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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 Gerke Gilian, Pretz Thomas, Pehlken Alexandra

"The evaluation of health hazards within the treatment of mineral and waste materials is gaining more and more importance in industrial countries. The need to control occupational health and safety has been recognised, and regulations which describe general protective measurements for personnel provide a tool to protect their health. It is the aim of the paper to give an outlook for practical approaches to risk assessment and to present measures for exposure reduction in accordance with the state of the art in Germany.Both the treatment of minerals and of waste materials are described in relation to the risk assessment. The method of evaluating health hazards in the two industries is similar and therefore both examples are presented next to each other.The example presented in the paper is the German “Biostoffverordnung” (the regulation for biological materials) which is important for the waste treatment industry. All kinds of waste treatment facilities (like composting facilities, waste dumps, sorting facilities for packaging materials) are obliged to carry out an assessment of health hazards for a variety of working areas and working places. The possible safety requirements deriving from this regulation are presented and discussed under the aspect of biological hazards."

Jan 1, 2003

By D. Whittles, S. Kingman, S. Bradshaw, N. Miles

The influence of microwave energy at high electric field strength on ore strength has been investigated. Two ores of varying mineralogy were treated in both multimode and single mode microwave cavities. After treatment, any change in strength relative to untreated ore was established. It was shown that in the multimode cavity reduction in strength was related to the applied power level. Results of tests carried out in the single mode cavities showed that, for both ores, reductions in ore strength > 50% could be achieved in very short periods (<1 second). Thermal stress analysis showed that the mechanism of microwave induced failure was the development of tangential stresses at the grain boundaries. It was concluded that operation at 915 MHz with high power and short residence times gives feasible scale-up possibilities.

Jan 1, 2003

By H. J. Schulze

From a colloidal science point of view (Schulze 1984, Nguyen & Schulze, 2004) five micro-processes are responsible for successful particle-bubble formation: the approaching of the particle to the liquid-air interface, the thinning and rupture of the intervening liquid film, the expansion of the three phase contact perimeter, the generation of sufficient large capillary force to stabilise the aggregates and the transport process of particles into and within the froth layer. Flotation reagents influence mainly the thinning and rupture of the intervening liquid film between particles and air bubbles, the expansion of the three phase contact after the rupture of the liquid film and the stability of the aggregates against external destruction forces in the flow field. But it exist also a non-negligible influence on the approaching of particles to the bubble surface during the encounter process and on their passing over into the froth layer and the froth stability.

Jan 1, 2003

By B. Y. M. Bueno

Biosorption of heavy metals can be an effective process for the removal of heavy metals ions from aqueous solutions. In this study, the adsorption properties of Rhodococcus opacus biomass for Pb(II) and Cu(II) ions was investigated. The effects of initial pH, initial metal concentration and biomass concentration on biosorption efficiency were studied in a batch system. Results showed that the initial pH would play an important role in the Pb(II) and Cu(II) ions removal by R. opacus and affected the zeta potential of R. opacus. The equilibrium adsorption was reached with 60 min. The Langmuir and Freundlich models were used for describing of adsorption isotherm data. The maxi-mum adsorption capacities of biomass were determined as 94.3mgg-1 and 32.2 mgg-1 for the Pb(II) and Cu(II) ions, respectively. The experimental data fitted to pseudo second order kinetic model. Adsorption capacity of Pb(II) ions was found to be reduced by the presence of the other competing metal ions in the system. The FT-IR results of R. opacus biomass showed that biomass has different functional groups and these groups are able to react with metal ions in aqueous solution.

Jan 1, 2014

By A. M. Raichur, S. P. Vijayalakshmi

Fine coal dewatering is a major problem in the coal industry because the fines hold significant amounts of water and account for two-thirds of the product surface moisture. Present methods include flocculation using polymeric flocculants followed by filtration. But the kinetics of filtration are not favorable with such flocculants. In this study, a novel method involving flocculation with microorganisms for improving the settling rates and dewatering kinetics has been investigated. Two Gram-positive microorganisms, Mycobacterium phlei and Bacillus subtilis were used as bioflocculants. The effect of time, pH and ionic strength of the electrolyte used on adhesion and flocculation were studied. Adhesion tests showed that maximum adsorption occurred in 20 minutes in the pH range of 2-7 and the total amount of bacteria adsorbed was almost the same with both the flocculants. Nearly 98% of the coal flocculated with both the microorganisms in about 5 minutes. The filtration rate of fine coal almost doubled with addition of bacteria and electrolyte and maximum filtration occurred near the point-of-zero-charge of the bacteria.

Jan 1, 2003

By Mohan Ram

Structural impurities in the crystal lattice of rock phosphate of Indian origin is a great challenge for beneficiation and practically possesses remote scope of upgradation to the desired level for industrial utilization. There is a wide occurrence of rock phosphate in different parts of India with different characteristics viz. siliceous, carbonaceous and ferruginous. The structural cationic replacement in the composition of apatite is due to the exchangeable cations present in the external impurities associated with the rock phosphate ore. The Indian rock phosphate ore from Purulia district, West Bengal is characterized as unusual structural composition due to the exchangeable cation in its composition. The elemental distribution of ore exhibits the disproportionate ratio of P2O5 and CaO which is 5.88: 3.31 in reference to the theoretical composition of P2O5: CaO in apatite which is 4.23: 5.55. The substitution by trivalent Al+++ cations within the structure of apatite in place of divalent Ca++ is found upto 18% and substitution of exchangeable cation in place of PO4 and F ion by CO3/SO4 is found upto 0.1% and OH ions upto 0.2% respectively in a lattice of apatite thereby diluting the grade of rock phosphate and restricting its industrial use even after beneficiation. This paper reveals the unusual compositional features of rock phosphate under study and is a guideline to the mineral industries using such rock phosphate. Keywords: external impurities, exchangeable cation substitution, structural compositional features, electron probe micro analyzer

Sep 1, 2012

By R. K. Dwari

The electrostatic beneficiation of coal is based on tribocharging characteristics of ash forming minerals and coal particles. The tribocharging of quartz, pyrite and coal particles contacted with various metals and polymeric materials have been measured and the charge acquisition is assessed through surface energy calculations from liquid contact angle data. The contact angles, before and after tribocharging of solids, are measured using Krüss tensiometer and Washburn?s method where the sample holders in tensiometer are specially constructed with tribocharger materials. The charge polarity and amount of charge acquired by quartz, pyrite and carbon with metal tribochargers were found in good agreement with the reported work functions of the contacting surfaces. The charge results with polymer materials differed from the work function values, presumably caused by surface contamination. The surface energy of quartz calculated by all the theoretical approaches in the literature showed that the tribocharging increases the surface energy. Both polar and non-polar components computed from Fowkes and Owens-Wendt-Rabel-Kaelble approaches dis-play that both these components increased after triboelectrification. However, the polar component divided into acid and base components, as in van Oss approach, manifest decreasing acid part and increasing base part. Since quartz charged negatively during tribocharging with metal surfaces and therefore accepted electrons, the determined acid and base surface energy components are consistent with charge transfer process. The results also elucidate an explicit correlation between the charges generated by powders and the surface acceptor (acid) and donor (base) electronic states and thereby the work functions. A novel fluidized bed tribocharger was designed and developed with internal baffle system for efficient contact electrification of mineral and maceral to produce high differential charging for efficient separation. The results achieved on coal with 45% ash content are presented and discussed.

Jan 1, 2014

By H. M. Yang

Structural alteration of pyrophyllite during mechanical activation in a planetary mill was investigated by X-ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) techniques. Mechanochemical effect markedly promotes the decrease in reflection intensities with increasing the grinding time. Prolonged grinding causes the pyrophyllite to become the amorphous structure. It can be indicated that pyrophyllite is very susceptible to alteration by grinding. Crystal size (d006) of pyrophyllite appears to be a limit after 2h grinding. IR spectroscopy analysis shows a little alteration in the bands of pyrophyllite after mechanical activation. The results indicate that the ordered structure of pyrophyllite is destroyed and lattice deformation occurs. Porous silica was then successfully prepared via leaching the mechanically activated pyrophyllite. Pyrophyllite was first ground for 6 h. Ground samples were subsequently leached with 4 M hy-drochloric acid at 80 °C for 2 h to produce porous silica with specific surface area of 188.1 m2/g, total pore volume of 0.18 mL/g and average pore size of 3.9 nm from N2 adsorption analysis. Otherwise, the porous silica obtained from direct leaching of the original pyrophyllite only has a specific surface area of 4.3 m adsorption analysis. 2/g and total pore volume of 0.03 mL/g. It is inferred that grinding is favorable for the formation of microstructure pores. It offers a simple and convenient route for the preparation of porous materials from natural minerals.

Jan 1, 2014

By Yongfu Yu, Xiaotie Wang, Fuguang Zhang, Liping Che

"The flotation process of native Rare Earth minerals such as bastnasite, monazite, mixed minerals of bastnasite and monazite, using the new effective collector Dh was studied in this paper, respectively, and the flotation properties are described. The good qualities of the new collector Dh were revealed through comparing with other collector of Rare Earth minerals. The test results of different ore samples show that at moderate pulp pH (8.5-9.5), Rare earth minerals can be effectively separated from barium, calcium and silicon bearing intergrowth minerals (barite, calcite and silicate minerals) and high quality Rare Earth concentrates can be obtained successfully by the new collector Dh, acid silica gel, turpentine and reagents fitting together rationally. In order to determine optimum technical conditions, the effect of pulp pH, pulp temperature, pulp density and the effect of dosage of reagents (Dh and acid silica gel) on the flotation were investigated in the test.Simultaneously, the paper explores the mechanism of the flotation of Rare Earth minerals from intergrowth minerals. The infrared spectra for Dh and Rare Earth cation by analysis in theory shows that Dh formed chelate complex with Rare Earth cation and were adsorbed on the surfaces of Rare Earth minerals. The mechanism of the intergrowth minerals depressed by acid silica gel can be explained as gummy colloid hydrolyzed from acid silica gel which are selectively absorbed on the gangue minerals, making them hydrophilic and depressed, with pulp pH value of alkalescent."

Jan 1, 2003

By Lei Pan, Roe-Hoan Yoon

"Direct force measurement for bubble-particle interaction has been difficult due to bubble deformation, which makes it difficult to know the separation distances between the two macroscopic surfaces. In the present work, we have developed a method of monitoring the deformation accurately, while directly measuring the interaction forces. In effect, we can ‘see’ bubbles interacting with mineral surfaces under different hydrodynamic and chemical conditions and determine both the hydrodynamic and surface forces involved. In the present work, a high-speed camera has been used to record the optical interference fringes of a thin liquid film (TLF) of water formed on a mineral surface. The recorded fringes are then used to reconstruct the spatiotemporal profiles, from which one can determine the hydrodynamic pressure using the Reynolds lubrications theory. From the forces directly measured in the present work and the hydrodynamic pressures obtained from the fringes, we have determined the disjoining pressure. The results show that air bubbles interacting with hydrophilic surfaces form stable TLFs with zero contact angles. The TLF formed on a hydrophobic surface thins fast, form a ‘pimpled’ film, and ruptures to form a finite contact angle. The new information obtained in the present work may be useful to better understand the role of hydrodynamic and surface forces affecting bubble-particle interactions."

Jan 1, 2014

By M. A. C. Goes

Over the last twenty years CETEM has been involved in the preparation and certification of reference material from ores, concentrates and related materials for use in analytical laboratories associated with mining, metallurgy and earth sciences. CETEM provides reference materials from mineral samples, not available from the existing sources, to meet the needs of the mining and mineral industry. CBPA-1 and CBPA-2 respectively are samples of copper sulphide ore and flotation concentrate, both originated from Sossego Mine, located in Pará State, Brazil. The batch characterization was carried out by a collaborative measurement program with participation of 20 industrial, commercial and government laboratories from South America, North America, Europe, Asia and Africa. The certificates and report were issued in December 2007 (http://www.cetem.gov.br/ mrc/ing). The objective of this paper was to describe the procedures for material preparation and the collaborative approach involving a collaborative interlaboratory measurement program to certify CBPA-1 and CBPA-2.

Jan 1, 2014

By C. S. Gundewar

Indian National Steel Policy envisages ambitious three fold rise in steel production by the year 2020. This paper covers the iron ore industry in India which cater to the need of iron ore requirement of Indian iron and steel sector as well as export commitment in addition to addressing the industry?s key concern to attain the same. The main contents are (i) resources and its exploitation; covering status of exploration, reserves and resources, province wise occurrences, distribution, nature of mineralization and generation of fines, etc ; (ii) use of iron ore in iron and steel making, covering physical and chemical requirements for pig iron and sponge iron production; (iii) ore characteristics and beneficiation practice in vogue; (iv) projected steel demand and requirement of quality iron ore and provision thereof; (v) recovery of iron values from in situ low-grade ores and stacked fine rejects (-10/-6 mm) inclusive of slimes (-0.15 mm) from tailing ponds; (vi) agglomeration of fine concentrates preferably by pelletization; (vii) measures to augment iron ore availability for future requirements.

Sep 1, 2012

By I. I. Maximov

The paper describes the results of studies performed with a view to develop an improved technology for processing high-grade massive and cupriferous ores of the Talnakh deposit, the main valuable components being nickel, copper and PGM. The studies? main task was production of nickel concentrate with nickel content of approx. 15%, nickel recovery being as high as possible. The studies were performed on two ore samples. One sample was a mix containing high-grade massive (78%) and cupriferous (22%) ores with nickel content of 1.93% and copper content of 3.6%; the other sample was a mix of high-grade ores with nickel content of 2.25% and copper content of 3.72%. Main ore minerals were copper sulfides ? chalcopyrite and cubanite, their total content being 10.5% ~ 11%, pentlandite (5.2% ~ 6.1%) and pyrrhotite (36.7% ~ 42.9%). Influence of grinding media on pentlandite and pyrrhotite separation results, achieved through combined use of triethylenetetramine (TETA) and sodium sulfite (SS), was also investigated. It is shown, that combined application of TETA/SS in the ratio of 1:2, permits to grind products in metal mill (mild steel) with metal balls (mild steel), achieving results that are similar to those achieved by means of grinding in inert grinding media with TETA/SS ratio of 1:1. Application of the developed technology provided for production of high-grade nickel concentrate with nickel content of 14.7% ~ 15.6%, nickel recovery being 76 % ~ 77%. Earlier experiments performed on the above mentioned ore mix permitted to produce nickel concentrate with nickel content of 10%, nickel recovery being 75.9%. Consequently, nickel content was increased by 4.7% ~ 5.6%, and a higher nickel recovery was achieved. The paper also describes metallurgical results related to nickel, copper and PGM with regard to all processing products.

Jan 1, 2014

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 Patricio Berrios, David Barriga, Peter Amelunxen, Gerson Sandoval, Roger Amelunxen

Laboratory test equipment and methods have undergone relatively little change since their introduction in the 1950’s. The Denver sub-A cell is still by far the most commonly used laboratory batch cell, but bottom-driven and instrumented cells are beginning to appear. Test procedures have also changed little over the past 60 years, and most engineers continue to rely on empirical models for predicted plant scale performance from laboratory scale tests. This approach is problematic, because changes in the froth phase characteristics in the lab hamper the reliability and reproducibility of the empirical extrapolation to plant scale. In a previous work, the authors reported on the impact of froth recovery at the laboratory cell, showing that variability in the froth recovery can lead to significant error in the modeled kinetic rate constant unless it is properly accounted for in the scale-up model. In this work, we review the role of hydraulic entrainment in the lab cell, and how variability in particle specific gravity, shape factor, and froth residence time can impact the entrainment recovery.

Jan 1, 2014

By ?. S. Yusupov, V. P. Isupov, N. Z. Lyakhov, A. G. Vladimirov, S. A. Kondratiev

"Considering the shortage of lithium reserves, the desirability has been shown of studying the possibility of processing into spodumene concentrates the concentration tailings and low-grade ore reserves at Transbaikalian Mining and Processing Project (ZabGOK). The mineral and chemical composition and the particle size distribution of the mineral feed, separability and recoverability of spodumene have been studied, forming the basis for the development of a concentration process and flowsheet for the studied mineral resource. Prospects have been established for impact ore grinding in a disintegrator, the efficiency of mechanochemical processes has been shown in the separation of quartz and feldspar and the recovery of lithium from concentrates.INTRODUCTION Lithium is widely used in various industries - nuclear power engineering, defense technology, power generation, ceramics, special-purpose glass and other technologies. The increasing demand for lithium and its compounds (lithium carbonate and hydroxide) for use in the manufacture of high-tech products (lithium-based materials for chemical sources of electric power and electrochemical energy) explains the need for establishing a sustainable raw material base (Mohr et al. 2012; Moores, 2007). The main sources of lithium are spodumene pegmatites (Vladimirov et al. 2012; Garret, 2004), brines (salars), and hydromineral materials (Garret, 2004; Zeng and Liu, 2009; Kotsupalo and Ryabtsev, 2008). However, in view of the absence in Russia of extractable hydromineral resources of lithium, the practical significance of spodumene ores remains decisive. Russia controls some of the world’s largest reserves of rare-metal pegmatites holding over 8 million tons of Li2O: approximately 7 million tons on the Kola peninsula and 1 million tons in the Sayan mountains. The main lithium mineral in pegmatites is spodumene LiAlSi2O6 containing 8.1% Li2O. It can be efficiently recovered by gravitational concentration and flotation. However, most of the deposits are located in remote areas and none is currently developed. In this connection, special research is focused on technogenic raw materials, which are increasingly seen as a solution to the resource base problem (Chanturia, 2008, Kurkov and Kotova, 2007)."

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 Wei Qu, Yongsheng Song, Xingyu Liu, Wenjuan Li, Shuang Liu, Guiying Zhou, Bowei Chen

The Pb,Sb,Zn multi-metal sulphide ore is processed in sequence of beneficiation of jamesonite, sphalerite . Due to relative large amount of collector (xanthate), activator (CuSO4) and regulator (lime) during different flotation stage, the flotation wastewater from sphalerite beneficiation stage can’t be directly recycled to the first lead flotation stage. In this paper, the flotation wastewater from sphalerite beneficiation stage was treated by Ozone and BAC technology, results showed that when the influent concentation of COD and copper ion were 850 mg/L, 10.48mg/L respectively, the Ozone and BAC technology could effectively treat such type of water. In the treated wastewater, the COD is 60mg/L, copper ion concentration is 0.023mg/L, pH is 7.0, which satisfy the need of Pb,Sb-Zn preferential floatation separation process. After recycle of the treated wastewater to Pb,Sb floatation circuit, qualified Pb,Sb concentrate and Zn concentrate were obtained.

Jan 1, 2014

By Alexander V. Epiforov, Stanislav V. Balikov

This paper describes of processing tests of 8 flotation concentrates containing precious and base metals by pressure oxidation (POX) method. Concentrates 1 and 2 were gold-copper concentrates. Zinc and silver were by-products in these concentrates. These concentrates were processed by POX with following cyanidation of POX solid residues, copper solvent extraction and zinc carbonate precipitation. The recoveries of gold, copper, silver and zinc from these concentrate were 98, 99, 30 and 99%, respectively. Concentrates 3 and 4 were lead-zinc concentrates. Silver was by-product in concentrate 3. Gold, silver and copper were by-products in concentrate 4. Concentrate 3 was processed by POX with following reduction smelting of POX cakes for primary lead recovery and zinc carbonate precipitation from POX solution. The recoveries of lead and silver into ingot were 96 and 98%, respectively. The recovery of zinc was 99%. Concentrate 4 was processed by POX with following zinc carbonate precipitation and reduction smelting of POX cakes. Copper was precipitated from the POX solution using sodium sulphide prior zinc precipitation. The recovery of zinc into carbonate concentrate was 99%. The recoveries of lead, gold and silver into lead bullion were 95, 99 and 98% respectively. The recovery of copper into sulphide concentrate was 99%. Concentrate 5 was gold-pyrite concentrate, and concentrates 6-8 were double refractory gold-arsenopyrite concentrates. Silver was by-product in these concentrates. These concentrates processed by POX and CIL. The recovery of gold from concentrate 5 was 98%, and from concentrates 6-8 was 85-90. Low gold recovery from concentrates 6-8 was associated with preg-robbing factor. The recovery of silver from gold-sulphide concentrates did not exceed 10-20%. The low silver recovery was associated with argentojarosite formation that is resistant to cyanidation. The flowsheets for complex processing of precious and base metals sulphide flotation concentrates based on this test work results were proposed.

Jan 1, 2018