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By B. Aydin, G. Erturk, G. Bulut

Coal is a complex material because of its structure consisting of carbon constituents and mineral matter. Flotation is readily carried out due to hydrophobic characteristic of coal. Therefore coal flotation is the most commonly used technique for fine coal beneficiation in order to acquire clean coal separating ash forming mineral matter from carbonaceous matter. In the coal flotation, floatability of coal both depends on characteristic of coal and used flotation reagent. Frothers as a flotation reagent are used to facilitate air dispersion into fine bubbles by prevention of bubble coalescence in the pulp phase, and stabilization of flotation froths. In this study, the effects of frother types and concentrations at different pH and particle size on the coal flotation were investigated. The representative sample was taken from Zonguldak, Turkey. It contains 9.1% ash and 7313 (kcal/kg) calorific value. Pine oil, Dowfroth 250, MIBC and Isooctanol were tested as frother types. It is determined that 1.92 ppm frother concentration is sufficient to float coal, except pine oil. In mixed frother tests, it is seen that Dowfroth 250 is more effective than others. No significant difference in coal recovery was observed for flotation tests at the different pH values. The best results are obtained in size of coal (-0.1 mm) with all frothers.

Jan 1, 2014

Considerable attention has been, and is being, given to the physics of water-films associated with bubble interactions at surfaces. In contrast, little information on the chemistry of such films has been reported. This communication reports a method using sum frequency vibrational spectroscopy (SFVS) to describe hydrogen bonding of interfacial water molecules in water films created with bubbles at hydrophilic and hydrophobic surfaces. The SFVS spectra of water films at hydrophilic silica surfaces differ significantly from the spectra of water at a hydrophobic silica surface. The SFVS spectra indicate that a very ordered water structure exists in water films at the hydrophilic silica surface during contact with a bubble and that the extent of hydrogen bonding increases with an increase in contact pressure. Such structural considerations as well as repulsive electrostatic and Van der Waals forces account for film stability for a bubble at the hydrophilic silica surface. In contrast, the SFVS spectra of water at a hydrophobic silica surface show a lack of hydrogen bonding and are characterized by a distinct absorption at about 3700 cm-1 similar to the spectrum of the air/water interface. These results suggest the presence of a water void, or water exclusion zone, at the hydrophobic surface, as supported by X-ray reflectivity measurements reported in the literature, by atomic force microscopy, and by the results from molecular dynamics simulations. Of course the water film at the hydrophobic surface is unstable with film thinning and rupture upon bubble contact. Under these circumstances it is shown that an attractive Van der Waals force between the bubble and the hydrophobic surface can be expected when the water exclusion zone is taken into consideration. As the thickness of the water exclusion zone increases to a thickness corresponding to the size of nano bubbles, the calculated attractive Van der Waals force increases. This analysis may help to explain the so-called ?short range? and ?long range? hydrophobic forces. Keywords: SFVS spectra, hydrophilic silica surface, hydrophobic silica surface

Sep 1, 2012

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 Zhen Hu, Chenghang Wang, Jianjian Zou, Xiujuan Li, Hanwen Li, Tai Wang, Baoxu Song

A rare earth deposit in Sichuan, China is rich in wulfenite in addition to bastnaesite and barite, and the deposit has already adopted high intensity magnetic separation technique to pre-enrich the rare earth minerals, during which the wulfenite and barite have been left in the non-magnetic product. Because the chemical composition of wulfenite is only 24.17% Mo and 42.15% Pb, it is very hard to obtain qualified lead or molybdenum concentrates by physical separation process. To pre-concentrate the wulfenite, flotation has been first introduced, and by using 100g/t GY-7 as dispersant, 1500g/t CP-1 as depressant and 160g/t GY-4 as collector, a floatation concentrate assaying 15.52% Mo with a recovery of 86.12% was obtained. Then a leaching process was conducted by using 1.2mol/L Na2S as leaching agent, and molybdenum can be translated into sodium molybdate in the solution with a leaching recovery of 99%. To recover rare earth oxides (REO) and lead from the leaching residue, a magnetic separation process has been conducted. Above all, by the whole process, the molybdenum recovery reaches 86.16% in the sodium molybdate solution, and a lead concentrate assaying 54.59% Pb with recovery of 27.99% could be obtained.

Jan 1, 2014

By Agnieszka Surowiak, Tomasz Niedoba

The paper presents a way of determining relations between ash content in coal, particle size and particle density by means of regression, multidimensional Morgenstern distribution functions and kernel approximation. The three-dimensional random vector (D, ?, ?), where D is a random variable describing particle size, ? - random variable describing particle density and ? - random variable describing ash content, where function ?=?(d, ?) is obtained by means of regressive function. The multidimensional Morgenstern distribution functions and kernel estimators with the use of Gauss function were applied to approximate the functions f(d, ?, ?) and f1(d, ?). This approach is a new way of multidimensional description of grained materials such as coal and it also allows to evaluate material features more properly than the classical statistical approach. The results were verified statistically.

Jan 1, 2014

By S. Kondratiev

Mechanism of the action of nonpolar physically adsorbed reactants in froth flotation is under discussion in the paper. It is shown that their basic influence on flotation includes removing of the kinetics restrictions of the flotation complex formation. Experimental data and practical evidence reported in the paper sustain the proposed mechanism. There are discussed potential dependence of the kinetics of dixanthogen formation on platinum and its influence on the induction time (IT).

Sep 1, 2012

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 Marzio Piller, Girolamo Belardi, Jure Mencinger, Paolo Bozano, Gianni Schena

"The hydrodynamics of the Tri-Flo™, a two stage cylindrical cyclone used in dense media separation, is studied using Computational Fluid Dynamics. The flow field is simulated with an Euler-Euler Volume of Fluid two-phase approach and the Reynolds stress turbulence model.A unique feature of the device is that the separation medium suspension is pumped and introduced tangentially into the two cylindrical compartments while the raw feed is conveyed to the feed hopper and fed at the axial inlet. This feature allows to use less pumping energy and limits the unavoidable production of fines. The Tri-Flo™ complex flow pattern is little known but central to the efficiency of the separation.The velocity field is computed within the two compartments of the separator. The interface of the air-core that forms in the inner axial part of the cylindrical sections is identified and visualized. The numerical results for a reduced-size 100 mm ID Tri-Flo™ are compared against laser Doppler measurements on a transparent acrylic model (Chinè, 1995) operated with water. The robustness of the model and its prediction capability are verified.The possibility to accurately predict the velocity profiles within the vessel and their dependence on the main Tri-Flo™ operating and geometrical variables paves the way to a better understanding of the functioning of the separator, its design improvements and scale-up."

Jan 1, 2014

By Kazutoshi Haga, Atsushi Shibayama, Altansukh Batnasan

"The aim of this study was to develop a hydromellurgical processing for removal of arsenic from high-arsenic copper sulfide ores and concentrates, providing increase in copper recovery. In this study, three different enargite ore samples containing 28.2–46.7% copper, 1.9–15.0% arsenic and 10.6–27.5% iron were used to determine optimum conditions for the extraction of copper and removal of arsenic. High pressure oxidative leaching process was preformed using various leaching reagents such as sulfuric acid (H2SO4), ferric sulfate (Fe2(SO4)3), hydrochloric acid (HCl), ferric chloride (FeCl3), sodium sulfate (Na2SO4), sodium chloride (NaCl) solutions and distilled water (DW), respectively, under the fixed conditions which were selected to be as follows: NaCl concentration, 0.34 M; concentrations of other leaching reagents, 0.1 M; particle size, -45 ?m; pulp density, 100 g/L; agitation speed, 750 rpm; leaching temperature, 160 ?C; leaching time, 60 min and total pressure (oxygen gas and vapor pressure) into an autoclave, 1 MPa. Results show that under the leaching conditions, more than 90% of copper leaching was achieved with lower than 2% arsenic content as a consequence of the formation of arsenic precipitates in a solution of Fe2(SO4)3–NaCl. It was determined that copper, arsenic and iron concentrations in the pregnant leach solution were 42 g/L, 0.3 g/L and 0.3 g/L, respectively. As a result, it can be concluded that the Fe2(SO4)3 solution in the presence of NaCl or FeCl3 are more efficient leaching media compared to other leaching agents under the high pressure oxidation conditions, because of their high copper recovery and lower arsenic level in the pregnant leach solution.INTRODUCTION Generally, copper is usually produced from copper sulfide ores by a combination of several processes which are flotation and smelting followed by refining [1-3]. Arsenic content in copper sulfide ores tends to increase due to the depletion of high grade copper deposits, hence conventional mineral processing and metallurgical processes cannot effectively treat these ores containing high levels of arsenic to obtain consistently high purity copper concentrates. Because high levels of arsenic in copper ores/flotation concentrates reduces the value of concentrates due to the restriction of smelting process and causes it to be a source of environmental pollution [4-6]. From this point of view, the known way of prevention against high-arsenic copper sulfide concentrates in further metallurgical treatments is to develop economically and environmentally competitive technologies for removal of arsenic impurity from copper sulfide ores before treating the ores/flotation concentrates by the pyrometallurgical routes."

Jan 1, 2018

By Rod Hocking, Nenad Djordjevic, Randolph A. Pax

"Semi Autogenous (SAG) mills exhibit complex interactions between the competing processes occurring inside them. Traditional practice is to measure the operation of the SAG mill at an operating point in terms of its load, power draw, steel load, ore throughput rate, water addition rate and more recently the feed size distribution. However significant departures from standard operating conditions can occur due to changes, for example, in ore hardness, the quest for higher throughputs and mill internal geometry.Fundamental to SAG mill operation are the internal processes that ensure that a given ore throughput and discharge grind size are obtained and maintained. These processes can be measured using non-contact acoustic emissions from the SAG mills which utilise the information rich noise that is generated by the grinding, flow and charge movement inside a mill. Non-contact acoustic in-mill measurements can be used for the validation of discrete element modelling (DEM). The approach being reported in this paper is to model the individual physical processes and then to simulate the assemblage of a physical mill.By modelling the assemblage of steel balls in a 1 m pilot mill and duplicating the experimental arrangement exactly with the PFC3D model, it was possible to replicate the pattern of falling balls in the experimental mill. Furthermore, the key features of the acoustic emission spectrum that was calculated compared favourably to the measured spectrum at low frequencies. The experimental spectrum is shown in Figure 1."

Jan 1, 2003

By Wenying Liu, Marek Pawlik

Long-chain ionic surfactants, with fatty acids and amines as the most important representatives, are widely used as collectors in froth flotation. These surfactants, generally referred to as weak electrolyte collectors, frequently form solid insoluble precipitates within a certain pH range. However, the action and behavior of these colloidal precipitates in froth flotation systems are not well understood and has not been well decoupled from those of dissolved forms. The objective of this study was to understand and compare the role of colloidal precipitates with that of the dissolved forms at gas-liquid and gas-liquid-solid interfaces. Using primary amine as the model surfactant, experiments were carried out to measure: the maximum volume of bubbles generated in the presence of dissolved and precipitated forms of the surfactant; surface tension for both forms of the surfactant using the drop shape and maximum bubble pressure methods; and contact angle using the sessile drop method. The experimental results showed that: in the presence of the precipitate, bubble volume was smaller, which was correlated with the lower surface tension and higher contact angle measured; the surface tension of solutions containing surfactant precipitate was affected by the surface age of liquid droplets. This study enhances understanding of the interfacial behavior of long-chain ionic surfactants under different conditions, which would help improve the efficiency of reagent utilization in froth flotation.

Jan 1, 2014

By V. A. Ivanova, T. N. Perunkova, N. O. Dorozhanova, G. V. Mitrofanova

"Oxyethylated compounds are used as reagents-regulators in the flotation of non-sulfide ores, in particular, apatite-containing ores. Thus, the necessary degree of selectivity in the flotation separation of two calcium-containing minerals of apatite and calcite is achieved only by using, in addition to a collector, regulators-reagents from the nonylphenol ethoxylates class. In order to establish the most optimal structures, this paper presents a comparative assessment of the physical-chemical and flotation properties of several classes of oxyethylated compounds - alkylphenol ethoxylates, aliphatic alcohol ethoxylates and oxyethylated carboxylic acid. The authors have studied their dispergating ability with respect to the air phase and calcium soaps of the carboxylic collector. Dependences of foaming properties of regulators on the degree of oxyethylation have been determined. Adsorption isotherms of sodium oleate on apatite and calcite in the presence of regulators have been obtained. It has been shown that the presence of oxyethylated compounds in the solution reduces the amount of the adsorbed fatty acid collector. The influence of the considered classes of regulators on apatite flotation has been studied. The interrelation of flotation properties of oxyethylated compounds and their molecular structure has been established.INTRODUCTION Flotation plays a leading role in complex apatite-containing ores processing. However, two calcium-containing minerals - apatite and calcite, which compose apatite-carbonate ores, are characterized by close flotation properties. Selective separation of these minerals is a difficult task, the solution of which is impossible without using reagents-regulators. One of the ways to ensure the selectivity of the flotation separation of calcium-containing minerals is the use of reagents-depressants such as sodium silicate, starch, cellulose derivatives, and others (Liu et al., 2016; Rao et al., 1989). Another method is the application of nonionic reagent regulators (Filippov et al., 2016; Filippova et al., 2014; Ignatkina, 2017), which contribute to the adsorption of the ion collector (Filippov and Filipova, 2006 Rao and Forssberg, 1997) and stability of formed froth (Sis and Chander, 2003)."

Jan 1, 2018

By R. Shiva Kumar, G. E. Sreedhar, Rajan Kumar, K. Suresh, A. K. Aketi Veera, M. Narasimha, P. S. Jodan

"In most of the coal washeries, Dense Medium Cyclone’s (DMC) are deployed to treat coarse coal fraction in the range of 50-0.5 mm. DMC’s are very popular due to its ability of high tonnage, ease of operation and effective separation at high near-gravity material (NGM) in feed coal. The ease or difficulty of washing is merely depending on the NGM fraction present in run of mine coal. However, the quantitative effect of NGM on DMC performance was not explored in the literature. Hence, in this investigation, the influence of NGM on DMC performance is focused. With the help of synthetically prepared coal mixture, the effect of NGM mass fraction on separation efficiency is studied in three different approaches. Firstly, by increasing the NGM coal fraction systematically from low to as high as possible; second by varying the distribution of NGM coal; and third by varying distribution of particles lying just above and below the near-gravity zone. Washability studies are also carried out to establish the theoretical yield for the prepared synthetic mixtures. Pilot-plant experiments are carried out in a 4-inch DMC with 1.4 operating separation density treating coal in the size range of 4 - 0.5 mm. From results, the partition curves are constructed by both density and size wise distributions. It is observed that at higher NGM coal fraction i.e above 60%, the performance of DMC is very poor with significant coal particles misplacement. In second approach with increased distribution at higher density fractions, the separation efficiency reduces. In third series the distribution of fraction in near-gravity zone doesn’t much effect the separation except the shift in separation density. It is observed that smaller size (-0.5 mm) coal particle having high NGM content seems have a profound effect on DMC performance leading to significant fines misplacement to wrong products."

Jan 1, 2018

By V. Beskrovnaya

Oxidised lead-bearing ores of one of the deposits of Russian Federation represent complex raw materials. Its main components are lead (3.2%~4.7%), silver (100~300 g/t) and zinc (0.7%~0.8%). The sample is characterized as oxidized ore. Silicium (37.4%) and iron (33.2%) are its main com-ponents and present in oxide form. Lead presents as cerussite, anglesite and plumbojarosite have a subject role. Zinc occurs as smithsonite. Certain part of zinc is associated with manganese minerals (psylomelane-pyrolusite). Close association of valuables with manganese-iron mineralization is ob-served. Silver is present in native finely dispersed form. Three options of flowsheets have been developed to recover valuables from the ore. 1. Hydrometallurgical flowsheet of lead and silver recovery on the basis of chloride leaching. 2. Flotation. 3. Flotation -flotation tailings cyanidation. Hydrometallurgical flowsheet of ore processing on the basis of chloride leaching (option I) al-lows to achieve recovery into saleable products of 68.8% Pb and 70.2% Ag. High quality lead concentrate with 71.7% lead and 700 g/t silver was obtained during flotation (option 2). Flotation tailings cyanidation (option 3) provides 24% silver additional recovery (from the ore). Technical and economical evaluation demonstrated that ore flotation (option 2) and flotation with subsequent flotation tailings cyanidation (option 3) are the most cost-efficient. Option II is the most cost-efficient variant of 1 tonne of ore processing (9.05 US dollars).

Jan 1, 2014

By A. Pandey

Over the years, Coal Beneficiation at Tata Steel - West Bokaro has seen varied changes. With increasing R.O.M throughputs & lowering of the concentrate ash, Fine Coal Beneficiation process has thrown up myriad challenges. Development of Synthetic Collector was initiated couple of years back with Technical assistance from NLC Nalco India Ltd. Coal from West Bokaro unit was sent to Nalco?s Naperville (US) research lab for developing Tailor made synthetic collector . After comprehensive lab flotation studies, synthetic collector was developed & recommended for plant evaluation. The lab scale results were very promising in terms of improved separation efficiency & yield at similar ash level. The collector sample received from Nalco research laboratory were revalidated at Nalco Kolkata lab and finally at Tata Steel West Bokaro lab, confirming the promising results. (S.E 25-30 % better than HS Diesel) The key factors playing out for this improvement initiative are a) Scope for improvement in Clean Coal Yield at same or lower ash level coupled with improved Selectivity and Separation Efficiency b) Introduction of a Synthetic Collector with a Green Chemistry and subsequent replacement of H S Diesel, which is highly inflammable with a less inflammable & safer product Trial was conducted at plant scale in two phases and comparative performance of the Collector vis-à-vis Diesel was evaluated across the following Coal Seams of Q- SE (Seam VII, VIII, VI, IX and X). The results generated are very promising and the improvements observed are summarized below. ? Separation efficiency improvement by more than 20% observed. ? Flotation Fines yield increase varied from 0.6- 1.5 % on raw coal basis across different seams. ? Consumption pattern is 20-25 % lower than Diesel. Keywords: synthetic collector, west bokaro, coal beneficiation, HSD

Sep 1, 2012

By V. V. Musaev, A. M. Klyushnikov, R. R. Galimov

"A study was made of chemical and material compositions of the oxidized gold-bearing ore of the Kochkovskoe deposit. It was demonstrated that examined ore consisted mainly of quartz, carbonate and feldspar with a gold content of 2.2 g/t and a silver content of 6.1 g/t. By means of agitation leaching tests it was founded that about 79-80 % of gold can be extracted from ore using cyanide leaching solutions. The achieved high-speed dissolution rate of gold was due to its presence in a finely dispersed state (less than 2.73 µm), which was confirmed by the research of Uralmekhanobr. It was proposed that the ore can be processed by heap leaching process using cyanide leach solutions. Technological studies on the modeling of the heap leaching process were initially carried out in percolators with a capacity of 5 kg on agglomerated ore. It was preliminary established that agglomeration should be carried out at a cement consumption of 12-16 kg/t, with the moisture content in pellets reaching up to 10-12 %. The best percolation leaching results can be obtained with ore crushed to the size of -20 mm. The maximum extraction of gold to the solution was 79-80 % while the L:S ratio reached 1.2-1.4:1.In cooperation with the research center of OJSC ""Berezovsky mine"" a semi-industrial heap leaching test was accomplished. The result of a test performed was an extraction of 78.5 % of Au and 21 % of Ag from ore to a pregnant solution. This extraction degree was achieved at a L:S ratio 0.9: 1. On the ground of results obtained, a technical regulation was developed for design of the heap leaching plant with the capacity of 500 thousand tons of ore per year.INTRODUCTION The ore of the Kochkovskoe deposit represents an important reserve of gold in the Zabaikal region. Of the upmost interest are oxidized ores, the processing of which can be carried out by heap leaching (HL) with cyanide solutions. The purpose of this work was to study the composition and to develop a technology for heap leaching of oxidized ore."

Jan 1, 2018

By Hamid-Reza Manouchehri, Hassna Aitahmed-Ali, Stellan Sundberg

"In flotation practices as the particle size becomes fine, e.g., p<20µm, the process efficiency declines markedly. When flotation of fine particles is necessary, one method to improve the recovery is selective agglomeration of fines. Different agglomerating methods have been introduced and tested; however, one method which has recently received great attention is to aggregate fine particles by magnetic force. A selective aggregation of the fine paramagnetic particles, e.g., sulfide minerals, can be achieved by applying a high intensity magnetic field during flotation conditioning. The method is simple, selective and effective for fines, and has a low operation cost. However, a minimum magnetic susceptibility of fine grains is required for this process. This method has been demonstrated in different sulfide minerals flotation plants. The implementation of the magnetic conditioning device, ProFlote, in both the Cu-Pb and the Zn circuit of Boliden’s Garpenberg plant in Sweden, where a complex massive sulfide ore is treated, is discussed herein. The preliminary results have shown an increase in the recovery of value minerals, in particular Zn and Ag and considerable reduction in Zn deportment to the final tail. Increases in Cu grade and decreases in Pb grade in Cu-con have been achieved as well."

Jan 1, 2014

By Liping Yu Che, Xiaotie Wang, Mingli Cao, Jizu Yongfu Yuan

"It is difficult separating fluorite from Ca, Ba, Si intergrowth minerals than simple from Si, using common reagents such as combination of oleic acid or paraffin soap and water glass, but the finest quality fluorite concentrate whose grade is over 96%F must be required in chemical plant.This paper studies the flotation process of native fluorite from calcite, barite and silicate minerals whose flotation properties is similar to fluorite, using new effective collector H602 and new depressor S602 that is cheaper in cost, and describes the flotation properties. In order to determine optimum flotation separation condition, the effect of pulp pH, pulp temperature, pulp density and the effect of dosage of reagents on flotation were investigated and the flotation result was provided by oleic acid collector and the results of collector H602 were compared with those of collector oleic acid in the test. The test result of ore samples shows that at moderate pulp pH values (10.5-11.5) and other moderate technical conditions, the fluorite mineral can be obtained by new reagents and the rational reagents combination. The conclusion is 98%F of fluorite concentrate can be obtained, using the combination of H602 and S602 and only 5 steps in techniques. The paper discusses the mechanism of the flotation separation of fluorite mineral from intergrowth minerals."

Jan 1, 2003

By Z. H. Xu

Flotation as a versatile multiphase separation technology has been practiced for more than 100 years in coal and mineral processing. Although effective over a wide particle size range, flotation for mineral separation has been largely understood as an art rather than a science, treating the flotation system as a black box. With rapid progresses in microscopic technologies coupled with high speed video recording and imaging analysis, ingénue design of visualization systems has made it possible to understand fundamentals of flotation by visualization. In this presentation, the state of the art where visualization plays a key role in advancing our fundamental knowledge of flotation will be reviewed. The areas to be covered include characterization of bubbles (shape, size, velocity and sol-ids loading) in a running flotation system, either column or mechanical cell, bubble-solid attachment, hydrodynamic cavitation in fine particle aggregation and flotation, froth imaging, particle-particle interactions by zeta potential distribution measurements, and heterogeneous gas nucleation by atomic force microscope imaging. With these capabilities, critical roles, good or bad, of ore proper-ties, solution chemistry, slurry hydrodynamics, and operation variables in flotation systems as applied to mineral, coal and oil sands processing were clearly elucidated.

Jan 1, 2014

By A. Ekrem Yüce, Gülay Bulut, Feridun Boylu, Vecihi Gürkan, Istanbul Technical University, H. MustafaTarkan

"Nickel sulphide ores subjected to this investigation were taken from Orhaneli district where widespread chromite mineralisation can be occurred. Significant amounts of magnetite and chromite have been existed in the ore together with sulphide and oxide type nickel minerals. Ore sample is constituted about 70% magnetite, 15% sulphide minerals, 5% chromite and iron oxides as well as 10% gangue minerals.According to the chemical analysis results, the representative ore sample contains 1.32% Ni, 10.8% SiO2, 78.4% Fe2O3, 1.3 g/t Ag and 1.0 g/t Au. Mineralogical examinations showed that pentlandite (Fe, Ni)9S8, violarite (Ni, Fe)3S4, millerite NiS and asbolane (Co, Ni)MnO2.(OH)2.1-2H2O were the main nickel minerals and magnetite, chromite, chromium spinals, pyrite, pyrhotite, chalcopyrite, cubanite, goethite, hematite, limonite, rutile, chlorite, talc and serpentine group minerals as associated minerals.The aim of this investigation was to produce valuable nickel concentrates by using gravity separation, magnetic separation and flotation methods. As a results of laboratory scale studies, alternative flow sheets for the production of nickel sulphide concentrate were developed. The related experimental results are given in Table 1."

Jan 1, 2003