Relevant bibliographies by topics / Chrome sulfure

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  1. Journal articles
  2. Dissertations / Theses
  3. Books
  4. Book chapters
  5. Conference papers
  6. Reports

Academic literature on the topic 'Chrome sulfure'

Author: Grafiati
Published: 4 June 2021
Last updated: 1 February 2022

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Journal articles on the topic "Chrome sulfure"

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Lafond, A., and A. Meerschaut. "Préparation, détermination structurale et propriétés magnétiques d'un nouveau composé lamellaire incommensurable: Le sulfure de gadolinium et de chrome." Materials Research Bulletin 28, no. 10 (October 1993): 979–87. http://dx.doi.org/10.1016/0025-5408(93)90135-z.

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Vialta, Airton, Cleide F. Catani, Renato B. Junior, and João L. Azevedo. "Isolation and characterization of selenate resistant mutants of Acremonium chrysogenum." Brazilian Archives of Biology and Technology 42, no. 3 (1999): 369–74. http://dx.doi.org/10.1590/s1516-89131999000300016.

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Mutants unable to convert exogenous sulfate to sulfite were isolated using the toxic analogue selenate. Three of twenty-eight isolated mutants were chromate sensitive. They showed a possible lesion in the gene that codes the ATP sulfurylase. The others were chromate resistant, and probably had a lesion in one or both of the genes that code the sulfate permease. Methionine increased the resistance levels to selenate. In addition, the frequency of spontaneous mutants obtained in a medium containing methionine was higher (between 2.4 x 10-6 and 18.0 x 10-6) than that obtained using a medium without any intentional source of sulfur (between 0.7 x 10-6 and 5.0 x 10-6). The original strain, as well as the mutants, were able to grow in a sulfur-free liquid medium even after 4 consecutive inoculation procedures. These results indicated the existence of sulfur traces in the medium and/or an efficient intracellular storage system. There was no significant difference between cephalosporin C production in mutants and the original strain.
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Liu, Cheng Jun, Jie Qi, and Mao Fa Jiang. "Experimental Study on Sulfuric Acid Leaching Behavior of Chromite with Different Temperature." Advanced Materials Research 361-363 (October 2011): 628–31. http://dx.doi.org/10.4028/www.scientific.net/amr.361-363.628.

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Utilizing Pakistan chromite as raw material, the rapid leaching of chromium and iron could be realized by the sulfuric acid leaching process on the condition of atmospheric pressure and the addition of oxidant A. And the leaching rate of chromium and iron would be 98.5% and 71.9%, respectively. The sulfuric acid leaching processes with different temperature were systematically studied by chemical analysis and phase analysis. The results showed that, with the increase of reaction temperature, the leaching rate of chromium would increase gradually, but the leaching rate of iron increased at first and then decreases and reached its maximum at 140°C. When the temperature > 160°C, the phases of the leaching residue were magnesium iron silicate and a few of silica, no chromohercynite, chrompicotite and magnesioferrite existed in the chromite. The leaching solution of sulfuric acid leaching process could be used for preparing the basic chrome sulfate, and there is no Cr6+ in the leaching residue and solution. The results would provide theoretical guidance for solving environmental pollution problem of Cr6+ in traditional chromate production process.
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Yatribi, A., and A. Nejmeddine. "Impact écotoxicologique du traitement chimique des eaux usées de tanneries: Analyse technico-économique." Revue des sciences de l'eau 13, no. 2 (April 12, 2005): 107–18. http://dx.doi.org/10.7202/705384ar.

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La toxicité des eaux usées du tannage au chrome et d'épilage-pelanage, avant et après traitement, a été évaluée par test Daphnia pulex. Cette évaluation a été déterminée à partir des équations de corrélation linéaires. Les résultats obtenus montrent que le tannage au chrome et l'épilage-pelanage présentent une toxicité élevée avec des valeurs des CI50 24h respectives de 0,15 et 3,36. Cette toxicité élevée pourrait être expliquée par la charge de ces effluents en chrome, en sulfures et en matière organique. Après traitement par précipitation chimique, la CI50 24h a connu une importante augmentation. Elle est passée de 0,15 à 26,58 et de 3,36 à 11,1 respectivement pour le tannage au chrome et l'épilage-pelanage. Par conséquent, ces effluents traités peuvent être classés comme rejets peu toxiques. Cette diminution de la toxicité est liée surtout à l'abattement des MES (95 %), de la DCO (55 %), de Cr (90 %) et des sulfures (50 %). Ce traitement a donc, un double intérêt; le premier est environnemental, le second est économique du fait de la possibilité de recyclage du chrome récupéré dans le tannage du cuir. En effet, l'application expérimentale du chrome dans le tannage a montré un résultat similaire à celui obtenu par le produit commercial. Ainsi, suite à une analyse technico-économique, le bénéfice réalisé par cette opération est estimé à 3112,50 $ par 1000 tonnes par an.
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Belal, Md, and Abu T. Khan. "Oxidative cross coupling reaction mediated by I2/H2O2: a novel approach for the construction of fused thiazole containing coumarin derivatives." RSC Advances 5, no. 126 (2015): 104155–63. http://dx.doi.org/10.1039/c5ra20405d.

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Various 2-phenyl-4H-chromeno(3,4-d)thiazol-4-one derivatives have been synthesized through C–H bond activation using sodium sulfide as a source of sulfur atoms and by employing I2 as a catalyst and H2O2 as the terminal oxidant.
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Dawara, Latika, S. C. Joshi, and R. V. Singh. "Synthesis, Characterization, and Antimicrobial and Antispermatogenic Activity of Bismuth(III) and Arsenic(III) Derivatives of Biologically Potent Nitrogen and Sulfur Donor Ligands." International Journal of Inorganic Chemistry 2012 (April 22, 2012): 1–9. http://dx.doi.org/10.1155/2012/372141.

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A series of Bi(III) and As(III) complexes with two N∩S donor ligands, 1-(4-chloro-2-oxo-2H-chromen-3-yl)-methylene)-thiosemicarbazide (L1H) and N′-[1-(2-oxo-2H-chrome-3yl-ethylidene]-hydrazinecarbodithionic acid benzyl ester (L2H) have been synthesized by the reaction of BiCl3 and Ph3As with ligands in 1 : 1 and 1 : 2 molar ratios. All the synthesized compounds were characterized by elemental analyses, melting point determinations, and a combination of electronic, IR, 1H NMR, 13C NMR spectroscopic techniques, and X-ray diffraction for structure elucidation. In order to evaluate the effect of metal ions upon chelation, both the ligands and their complexes have been screened for their antimicrobial activity against the various pathogenic bacterial and fungal strains. The metal complexes have shown to be more antimicrobial against the microbial species as compared to free ligands. Both the ligands and their corresponding metal complexes have been tested for their antifertility activity in male albino rats. The marked reduction in sperm motility and density resulted in infertility. Significant alterations were found in biochemical parameters of reproductive organs in treated animals as compared to control group. It is concluded that all these effects may finally impair the fertility of male rats.
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Yanjiao, Gao, Huang Runzhu, and Song Tiehong. "Using Fenton Oxidation Method to Advanced Treatment of Landfill Leachate." Open Chemical Engineering Journal 9, no. 1 (July 31, 2015): 58–61. http://dx.doi.org/10.2174/1874123101509010058.

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Hydrogen peroxide and ferrous sulfate were used to advanced treatment of landfill leachate effluent from biochemical tanks. Some influences on removing COD and chroma including the pH value of solution, the dosage of ferrous sulfate, the dosage of hydrogen peroxide and reaction time were investigated. The test results showed that for removal of COD and chroma the optimal pH was 3.0, the best ferrous sulfate and hydrogen peroxide dosage was 1500mg/L, 20mL/L respectively, and the optimal reaction time was 60min. Under optimal conditions, COD and chroma removal rate could reach 79.7% and 95.2% respectively.
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Sharifi, Majid, Najmoddin Arab, and Gholamreza Khalaj. "Prediction of Toughness through Evaluation of Alloying Elements Distribution Pattern at Heat-Affected Zone in Submerged-Arc Welding Process of API X70 Steel." Applied Mechanics and Materials 467 (December 2013): 35–40. http://dx.doi.org/10.4028/www.scientific.net/amm.467.35.

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Six 56" × 19.8 mm, API X70 PSL2 pipes were produced from three different plate suppliers and then three samples in pipe transverse direction and perpendicular to welding seam were taken out from welding area of each supplier. Sampling carried out from weld metal, HAZ and base metal of each sample, then all 27 prepared samples were analyzed. Afterwards the amounts of 14 alloying elements were considered. The results showed that content of Carbon, Sulfur, Boron, Phosphorous, Copper, Manganese, Aluminum, Titanium and Molybdenum have been increased in the HAZ and Silicon, Nickel, Chrome, Vanadium and Niobium decreased. So it is predicted that an increase in Carbon, Aluminum, Phosphorous, Sulfur and Boron content, also a decrease in Silicon, Chrome and Nickel will cause a drop in the HAZ toughness and an increase in Titanium, Manganese, Copper and Molybdenum content, also decrease in Vanadium and Niobium will cause a rise in HAZ toughness.
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Khan, M. Rafiq. "Techno-Economic Evaluation of Chromium Recovery Pilot Plant Installed at Kasur Tanneries Complex, Pakistan." Pakistan Development Review 46, no. 4II (December 1, 2007): 1155–66. http://dx.doi.org/10.30541/v46i4iipp.1155-1166.

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Chromium metal is widely used as a tanning agent worldwide. The process called chrome-tanning is accomplished in three steps: Pickling, Tanning and Basification1 (Pakistan Tanners Association). Chromium sulfate is the most widely used chemical in this process. Approximately, 60-70 percent of chromium sulfate applied is taken up by the hides and skins, while its 30 to 40 percent remains un-used and is discharged as a component of wastewater into natural water bodies such as rivers, streams, etc., which has adverse environmental impacts on living organisms particularly to humans and animals [Weitz and Luxenberg (n.d.)], and water animals such as fish [Eisler (1986)]. The diseases especially encountered in humans, are of nervous disorders. The pollution from tanneries effluent particularly their chromium component has formed the basis that many developed countries have banned tanning on their soils. Chrome tanned leather, being the need of people all over the world, has the edge that its manufacture cannot be stopped. This has given some economic advantage to some developing countries including Pakistan to manufacture leather and export it to the developed countries. To sustain, different methods have been developed to recover chromium from the tannery effluents before their drainage in the natural water bodies. A few examples of these methods are High Chrome Exhaustion, Direct Recycling of the Spent Tanning Float and Chrome Recovery and Reuse [Arrafay Labs (2003)].
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Garcia, Edivaldo E., Cláudia C. M. Kimura, Ariovaldo C. Martins, Gisele O. Rocha, and Jorge Nozaki. "Chromatographic characterization of products isolated from chrome shavings." Brazilian Archives of Biology and Technology 42, no. 3 (1999): 281–90. http://dx.doi.org/10.1590/s1516-89131999000300003.

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Gel permeation chromatography and high performance liquid chromatography were employed for separation and chemical characterization of products isolated from chrome shavings. After enzymatic hydrolysis, the products isolated were peptides of higher molecular weight. Peptides of lower molecular weight and free aminoacids were the main products using sulfuric acid in chrome shavings solubilization. Glycine (17%) , glutamic acid (10.6%) , alanine (9.2%) , and arginine (8.2%) were the principal amino acids found. Phenylalanine(1.8%) was the main aromatic amino acid , while tryptophane was completely absent.
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Dissertations / Theses on the topic "Chrome sulfure"

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Thiollier, Anne. "Catalyseurs d'hydrotraitement à base de sulfure de chrome." Lyon 1, 1999. http://www.theses.fr/1999LYO10233.

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Les normes antipollution de plus en plus severes concernant les rejets d'oxydes de soufre dans l'atmosphere, necessitent le developpement de catalyseurs d'hydrotraitement plus actifs que les catalyseurs conventionnels nimo/al 2o 3 et como/al 2o 3. Pour cela, dans ce travail deux axes de recherches visant a ameliorer ces catalyseurs ont ete abordes : le remplacement du support alumine par la zircone et la mise au point d'une nouvelle phase active a base de sulfure de chrome. Dans une premiere partie, des catalyseurs (ni)mo/zro 2 prepares par une technique de precipitation, ont ete evalues dans les reactions d'hydrodesulfuration du thiophene et d'hydrogenation de la tetraline. Dans la reaction d'hydrogenation, des activites tres elevees ont ete observees. Elles ont ete reliees a une reduction plus facile du sulfure de molybdene sur zircone que sur alumine. Dans une deuxieme partie, des catalyseurs (ni)mo/cr 2o 3zro 2 ont ete synthetises par impregnation de cr 2o 3zro 2 obtenu par coprecipitation, et etudies dans les memes reactions modeles. Dans la reaction d'hydrogenation de la tetraline, ces solides presentent des activites specifiques trois fois superieures a celle du catalyseur de reference nimo/al 2o 3. Un ensemble de caracterisations physico-chimiques (drx, xps, microscopie electronique) a permis d'attribuer ces proprietes catalytiques a la presence du sulfure cr 2s 3 forme par la transformation de cr 2o 3 au cours de l'activation du catalyseur. La troisieme partie de ce travail a ete orientee vers une meilleure connaissance des proprietes de ces sulfures et plus particulierement vers l'etude de thiospinelles mcr 2s 4. Differentes methodes de preparation ont permis d'obtenir ces sulfures mixtes avec des caracteristiques texturales adaptees a une application catalytique. Nous avons observe que la nature du second metal influait fortement sur les proprietes catalytiques, et une correlation entre l'activite et la reductibilite de ces solides a ete demontree.
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Hoerner, Bertrand. "Corrosion sous contrainte de l'acier inoxydable supermartensitique 12chrome 4. 5nickel 1. 5molybdène dans un milieu sans sulfure d'hydrogène." Saint-Etienne, EMSE, 2007. http://www.theses.fr/2007EMSE0017.

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Les aciers inoxydables supermartensitiques sont utilisés dans le transport pétrolier et présentent une sensibilité de la zone affectée thermiquement (ZAT) à la corrosion sous contrainte. Nous avons caractérisé par traction lente la fissuration de la ZAT dans un milieu d’essai sans H2S. L’étude s’est focalisée sur l’effet de la teneur en carbone, de la réaffectation de la ZAT et d’un traitement post soudage sur la tenue à la corrosion sous contrainte. Notre étude a montré que la ZAT est sensible à la corrosion sous contrainte en milieu sans H2S et que sa réaffectation durant le soudage amenait à la création de carbures de chrome intergranulaires qui induisent une zone déchromée (15 nm). La fissuration peut alors se développer par dissolution le long de cette zone. Nous avons montré que l’augmentation du rapport chrome/carbone à un certain seuil permet de limiter la densité de carbures et d’avoir une zone déchromée discontinue ce qui inhibe la fissuration. Nous avons observé que l’application d’un traitement post soudage permet une rechromisation autour des carbures de chrome : après un traitement à 650°C durant 20 minutes, la ZAT ne présente plus de fissures
Supermartensitic Stainless steels are used in the oil and gas application and have a sensitivity of the heataffected zone (HAZ) to stress corrosion cracking. We carried out slow strain rate tensile test to characterize cracking of the HAZ in a H2S free environment. The study focus on the effect of carbon, the reassignment of the ZAT and post weld treatment on the cracking resistance. Our study show that the ZAT is sensitive to stress corrosion cracking in the free H2S environment and that the reassignment during welding led to the creation of intergranular chromium carbides which induce a depleted zone (15 nm). The cracks can grow by dissolution along this zone. We show that the increase of the chromium / carbon ratio beyond a threshold reduces the density of carbides and had a discontinuous depleted zone which inhibits cracking. We observe that the application of a post-weld heat treatment allows desensitisation around chromium carbides: after treatment at 650 ° C for 20 minutes, no crack appears in HAZ
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Demoisson, Frédéric. "Réactivité aux échelles micronique et submicronique de particules colloïdales : oxydation d'un sulfure de fer (pyrite) par du chrome (VI) et sorption sur un hydroxyde d'aluminium (gibbsite) d'espèces organiques." Nancy 1, 2006. http://docnum.univ-lorraine.fr/public/SCD_T_2006_0004_DEMOISSON.pdf.

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Deux systèmes à pouvoir d'oxydoréduction et de sorption de surface sont étudiés : l'oxydation de pyrite (FeS2) par du chrome (VI) et l'adsorption d'espèces 2,4-dinitrobenzoate sur gibbsite (γ-Al(OH)3). L'enjeu du premier système est d'appréhender le processus d'oxydation de la pyrite en utilisant une sonde métallique, le chrome (VI). L'analyse de la solution par spectroscopie UV-visible et la caractérisation de la phase solide par spectrométries Raman confocal, XPS, EXAFS et XANES permettent de proposer un modèle de mécanisme d'oxydation/dissolution. L'objectif de la seconde étude est de mettre en évidence une différence de réactivité de surface entre deux types de face cristalline de la gibbsite à l'aide d'une sonde organique en utilisant la spectroscopie optique en champ proche (SNOM). Les corrélations faces cristallines/spectres en champ proche indiquent une réactivité différente entre les hydroxyles mono et bi-coordonnées de la phase minérale. Un modèle de sorption est présenté
Two systems characterised by oxydoreduction and sorption of surface reactions are studied: the pyrite oxidation (FeS2) by chromium (VI) and the sorption of dinitro-2,4 benzoic species on gibbsite (γ-Al(OH)3). The aim of the first system is to study the pyrite oxidation processes of the pyrite by using chromium (VI) like a metal probe. The solution analysis by UV-visible spectroscopy and the solid phase characterisation by confocal Raman spectrometry, XPS, EXAFS and XANES allow to suggest a mechanism model of oxidation/dissolution. The objective of the second study is to display a specific chemical reactivity between two crystalline face types of the gibbsite by using an organic probe with the help of sub-wavelength spectroscopy (SNOM). Correlations between crystalline faces and near field spectra show difference reactivity between mono and bi coordinated OH groups from the mineral phase. A model of sorption is presented
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Aubertin, Nadine. "Caractérisation d'une nouvelle série d'oxysels à base de ferrate (VI) et application dans le traitement des eaux." Nancy 1, 1994. http://www.theses.fr/1994NAN10015.

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Cette étude montre dans un premier temps qu'il est possible, à température ambiante et à l'état solide, de stabiliser le groupement feo#4#2# par substitution de fe(VI) par un atome x (x=s(+VI), cr(+VI), p(+V) et al(+III), par formation d'une solution solide k#2(fe#1##x,x#x)o#4. Nous avons montré que chromates et ferrates pouvaient constituer des solutions solides continues; avec les sulfates également, le sel de fer à oxyder a une incidence sur la teneur en fe(VI) du matériau fini; ainsi avec la jarosite, nous avons obtenu un mélange titrant a plus de 10% de fe(VI), alors qu'avec le sulfate ferreux, la teneur en fe(VI) n'excédait pas 7%. Les phosphates et aluminates sont moins favorables à la substitution des ferrates du fait de la charge différente des groupements tétraédriques. Au cours de ces différentes synthèses, nous avons également mis en évidence l'existence d'un nouveau sel ferrique de formule k#2feo(oh)#3 hydroscopique. Nous nous sommes intéressés, dans un deuxième temps, aux propriétés du sulfato-ferrate de potassium et plus particulièrement à sa stabilité thermique et sa stabilité en solution aqueuse. Nous avons dans un troisième temps, étudié l'efficacité des sulfato-ferrates de potassium dans le traitement des eaux usées urbaines d'une part et a potabilité d'autre part, en comparaison avec des réactifs couramment utilisés dans ce domaine, à savoir le chlorure ferrique et le sulfate d'aluminium hydrate. Les résultats obtenus quant à l'abattement de la D. C. O. , M. E. S. T. , phosphates, coliformes, métaux lourds, cyanures, pesticides et hydrocarbures sont de matière à envisager des tests à une plus grande échelle et ouvrent ainsi la voie à de nouvelles techniques de traitement des eaux
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Pouget, Stéphanie. "Contribution à l'étude de l'influence de la dilution sur les propriétés magnétiques de composés isolants frustrés." Toulouse, INSA, 1993. http://www.theses.fr/1993ISAT0039.

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Nous avons principalement etudie le systeme ferromagnetique heisenberg-3d frustre cdcr#2#(#1##x#)in#2#xs#4, dans la limite des faibles dilutions x. La structure des phases ferromagnetiques et verre de spin reentrante a ete exploree par diffraction de neutrons et mesures d'aimantation macroscopiques. Les resultats s'interpretent dans le cadre d'un modele inhomogene du systeme de spins. Par diffusion de neutrons aux petits angles, spectrometries trois-axes et d'echo de spin, nous avons caracterise le comportement critique statique et dynamique des composes x=0 et 0. 05. Cette etude a revele la pertinence de la dilution et ainsi un des effets de la frustration qui est de porter le systeme dans la limite des forts desordres. Nos resultats suggerent l'existence de deux comportements statiques differents du compose cdcr#1#. #9in#0#. #1s#4, de part et d'autre de t#c, concernant la dynamique, nous avons mis en evidence une evolution non monotone du temps de relaxation en fonction du moment transfere, pour des valeurs de celui-ci tres inferieures a l'inverse de la longueur de correlation, et voisines de l'inverse de la distance moyenne entre impuretes in#3#+. La derniere partie de ce travail est consacree au systeme frustre ising-3d fe#1##xmg#xbr#2. Les mesures de la dispersion des ondes de spin pour differentes directions du moment transfere nous ont permis de preciser le modele des interactions d'echange pour le compose febr#2. Nous avons etudie la transition de phase para-antiferromagnetique pour les deux valeurs de la dilution x=0 et 0. 1. Les resultats sont interpretes dans le cadre d'une theorie classique de champ moyen
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Ferrante, Véronique. "Rôles des micro-organismes et de la teneur en chrome dans la corrosion d'aciers fer-chrome en présence de bactéries sulfato-réductrices." Compiègne, 1991. http://www.theses.fr/1991COMPD390.

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S'il est largement admis que la présence de bactéries sulfato-réductrices est susceptible d'aggraver la corrosion aqueuse des aciers, les modalités d'un tel phénomène ne sont pas encore définitivement établies. Notre étude vise à préciser les rôles exacts joues dans la corrosion, par la présence de cellules bactériennes de D. Vulgaris d'une part et par des paramètres chimiques comme la composition du matériau et l'accumulation de sulfures en solution d'autre part. L'emploi de techniques expérimentales relevant aussi bien de la microbiologie que de l'électrochimie ou de l'analyse chimique a permis de souligner l'inter-dépendance existant entre les bactéries et le matériau ainsi que l'importance de la composition de l'acier vis-à-vis de l'adhésion des micro-organismes et de la corrosion généralisée. Les cellules et les sulfures dissous ne semblent pas influencer remarquablement la corrosion généralisée. Cependant, les modifications d'état de surface qu'ils entraînent pourraient être à l’origine de phénomènes de corrosion localisée.
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Boursiquot-Michel, Sophie. "Synthèse, caractérisation et réactivité vis-à-vis du chrome (VI) de la mackinawite (FeS)." Nancy 1, 2002. http://docnum.univ-lorraine.fr/public/SCD_T_2002_0236_BOURSIQUOT-MICHEL.pdf.

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Cette étude porte à la fois sur la synthèse et la caractérisation d'un sulfure de fer, la mackinawite et sur sa réactivité vis-à-vis d'un polluant métallique, le chrome (VI). Dans un premier temps, la synthèse de la mackinawite a été conduite à partir de deux modes de synthèse couramment rapportés dans la littérature et qui mettent en jeu l'ajout d'une solution de soufre (-II) à une solution contenant du fer (0) ou du fer (II). La caractérisation des propriétés physico-chimiques a tout d'abord mis en évidence que les deux modes de synthèse ne sont pas équivalents du point de vue de la cristallinité de la phase obtenue : le produit obtenu à partir de fer (II) est mal cristallisé alors que celui synthétisé à partir de fer métallique est bien cristallisé et identique à la mackinawite naturelle. C'est alors ce second mode de synthèse qui a été retenu pour la suite de cette étude. Par ailleurs, l'altération des propriétés physico-chimiques de surface de la mackinawite a été mise en évidence, avec l'existence d'une couche constituée de fer (II) et de fer (III) liés à du soufre (-II). Enfin, l'étude de l'oxydation s'est quant à elle avérée complexe en raison de la présence simultanée de plusieurs produits d'oxydation qui sont la greigite, le soufre élémentaire et des (oxyhydr)oxydes de fer, la magnétite et éventuellement la goethite. Le soufre élémentaire et les (oxyhydr)oxydes de fer sont les produits finals de la réaction, à partir desquels un mécanisme d'oxydation de la mackinawite par l'oxygène a été proposé. La deuxième partie de ce travail, consacrée à l'étude de la réactivité mackinawite-chrome (VI) a démontré l'efficacité de la mackinawite à éliminer le chrome (VI) en solution. L'élimination résulte d'un mécanisme d'oxydoréduction en solution, le chrome (VI) réagissant avec le fer (II) ainsi que les espèces du soufre issus de la dissolution de la mackinawite. L'analyse structurale des produits de la réaction révèle la présence de mackinawite résiduelle, de greigite, de goethite, de soufre élémentaire et d'une phase constituée de fer, d'oxygène et de chrome. Un mécanisme réactionnel de réduction du chrome (VI) par la mackinawite a été proposé. Il semblerait que la précipitation des produits de la réaction constitue le facteur limitant la réduction du chrome (VI) par la mackinawite
This study is about the synthesis, the characterisation of an iron sulphide, mackinawite (FeS) and the reactivity with a metallic pollutant, chromium (VI). First of all, the synthesis of mackinawite was driven from two ways of synthesis currently reported in the literature and which involve the addition of a sulphur (-II) solution to a solution containing iron (0) or iron (II). The characterisation of the physical chemistry properties has shown that the crystallinity of the products obtained from the two ways of synthesis are not equivalent: the product obtained from iron (II) is poorly crystallised whereas the one synthesised from metallic iron is well crystallised and identical to natural mackinawite. The second way of synthesis has then been retained for this study. Otherwise, the alteration of the physical chemistry properties of the surface of mackinawite has been underlined, with the presence of both Fe(II) and Fe(III) bonded to sulphur. At last, the oxidation study has been complex, due to the simultaneous presence of several oxidation products which are greigite, elemental sulphur and iron (oxyhydr)oxides, magnetite and eventually goethite. Elemental sulphur and iron (oxyhydr)oxides are the final products of the reaction, from which a mechanism of mackinawite oxidation has been proposed. The second part of this work concerns the study of the mackinawite/chromium (VI) reactivity and has demonstrated the ability of mackinawite to remove chromium (VI) from solution. The elimination of chromium (VI) results from an oxidoreduction mechanism in solution, chromium (VI) interacting with iron (II) and sulphur species arising from the mackinawite dissolution. The structural analysis of the reaction products reveals the presence of residual mackinawite, greigite, goethite, elemental sulphur and a phase including iron, oxygen and chromium. A reaction mechanism of chromium (VI) reduction by mackinawite has been proposed. It seems that the precipitation of the reaction products is the limiting factor in the chromium (VI) reduction by mackinawite
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8

Saifi, Ali. "Contribution à l'étude des propriétés magnétiques des systèmes spinelles isolants CdCr2xIn2-2xS4 et ZnCr2xGa2-2xO4 : phases type verre de spin." Paris 6, 1986. http://www.theses.fr/1986PA066519.

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Ces systèmes présentent la percolation et la frustration. Le premier composé est ferromagnétique, tandis que le second présente des interactions antiferromagnétiques. On étudie en fonction de x les transitions de ces composés. Les transitions de phase du gallate ont été étudiées par effet Mössbauer. On a mis en évidence que pour x0,75 l'ordre magnétique tend vers un ordre caractéristique de la "vraie" phase verre de spin.
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9

Santos, Figueroa Luis Enrique. "New approaches for the development of chromo-fluorogenic sensors for chemical species of biological, industrial and environmental interest." Doctoral thesis, Universitat Politècnica de València, 2015. http://hdl.handle.net/10251/43216.

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El presente proyecto de investigación está enfocado al desarrollo de sensores químicos fluoro-cromogénicos, para la detección y determinación de especies químicas de interés biológico, industrial y medioambiental de forma selectiva y con alta sensibilidad. En forma general, se busca el diseñar nuevos sistemas sensores basados en compuestos (receptores) formados por dos unidades: una unidad coordinante que interacciona con el anión a determinar y una unidad generadora de señal que alerta del reconocimiento molecular efectuado. Durante este estudio se están preparando diversas moléculas receptoras funcionalizandas con grupos modificadores de estructura para evaluar su influencia sobre las capacidades de detección y selectividad como receptores de especies específicas en diferentes condiciones y medios. Las diferentes aproximaciones en prueba implican a su vez el diseño y síntesis molecular, así como el análisis de las diferentes señales ópticas producidas en el reconocimiento, con el fin de diseñar sistemas de alta eficacia y eficiencia, y con posibilidades reales de aplicación.
Santos Figueroa, LE. (2014). New approaches for the development of chromo-fluorogenic sensors for chemical species of biological, industrial and environmental interest [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/43216
TESIS
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10

Ustaoglu, Emre. "Optimization Of Conditions In Sulfuric Acid Leaching Of Turkish Chromite Concentrates." Master's thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/2/12607344/index.pdf.

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In this thesis work, a high grade chromite concentrate obtained from PinarbaSi, Kayseri region of Turkey was reacted with sulfuric acid solution to determine the optimum conditions of leaching of chromite ores. Conventional methods for producing chromium are still valid in industry. The main process in production includes soda melting and taking it into solution in the form of chemical compounds such as sodium dichromate. Three and six valence states of chromium have importance in production. Trivalent chromium, chrome ore or chromite have no harmful effects. However, compounds of hexavalent chromium show toxic, irritating and corrosive action to people and environment. In the mentioned conventional method, main products consist of hexavalent chromium compounds. In this study, only trivalent chromium remained in the leach solution and did not change to hexavalent state. Obtained product after leaching was chromium(III) sulfate. The maximum extraction of chromium in the absence of perchloric acid was 94.1 % under the conditions of 175 °
C, 6 hours and 84.6 wt % sulfuric acid. The maximum extraction of chromium in the presence of perchloric acid was 98.7 % under the conditions of 175 °
C, 2 hours, 84.6 wt % sulfuric acid and ½
perchloric acid / chromite ratio. The latter one was also the highest recovery value obtained during the experiments. Moreover, in none of the analyzed samples, appreciable amounts of hexavalent chromium was found during analyses.
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Books on the topic "Chrome sulfure"

1

Stypuła, Barbara. Pasywacja chromu w wodnych i bezwodnych roztworach kwasu siarkowego. Kraków: Wydawnictwa AGH, 1994.

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Danford, Merlin D. The corrosion protection of several aluminum alloys by chromic acid and sulfuric acid anodizing. Huntsville, Ala: George C. Marshall Space Flight Center, 1994.

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Saruchera, Thomas. The distribution of sulfur during chromite reduction in the presence of NI3S2 and during desulphurization / Thomas Saruchera. Sudbury, Ont: Laurentian University, School of Engineering, 1991.

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Chudoba, Karl F., and Carl Hintze. Sulfate, Chromate, Molybdate, Wolframate, Uranate. De Gruyter, Inc., 2019.

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5

George C. Marshall Space Flight Center., ed. A comparison of chromic acid and sulfuric acid anodizing. [Marshall Space Flight Center, Ala.]: National Aeronautics and Space Administration, George C. Marshall Space Flight Center, 1992.

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The corrosion protection of several aluminium alloys by chromic acid and sulfuric acid anodizing. Hampton, Va: National Aeronautics and Space Administration, Langley Research Center, 1994.

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Center, Langley Research, ed. The corrosion protection of several aluminium alloys by chromic acid and sulfuric acid anodizing. Hampton, Va: National Aeronautics and Space Administration, Langley Research Center, 1994.

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Book chapters on the topic "Chrome sulfure"

1

Okrusch, Martin, and Siegfried Matthes †. "Sulfate, Chromate, Molybdate, Wolframate." In Mineralogie, 107–14. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-540-78201-8_7.

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Okrusch, Martin, and Siegfried Matthes. "Sulfate, Chromate, Molybdate, Wolframate." In Mineralogie, 129–36. Berlin, Heidelberg: Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-34660-6_9.

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Conference papers on the topic "Chrome sulfure"

1

Koop, Rodney, and Yukimori Moji. "Boric/Sulfuric Acid Anodize-Alternative to Chromic Acid Anodize." In Airframe Finishing, Maintenance & Repair Conference & Exposition. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 1992. http://dx.doi.org/10.4271/920944.

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Nagaraj, B. A., D. J. Wortman, A. F. Maricocchi, J. S. Patton, and R. L. Clarke. "Development of Corrosion Resistant Coatings for Marine Gas Turbine Applications." In ASME 1990 International Gas Turbine and Aeroengine Congress and Exposition. American Society of Mechanical Engineers, 1990. http://dx.doi.org/10.1115/90-gt-200.

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The performance of a number of selected diffusion and overlay coatings was evaluated using an atmospheric pressure burner rig; the test environment contained compounds of vanadium, sodium and sulfur. The tests were designed to simulate the deposit chemistry and sulfur trioxide partial pressures expected in a marine gas turbine engine operating on contaminated fuel. The tests were performed for up to 1000 hours at 1300°F and 1650°F. At 1650°F, virtually all the coatings tested were severely corroded, emphasizing the necessity of improved coating materials such as ceramics to resist vanadic corrosion. At 1300°F, FeCrAlY, pack chromide and CoCrAlY coatings with high chromium performed well. Yttria stabilized zirconia coatings, with selected bond coats, were evaluated with fuels containing low (0.3ppm) and high (21ppm) concentrations of vanadium in atmospheric burner rig at 1650°F. Reaction products, primarily yttrium vanadate, were observed in both tests. The results are discussed in terms of bond coat corrosion and chemistry of the test environment.
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Hannon, C. L., J. Gerstmann, F. B. Mansfeld, and Z. Sun. "Development of Corrosion Inhibitors for Absorption Heat Pumps." In ASME 2002 International Mechanical Engineering Congress and Exposition. ASMEDC, 2002. http://dx.doi.org/10.1115/imece2002-33411.

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This paper describes the results of a research project to develop a non-toxic corrosion in hibitor for the protection of carbon steel surfaces of ammonia-water absorption heat pumps through the use of rare earth metal salt (REMS) compounds. Chromate compounds are currently used as corrosion inhibitors in these systems, but are toxic, environmentally harmful, and their use is being phased out. Corrosion concerns in ammonia-water absorption systems are primarily those of non-condensable (NC) gases generated by corrosion reactions impeding the heat and mass transfer processes in the system. The research focused on the development of a dual-protection REMS based strategy of applying a cerium-oxide/hydroxide coating to the metal surface in a process called cerating, in conjunction with a cerium-sulfate solution-based inhibitor. A laboratory test was conducted in test rigs designed to simulate the conditions of temperature and ammonia concentration found in the desorber component of advanced ammonia-water absorption systems. The test compared the NC gas generation rate in a rig with cerated steel surfaces to a rig using sodium chromate as a solution based inhibitor. The cerated test rig demonstrated an NC gas generation rate about 3 times lower than that of the chromate protected rig. Neither rig showed any indications of significant corrosion activity. This work has shown that cerating can provide superior suppression of NC gas generation in ammonia-water absorption systems compared to sodium chromate, in a process that is simple and readily applicable to the commercial manufacture of equipment.
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Nurjaman, F., A. Shofi, U. Herlina, B. Suharno, A. R. Faradila, Laurensia, and S. Subandrio. "Reduction process of low-grade chromite sand using calcium carbonate and calcium sulfate as additives and coal as reductant." In PROCEEDINGS OF THE 3RD INTERNATIONAL SEMINAR ON METALLURGY AND MATERIALS (ISMM2019): Exploring New Innovation in Metallurgy and Materials. AIP Publishing, 2020. http://dx.doi.org/10.1063/5.0001853.

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Craig, Steven, and Patcharapun Soodsakorn. "Overcoming Extreme Technical and Logistical Challenges to Successfully Cleanout 76,000-LBM Proppant." In SPE/ICoTA Well Intervention Conference and Exhibition. SPE, 2021. http://dx.doi.org/10.2118/204437-ms.

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Abstract A fracture treatment in offshore Tunisia screened out leaving over 76,000-lbm proppant in the wellbore. The well was significantly under-hydrostatic. The platform was small and had limited deck space and low capacity cranes. The completion incorporated chrome tubulars with a history of causing abrasion failure to coiled tubing strings. The challenge was to efficiently and safely clean out the proppant with coiled tubing (CT). A prior cleanout campaign had been conducted with concentric CT and jet pumps. An initial design focused on repeating this method. The engineering analysis had to account for fluid and nitrogen pumping being conducted from a supply vessel, limited nitrogen volume, low the solids return rate due to surface handling limitations, and no fluid discharge permitted to sea. A combined engineering, logistical study, laboratory testing and risk assessment was undertaken over the course of three months. Engineering utilized advanced cleanout modelling software to review concentric CT cleaning, forward cleaning (with and without optimizing cleaning Bottom Hole Assembly (BHA) and with various sizes of CT), and reverse circulating. Logistics analyzed the overall operation time, fluid and nitrogen requirements and the number of boat trips to replenish/change well returns and nitrogen. Three additional challenges were present. First, proppant could have packed off creating difficulties for some of the processes under review. Laboratory testing was conducted and confirmed this would not be a concern. Second, the well was sour and considerations for protecting the CT string and handling hydrogen sulfide (H2S) in the return stream were required. Third, CT string optimization was required to reduce potential abrasion failures. Avoiding CT failure was paramount as the string would be boat spooled onto the platform and any failure would severely impact operating time and project finances. The chosen method was primarily fluid only reverse circulating when cleaning above the formation, changing to forward circulated two phase operation when close to the formation. The downhole pressure gauge in the completion provided early warning of lost returns or of gas kicks. The operation was successfully, efficiently and safely completed in August 2019. The well was handed back to production 8 days ahead of schedule. The paper will cover the complete concept and detail design, execution and post-job analysis.
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Reports on the topic "Chrome sulfure"

1

Thornton, E. C., M. A. Baechler, M. A. Beck, and J. E. Amonette. Laboratory evaluation of the hydrogen sulfide gas treatment approach for remediation of chromate-, uranium(VI)-, and nitrate-contaminated soils. Office of Scientific and Technical Information (OSTI), August 1994. http://dx.doi.org/10.2172/10189698.

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