Letteratura scientifica selezionata sul tema "Flotation – South Africa"
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Articoli di riviste sul tema "Flotation – South Africa"
1
Haarhoff, Johannes, e Lucas R. J. van Vuuren. "Design parameters for dissolved air flotation in South Africa". Water Science and Technology 31, n. 3-4 (1 febbraio 1995): 203–12. http://dx.doi.org/10.2166/wst.1995.0530.
Testo completoAbstract (sommario):
Dissolved air flotation has been used in South Africa for more than 25 years in the field of water and waste-water treatment, with practically all the development and verification done locally. This substantial body of knowledge and experience was recently condensed into a document titled A South African Design Guide for Dissolved Air Flotation. A general literature survey was combined with a detailed survey of 26 dissolved air flotation plants operating in Southern Africa, to arrive at suggested design parameters. Two broad categories of applications were covered in the guidelines - those of water clarification, and of activated sludge thickening. A clear trend emerged from the data collected. Drinking water clarification plants were generally designed within a fairly narrow range of the most design parameters, and the perception of operators and managers was that these clarification plants performed very efficiently. Sludge thickening plants, on the other hand, showed considerable variability in terms of most design parameters, and the general perception of its efficiency consequently varied from highly positive to negative. The paper includes summaries of the ranges of the actually surveyed design parameters, the suggested design values and a comparison with typical design values available from other countries.
2
Afolabi, Ayo Samuel, Ambali Saka Abdulkareem e Edison Muzenda. "Effect of Flotation Parameters on Recovery of South Africa Nickel Sulphide Ore". Applied Mechanics and Materials 260-261 (dicembre 2012): 961–68. http://dx.doi.org/10.4028/www.scientific.net/amm.260-261.961.
Testo completoAbstract (sommario):
This study investigated the effects of flotation parameters on the recovery of low grade nickel sulphide ore. The parameters investigated are the particle size, flotation time, temperature and pH of the pulp. The analyses of the results obtained showed that particle size, pH, and flotation time had significant effects on the recovery of nickel sulphide ore. The particle size distribution showed that the breakage rate increased in coarse particles and decreased with reduction in particle size. The optimum particle size was found to be 87% passing 75 µm with the highest nickel recovery of 35% at 15 minutes while 68, 79, and 97% passing 75 µm produced nickel recovery of 15, 20 and 16% respectively. The maximum nickel recovery of 35% was achieved at pH of 10.5 which indicated that the nickel sulphide ore has good floatability at alkaline pH range. It was also observed that the recovery of nickel increased with flotation time and the highest recovery was obtained at flotation time of 15 minutes.
3
O'Connor, C. T., e R. C. Dunne. "The practice of pyrite flotation in South Africa and Australia". Minerals Engineering 4, n. 7-11 (gennaio 1991): 1057–69. http://dx.doi.org/10.1016/0892-6875(91)90083-8.
Testo completo
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Officer, J., J. A. Ostrowski e P. J. Woollard. "The design and operation of conventional and novel flotation systems on a number of impounded water types". Water Supply 1, n. 1 (1 gennaio 2001): 63–69. http://dx.doi.org/10.2166/ws.2001.0008.
Testo completoAbstract (sommario):
This paper describes the design of conventional Dissolved Air Flotation (DAF) systems, and the novel Counter Current Dissolved Air Flotation Filtration (COCODAFF®) process. The operation and performance of these plants on a variety of water types in the United Kingdom and South Africa is also described. The advantages of flotation processes for the treatment of impounded waters either high in colour, or with a high concentration of algae, is discussed. Other topics covered in this paper are hydraulic flocculation, and the application of Finite Element Analysis (FEA), to the design of flotation plants. It is concluded that the COCODAFF® process offers a number of advantages over conventional DAF systems.
5
Aleksandrova, Tatyana, e Cyril О’Connor. "Processing of platinum group metal ores in Russia and South Africa: current state and prospects". Journal of Mining Institute 244 (30 luglio 2020): 462–73. http://dx.doi.org/10.31897/pmi.2020.4.9.
Testo completoAbstract (sommario):
The presented study is devoted to a comparative review of the mineral raw material base of platinum group metals (PGMs) and technologies of their processing in South Africa and Russia, the largest PGM producers. Mineralogical and geochemical classification and industrial value of iron-platinum and platinum-bearing deposits are presented in this work. The paper also reviews types of PGM ore body occurrences, ore processing methods (with a special focus on flotation processes), as well as difficulties encountered by enterprises at the processing stage, as they increase recovery of the valuable components. Data on mineralogical features of PGM deposits, including the distribution of elements in the ores, are provided. The main lines of research on mineralogical features and processing of raw materials of various genesis are identified and validated.
Sulfide deposits are found to be of the highest industrial value in both countries. Such unconventional PGM sources, as black shale, dunites, chromite, low-sulfide, chromium and titanomagnetite ores, anthropogenic raw materials, etc. are considered. The main lines of research that would bring into processing non-conventional metal sources are substantiated.
Analysis of new processing and metallurgical methods of PGM recovery from non-conventional and industrial raw materials is conducted; the review of existing processing technologies for platinum-bearing raw materials is carried out. Technologies that utilize modern equipment for ultrafine grinding are considered, as well as existing reagents for flotation recovery; evaluation of their selectivity in relation to platinum minerals is presented.
Basing on the analysis of main technological processes of PGM ore treatment, the most efficient schemes are identified, i.e.,gravity and flotation treatment with subsequent metallurgical processing.
6
Dzvinamurungu, Thomas, Derek Hugh Rose, Karel Stephanus Viljoen e Antoine Floribert Mulaba-Bafubiandi. "A Process Mineralogical Evaluation of Chromite at the Nkomati Nickel Mine, Uitkomst Complex, South Africa". Minerals 10, n. 8 (12 agosto 2020): 709. http://dx.doi.org/10.3390/min10080709.
Testo completoAbstract (sommario):
A process mineralogical study based on three texturally and mineralogically different chromite-bearing ore types at the Nkomati nickel mine was undertaken, with focus on chromite. Chromite is a by-product of the Ni-Cu-Co-PGE ore at Nkomati Nickel mine. These being the PCMZ_MG (medium-grade Ni-Cu sulphide silicate ore with disseminated chromite), PCMZ_HG (high-grade Ni-Cu sulphide silicate ore containing disseminated chromite) and MCHR (massive chromite unit) ore types. These were processed using benchtop flotation followed by gravity concentration using a shaking table at different grind sizes. Quantitative mineralogical data was obtained using a 600F Mineral Liberation Analyser for the unprocessed and processed ores at three selected target grinds. The Mineral Liberation Analyser data indicated that increased milling does not relate to increased chromite grades and recoveries, particularly for the disseminated PCMZ type ores based on laboratory-scale gravity concentration. The recovery is controlled largely by the chromite chemistry. The results also showed that the MCHR samples that underwent a pre-flotation stage before gravity separation had better Cr2O3 grades (45% to 47%) and recoveries (52% to 61%) than MCHR ore that did not undergo a pre-flotation stage, which recorded grades ranging from 44% to 46% and recoveries ranging from 43% to 60%. This holds promise for the blending of MCHR ores with the PCMZ ores. The PCMZ ores also displayed better Cr2O3 grades and recoveries at coarser grinds. The optimal target grind to process all three ore types is a P80 of 75 μm, which is the current grind size employed at Nkomati Nickel mine. Due to the low nickel price and grade the Nkomati Nickel mine is currently under care and maintenance.
7
Mhonde, Ngoni, Mariette Smart, Kirsten Corin e Nora Schreithofer. "Investigating the Electrochemical Interaction of a Thiol Collector with Chalcopyrite and Galena in the Presence of a Mixed Microbial Community". Minerals 10, n. 6 (19 giugno 2020): 553. http://dx.doi.org/10.3390/min10060553.
Testo completoAbstract (sommario):
High microbial cell counts have been recorded in sewage waters employed as process water in mineral beneficiation plants across the world. The presence of these microbes can negatively impact flotation performance through mineral passivation, although some microbes improve flotation performance as investigated in various bio-flotation studies. The current study aims to understand the electrochemical behaviour of minerals in the presence of a sodium ethyl xanthate (SEX) collector and microbes originating from a sulphide ore processing plant in South Africa. The electrochemical response was correlated to observe flotation performance. Mixed potential measurements were conducted in parallel to microflotation tests, to assess the hydrophilicity or hydrophobicity induced on sulphide minerals adapted to microbe-laden synthetic plant water. Sulphide minerals’ mixed potentials and interactions of SEX with sulphide minerals were dramatically reduced in the presence of the mixed microbial community (MMC). The observations were correlated with poor flotation efficacy noted in microflotation tests. These fundamental results shed light on how the adsorption of thiol collectors on sulphide minerals is adversely affected by microbes, prompting a discussion on flotation process monitoring when mineral beneficiation is conducted using microbe-laden water.
8
O’Connor, Cyril, e Tatiana Alexandrova. "The Geological Occurrence, Mineralogy, and Processing by Flotation of Platinum Group Minerals (PGMs) in South Africa and Russia". Minerals 11, n. 1 (7 gennaio 2021): 54. http://dx.doi.org/10.3390/min11010054.
Testo completoAbstract (sommario):
Russia and South Africa are the world’s leading producers of platinum group elements (PGEs). This places them in a unique position regarding the supply of these two key industrial commodities. The purpose of this paper is to provide a comparative high-level overview of aspects of the geological occurrence, mineralogy, and processing by flotation of the platinum group minerals (PGMs) found in each country. A summary of some of the major challenges faced in each country in terms of the concentration of the ores by flotation is presented alongside the opportunities that exist to increase the production of the respective metals. These include the more efficient recovery of minerals such as arsenides and tellurides, the management of siliceous gangue and chromite in the processing of these ores, and, especially in Russia, the development of novel processing routes to recover PGEs from relatively low grade ores occurring in dunites, black shale ores and in vanadium-iron-titanium-sulphide oxide formations.
9
O’Connor, Cyril, e Tatiana Alexandrova. "The Geological Occurrence, Mineralogy, and Processing by Flotation of Platinum Group Minerals (PGMs) in South Africa and Russia". Minerals 11, n. 1 (7 gennaio 2021): 54. http://dx.doi.org/10.3390/min11010054.
Testo completoAbstract (sommario):
Russia and South Africa are the world’s leading producers of platinum group elements (PGEs). This places them in a unique position regarding the supply of these two key industrial commodities. The purpose of this paper is to provide a comparative high-level overview of aspects of the geological occurrence, mineralogy, and processing by flotation of the platinum group minerals (PGMs) found in each country. A summary of some of the major challenges faced in each country in terms of the concentration of the ores by flotation is presented alongside the opportunities that exist to increase the production of the respective metals. These include the more efficient recovery of minerals such as arsenides and tellurides, the management of siliceous gangue and chromite in the processing of these ores, and, especially in Russia, the development of novel processing routes to recover PGEs from relatively low grade ores occurring in dunites, black shale ores and in vanadium-iron-titanium-sulphide oxide formations.
10
Giesekke, E. W., e P. J. Harris. "The role of polyoxyethylene alkyl ethers in apatite flotation at foskor, phalaborwa (South Africa)". Minerals Engineering 7, n. 11 (novembre 1994): 1345–61. http://dx.doi.org/10.1016/0892-6875(94)00075-1.
Testo completoTesi sul tema "Flotation – South Africa"
1
Moore, Bronwyn Ann. "Investigation into the technical feasibility of biological treatment of precious metal refining wastewater". Thesis, Rhodes University, 2013. http://hdl.handle.net/10962/d1002013.
Testo completoAbstract (sommario):
The hydrometallurgical refining of platinum group metals results in large volumes of liquid waste that requires suitable treatment before any disposal can be contemplated. The wastewater streams are characterized by extremes of pH, high inorganic ion content (such as chloride), significant residual metal loads and small amounts of entrained organic compounds. Historically these effluents were housed in evaporation reservoirs, however lack of space and growing water demands have led Anglo Platinum to consider treatment of these effluents. The aim of this study was to investigate whether biological wastewater treatment could produce water suitable for onsite reuse. Bench-scale activated sludge and anaerobic digestion for co-treatment of an acidic refinery waste stream with domestic wastewater were used to give preliminary data. Activated sludge showed better water treatment at lab scale in terms of removal efficiencies of ammonia (approximately 25%, cf. 20% in anaerobic digestion) and COD (70% cf. 43% in digestion) and greater robustness when biomass health was compared. Activated sludge was consequently selected for a pilot plant trial. The pilot plant was operated on-site and performed comparably with the bench-scale system, however challenges in the clarifier design led to losses of biomass and poor effluent quality (suspended solids washout). The pilot plant was unable to alter the pH of the feed, but a two week maturation period resulted in the pH increasing from 5.3 to 7.0. Tests on algal treatment as an alternative or follow-on unit operation to activated sludge showed it not to be a viable process. The activated sludge effluent was assessed for onsite reuse in flotation and it was found that there was no significant difference between its flotation performance and that of the process water currently used, indicating the effluent generated by the biological treatment system can be used successfully for flotation. Flotation is the method whereby minerals refining operations recover minerals of interest from ore through the addition of chemicals and aeration of the ore slurry. Target minerals adhere to the bubbles and can be removed from the process.
2
Von, Holt Sean Thomas. "An investigation into column flotation of South African coals". Master's thesis, University of Cape Town, 1992. http://hdl.handle.net/11427/21992.
Testo completoAbstract (sommario):
Bibliography: pages 245-254.The high efficiency of separation of fine (typically the -150 μm fraction) particles achievable with column flotation technology is well established. The principal aim of this thesis is to investigate whether column flotation can be used to recover saleable, particularly low-ash quality, coal from South African coal fines which are presently discarded. Samples of thickener underflow fines from the Durnacol, Kleinkopje and Greenside Collieries were used in laboratory column testwork. In addition, on-line column trials were performed at the Kleinkopje Colliery. The effects of co 1 umn operating parameters were established using both one-variable-at-a-time testing and fractional factorial design experiments. An investigation into coal slurry conditioning using oil and oil-water dispersions was also undertaken. The results of laboratory and plant column testwork showed that it was possible to recover the desired quality products from all three of the coal fines samples investigated. For all the coals tested, better grades were obtained at any given yield from column cell flotation than with conventional (batch) froth flotation. The test results also demonstrated that the column cell is best suited to recovering and upgrading the finer (< 75 μm) size fractions. Column performance was found to be strongly affected by the petrographic composition of the coal fines feed, i.e. by coal TYPE. Coals with high vitrinite and, conversely, low inertinite contents were found to be the most easily floatable. Depending on the coal TYPE, the rate of mass transport in either the pulp or froth phase was found to be rate limiting; this in turn dictated which operating parameters affected product yields and grades. Existing methods of conditioning coal slurries were found to be inadequate. Considerable scope for improvement in coal conditioning lies in better choice of collector and "promotor" reagents as well as in designing more energetically efficient conditioning vessels.
3
Fickling, Ronald Sidney. "An investigation into the froth flotation of four South African coals". Master's thesis, University of Cape Town, 1985. http://hdl.handle.net/11427/22398.
Testo completoAbstract (sommario):
Bibliography: pages 130-136.Froth flotation is used extensively throughout the world to beneficiate fine (-0,5 mm) coal. However when the same technology is applied to the majority of South African coals it has proved relatively unsuccessful. As the beginning of an ongoing research program, this thesis examines the effects of basic flotation parameters on the beneficiation by flotation, of four South African coals, to identify research areas where a more in-depth investigation is needed. An important conclusion is that South African coals are floatable, and flotation selectivity can be obtained, provided process parameters are controlled within a narrow range. A more in-depth study of the liberation characteristics of the coal and gangue and of the individual macerals is needed because only this will limit the final result. Finally, more research is needed to identify chemicals which exhibit a high degree of specific adsorption on the individual coal components, so that ultimately maceral selectivity can be achieved.
4
Bezuidenhout, Jacques. "An investigation into the role of DTP as a co-collector in the flotation of a South African PGM ore". Master's thesis, University of Cape Town, 2011. http://hdl.handle.net/11427/10119.
Testo completoAbstract (sommario):
The primary aim of this study was to investigate, using a combination of batch flotation and ToF-SIMS experimental techniques, whether a collector-collector synergistic interaction between SIBX and diethyl DTP will result in significantly enhanced copper, nickel, platinum and/or palladium recoveries and grades in a PGM containing ore from South Africa.
5
Moodley, Taswald Llewelyn. "The development of an experimental technique for UG-2 ore flotation". Thesis, 2013. http://hdl.handle.net/10413/11216.
Testo completoAbstract (sommario):
Production of platinum and associated metals is a major source of revenue for South Africa. Significant losses occur in the concentrating stage (10 to 15 per cent) and this research is focused on optimising platinum flotation. Research begins by conducting laboratory batch flotation tests. However, subsequent pilot-plant tests often produce different results. It is believed these differences arise from the artificial nature of laboratory techniques. This project was focused on improving flotation techniques in the laboratory.
The largest source of platinum in South Africa is the UG2 reef and two samples of this ore were used for testing: ‘good’ and ‘bad’ ore. These had different characteristics with regards to the recovery of PGMs and the presence of talc. The latter is an unwanted floatable mineral, which must be depressed to prevent excessive recovery.
The conventional laboratory test procedure makes use of batch tests in various sizes of flotation cells. The procedure was made more realistic, by using four stages of flotation, rather than just two, to mimic a typical platinum flotation plant. The use of four stages made it possible to separate the fast-floating and slow-floating stages and to control froth conditions accordingly. Attention was also given to the fact that in laboratory tests, water is often added to the ‘cleaner’ stage of flotation, to make up the level. Experiments showed that this dilution, which does not take place in practice, had a significant impact on overall efficiency.
A method of measuring frother concentration was developed and used to determine the realistic level of frother in cleaning tests. Tests at these levels of frother concentration showed that significant improvements could be made to plant performance, by making use of a thickener to reduce the frother concentration in the cleaning stages.
The improved test procedure was used on both good and bad ores, and the effect of regrinding was also tested. A combined solids recovery of 2 % over both cleaners was targeted for all test work. At this recovery, the regrinding of the bad ore increased the PGM recovery from 67 to 76 per cent at the cost of an additional 8 g/t depressant.
An investigation of the effect of frother concentration in the cleaning stage, using good ore, demonstrated that that rejection of chromite could be improved significantly by reducing frother concentration. The tests mimicked the use of a thickener to separate some of the water with a high concentration of frother. Tests conducted on the good ore showed that use of two thickeners, as opposed to none, reduced the Cr2O3 content of the final concentrate from 4.2 to 3.2 per cent for the equivalent concentrate mass and PGM recovery. The depressant requirement was also reduced from 67 to 55 g/t. These tests provided insight on how to improve performance on a platinum flotation plant, particularly when floating the bad ore.
6
Pauck, W. J. "Neural network modelling and prediction of the flotation deinking behaviour of complex recycled paper mixes". Thesis, 2011. http://hdl.handle.net/10413/8465.
Testo completoAbstract (sommario):
In the absence of any significant legislation, paper recycling in South Africa has grown
to a respectable recovery rate of 43% in 2008, driven mainly by the major paper
manufacturers. Recently introduced legislation will further boost the recovery rate of
recycled paper. Domestic household waste represents the major remaining source of
recycled paper. This source will introduce greater variability into the paper streams
entering the recycling mills, which will result in greater process variability and operating
difficulties. This process variability manifests itself as lower average brightness or
increased bleaching costs. Deinking plants will require new techniques to adapt to the
increasingly uncertain composition of incoming recycled paper streams. As a
developing country, South Africa is still showing growth in the publication paper and
hygiene paper markets, for which recycled fibre is an important source of raw material.
General deinking conditions pertaining to the South African tissue and newsprint
deinking industry were obtained through field surveys of the local industry and
assessment of the current and future requirements for deinking of differing quality
materials.
A large number of operating parameters ranging from waste mixes, process variables
and process chemical additions, typically affect the recycled paper deinking process.
In this study, typical newsprint and fine paper deinking processes were investigated
using the techniques of experimental design to determine the relative effects of
process chemical additions, pH, pulping and flotation times, pulping and flotation
consistencies and pulping and flotation temperatures on the final deinked pulp
properties.
Samples of recycled newsprint, magazines and fine papers were pulped and deinked
by flotation in the laboratory. Handsheets were formed and the brightness, residual ink
concentration and the yield were measured. It was determined that the type of
recycled paper had the greatest influence on final brightness, followed by bleaching
conditions, flotation cell residence time and flotation consistency. The residual ink
concentration and yield were largely determined by residence time and consistency in
the flotation cell.
The laboratory data generated was used to train artificial neural networks which
described the laboratory data as a multi-dimensional mathematical model. It was found
that regressions of approximately 0.95, 0.84 and 0.72 were obtained for brightness,
residual ink concentration and yield respectively.
Actual process data from three different deinking plants manufacturing seven different
grades of recycled pulp was gathered. The data was aligned to the laboratory
conditions to take into account the different process layouts and efficiencies and to
compensate for the differences between laboratory and plant performance. This data
was used to validate the neural networks and select the models which best described
the overall deinking performances across all of the plants. It was found that the
brightness and residual ink concentration could be predicted in a commercial operation
with correlations in excess of 0.9. Lower correlations of ca. 0.5 were obtained for yield.
It is intended to use the data and models to develop a predictive model to facilitate the
management and optimization of a commercial flotation deinking processes with
respect to waste input and process conditions.Thesis (Ph.D.)-University of KwaZulu-Natal, Durban, 2011.
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Mashamaite, Aubrey Nare. "Electroflocculation of river water using iron and aluminium electrodes". Thesis, 2008. http://hdl.handle.net/10352/269.
Testo completoAbstract (sommario):
M. Tech. (Chemical Engineering, Faculty of Engineering and Technology), Vaal University of Technology.A novel technology in the treatment of river water, which involves an electrochemical treatment technique to produce domestic or drinking water is being investigated using aluminium and iron electrodes in an electrochemical circuit. Coagulation and flocculation are traditional methods for the treatment of polluted water. Electrocoagulation presents a robust novel and innovative alternative in which a sacrificial metal anode treats water electrochemically. This has the major advantage of providing mainly active cations required for coagulation and flocculation, without increasing the salinity of the water. Electrocoagulation is a complex process with a multitude of mechanisms operating synergistically to remove pollutants from the water. A wide variety of opinions exist in the literature for key mechanisms. A lack of a systematic approach has resulted in a myriad of designs for electrocoagulation reactors without due consideration of the complexity of the system. A systematic, holistic approach is required to understand electrocoagulation and its controlling parameters. An electrocoagulation-flotation process has been developed for water treatment. This involved an electrolytic reactor with aluminium and/or iron electrodes. The water to be treated (river water) was subjected to coagulation, by Al(III) and Fe(II) ions dissolved from the electrodes, resulting in floes floating after being captured by hydrogen gas bubbles generated at the cathode surfaces. Apparent current efficiencies for AI and Fe dissolution as aqueous Al(III) and Fe(II) species at pH 6.5 and 7.8 were greater than unity. This was due to additional chemical reactions occurring parallel with electrochemical AI and Fe dissolution: oxygen reduction at anodes and cathodes, and hydrogen evolution at cathodes, resulting in net (i.e. oxidation plus reduction) currents at both anodes and cathodes. Investigation results illustrate the feasibility of ferrous and aluminium ion electrochemical treatment as being a successful method of water treatment. Better results were achieved under conditions of relatively high raw water alkalinity, relatively low raw water turbidity, and when high mixing energy conditions were available.
Libri sul tema "Flotation – South Africa"
1
Jonker, L. The beneficiation of a South African Wollastonite by magnetic separation and flotation. Randburg, South Africa: Council for Mineral Technical Technical, 1987.
Cerca il testo completoAtti di convegni sul tema "Flotation – South Africa"
1
"Bio-Delipidation of Dissolved Air Flotation Pre-Treated Poultry Slaughterhouse Wastewater". In Nov. 19-20 2018 Cape Town (South Africa). Eminent Association of Pioneers, 2018. http://dx.doi.org/10.17758/eares4.eap1118213.
Testo completo
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"The Impact of using Mining Pit Water on Flotation Performance of a Sedimentary Phosphate Ore". In Nov. 18-19, 2019 Johannesburg (South Africa). Eminent Association of Pioneers, 2019. http://dx.doi.org/10.17758/eares8.eap1119246.
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