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By F. S. Hoseinian, K. Filho, D. Deglon, T. Souza, M. Safari

"This paper investigates the reverse flotation of hematite in three laboratory flotation cells with very different contacting environments. The main objectives are to investigate the recovery of coarse quartz by flotation and fine hematite by entrainment. The laboratory flotation cells used were the mechanical, oscillating grid and pneumatic cells. The effect of froth height and solid concentration were investigated in the mechanical and pneumatic cells. The effect of impeller speed and energy input were investigated in the mechanical and oscillating grid cells. Froth height results show that coarse quartz particle recovery decreases almost linearly with increasing froth height due to increased detachment of coarse quartz particles in the froth. Fine hematite particle recovery also decreases almost linearly with increasing froth height due to decreased water recovery and associated entrainment. Agitation/energy input results show that coarse quartz particle recovery increases with increasing impeller speed to an optimum, after which this decreases dramatically. The increase is due to improved gas dispersion, generation of smaller bubbles and increased bubble-particle collision and attachment. The decrease is due to significantly increased bubble-particle detachment at higher impeller speeds. The recovery of coarse quartz particles in the OGC is higher than that in the mechanical cell with an optimum at a much lower energy input. Solids concentration results show that both mass recovery and water recovery increase with increasing solid concentrations. The pneumatic cell achieves higher mass recoveries and lower water recoveries than those in the mechanical cell at equivalent solids concentrations and operating conditions. INTRODUCTIONFlotation is a selective process for separating different minerals from each other. The flotation separation efficiency depends on the recoveries of the mineral species by both true flotation and entrainment (Neethling and Cilliers 2009; Wang et al. 2015). Both chemical variables and hydrodynamic conditions within the flotation cell affect the recovery and selectivity of the flotation process. Cationic reverse flotation of hematite is a common method for selective separation of quartz from iron ores to produce pellet feed. The presence of coarse quartz particles in the tailings and fine hematite particles in the concentrate are two major challenges in the reverse flotation of hematite (Vieira and Peres 2007)."

Jan 1, 2018

By M. S. Eygi

This study covers the investigations based on the electrokinetic and rheological properties to explain the interactions between kaolin minerals and commercially available polyelectrolyte in anionic character. Additional adsorption test were also conducted to support the interaction mechanism. Adsorption tests showed that adsorption densities decrease by increasing the solid content. In-creasing the solids contents from 1% to 30% by weight resulted in the decrease on adsorption from 2.14 mg/g to 1.85 mg/g. Because of its difficulty, the solids ratio at 70% was not studied. However, following to trend of the curve plotted adsorption density-solid ratio, an estimation was made and adsorption density at 70% solid content was extracted from the curve as 1.75~1.80 mg/g. The electrokinetic studies pointed out that the presence of polyelectrolyte increase the zeta potential of kaolin from 40 mV to 60 mV which is reasonable conditions to disperse and stabilize the kaolin slurry and lower the viscosity. When these result of the different tests are combined and considered together, 2 mg/g polyelectrolyte concentration was noted as optimal concentration where adsorption density, viscosity and zeta potential of the slurries give maxima and remain constant after this concentration.

Jan 1, 2014

By J. K. Wen

The Mojiang nickel deposit is situated in Mojiang county, yunnan province, a tropical area in the southwestern China. The known geological resource (measured and inferred) includes 4 million tons of nickel sulphide ore at an average grade of 0.50% Ni and 0.34% As. Nickel minerals are mainly gersdorffite (NiAsS), millerite(NiS), morenosite (NiSO4?7H2O), and more than 50% nickel minerals is gersdorffite which contains arsenic. Pyrite is the dominant sulfide mineral, 22% in the ore and part of nickel minerals are locked in pyrite. It is difficult to attain the nickel concentrate quality allowed by a smelter and the acceptable nickel recovery through flotation due to the high arsenic in the ore and the nickel minerals locked in pyrite. The shake flask tests and column tests for nickel recovery from the Mojiang nickel sulfide ore had been finished by the end of 2003. The column bioleaching tests were carried out using the columns with diameter of 120 mm and height of 1200 mm, and 70% of nickel dissolution was attained in 300 days. A 10,000t pilot test heap was built in the Mojiang Nickel Mine by June 2003. The ore used in the test heap was supplied from the underground mine and was crushed to -20 mm before being feeding to the test heap, which is 4~5 m high, 30 m wide and 50 m long. The naturally adapted mesophile and moderate thermophile have been inoculated into the leaching pile by June 2003. The operating temperature in the heap ranges from 38? to 55?, varying with season. 30% of nickel dissolution was achieved in 3 months and the typical pregnant leach so-lution (PLS) contains 2~3 g/L Ni and 20~30 g/L Fe. The Ni sulfide which was produced by us-ing Na2S 10 t/t?Ni contains 16%~20% Ni and Ni recovery was 98%. 70% of Ni dissolution is expected in 12 months. The test heap was scaled up to 60,000 t of ore per year by mid of 2005. In this paper metallurgical studies and performance of the pilot test heap will be described. The results of mineralogy, shake flask tests and column tests on bioleaching of the nickel sulfide ore are reviewed. The key test heap operation parameters, the performance of bio-heap leahing-Na2S precipitation, ferrous oxidation-ferric precipitation-Na2CO3 precipitation, bacteria in the pile, water and acid balance, effluent disposal, capital and operation costs are also discussed.

Jan 1, 2014

By Tim Suljada, Mary Stewart, Jim G. Petrie, Damien Giurco

"The minerals industry is being challenged to reduce the amount of virgin ore that is mined, and to replace this material through the recycling of used commodity items and scrap, or by the reprocessing of waste materials. It is argued here that the existing technology base of minerals processing and refining offers real potential for handling these secondary resources. The challenge is to develop tools by which the most preferable recycling routes (both economically and environmentally) can be identified from a list of feasible alternatives, taking into account any operational constraints of these technologies.This paper describes an heuristic approach to developing the family of all technically feasible flowsheets to address this challenge, from which a preferred option may be selected according to a set of decision criteria (economic and environmental). Our approach uses conventional flowsheeting techniques of selecting flow variables and splitter functions, supported by design performance information for each unit operation. This set of design decision variables is augmented by knowledge of the suitability of a particular waste or scrap stream for a given unit operation within a flowsheet. We achieve this by comparing the composition of the scrap stream with the range of mineral streams for which the unit operation was designed initially. This is inspired by the “overlap” approach proposed by Legarth, where an “overlap” of 1 would suggest that there is high degree of compatibility between a given secondary resource stream and a primary mineral stream as inputs to a specific technology. The “overlap” concept has been extended to include information about the physical characteristics of secondary resource streams, as well as information relating to synergistic / antagonistic influences of minor elements present in the waste stream. A flowsheet which delivers a product of acceptable quality from a given secondary resource material is built up from a progression of unit technologies. The exercise is repeated to generate the family of all feasible flowsheets from combinations of acceptable unit technologies."

Jan 1, 2003

By U. A. Peuker, A. Grohme

"The cost effective and sustainable production of high purity rare earth elements is still challenging. The most commonly used method, known as solvent extraction, is very complex, needs many steps to separate the rare earth ions in a high purity, and causes a lot of environmental problems. An alternative method is the utilization of a separation column filled with adsorbent material. Within the column the desired target substance can be selectively separated out of a multi component mixture in one step. To find out if an adsorption material is suitable for the separation with a column, a characterization of the adsorbent material is necessary. In this paper are described the usage of modified activated carbon (oxygen and phosphorous modification), Di-(2-ethylhexyl) phosphoric acid (D2EHPA) impregnated Amberlite® XAD 7 HP and Lewatit® VPOC 1026 as adsorption materials. Several adsorption isotherms and process conditions are determined to characterize the selectivity between the adsorption materials and different rare earth ions. With these isotherms the mass specific rare earth ion retention for the adsorbent materials can be calculated. In addition to the isotherms the best working parameters are investigated e.g. pH-value and the time for equilibration. Finally, the separation factors between two rare earth elements are determined. The separation factor shows how successful a two element system can be separated."

Jan 1, 2014

By Chuanyao Sun, Yang Yu, Zhen Guo Song, Wei. Ming’An

"Carbonate minerals are very important mineral source of extracting metal, radioactive element and rare earth elements. Furthermore,some carbonate minerals, such as calcite and dolomite, are common and important components of sediments and sedimentary rocks. Many flotation processes involve the separation of valuable minerals with carbonate minerals. So it is of great significance to the flotation theory and industrial practice to investigate the flotation behaviors of carbonate minerals. As regulators, metal ions play a major role in minerals flotation. The study of influence law of metal ions on minerals flotation is helpful to eliminate or utilize the effect of metal ions. In this study, calcite and smithsonite laboratory scale flotation, surface analysis and zeta potential determination in the presence of Fe(II) ion were performed to investigate the effect of Fe(II) on carbonate flotation. The results show that Fe(?) depresses the flotation of calcite and smithsonite. The depression effect of Fe species on calcite and calamine flotation can be improved with the increase of Fe(?) concentration. The zeta potential measurements and surface analysis show the existence of iron hydroxide products on mineral surface, which may be link to carbonate site instead of exchanging with calcium on the mineral surface. Fe species on the mineral surface inhibit the interaction between the reagents and calcite/smithsonite through the formation of surface precipitation coating on the calcite/smithsonite surface when the Fe(?) concentration is higher."

Jan 1, 2014

By Chen Zhiqiang, Luo Chuansheng, Chen Ziqiang, Liu Jianguo, Rao Jinshan

To comprehensively utilize the valuable resource in tailings, increase the economic benefit of mine, reduce the amount of tailings, prolong the service life of tailing dam, the comprehensive utilization of tailing resource is arousing the attention of more and more mines. Research of comprehensive recovery of feldspar and silica from Cu-Mo floatation tailings has been furthered. Technology of "De-sliming-Magnetic Separation-Reverse Flotation-Feldspar and Silica Separation" has been developed to utilize the resource. Slime is removed and reagents cost is reduced by de-sliming. The specific effective collector ZL is used in gangues reverse flotation, and GZ-818 is the collector in feldspar and silica separation. The grinding operation is vital to ensure the liberation degree of feldspar and to eliminate the reagents pollution on minerals surface. To a Cu-Mo flotation tailing assaying K2O 5.22%, Na2O 2.22%, Fe2O3 1.95%, Al2O3 12.05%, SiO270.66%, superfine K-feldspar and silica concentrates can be produced. The feldspar concentrate productivity is 29.67% assaying K2O 8.99%, Na2O 2.86%, Fe2O3 0.16%, Al2O3 16.99% and SiO2 68.92%. The silica concentrate productivity is 14.20% assaying 0.17% K2O, 0.04% Na2O, 0.01% Fe2O3, 0.55% Al2O3 and 98.17% SiO2. The technology provides technological reference model for the similar mines.

Jan 1, 2014

By W. Z. Zu

In proved reserves of vanadium-containing titanomagnetite in Panxi, China, iron grades of ores were 50% ~ 15%. China?s metallurgical industry departments defined the iron ores containing 50% ~ 20% TFe as exploitable resources and the extreme lean iron ores containing 20% ~ 15% TFe as temporary unexploitable resources, the extreme lean ores were as waste rejected into waste dump in mining process. This paper researched process mineralogy of the extreme lean ores, adopted mineral processing technology responded to the properties of the ores to treat the ores and obtained quality vanadium-iron concentrate, titanium concentrate and sulfur concentrate, therefore successfully utilized the extreme lean ores, changed the ores from waste resources to exploitable resources.

Jan 1, 2014

By Matt Kilburn, Liming Lu, Steve Suthers, Alexander Edenton, Rodney Smyth, Matt Adam

"Magnetite concentrate is naturally good for pelletising. However, due to the depletion of reserves of traditional high grade hematite iron ore worldwide, the usage of magnetite concentrate in sintering is expected to increase substantially. Magnetite concentrate is typically high in Fe grade and releases extra heat when oxidised to hematite. This will not only improve the quality of agglomerates produced, but also have a potential beneficial impact on the fuel consumption of the agglomeration process. There are an increasing number of magnetite projects currently being considered and developed. However the concentrates from some of these projects are too coarse as pellet feeds and much finer and denser than normal sinter feeds. Accordingly, special strategies are required in order to utilise the coarse magnetite concentrates at high proportions in pelletising and sintering. This paper discusses various raw material preparation technologies and blending optimization methods demonstrated to be effective for improving the sintering and pelletising performance of coarse magnetite concentrates. Pre-granulation and addition of binders, such as hydrated lime, were found to be particularly efficient in recovering the sintering productivity of sinter blends containing magnetite concentrates. In pelletising, HPGR (High Pressure Grinding Rolls) grinding enabled production of good quality pellets from 100% magnetite concentrates and optimized blends containing up to 70% magnetite concentrates also formed good pellets.INTRODUCTION Magnetite concentrates are often used as feed materials for pellet plants or sinter plants depending on their grades and grain sizes. To achieve the required quality of green and fired pellets, the concentrates often need to be ground very fine (80% passing 38- 45 m), which inevitably consumes a great amount of energy. Therefore, efficient grinding processes are required to reduce the amount of energy consumption needed to achieve the sizing and chemical specification of pellet feeds. The use of magnetite concentrates in sintering has the potential to improve sinter chemistry, which is deteriorating over time due to the slowly decreasing grade of direct shipping iron ores around the world (Yang and Mathews, 1997; Yang and Witchard, 1998, Yang and Davis, 1999; Yang 2005). However, methods are required to allow the utilisation of high levels of concentrates in sintering while maintaining productivity and sinter quality (Han and Lu, 2017)."

Jan 1, 2018

By C. Dorfling, P. Albertyn

"Hydrometallurgical recovery of metals from printed circuit board waste typically involves multiple leaching stages; conventionally, base metals dissolution by mineral acids is followed by leaching of gold using cyanide or halide based lixiviants. Alternative lixiviants for gold leaching can reduce the potential hazardous nature of operation. The aim of this study was to investigate the feasibility of using thiosulfate as lixiviant for gold leaching from waste printed circuit boards. Batch leaching tests were performed to investigate the effects of thiosulfate concentration (0.1 – 0.2 M), ammonium concentration (0.2 – 0.4 M), pH (9 – 10.5), solids content (25 – 50 g/L), and copper content of the feed material on the gold leaching behavior. The concentrations of metals in liquid samples were determined by means of inductively coupled plasma atomic emission spectroscopy, and high pressure liquid chromatography was used to evaluate thiosulfate degradation/consumption. The ratio of thiosulfate to ammonia was found to have the most significant effect on the extent of gold leaching, with the best gold extraction observed at a ratio of 0.5 mole thiosulfate per mole ammonia. The lower pH range of 9 – 9.5 generally produced better Au leaching, while low copper extraction during the first stage base metal leaching stages has proven to be detrimental to gold leaching from the residue. Thiosulfate degradation/consumption increased and gold extraction decreased with higher residual copper in the feed. An optimum gold extraction of 78.5 % from base metal leach residue was achieved with 0.2 M thiosulfate, 0.4 M ammonia, and 0.02 M cupric ions at 25°C in the pH range 9 – 9.5.INTRODUCTION Background and Aim The recycling of e-waste is becoming increasingly important as it provides certain economic benefits apart from the obvious environmental benefits. Printed circuit boards (PCBs) are found in most forms of e-waste and contain especially high concentrations of base and precious metals. Hydrometallurgical processes are often considered for the recovery of valuable metals from PCBs; these processes normally implement several leaching stages to selectively recover certain metals."

Jan 1, 2018

By N. Schreithofer

Varying flow regimes, particle populations and consequently different types of bubble-particle interactions characterize the different zones of a flotation cell. The understanding of the role of the different zones of turbulent intensity on the particle-bubble interactions is of primary importance to optimization and scale-up of flotation processes and machinery. In order to study particle-bubble interaction in turbulent flow a completely new approach was taken. A laboratory scale stationary turbulence device was developed and built. The set-up allows the observation of particle-bubble interactions in various turbulence intensities, particle and bubble sizes and surfactant concentrations. The experimental set-up consists of a transparent, specially designed tank in which liquid flows between carefully designed and placed obstacles that create different turbulent flow fields. Bubble-particle aggregates are introduced into this turbulent zone. The behaviour of the aggregates, such as attachment /detachment of particles to/from air bubbles is recorded by a High Speed Imaging (HSI) system (5400 fps). The images are then analysed and the dependence of attachment/detachment process is described as a function of turbulent intensity in different conditions for different surfactant concentrations. This paper introduces this method to study particle-bubble interactions in turbulent flow and correlation to Computational Fluid Dynamics (CFD) simulation. CFD modelling is validated for two and three phase systems; liquid-gas with liquid and solid tracers respectively. The CFD simulations using the RANS k-S turbulence model showed good correlation to the experimental data and the experimental method is a promising tool for investigation of particle-bubble interaction in turbulent flow.

Jan 1, 2014

By M. L. Liu

This work reports the results about the determination of mean activity coefficients and relative partial molar free energies for copper sulfide mineral bioleaching solutions by potentiometric method at 25ºC. The experimental potentiometric data were obtained by combining a solid state membrane-cupric ion selective electrode (Cu2+ ISE), containing a KNO3 filling solution, and an Ag/AgCl electrode. The measurements were performed in different series of copper sulfide mineral bioleaching solutions. The non-ideal behavior of the system was described on the base of the Pitzer ion-interaction model for mixed salts. Meanwhile, the relative partial molar free energies of bioleaching solution were investigated. The determination of the thermodynamic properties offers a basic data for the study of copper sulfide mineral bioleaching solutions.

Jan 1, 2014

By Yizhong Yuan, Dao Li, Nannan Xue, Tao Liu, Yimin Zhang

A new multi-stage counter-current circulation leaching process for extracting vanadium from stone coal was proposed, and the main factors on multi-stage counter-current circulation acid leaching process were investigated. The results show that the vanadium recovery could reach 86% under the conditions of sulfuric acid concentration of 4 M, liquid to solid ratio of 2 mL/g, temperature of 95 °C, reaction time of 60 min, mean particle size of 125 µm and circulation acid leaching stage of three. The losses of vanadium in acid leaching solution appeared during the four-stage acid leaching process. The strong adsorption performance of new formed KAl(SO4)2(H2O)12 crystal was main reason.

Jan 1, 2014

By R. Singh

The paper presents the results of characterization and beneficiation studies carried out on a lean grade tungsten ore sample from Degana, India. Basically, three different routes, involving gravity separation, magnetic separation, and froth flotation were studied for concentration of the sample by physical and physico-chemical methods. Considering the low recovery by physical methods, efforts were put in to produce a tungsten concentrate by physical methods suitable for subsequent hydrometallurgical recovery of tungsten as ammonium para-tungstate. This strategy proved quite helpful in minimizing the losses of tungsten in tailings. Based upon these studies a novel integrated technological process flow-sheet was developed for the exploitation of lean grade tungsten ore deposit of Degana, India. Keywords: lean tungsten ore, characterization, beneficiation, gravity and magnetic separation, hydrometallurgical extraction, integrated process route

Sep 1, 2012

By Shailin Lalloo, Allan B. Nesbitt

A fluidised bed was exposed to high gravities by placing it in a centrifuge. The bed expansions were measured and compared with the bed expansions predicted by the Richardson-Zaki model (1954). The Richardson-Zaki model was found to predict effectively the fluidisation behaviour of defined particles in this increased gravity environment.

Jan 1, 2003

By E. Pourjenaei, P. Ghobadi

High Pressure Grinding Roll (HPGR) is efficient equipment in comminution process. HPGR could be a good option for preparing ball mill feed at the first stage of grinding due to its high efficiency and low energy consumption. Closing with a screen, these mills are utilizing as one of the principle parts in mineral processing industries, especially for iron ores. Recently, HPGRs are working as primary mills at 4 developing lines in Gol-e-Gohar Iron Ore Processing Complex, Iran. Different mechanism of particle crushing in compare to the other tumbling mills makes the HPGR as certain equipment with its own particular controlling parameters. Hydraulic pressure, roller speed and level of material inside feeding hopper are the most important variables influencing grinding efficiency of the HPGR. To figure out how they impress the process and operation situation, different industrial tests were carried out and the best result (d80 about 8 mm for HPGR discharge) was achieved at 180-190 bar pressure (P), 300 rpm speed (S) and 50% of hopper level (L). It is worth noting that this finding has been observed through past pilot test too. We also used design expert method (DX7 software) to develop the best design and analysis the test results, as well. According to the mechanical restriction of HPGR and process limitation in the plant (based on the industrial results), we adjusted value of each parameter in a logical range. Therefore, 20 industrial tests were conducted, as DX7 recommended, and the various impacts of the parameters and their interaction were identified based on statistical analysis. As the authors expected, it was revealed that after presser, roller speed is a critical variable because of its significant role in residence time of the particles between the rollers. The function below has been determined to explain the relation between different parameters and the response.

Jan 1, 2018

By J. Vilcáez

The copper extraction yield from thermophilic bioleaching of chalcopyrite depends on temperature, pH, and the oxidation-reduction potential (ORP), as well as the activity of the microbe used. We studied copper extraction yields obtained from chalcopyrite with three thermophiles, Acidianus brierleyi, Sulfolobus metallicus, and Metallosphaera sedula, under various pH and temperature conditions and with different initial amounts of ferric iron. The results indicated that the capacity of each thermophile strain to leach iron as Fe3+ differed, which affected the influence of pH, temperature, ORP, and microbial activity level on the yield of copper. Microbial activity can cause ORP to be close to the critical value (450 mV) at which copper extraction at 65 °C can be higher than that at 80°C. An initial pH of 1.5 retards the precipitation of jarosite, allowing temperatures as high as 80°C to result in copper extraction yields close to 100%. However, if a thermophile with a poor capacity to form Fe3+ is employed, 100% copper extractions can also be obtained at pH 2.5, because ORP is low as result of low amounts of Fe3+ in solution. Optimum temperatures for the growth of thermophiles did not always mean high copper extraction yields. Conversely, high biomass concentrations depending on the capacity of the thermophile strain to leach iron as Fe3+, can result in excess Fe3+ in solution, leading to the precipitation of large amounts of Fe3+ as jarosite. The bioleaching capacity of A. brierleyi was reduced or suppressed when insufficient initial Fe3+ was pro-vided to trigger the leaching reaction, whereas S. metallicus and M. sedula were less sensitive to the initial availability of Fe3+. This result confirmed that a direct enzymatic attack on the mineral surface could initiate the leaching reaction, but later ORP governed the leaching rate of chalcopyrite.

Jan 1, 2014

By S. S. Lu

In sodium oleate and salicylhydroxamic acid systems, sequence of floatability of three sulfate minerals is: barite>celestite>gypsum, in lauryl amine system is: gypsum>celestite>barite. XPS and infrared spectrum analysis are used to find that it is chemical reaction between sodium oleate and three minerals, physical adsorption on the surface of minerals for lauryl amine, and it is chelating reaction between salicylhydroxamic acid and three minerals possibly. Theoretical calculation on chemical bonds in crystal structures of three minerals is carried out, finding that breaking degree of Mn+?O2- in crystal structures of three sulfate minerals is closed related with floatability.

Jan 1, 2014

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 V. Panayotov

Flotation practice usually uses the Sheridan-Grizvold selection method, where zinc minerals are activated by addition of copper sulphate and depressed by addition of sodium cyanide, ferrous sulphate, zinc sulphate or various mixtures of these reagents. The method is suitable for the flotation of sulphide ores, which, do not bear precious metals, such as silver and gold. When classical technology with cyanide is applied to depress zinc minerals, the precious metals, which are contained mainly into lead minerals, are dissolved into the solution, which represents a technological loss. In order to avoid this process, we have made use from the knowledge on the semiconducting properties of lead and zinc sulphide minerals. We have changed the surface charge of minerals by means of an electrochemical impact realized by direct current application and specially designed set of insoluble or semi-soluble electrodes. Thus, flotation separation of lead and zinc sulphide minerals was achieved, at increased recovery of lead, zinc and silver. The technology proposed was implemented in a Bulgarian flotation factory; it worked over 5 years providing significant, positive economic, technological and environmental impact. Silver recovery was increased by 0.8-1.0 %, and lead and zinc recovery was increased by 0.8-1.0 %. The technology is easily controllable and adaptable to raw materials and parameters of the technological process. It can be paid back for 6-8 months after the implementation. Keywords: lead-zinc flotation separation, electrochemical impact

Sep 1, 2012