Search Documents

By V. V. Lodeischikov

This paper covers some problems of treatment of complex gold ores and concentrates containing copper, lead, zinc, antimony and uranium. All these metals may present in ores both as major and associated components. The paper suggests recommendations for early determination of relative value of the metals in ores, which largely contribute to the selection of concentration and metallurgical flow sheets. The focus of this work is on treatment of complex ores in gold plants. The metal extraction technologies used by such gold plants are typically aimed at maximum gold recovery. Therefore, production of base metals as by-products requires significant updating of the existing process flow sheets based on economic, environmental and other considerations. At the same time, cooperation between gold plants and base-metal plants is of great importance. This paper provides an overview of worldwide existing and innovative processes of base metals extraction from complex and refractory gold ores.

Jan 1, 2014

By S. Narra, M. Nelles, I. Eickhoff, S. Teitge

"The aim of the research is to develop a holistic process flow for the recycling of glass fibres from glass reinforced plastics (GRP) and carbon fibres from carbon fibre reinforced plastics (CFRP), wherein the dissolution of the fibre epoxy resin matrix, separation of fibre fractions and their renewed material use is intended. In clear distinction to the previous research and development projects, the aim here is to recycle complex composite structures such as dismantled/disused wind turbine rotor blades and end-of-life composite wastes. In the course of the study, mechanical, hydrothermal and thermal processes and their combined procedures will be developed. As the fibre length is a decisive quality criterion in the recycling of composite materials, the further focus of the study will be the development of upstream and downstream material processing, in which the fibres are retained in their original form. The evaluation of the recycled fibres obtained is based on the elemental composition, measurement and morphological evaluation of individual filaments by scanning electron microscope (SEM), micro tensile tests on single fibres and their comparison to virgin fibres. The resulting process water is analysed by gas chromatography and mass spectroscopy (GC-MS) and a potential recirculation is determined. In cooperation with companies from the composite processing industry as well as recycling companies, a return of the recycled fibres to the known manufacturing process will be examined and an energetic and economic evaluation of the overall process will be carried out. Ambitious aim of the study is to achieve an actual recycling instead of the present downcycling or the energetic utilization. INTRODUCTION As global warming increases, so does the awareness of consumption and production of energy. To counteract the effects of global warming, renewable energy has been increasingly used during the last two decades, not only in Germany, but worldwide. Both, hydropower and wind energy, hereby play a fundamental role. After the end of their useful life of 20 to 30 years, the wind turbines (WTs) are being dismantled. Due to their foundations and tower segments, their recycling rate hereby exceeds 90% by mass. So far, the resulting rotor blade waste played a minor role accounting for only 2 - 3 weight-% of the total plant. Rotor blades of modern wind turbines are made of glass and carbon fibers, which are embedded in an epoxy or polyester resin matrix, balsa wood, PU or PET foams as fillers as well as various paints and coatings. These wastes currently end up in waste incineration or are sold to non-European countries."

Jan 1, 2018

By M. I. Panayotova

Some of effluents released by copper smelting plants are highly acidic (pH = 0~1) and contain arsenic and copper in relatively high concentrations (10~20 g/L). Usually arsenic is removed by precipitation with different reagents, such as lime, iron salts, calcium salts, aluminium salts, etc. Precipitates (often voluminous) that require further handling are formed and copper and other valuable components are lost. A method is presented for copper and arsenic extraction from acidic effluents. Effluents are treated in specially designed closed electrochemical cell without chemicals? addition. Gases formed are collected and treated for decomposing the eventual traces of As-bearing compounds and ensuring the environment protection. Initially copper of grade of 85 % is electro-won. Further about half of the initially available arsenic is separated as low-soluble, low volume mixture of intermetallic compounds, oxides and some elemental arsenic. At the next stage the main part of the left arsenic is immobilized as low soluble stable compound. Arsenic content in the treated acid is in the range 0.20~0.25 g/L. Acidity of treated effluent after first two stages remains practically unchanged and the solution can be re-used. Physicochemical and electrochemical processes, governing copper and arsenic removal, are discussed.

Jan 1, 2014

By A. V. Abshilawa, D. G. Talakhadze, R. I. Sturua

"Processing of the tailings accumulated over the lifetime of Madneuli Copper Concentrator is an opportunity to extract additional salable copper and gold products. This paper presents a pre-concentration process for the valuable components (copper and gold) of the accumulated tailings. The developed process makes it possible to obtain a copper pyrite concentrate with a yield of 14.05%, copper grade of 1.36%, and recovery of 83.22% containing 3.78 g/ton of gold at a recovery of 84.31%. The bulk concentrate is produced by a combined process bringing together selective flotation to produce salable copper concentrate and hydrometallurgical processing of the selective flotation tailings to recover gold. KEYWORDS: FLOTATION, ALBION PROCESS, LEACHING, COPPER CONCENTRATE, SELECTION Madneuli Copper Concentrator, Georgia, was put into operation in 1975. Over its lifetime, 40 mn tons of tailings have been accumulated at the tailings storage facility (TSF). Sampling of the TSF has indicated that the average copper and gold grade is 0.23% and 0.56-0.65 g/ton, respectively. Accordingly, the TSF can be classified as a technogenic reserve. This paper discusses pre-concentration of valuable components using flotation, followed by processing of the bulk concentrate in the Albion process. Mineralogical analysis of the accumulated tailings showed that the main ore mineral is pyrite (11.71%). Copper minerals are mainly represented by chalcopyrite (0.7%). The main nonmetallic mineral is quartz (67.3%); sericite, chlorites, etc. also occur. Pyrite is present both as liberated grains and intergrowth. The absolute majority of copper minerals are found as intergrowth with pyrite, less often with quartz. Ore minerals are slightly oxidized. Chemical analysis results are shown in Table 1. Particle size distribution shows that the size class -0.2 mm - 0.045 mm has the highest grade of 0.85 to 0.97 g/ton of gold. Size class +1.25 mm has the lowest grade. Based on the chemical and mineralogical studies and particle size distribution, an optimized process was developed for pre-concentration of the valuable components prior to hydrometallurgical processing. Several gravitation, direct selective, bulk, and bulk selective flotation processes were trialed. (1,2)"

Jan 1, 2018

By Vasily V. Lodeischikov, Adolf F. Panchenko, Olga D. Khmelnitskaya, Vladimir E. Dementyev

Pilot plant tests of underground gold leaching from Maminskoye deposit oxide ores at a grade of 0,7 g/t Au were carried out. The underground leaching flow sheet includes Au dissolution by chlorine-containing solutions, Au adsorption from solution on active carbon, carbon concentrate ashing and calcine melting to produce high grade gold concentrate. The underground leaching system throughput was 15 m3 of solution per hour. Gold concentration in pregnant solutions was 0.12-0.13 mg/l. Gold recovery from solutions into carbon was in the range of 63-84%. It was demonstrated that the low Au recovery in the adsorption cycle was due to the presence in pregnant solutions of "active" chlorine, which destroys active carbon and causes a sharp decrease of the carbon loading capacity for gold. To improve the adsorption indices, previously dechlorinated pregnant solutions using bituminous coal or Na2S2O3, is recommended. Ion exchange process was tested as an alternative for gold extraction from dechlorinated solutions. In the testwork period, 4.4 kg of gold were produced with a chlorine consumption of 3.5 kg per 1 g of gold. During the tests a program of environmental protection measures was completed to provide the necessary safety precautions of the underground leaching works.

Jan 1, 2003

By S. V. Balikov

A close association of fine gold with pyrite and arsenopyrite is observed at many gold ore deposits. Gold forms and gold distribution in sulfides of different deposits were studied. A comprehensive method including optical spectrum analysis, X-ray diffraction analysis, high-temperature X-ray diffraction analysis, scanning electron microscopy and X-ray microanalysis was used for the de-tailed investigation of the defectiveness of the structure of pyrites from different deposits. It was shown that gold content in pyrites varied from 1.5 g/t to 100 g/t compared with 30 g/t to 230 g/t in arsenopyrites. The nature and arrangement of inner inclusions of foreign minerals in pyrites as well as occurrence of fractures and macro- and microdefects were examined. Iron, sulfur and arsenic contents in all pyrite samples were determined. Chemical composition of the detected inclusions was defined. Parameters of submicroscopic structure of pyrite were estimated using X-ray Fourier line shape analysis. Estimation of real structure characteristics with calculation of submicroscopic D-blocks and root-mean-square lattice deformation 2()evalues was performed. Defectiveness of the pyrite structure can be defined by the following parameters: K?1 and K?2 reflection resolution and its intensity within high Bragg angles; S content to Fe content ratio; the arsenic content and the local variation in its concentration within the pyrite grain; the size of submicroscopic blocks and the crystal lattice disturbance value. The performed analysis showed some relationships between these parameters and refractoriness of the pyrite concentrates. It was observed that at S/Fe ratio close to or higher than stoichiometry and at a low arsenic content (less than one per cent) pyrite concentrates were not refractory. The analysis results showed that concentrates of the Beryozovskaya gold plant (0.02~0.07 As%) and concentrates of the Kommunarovskaya gold plant (less than 0.05 As%) as well as some pyrites from the Sukhoi Log gold deposit had the same characteristics. It was found that average arsenic content did not excess 0.2 per cent. Arsenic distribution within the grain of all these pyrites was uniform. At S/Fe ratio lower than or close to stoichiometry and at high arsenic content (more than one per cent) and significant variation in its distribution within a pyrite grain the pyrite concentrates are refractory. Such pyrites are typical for the Sukhoi Log, the Bakyrchik and the Mardzhanbulak gold deposits. Direct correlation between arsenic and gold contents, in particular, in fine grains of pyrite was observed by many researches. This correlation was explained by impregnation of arsenopyrite which normally contains more gold than arsenic pyrites. The analyses results showed that no arsenopyrite impregnation was found: arsenic distribution within the grain was uniform but its concentration varied greatly. Such pyrite concentrates are more refractory. This paper presents the results of analyses of sulfides to determine the amenability of the associated gold recovery by hydro- and pyrometallurgy.

Jan 1, 2014

By Irena Grigorova

"Vermiculite is a naturally occurring mineral compound composed of shiny flakes, resembling mica. Worldwide, vermiculite has been used in various industries since 1920. When heated to a high temperature, flakes of vermiculite expand several times their original size. The expanded vermiculite is a lightweight, fire-resistant, absorbent, and odorless material. These properties allow vermiculite to be used to make numerous products, as an additive, for example to potting soil, in agricultural, construction, horticultural and industrial applications, including pesticides, insulation, potting mixes, brake pads, sound deadening materials, fire protection, paints, sealants, insulating concrete and etc. Over recent years researchers have been looking for effective economic and environmental methods and solutions for fine technological waste utilization. As a result of vermiculite ore processing large quantities of fine waste dust are formed. Until now there has been no application for this waste product. Currently this waste product is stockpiled using valuable land space, and is a potential contaminant. The paper presents the results of a study on the possibility to obtain briquettes from fine vermiculite by-product. The particle size distributions, chemical and mineralogical compositions of vermiculite were determined. It was established that consolidation of vermiculite dust by methods of briquetting and its consequent application in agriculture as meliorants for physico-chemical treatment, improves soils aeration structure and properties."

Jan 1, 2014

By C. Çelik

Nowadays the optical sorting of industrial minerals is one of the most important processing methods which has cost efficient production possibilities. This method is used for industrial and raw materials that have different colour and brightness features. Initially this technology is used for sorting of foodstuffs and recovered glass, but for a long time also as physical mineral processing method for both industrial minerals like: limestone, marble, talc, basalt, flint, quartz and secondary raw materials like: building rubble, refractory materials, glass, plastic and household waste. In this study via optical sorting the separation of quartz out of a flint mix, which consists of the particles with different colors and brightness, is aimed. Experiments are performed on an optical sorting machine named CombiSense® 1200 at the institute of ?Aufbereitung mineralischer Rohs-toffe? RWTH Aachen. This automatic picking device was developed by the company ?Separation Systems Engineering (SSE), Wedel?. Hand picking method is used for product analysis and the efficiency tables are prepared on every step accordingly. This process enables to reach quartz products with purity up to 100%.

Jan 1, 2014

By I. A. Agapov, I. S. Anisimov, N. V. Rylov, A. M. Sagitova

"The smelter slags represented silicate crystalline rock with medium to coarse-grained structure with spinifex skeletal network of olivine in hedenbergite matrix. Accessory magnetite, pyrrhotite and copper sulfides chalcopyrite, bornite, covellite, chalcocite and digenite occurred in dissemination in silicate matrix. The sample was studied by optical and electron microscopy with support of quantitative XRD. Modal mineralogical composition included olivine, pyroxene, magnetite, chalcopyrite, quartz, pyrrhotite. Copper deportment showed copper distributed in chalcopyrite (40 %), cuprite (22 %), covellite (21 %), bornite, chalcocite, digenite (5 %), Cu-bearing pyrrhotite (4 %) and spinel (2%). Liberation of copper minerals in the material ground to P80=71 µm was good with over 90 % sulfides in free grains and floatable binaries. The results showed theoretical possibility of 65 % copper recovery by flotation. Conclusion based on mineralogical data was precisely confirmed with flotation tests studies that proved to recover around 60 % of copper to commercial grade concentrate. INTRODUCTION Annual world copper matte smelter slags production is estimated to be millions of tones and contain thousands tones of unrecovered Cu, Zn and significant amounts of Ag and Au. Mineralogical study of one large processing sample of material of historical piles of Cu matte smelter slag was carried out to find possibility to recover copper and define theoretical recovery by flotation. The study of the slag material was aimed to determine possibility of upgrading the material on existing copper flotation plant to develop additional mineral resources. The objectives for mineralogical investigation were to target for best liberation fineness, determine theoretical recovery and possible concentrate quality for sulfide flotation tests. MATERIALS AND METHODS Large representative processing sample was collected by mixing of 120 t of slag material representatively excavated from historical piles of Cu matte smelter slag. The sample was used to define the processing technology to recover copper and gold from the material."

Jan 1, 2018

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 R. V. Kononko, A. Yu. Chikin, R. N. Rakhmeev, Yu. O. Fedorov

"The focus of the study is finding a solution that can help to improve diamond recovery in diamond-bearing gravity concentrates upgrading flowsheets. The purpose of the study was to develop and prove scientifically a separation method of diamonds recovery from gravity concentrates regardless of their fluorescence ability induced by X-ray radiation. Two promising recovery methods applicable to diamonds of this type are proposed, i.e. an X-ray radiometric method based on an instantaneous analysis of a secondary X-ray spectrum of separated particles, and a triboelectric method that relies on noncontact measurements of particle charges obtained during its motion in a vibratory tray. As a part of the laboratory study, X-ray fluorescence spectra of the collection of diamond crystals and main associated minerals and rocks at a particle size of -6+3 mm were produced. The analysis of the produced secondary X-ray spectra showed a significant difference between crystals, minerals and rocks within the analytical area of Ca, Fe and Zr due to the absence of calcium, iron and zircon elements in diamonds. Additionally, the scattered X-radiation level of diamonds substantially increased under the influence of X-ray radiation. Such a difference is a physical base of a new method of diamonds recovery from mineral mixtures. The laboratory study on triboelectric characteristics showed that a significant portion of diamonds gained an electric charge of a magnitude that was much higher, compared to associated minerals and rocks. The laboratory and industrial tests and the separation indicators demonstrated a high efficiency. A proposed X-ray radiometric method provides recovery of all types of diamonds regardless of X-ray fluorescence levels, with high selectivity and recovery rate of at least 98%. This proposed separation method is protected by a patent of Russian Federation (No. 2551486, “A method of X-ray radiometric separation of diamond-bearing materials”). Triboelectric separation organized in two stages (main and control) ensures recovery of up to 98-100% of diamonds at a particle size -5+2 and -2+1 mm,. More than 10 triboelectric separators successfully operate in active diamond processing plants in the Russian Federation."

Jan 1, 2018

By Alban Lynch, Benigno Aquino, Hakan Dündar, Alexander Kalugin, Marco Delgado, Alberto Palomino, Ali Türkistanli

Dynamic separators are efficient dry classifiers because new designs during the last 50 years have reduced the by-pass and improved the partition curve. By contrast cyclones have been used as classifiers in wet grinding circuits for 50 years but without serious change and the early problems which were caused by high and variable by-pass, and different mineral specific gravities, still exist. High frequency screens are now used for wet separation and the operating characteristics of closed grinding circuits using cyclones or screens are discussed. Data come from circuits at the Condestable, Cerro Lindo, El Brocal and Catalina Huanca mines in Peru, the Eczacibasi mine in Turkey, and the Apatit mine in central Kola Peninsula in Russia. All classifier data are described by their partition curves and all mill data by their breakage rates. With cyclones the by-pass, d50, and sharpness of the partition curve change as operating conditions change but with high frequency screens the values vary little because the by-pass is low, the sharpness is high, and d50 depends on the aperture size. Data from all plants indicate that lower by-pass and sharper separation improve breakage rates and throughputs. An initial model of the screen is proposed.

Jan 1, 2014

By Buks Kruger

"After the milling and flotation of the platinum bearing ore, the flotation concentrate is electrically smelted in 6-in-line electric arc furnaces and the resulting furnace matte treated in Peirce Smith converters to remove the iron sulphide. The iron free (less than 1% Fe) converter matte is then granulated and sent to the Base Metals- and Precious Metals Refineries for further processing.During the smelting and converting processes two distinct gas streams are produced.The Peirce Smith converter off gas contains 4% - 9% SO2 which is treated in a conventional Sulphuric Acid Plant to produce sulphuric acid (H2SO4).The electric furnace off gas contains 0.9% SO2 and was (until September 2002) vented through a 91 meter high stack to atmosphere.Off gasses which contain less than 3% SO2 is difficult to handle and quite a few processes had been developed over the years to cope with this gas. A broad spectrum of process suppliers and technology approaches is available and the different technologies can be divided into a few main approaches i.e.Scrubbing of the off gas with an alkaline solution to produce an environmentally friendly and stable waste product which can be discharged onto a tailings dam or permanent landfill site.Physical absorption of the SO2 into a chemical solution to produce high quality chemically pure process chemicals.Catalytic reaction of SO2 with O2 to produce SO3 which is absorbed in water to produce sulphuric acid of less than 90% strength.In October 2002 Impala Platinum commissioned a Sulfacid Plant at its Smelter in Rustenburg which recovers the SO2 from the electric furnace off gasses into a weak sulphuric acid solution.The Sulfacid Plant technology is widely used in the paint pigment industry. This is, however, the first application of the technology on electric furnace off gas.The furnace off gasses contains flue dust which is removed in electrostatic precipitators. The gas exiting the precipitators normally still contains between 40 mg/Nm3 and 60 mg/Nm3 dust and passes through a quench-scrubber before entering the reactors. The quench-scrubber cools the electric furnace offgas down from ± 200 °C to 60 °C and act as a final dust removal stage."

Jan 1, 2003

By R. X. Li

The overall flow-sheet of producing chromium (III) sulfate is described in this paper. The suitable conditions of each process such as sintering, leaching, aluminum removal, reduction, and de-composition conditions were experimentally studied. The results show it is reasonable to produce chromium (III) sulfate with the flow-sheet pointed out in this research work. The final product is Cr2(SO4)3 solution contained 150~250g/L Cr.

Jan 1, 2014

By Marko Hilden

"A stochastic model of mineral texture is discussed and used to demonstrate that grain association within the intact texture has a significant effect on the liberation characteristics of breakage products. The majority of previous models have simulated texture and liberation of binary systems. This new model is able to simulate complex multi-component (multi-mineral) aggregate textures and their breakage products. Grain size distributions can be defined for each of several minerals. Mineral-mineral associations can be controlled by inserting mineral grains within grains of another mineral. Repeated Monte Carlo sampling of the aggregate is used and the liberation properties of the fragments are calculated. These are analysed to generate data in a similar form as reported by mineral liberation analysis systems, including density distributions, liberation distributions, and particle class distributions. Simulations results are presented where the model has been fitted to complex sulphide ores with four minerals. Comparison of the simulated particles and experimental data show that the model is able to reproduce similar particle class distributions as measured by QEMSCAN. The texture of real complex ores can be simulated and fitted to conventional mineral liberation analysis data. The model should provide a useful and practical means of modelling the effects of mineral texture on separation processes and in geometallurgical models."

Jan 1, 2014

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 H. M. Gao

According to the difficulty of dolomite removal from collophanite,normal-reverse floatation process has been adopted in floatation with the use of highly selective collector G-4 and depressant S721. Good indexes of flotation have been obtained with the run-of-mine ore containing 17.96 % P2O5 and 2.31 % MgO being upgraded to a concentrate containing more than 30% P2O5 and less than 1% MgO. The reagent interaction mechanism in low grade collophanite flotation has been stu-died by FTIR analysis and theoretical calculation. The results indicate that the interaction between collector G-4 and collophanite is the result of chemical adsorption in combination with physical ad-sorption with chemical adsorption playing the major role. Depressant S721 adsorbs on dolomite surface to form a water film and effectively depresses the flotation of dolomite and reduces the MgO content in the concentrate.

Jan 1, 2014

By G. Önal

Recovery of nickel and chromite from the tailings has been studied on the samples with 0.214 % Ni and 5.10 % Cr2O3 content and taken from Orhaneli Chromite Concentration Plant. Mineralogical examinations of the samples showed the existence of chromite, olivine, pyroxene, chrysotile, anti-gorite, chlorite, idingite, tremolite and calcite together with trace amounts of millerite, pentlandite, pyrite, pyrrhotite, hematite and limonite type iron oxide minerals in partially serpantinized dunite type particles. In order to recover chromite from Chromite Concentration Plant tailings Mozley Table and Knelson Separator are used and concentrates containing approximately 42% and 46% Cr2O3 are produced respectively with 40% recovery. Most of the nickel remained in the tailings. Therefore, acidic leaching tests are performed in order to dissolve nickel from these tailings. Effects of particle size, acid concentration, temperature, leaching time and solid/liquid ratio on the nickel leaching efficiency are investigated. The optimum leaching conditions are found as 250 g/L acid concentration, 1/5 solid/liquid ratio, 2 hours of leaching time and 60°C temperature, almost all nickel is dissolved at the optimum conditions and acid consumption is about 841 kg/t. Repeated leaching tests are carried out in order to have enough Ni content in the leach liquor for the further treatment of solutions. After repeated leaching tests, leach liquor contains 3 kg/m3 Ni, 48 kg/m3 Fe, 2.2 kg/m3 Si, 23 g/m3 Cr and 590 kg/m3 H2SO4. Ni is recovered from that solution by precipitating with H2S followed by HNO3 dissolution and precipitating Ni as hydroxide with 63% Ni content. Leach cakes are subjected to the gravity separation (Mozley table) to recover the remained chromite and a chromite concentrate with 47% Cr2O 3 content is produced with 53% recovery. As a result of the abovementioned tests, a conceptual process flow sheet is proposed for the treatment of these chromite concentration plant tailings.

Jan 1, 2014

By V. M. Mankov, O. V. Zamyatin

"Fine free gold at a size of minus 250-100 µm can be effectively recovered from mineral materials (buried clay placers, saprolites, gold-bearing aggregates, technogenic sands etc.), or MM, using some developed and implemented in practice cost-effective basic technological schemes of MM processing at every stage: exploration, main concentration processes, upgrading of gravity concentrates etc. Such technologies are based on mineral materials composition, different content of fine gold mass fractions, and include improved two-stage sluicing technology, jigging technology, advanced technology and integrated technology. The main operation principle of the given technologies is gravity concentration. They provide recovery of fine gold of any size from MM, including gold finer than 100 µm, using concentration systems and plants with a capacity of 1-2 and up to 100-200 m3 per hour. Selection of a cost-effective technology depends on its technical and economic viability regarding to mineral material composition, optimum performance and concentration rate. The developed technologies of mineral materials concentration establish a balance between technological, technical and economic factors, and ensure profitable development of deposits containing free gold and characterized by a complex composition of concentrating material. Free gold recovery with these systems increases by 2.0-2.5 times for gold particles at a size of minus 250+100 µm and 10-30 times for gold particles of minus 100 µm, compared to conventional sluicing systems. The Irgiredmet Institute has developed and supplies primary concentrate washing machines for upgrading gravity concentrates of up to 100 mm in size, with a capacity of 1.0-5.0 m3/h, fitted with various production equipment including pyro- and hydrometallurgical systems. Additionally, the Irgiredmet Institute develops and manufactures systems of mechanized processing of geological and technological samples (UOMP; registered design certificate No.27505, Russia) designed for complete recovery of free gold in the process of geological samples handling and decreasing of a human factor influence. A system includes a package of technologically associated disintegration, classification and concentration equipment with some “know-how” elements that provide effective recovery of fine gold at the exploration stage. A number of Irgiredmet’s patented technologies and systems (patents of the Russian Federation) have no equivalents in the field of mineral processing and provide designing of technologically practical and cost-effective flowsheets that offer higher recovery of gold of different sizes (fine gold), at every stage of processing of mineral materials including basic concentration processes, upgrading and exploration etc."

Jan 1, 2018

By Thenepalli Thriveni, Seong-Young Nam, Nam-Il Um

New modern water treatment technologies required for arsenic removal from waste waters contaminated extensively by various background sources from mining, industrial waste, agricultural waste, painting industry and natural geological bed rock system etc. Arsenic is a widely dispersed element in the earth's crust and exists at an average concentration of approximately 5 mg/kg. Arsenic (As) and heavy metals may be released from the mine wastes to the ground and surface water systems, as well as the geological environment due to their solubility and mobility. This research focuses on the effect of accelerated carbonation process for successful removal of heavy metal arsenic anions from artificial waste water and mining waste waters. This accelerated carbonation process is a simple and novel method with 85 ~ 88% removal efficiency. Carbonation has been studied as a process to further improve immobilization of solidified/stabilized waste and granular waste. After successful removal of arsenic anions from solid mining waste and its potential benefits for producing construction materials. Besides, the industrial and urban management systems are generating bulk solid mining wastes, and most often dumping them in open fields. To prevent the landfilling with mining waste, many efforts are being made for the recycling of different types of mining solid wastes with a view to utilizing them in the production of various construction materials.

Jan 1, 2014