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By Ray Everson, Henry Kasaini

"Adsorption of Pd (II) anions on the surface of activated carbon (Norit 0.8) occurred at high proton concentration (0.01 – 2.5M, HCl) in the feed and averaged 27 mg/g. The adsorption process was interpreted in terms of surface ionisation and adsorption model. Enthalpy of adsorption averaged 0.4 kJ/mole indicative of an instantaneous physical adsorption process. We found that the Toth isotherm fit the adsorption data fairly accurately. A combination of the Langmuir and Freundlich equations yields an effective three-parameter Toth equation (1) which is frequently used to describe adsorption on heterogeneous surfaces.Figure 1 shows the comparison between experimental results and the model isotherms. We found that Langmuir isotherms underestimated the adsorption capacity on the porous surface while the Freundlich isotherm overestimated adsorption. Furthermore, the surface coverage at equilibrium was well described by both the Langmuir and Toth isotherms. But, Freundlich isotherm predicted a surface fraction coverage that was higher than unit. Based on better prediction of surface coverage and a reasonable fit to adsorption data, we concluded that the Toth isotherm best described the adsorption data of palladium. The adsorption process was limited by mass transfer resistance through the external film. We estimated the rate constant from equation (2), where e, ?b, and rp are porosity, fluid density and particle radius, respectively"

Jan 1, 2003

By B. Rai

Processing of dolomitic phosphate ores remains one of the most challenging problems in phosphate ore beneficiation. The beneficiation plant at Jhamarkotra in Rajasthan, India for example is currently using a conventional double stage flotation process which involves first a fatty acids flotation to produce a combined dolomite-apatite concentrate (bulk concentrate) from associated silicate gangue. Dolomite is then separated from this bulk concentrate by flotation with fatty acids collectors and depressing apatite with phosphoric acid and sulphuric acid. This process requires addition of large dosages of reagents (H3PO4 and H2SO4) to depress apatite and to maintain highly acidic pH during flotation. Furthermore several cleaning and scavenging stages are needed to obtain the product of desired quality. We have developed and employed a molecular modelling based methodology of designing selective reagents for apatite-dolomite separation. We have been able to take into ac-count the differences in the distribution of calcium cations on these two surfaces in our design and hence develop novel phosphonic acid based depressants for apatite-dolomite separation with con-ventional fatty acids as flotation collectors. We have demonstrated the utility and power of molecular modelling based reagents design approach through this work on beneficiation of Jhamarkotra dolomitic phosphate ore using our novel phosphonic acids based depressants at pH?s close to natural pH. It was possible to reduce the MgO content of the ore from as high as 13.3 % to 1.5% in a single stage flotation. Our flotation separation results on Jhamarkotra ore with these new phosphonic acids based tailor-made depressants for apatite-dolomite flotation separation are discussed in this paper along with results of corresponding molecular modelling computations on the same system.

Jan 1, 2014

By F. A. V. Guimarães, A. M. Costa

"The moisture in sintering is a very important parameter for the performance of the process. It allows that the granulation takes pace in an efficient way making the water bridges between the bigger particles used as nucleus and the finer particles that perform the coating of those coarse particles. The formation of the micro pellets is extremely important to prevent loss in permeability of the bed in the sintering grate, avoiding excessive fuel consumption and producing a quality sinter. The aim of this project is to use some of the methodologies for determine the saturation degree on ores and coal to determine the optimal moisture for sintering. In the sinter pot grate series, 3 to 4 assays in a series of 10 are required to determine the optimal moisture for the process. The saturation degree curve test has shown that is really viable to use this technique to skip those tests and go directly to the series to determine productivity and the coke / anthracite consumption. In an industrial scale can be used to adjust the water addition in the conventional mixing methods used in the sintering plants to increase productivity in the process.INTRODUCTION Sintering Sintering is a high temperature agglomeration process in which iron ore fines are partially melted and bonded together using fluxes and a source of fuel, usually coke breeze. The agglomerated product, sinter, has improved metallurgical properties making it an ideal ferrous burden that enable the passage of hot gases in the iron-making blast furnace. The sintering process is normally carried out over three basic stages: granulation, ignition/sintering, and product sizing. In the granulation stage, iron ore fines (usually a blend of selected ores), sinter return fines, fluxes and fuel, and are mixed with water and micro-pelletised in a drum or disc before being introduced in the main granulation circuit. (Wang, Teng, & Wang, 2017)."

Jan 1, 2018

By David G. Hulbert, Daniël J. Oosthuizen, Bernard Muller, Daniël de V. van der Spuy

"OVERVIEWExpert Online is a software system that aims to mimic an informed expert on a minerals processing plant. The primary objective of Expert Online is to provide operators with effective training and on-the-job assistance. Training will mostly be done off-line (e.g. using simulators of the plant), while on-the-job assistance will help the operator during normal operation to run the plant in an effective manner. Although Expert Online focuses on the operator, it is expected to also be of value to other plant personnel, including supervisors and plant managers.Expert Online will make use of novel artificial intelligence technology (developed by MINTEK) known as the Interpreting Expert System (IES). Previously the IES was only able to explain the actions taken by the controller. Expert Online will extend this functionality to also take the process dynamics into account.Expert Online is being developed by a South African consortium comprising MINTEK (focusing on the research and development of the system as a whole), Lonmin (globally one of the biggest platinum producers, with plants suitable to test Expert Online on) and the University of Natal (academic partner, providing consultation and focusing on complex process modelling). The initial application of Expert Online will be on milling- and flotation plants.This paper discusses the structural design of Expert Online for implementation on the latest version of MINTEK’s open control platform, PlantStar, as well as several advances and additions since the previous implementations of the Interpreting Expert System."

Jan 1, 2003

By M. Zolghadri

MIBC and sodium metasilicate are used as a frother and a dispersant in coal flotation respectively. In order to study interaction between them, flotation experiments were performed on fine coal (<150 microns). It was found that if the frother (MIBC) dosage is in excess of a certain limit, it has an activation effect on the gangue minerals associated with coal. In addition, it was found that however sodium metasilicate can disperse clay slimes eliminating slime coating, but in the case of excess dosage, could intensify activation effect of MIBC, which is undesirable in coal flotation. Keywords: coal flotation, sodium silicate, frother, dispersion, activation

Sep 1, 2012

The status of utilization of copper ore resources, and the application and development of biohydrometallury technology in the world is reviewed. Based on the characterization of Zambia?s copper resources, biohydrometallurgy technology is shown to be a practical approach to extract and utilize the enormous low grade copper resource, such as ore tailings and low grade copper ore in this country. Through the cooperation of CSU, China and MMMD, Zambia, ?CNMC-CSU Demonstration Base of Biohydrometallurgy Technology in Zambia? was launched and several biohydrometallurgy plants are being constructed. This indicates that the biohdyrometallurgy technology would be applied soon in Zambia and in the whole Africa. Biohydrometallurgy technology stands as an efficient alternative to the traditional pyrometallurgy process and it can be the key to unlock mineral resources value. Keywords: biohydrometallurgy, low grade copper ore, Zambia, Central South University

Sep 1, 2012

By P. K. Sen, Mrinal K. Ghose

Tailing slurry is usually abrasive and possesses high viscosity. This paper examines the existing iron ore beneficiation process and focuses on some of the key environmental issues related to the disposal of tailings. It identifies that almost 32% of the iron ore extracted ends up as tailings and they are usually disposed in slurry form in tailing ponds. By the year 2000, 27 Mt of iron ore tailings were generated in India, which has become one of the biggest waste handling problems to the industry. Characteristics of the tailings vary widely. So the physical nature of tailings cannot be considered separately in isolation without considering the mill effluent from the beneficiation plant. In the present investigation, studies were carried out in three iron ore mines in India to evaluate the characteristics of tailings from the beneficiation plant. The tailing samples were collected from different locations during a time period of one year and analyzed. The results will be discussed and the characteristics of the tailings have been evaluated. The disposal system of tailings at the three mines was evaluated. The research on the settling characteristics of tailings indicates that the area provided in the existing tailing ponds in India is much more than that of the experimental results. This paper concludes that sedimentation tests are essential to design appropriate tailings pond with respect to size. In the proposed scheme it is suggested that an additional unit process, i.e. sedimentation tank be added to the process before the disposal of tailings to the tailing pond.

Jan 1, 2003

By Hossein Zarei, Masoud Kashani, Mehdi Safari

The feed of flotation unit in Angouran mine, as a part of Iranian Lead and Zinc National Corporation, contains about 34.26% zinc (about 12% Zn sulphide) and 10.14% lead (about 2% Pb sulphide). The grade of Pb and Zn in the final concentrate (rougher+scavenger), under optimal conditions (200 g/ton PEX, 500 g/ton zinc sulfate, 30 g/ton MIBC and pH = 7.5), was 63.18% and 13.01%, respectively, and the total Pb (sulphide-oxide) recovery was about 19% which included 95% Pb sulphide. The grade of Pb and Zn in rougher concentrate step was about 71.86% and 5.97%, respectively, when PEX (Potassium Ethyl Xanthate) was used as collector. While in the presence of PAX (Potassium Amyl Xanthate), the grade of Pb and Zn in rougher concentrate step was 66.8% and 10%, respectively. Tailing of the galena flotation (with 8.48% Pb grade and 34.92% Zn grade under the optimal conditions) was used as a feed for sphalerite and oxide section flotation.

Jan 1, 2014

By R. S. Wang, S. Z. Zhou, L. Wan, K. W. Zeng, Z. J. Sun, W. G. Wu, Z. B. Qian, X. R. Zhang, Z. K. Hu, Y. Yu

"In view of the present situation that the traditional environment friendly depressants for galena aren’t very effective in the separation of mixed concentrate including copper sulfide and lead sulfide, this research describes a new environment friendly depressant PD-1 and investigates its effects and mechanism in the separation of chalcopyrite and galena. This study is carried out through flotation tests, analysis of infrared spectra and absorption measurements. It is shown that when O-isopropyl-N-ethyl thionocarbamate (Z200) is used as collector, chalcopyrite and galena can be separated in the presence of PD-1 under appropriate conditions. Therefore, it can be concluded that PD-1 has an excellent depression ability and great selectivity for galena. Meanwhile, analysis of infrared spectra demonstrates that PD-1 can strongly absorb on the galena surface by chemical interaction with Pb2+, while it hardly absorbs on the chalcopyrite surface. In addition, the results of absorption measurements reveal that competitive adsorption occurs on the galena surface between PD-1 and Z200, PD-1 can block the absorption of Z200 on the galena surface. However, PD-1 has a little effect on the absorption of Z200 on the chalcopyrite surface under above conditions. What’s more, the hydrophilic groups of PD-1 molecules can make galena effectively depressed. The results of mechanism analysis are in accordance with those of flotation tests.INTRODUCTION In the processing of copper-lead sulfide ores, the process, copper increase and lead reduction (Zhang et al., 2017) after reagents removal of rough concentrate produced by mixed flotation of chalcopyrite and galena, is usually adopted. However, as a result of tight symbiosis and the similar flotability of chalcopyrite and galena, the separation is difficult (Hu and Feng, 2006). There are 3 kinds of depressants for galena in the separation of chalcopyrite and galena concentrate,including dichromate, sulfite and combined depressants of organic or inorganic reagents (Wei, 2012). As dichromate would cause serious environmental pollution, it is gradually banned to be used in industry (Xu et al., 2017; Lin et al., 2017). what’s more, due to the need of acidic slurry, using sulfite is not conductive to the maintenance of equipment and stable production(Wang, 1999). As for the combined depressants, they also have disadvantages of complex pharmaceutical system and no ideal separation effect (Wei and Sun, 2008). Therefore, the development of new safe and effective depressants for galena is a research focus for researchers in the minerals processing (Chen, 2000). In this paper, a new type of organic depressant PD-1 is applied to the copper-lead separation process of ""copper increase and lead reduction"" using Z200 as the collector. In addition, the performances and mechanism of its depression to galena are studied emphatically."

Jan 1, 2018

By Xuliang Yang, Yuemin Zhao, Bo Zhang, Liang Dong, Cheng Sheng, Gongmin Li, Zhenfu Luo, Yaqun He, Chenlong Duan

Coal plays an important role in the primary energy consumption of all over the world. In 2012, coal reached the highest share (29.9%) of global primary energy consumption since 1970. Coal burning mainly contributes to the emission of SO2, NOX, Hg and other impurities that jeopardize the future of environment. . Beneficiation before coal utilization is the most economical and effective technology for removing the hazardous material and gangue. In this paper, a novel process of dry beneficiation based on gas-solid two-phase flow composed of the compound dry cleaning separator (FGX), the air dense medium fluidized bed separator (ADMFB) and the vibrated fluidized bed with autogenous medium (VFB) is proposed. The main equipment and the flowsheet of the united system are described in detail. Separating principle of the FGX, ADMFB and VFB devices are all based on gas-solid two-phase flow. In FGX, gassolid suspension is composed of continuous gas flow and coal powder in feed coal. Large size coal (+6- 80mm) can be pre-separated effectively, and large size gangue can be removed effectively. Moreover, - 6mm particles fed serve as autogenous medium in FGX. The probable E value is 0.13 for -80 mm raw coal. In ADMFB, magnetic powder with -0.3 + 0.045 mm size fraction and coal powder in feed coal are compound medium solids. The separation density can be adjusted and controlled according to properties of raw coal. -50 + 6 mm raw coal can be cleaned efficiently, the probable E value is 0.05. In VFB, -6 + 1 mm coal can be separated. Generally, -80 mm raw coal can be cleaned efficiently in the united system based on gas-solid two-phase flow.

Jan 1, 2014

By Vladko Panayotov, Marinela Panayotova

"Recently, in order to extract metals, the industry is trying to process old metallurgical slag. The material requires very fine grinding that results in enhanced slime-formation. This in turn leads to problems in the course of the flotation process and to a loss of metal. In addition, it causes difficulties in the wastewater treatment aimed at water reuse. The aggregation and separation of the fine particles and their further subjecting to mineral processing would result in more efficient use of raw materials. Closing the water cycle also would be facilitated. The paper presents results from studying sixteen flocculation reagents, commercially available for treating municipal wastewater, including products based on nanotechnology, for their ability to rend the production wastewater in suitable for reuse in the flotation. It turned out that, from all studied reagents, the cationic C-587 is suitable for the purpose. Some of reagents were studied for their ability to flocculate selectively, in presence of coke fines, rich in copper fines which are produced at grinding of a slag from lead-zinc metallurgy. Most promising reagents are chosen, based on the chemical analysis of the flocculated materials. Open-cycle rough copper flotation experiments with the flocculated fines and recycled wastewater gave encouraging results."

Jan 1, 2014

By Evgeni Visariev

In Copper smelter Aurubis Bulgaria, the copper in slag from the Flash furnace and the Converters is recovered by flotation. The scheme of slag processing is crushing, two stage grinding (autogenous and ball) and flotation. Till 2010 the grinding cycle in the plant was in two stages ? the first stage was AG Mill 70?23 working with a classifier and the second stage was ball mill 3.6/5.5 working with a hydrocyclone. In 2010 a new AG Mill 65x78 with hydrocyclone was put in operation in order to increase throughput of the plant. The second stage of the grinding cycle is with the same ball mill. The Old AG mill processed 55-60 t/h slag with particle size -0.071 mm 75% or over 75 t/h with particle size -0.071 mm 35-40 %. The new AG Mill was designed for throughput 105 t/h with particle size -0.071 mm over 70 %. After the start up there were some problems with the equipment ? block up of AG Mill?s grate and pumps for feeding of the hydrocyclone. For optimization of the process a lot of general tests were made. One of the main problem was a wearing of the sand nozzles. Different materials (rubber, ceramic, metallic) for the sand nozzles were tested. The openings of the grate were changed. This paper presents: ? the optimal technological parameters of the old and the new working scheme; ? how the technological parameters of the new working scheme change when the hydrocyclone works with different nozzles; ? the effect of the change of the grate openings; ? the problems with the increase of the circulating load; ? a final decisions for improvement of the grinding cycle work. Keywords: spigot, wearing, classification, effectiveness, circulating load, autogenous, mill

Sep 1, 2012

By Gábor Mucsi, József Faitli, Imre Gombköto, Sanjay Kumar, Zoltán Molnár, Balázs Ráczkevi, Ádám Rácz

"Generally, fly ash particles are very fine (< 100 ?m), mainly spherical and glassy materials form an outer shell on it. This paper deals with the laboratory investigation of ground fly ash based geopolymer. This material can be applied in many fields, mainly in the construction industry, e.g. non-structural elements, concrete, pavements and products, containment and immobilization of toxic, hazardous and radioactive wastes, advanced structural tooling and refractory ceramics, and fire resistant composites used in buildings, etc. The preparation of fly ash using high energy density milling is presented. Systematic experimental series were carried out in order to optimize the preparation process. The particle size distribution (LPSA) and structure of fly ash (FTIR) and the uniaxial compressive strength ,the permeability and structure of geopolymer product, furthermore the rheology of geopolymer paste were investigated. The product properties were studied as a function of the fly ash fineness. As a result of the investigation the relationship between the grinding circumstances, the ground material properties and the geopolymer characteristics was identified. It was found that the above mentioned physical properties of the geopolymer strongly depend on the grinding process."

Jan 1, 2014

By Klaus M. Hahn, Kurt Aasly, Jutta Lennartz, Hermann Wotruba, Ben Snook, Przemyslaw B. Kowalczuk, Rolf Arne Kleiv

"Seafloor massive sulphide (SMS) deposits have been identified as important marine metal resources for the future. However, literature on mineral processing of SMS is currently limited, and to date, no research has been published on processing of SMS from either active or inactive hydrothermal vent fields on the Arctic Mid-Ocean Ridge. In this paper, individual SMS rock samples from the Loki’s Castle area were tested. Chalcopyrite, isocubanite and sphalerite represented the main copper and zinc bearing minerals in the SMS samples, whereas the gangue consisted of barite and silica. Based on the X-ray transmission response (XRT), i.e. differences in the atomic number of elements in tested samples, and using portable XRF (PXRF) values of elemental composition, individual particles were classified as a either product (low barium / high to low silicon / high copper and zinc) or waste (high barium / high silicon / low copper and zinc). The classification was based on the elemental composition of the samples with the cut-off grade equal to 0.5% for copper. It was shown that the XRT discrimination analysis correlated well with elemental (PXRF) data classification. The results clearly indicate that X-ray transmission sensor-based sorting can be used a useful technique for preconcentration of SMS rock samples. INTRODUCTION Due to different compositions of investigated samples, sensor-based sorting is a useful technique for preconcentration of different materials. The aim of using sensor-based sorting is to upgrade an ore by reducing the quantity of overall waste material reporting to the next processing stage. This can be achieved by eliminating (reducing) the waste fraction. By applying sensor-based sorting, the energy consumption for particle comminution as well as the required process water and reagents can be decreased. The total volume of the waste rejection leads to a proportional reduction in the total energy costs (Lessard et al., 2014, 2016)."

Jan 1, 2018

Coal preparation plants usually operate with water in a closed circuit mode. In this practice, large quantities of water is continuously being recycled. To compensate the natural losses, only small quantity of fresh make up water is added into the circuit. As a result, a gradual build up of residual concentrations of flotation reagents (frothers, collectors, coagulates etc.) take place in the water and the concentration levels of the contaminants increase. Besides, the recycled water accumulates higher amounts of total dissolved components (1600 ppm) and hardness (740 ppm) than the fresh water. Nearly 80 ? 85% of the process water used in a coal preparation plant is utilized in treating the coal fines in flotation circuit. The presence of certain alkali earth metal ions (e.g., Ca++, Mg++) may adversely affect the flotation performance as they precipitate sparingly soluble hydroxyl complexes on the coal surface and change its surface charge. These studies showed that the use of recycled water in flotation has a significant effect on the selectivity and kinetics of the flotation process because, the dissolved compounds, both inorganic and organic, alter the chemistry radically. By treating the recycled water through a softening process, the concentrations of alkali earth metals and hardness were reduced significantly. The concentration of alkali earth metals and hardness were reduced to 10 ppm and 35 ppm respectively in the softened recycle water. From the selectivity studies, it has been observed that the flotation yield and recoveries increased by four to seven units by softening the recycled water. The kinetic studies indicated that the clean coal particles followed first-order kinetics. The kinetic parameters namely, flotation rate constant (k) and maximum recoveries (R8) of flotation, were found higher with softened recycle water than the recycled water. This reduces the residence time in the flotation cell and thereby, increases its productivity. Keywords: coal flotation, hardness of water, water chemistry, softening process, selectivity, kinetics, flotation rate constant and maximum recovery

Sep 1, 2012

By T. M. Bhatti

The main purpose of present study was to characterize the dissolution of uranium from low-grade black shale with indigenous isolated strain of Acidithiobacillus ferrooxidans (BSAF-01). The nature of shale is quartzite-schistose and contains uranium content of 0.005% U3O8 (50 ppm U3O8). Uranium is present in the tetravalent oxidation state (U4+) in the shale matrix. The main minerals identified are graphite, quartz, pyrite, mica minerals (phlogopite, biotite, sericite, and chlorite), microcline, K-feldspar and kerogen (hydrocarbon-compounds). Bacterial oxidation of pyrite was an acid-generating system and produced sulfuric acid and ferric sulfate during this biological phenomenon. A series of bioleaching experiments were conducted in shake flasks for leaching of uranium from black shale. The leaching experiments were performed at 50% pulp density using indigenous Fe- and S-oxidizing bacterium (Acidithiobacillus ferrooxidans). Bioleaching data revealed that about 90% ~ 95% U3O8 was leached out from black shale ore. Uranium dissolution from shale depends on pH (pH 1.5~1.9), redox potential (=500 mev) and the concentration of Fe2+ and Fe3+ ions in the leaching environment. The oxidative leaching of U4+ involves a redox reaction with Fe3+ as an oxidant and bacterial re-oxidation of Fe2+ in acidic leaching environment. Uranium leaching efficiency was attributed to the sulfuric acid and ferric sulfate production during bacterial oxidation of pyrite.

Jan 1, 2014

By Remmerswaal, U. Boin, M. B. G. Castro

"To design sustainable products that can be recycled with high resource efficiency, low environmental impact and economic feasibility, the choice of materials and materials combinations, made in the design stage, is fundamental. The products we design, manufacture and use now will be the resources of the future. Designers are able to select materials for a product according to the many functional requirements they must fulfil. But they have a limited knowledge of the recycling processes and its requirements regarding quality of the secondary material streams. Resource Engineers have to manage the processing of these streams, that are becoming more complex with the increasing variety of materials and decreasing size of components. After mechanical separation of the materials streams resulting from shredding of EOL (endof- life) products, there is always a degree of contamination, from two possible causes:Incomplete liberation: the bonds between different materials combined in a component are not completely destroyed by shredding, resulting in some particles containing two or more materials attached;Separation efficiency: the mechanical separation processes are not able to separate perfectly the many material particles; there are always a number of foreign particles in the recovered streams.Sometimes, those contaminants cannot be removed by the industrial metallurgic recycling processes, and a more serious problem occurs when the contamination levels compromise the recycling of the material stream by lowering its quality (i.e. the properties of the recycled material will be lower due to the contamination). As a consequence, the material must be diluted in virgin raw material and/or used in a less demanding application (downgrading), causing resource depletion and increased energy use, waste production and recycling costs. In order to make the best choice of materials combinations for a product, a systematic approach is necessary, that can close the gap between the knowledge areas of Product Design and Recycling Technology."

Jan 1, 2003

By Zehong Wang

Selecting sodium polyacrylate (PAAS) as grinding aid, the effect of grinding aid on the grinding efficiency of bauxite taken from Shanxi province was studied and its mechanisms were analyzed by measuring the variation of adsorption characteristic, pulp viscosity, surface electric potential of the bauxite and the surface appearance of particles. The results showed that, compared with no grinding aids added the content of -0.074mm in the ground product was increased by 5.45 percentage points under the optimal grinding conditions adding PAAS as grinding aid when the amount of PAAS was 0.7%wt of bauxite. Because the physical adsorption and chemical adsorption were occurred on the bauxite surface, which could reduce the pulp viscosity, change the surface electric potential of the bauxite, enhance the surface appearance of particles and lower the surface hardness of the bauxite, the grinding efficiency of bauxite was increased by PAAS. Keywords: bauxite, grinding aids, grinding efficiency, mechanism

Sep 1, 2012

This study examines the surface alteration and flotation behaviour of synthetic moncheite, PtPd(BiTe)2, in the presence of pentlandite. The telluride minerals contribute around 20% ~ 30% and up to 45% of the PGM present in the Platreef ore and are considered to be slow floating as there is evidence of these minerals reporting to the tailings. It was proposed that oxidation products from other minerals and grinding media would affect the mineral surface composition and floatability thereby causing inadvertent depression of moncheite due to precipitating ions. ToF-SIMS analyses (time of flight secondary ion mass spectrometry) was used to characterise the mineral surface as well as the extent of surface alteration. Microflotation was used to deter-mine the hydrophobicity of the synthetic minerals. Conditioning of moncheite in the presence of pentlandite reduced the flotation response of the + 38 -106µm size fraction from > 99% to 56%. This was due to pentlandite dissolution products (iron and nickel hydroxy species) which formed overlayers on the mineral surfaces thereby inhibiting the adsorption of collector. In addition, further grinding of these samples, with and without pentlandite conditioning showed a negative effect on recovery due to the fineness of the particle size distribution and there was no advantage gained from any possible exposure of fresh sites in the sample.

Jan 1, 2014

By O. D. Khmelnitskaya

The research on selecting of an efficient technology of pyrite cinders complex treatment, sulfuric acid production wastes, have been made. The grades in the initial product were 2.04 g Au/t, 35.0 g Ag /t, 0.38%Cu, 1.1% Zn. Laboratory tests on cyanide technology, thiourea and sulphite leaching were carried out. Magnetic and flotation beneficiation and biohydrometallurgical technology were tested. After considering the results of the tests, the most economically efficient technology of pyrite cinders complex treatment with cyanide leaching of precious metals was determined. The technology involves water washing of soluble copper and zinc compounds, lime treatment and cyanide leaching of gold and silver, detoxification and utilization of mineral wastes. The precious metals are recovered from solutions by cementation onto zinc. Copper is recovered from rinse waters by SW/EW and then zinc is precipitated as hydroxide. All the solutions and organic agent are used in recirculation and therefore the technology is practically waste-free. Mineral wastes can be used as iron-containing materials for cement industry. The technology has been tested in pilot-plant scale under continuous operation with complete re-circulation of cyanide solutions. In this process recovery of 54% Au, 45% Ag, 30% Cu and 50% Zn has been achieved.

Jan 1, 2014