the help ofthese calculations, the influence of the slag carryover on the top slag, aluminumcontent in steel and sulfur distribution ratio as well as predictions of stable phasesof inclusions were studied. In addition, inclusion determinations of tool steel gradesamples collected during various stages of the ladle treatment in a scrap-based steelplant were carried out using both 2D and 3D methods. Furthermore, inclusiondeterminations of bearing steel grade samples from a runner system after ingotcasting were performed using a 2D metallographic method (CS-method). Also, theINCAFeature software was used, when using cross sectional method, in order tocollect more statistics of the inclusion characteristics. It was found that slag carryover has a large influence on the composition of theactual top slag as well as the aluminum content in the steel as well as the sulfurdistribution ratio. In addition, steel and slag were found to be in “near”-equilibriumconditions, after the completion of the vacuum degassing operation. Furthermore,the composition of small-size inclusions in samples taken from tool steel was foundto be very scattered. Moreover, the composition of the large-size inclusions wasfound to be less scattered. Furthermore, closer to the top slag composition insamples collected after vacuum degassing. Finally, the accuracy of the inclusioncomposition determinations of tool steel samples using the electrolytic extractionmethod was found to be better than for the cross sectional method. The worseaccuracy of the CS-method is due to a considerable effect of matrix elements oninclusion composition.QC 20100709
47
Kalcioglu, Ali Ferdi 1960. "Distribution of antimony between carbon-saturated iron and blast furnace slags." Thesis, The University of Arizona, 1989. http://hdl.handle.net/10150/277129.
Full textAbstract:
Understanding the effects of the process parameters on the distribution behaviour of antimony between metal and slag in the iron blast furnace is critical to develop a universal method of controlling temper embrittlement in commercially pure low alloy steels.
48
Pacheco, Ronaldo Feu Rosa. "Estudo sobre a utilização das escórias de aciaria LD naturais ou modificadas para substituição parcial do cimento ou como adição ao clínquer." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/3/3133/tde-28112017-082247/.
Full textAbstract:
Este trabalho visa estudar o emprego da escória de aciaria a oxigênio (EACN) na construção civil. Para isso, elaborou-se um programa experimental em seis etapas: a primeira compreendeu a caracterização da EACN, do cimento, do clínquer e do gesso; na segunda, a EACN foi cominuída até valores de tamanho de partículas inferiores a 0,075mm; em seguida, caracterizada física, ambiental, química, mineralógica, microestrutural e termicamente, e teve a sua atividade pozolânica determinada; a terceira compreendeu a ativação da escória com hidróxido de sódio; na quarta, foram realizados ensaios de pega expansibilidade, resistência axial à compressão e durabilidade de argamassas de cimento CP V-ARI com substituição parcial do cimento por EACN; na quinta, obteve-se uma primeira escória de aciaria modificada (EACM1) mediante o processo pirometalúrgico da EACN em forma de pó, para alterar a composição química e estrutura para amorfa, tornando-a mais reativa, sendo submetida aos mesmos ensaios da quarta etapa, à exceção dos ensaios de pega e expansibilidade; na sexta e última, obteve-se uma segunda escória modificada (EACM2) pirometalurgicamente: a composição química próxima da escória de altoforno e amorfa. A carga desse processo pirometalúrgico foi calculada pelo software Factsage. Parte dessa escória modificada foi cominuída adicionalmente, de modo que foram obtidas amostras sem moagem adicional (EACM2a) e com moagem adicional (EACM2b). A escória modificada foi submetida aos ensaios da quinta etapa, mais o grau de vitrificação e a reatividade por microscopia de luz transmitida. Os resultados obtidos mostraram que argamassas em que parte do cimento CP V-ARI é substituída por escórias de aciaria (naturais ou modificadas) atendem às especificações de resistência à compressão nos seguintes casos: escória natural e modificada 1: substituição de até 10% do cimento CP V-ARI; escória modificada 2a, substituição de até 20% de cimento; escória modificada 2b, substituição de até 40% do cimento. Observou-se que a escória modificada 2b apresentou resistência à compressão superior ao traço referência nas idades de 28 dias e 91 dias. Apresenta-se ainda a utilização da EACM2b com o clínquer. Outros ensaios e comparações são apresentados para discutir o comportamento observado das escórias em estudo.This study aims at employing BOF steel slag (EACN) in civil construction. Thus, the study developed an experimental program in six stages: the first one comprised the characterization of BOF steel slag, cement, clinker and gypsum; in the second stage BOF steel slag was reduced to particles sized less than 0.075mm; then, it was physical, environmental, chemical, mineralogical, microstructural and thermally characterized, it also had its pozzolanic activity determined; the third stage comprised the activation of BOF steel slag with sodium hydroxide; during the fourth stage, we carried out setting time, expansibility, axial compressive strength and durability tests for mortars made with cement CP V-ARI and partial substitution with BOF steel slag; in the fifth stage, we obtained the first modified BOF steel slag (EACM1) through pyrometallurgical process of powdered BOF steel slag so as to alter its chemical and structural makeup, making it more reactive to be submitted to the same tests of the fourth stage, except the setting time and expansibility tests; in the sixth and final stage, we obtained the second pyrometallurgically modified BOF steel slag: chemical makeup close to blastfurnace slag. The load of this pyrometallurgical process was calculated using software Factsage. Part of this modified slag was ground additionally, so that samples without additional grinding (EACM2a) and with additional grinding (EACM2b) were obtained. The modified slag underwent the fifth-stage tests, and the degree of vitrification and transmitted light microscopy reactivity. The results obtained show that mortars in which part of CP V-ARI cement was replaced with BOF steel slag (natural or modified) meet the compressive strength specifications in the following cases: Natural and modified slag 1: substitution of up to 10% of CP V-ARI cement; Modified slag 2a, substitution of up to 20% cement; Modified slag 2b, substitution of up to 40% cement. We observed that modified slag 2b showed higher compressive strength than the reference mix at ages 28 and 91 days. We also present the use of EACM2b as clinker. Other tests and comparisons are presented so as to discuss the observed behaviors of the study slags.
49
Murphy, Jeffrey N. "Recycling steel slag as a cement additive." Thesis, 1995. http://hdl.handle.net/2429/4326.
Full textAbstract:
In Canada, approximately 1 million tonnes of steel slag are produced annually, but, at
the present time, there is no economic outlet for the large scale recycling of this by-product.
The overall objective of this work was to determine whether steel slag might be processed
into a sufficiently cementitious material to allow it to be recycled as an additive to ordinary
Portland cement clinker. Blending steel slag with with clinker in a modest ratio of 1:10, it
would be possible to effectively recycle all of this steelmaking by-product. Although steel
slag has a composition which is similar to that of Portland cement, (consisting mainly of
lime, silica, and iron oxide), there are important compositional, mineralogical, and process
related differences. Steel slag has limited cementitious properties due to both a lack of
tricalcium silicate and the presence of wustite solid solutions as a predominant mineral
phase. Even though wustite (FeO) possesses no inherent cementitious properties, it has been
shown that hematite (Fe2C<3) will form hydraulic minerals when cooled from a slag melt.
Thus, the valence state of the iron oxide in slag and cement systems will directly influence
the cementitious properties of the material.
This work explores the effects of Fe oxidation state, overall composition, and cooling
rate on the mineral structure, crystalline formation, and glass forming ability of several
synthetic slags and one commercial BOF slag. XRD, SEM, and EDX analyses were
performed on both slow cooled and quenched slags, which had been oxidized. These
analyses, of both synthetic and commercial slag, suggest that the trivalent iron (Fe2C«3)
promoted both cementitious mineral formation in the slow cooled slags and glass formation
in the quenched slags. The rate of cooling directly influenced the crystalline formation and
mineral structure in the solidified product. The slow cooled slags tended to form highly
crystalline polycomponent mineral systems, whereas the rapidly cooled granulated slags
formed a predominantly amorphous material containing the primary Portland cement
minerals.This granulated slag product was blended with Portland cement in varying ratios and
hydrated to form cylindrical compression specimens. The preliminary compression results
indicate that, for a hydration period of 1 to 35 days, blends with a 10% slag addition had
increased strength relative to that of Portland cement. Blends with 20% slag maintained the
same strength as Portland cement, while those with a 45% slag addition exhibited a
significant loss in strength, for the hydration period tested. Therefore, the optimization of
certain slag processing conditions enhanced the cementitious nature of the material allowing
it to be blended with Portland cement, (at additions of up to 20% by weight), without
affecting the strength performance of the material.
50
Tsai, Hung-Ming, and 蔡宏明. "The Study of Steel Desulphurization with the Recycled Ladle Slag and Synthetic Slag." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/82904298602611158227.
Full textAbstract:
碩士國立中興大學
材料科學與工程學系所
100
This study is aiming at the topic of molten steel slag desulfurization. Through the analysis of such as TGA/DTA of slag; XRD phase identification; XRF and C/S Determinator; active-CaO content in slag; to compare the characteristic and composition difference between the recycled ladle slag and synthetic slag. Then we use these materials individually or mixed with lime as a desulfurization agent, to charge into high frequency induction furnace to refine low carbon liquid steel. The steel samples then are analyzed by OES, N/O Determinator; OM and EDS to evaluate their desulfurization ability, also the metallurgical requirement for desulfurization of molten steel. The experiment result show that desulfurization rate and sulfur distribution ratio is in proportion to the basicity of slag; however the active-CaO content in desulfurization agent is actually the determining factor. When only using the recycled ladle slag as desulfurization agent, due to its small amount of active-CaO content, It actually has no desulfurization capability. While the slag component resulted in former reaction can only acted as a fluxing material, it can lower the melting point of desulfurization agent and increase the fluidity, but if additional lime was not added, it has no desulfurization ability. On the other hand the synthetic slag not only has the advantage of low melting point, but it has 14% active-CaO content inside it, so it can act at the beginning of refining to start a desulfurization, if lime is added, it will have the best desulfurization effect. Other experiment outcome shows the precondition for best desulfurization action is to reduce the oxygen content in molten steel in advance, while the ( T-FeO %)+ ( MnO %) amount in slag just represents the oxidization degree of molten steel.