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By L. K. Smith

Flotation work conducted by CSIRO on both single minerals and high-arsenic copper ores from a number of sources, has shown it is possible to produce separate low-arsenic copper concentrates and high-arsenic copper concentrates from high-arsenic copper ores. The procedure involves controlled separations at high or low pulp potential regions exploiting subtle differences in the flotation behavior of the arsenic-bearing and non-arsenic-bearing copper minerals. An overview of several case studies investigating the applicability of the controlled potential flotation approach to the separation of copper and arsenic from sulfide copper ores is presented. It highlights the variables which influence the efficiency of the separation which include mineralogy, liberation and reagent selection. The procedure can produce a saleable low-arsenic copper concentrate, which can be directly smelted without penalty, and a high-arsenic low copper concentrate, which will require further processing. Keywords: flotation, copper, arsenic, controlled-potential flotation

Sep 1, 2012

By Lj. D. Andric

Development of modern devices for mechanical and mechanochemical materials activation has been dated since the beginning of last century. Rapid development of high-energy mills that are different in type, size, design and performances, has been occurred during the last four decades. Because of complete understanding of mechanical processing, entire knowledge of theoretical principles of high-energy mills is necessary. These principles are main causales of process that are happened in materials during the mechanical activation. This paper is occupied by theoretical principles of operation of high-energy mills. Conventional high energy mills with balls, high-energy planetary mills and high-energy vibrational mills are particularly considered in the paper.

Jan 1, 2014

The traditional technological flow sheets for processing of ferrous quartzite (magnetite ores) al-low production of the iron concentrates with Fe content of 65%~68 % and recovery level about 55 %. The losses of iron with the tails of wet magnetic separation are related to hematite and quartz-magnetite particles, which are not extracted under low magnetic field employed. This work presents the results of the application of reverse cationic flotation for production of hematite concentrates with weak silica content from the tailings of wet magnetic separation of mag-netite. Fine particle size, complex mineralogy and presence of locked particles determine the impos-sibility of direct production of hematite concentrate by flotation or magnetic separation. The gravity concentration allows obtaining of iron concentrate from the well-prepared feed (size fraction -53+20 µm) but with very low recovery. Thus, hematite concentrates with weak silica content and satisfactory iron recovery were obtained by reverse cationic flotation, when it was fed with iron pre-concentrate produced by high gradient magnetic separation. The best flotation results were obtained by the use of formulations based on amines of different molecular structure that modulate the structure of adsorption layer, and favour a shifting of hydro-philic-hydrophobic balance on the surface of silicates with adsorbed starch and their preferential transfer into the froth product.

Jan 1, 2014

By H. Matsuoka, M. Kawata, K. Haga, K. Mitsuhashi, C. Tokoro, A. Shibayama, R. Kawarabuki

"The mineral surface characteristic is important for the flotation because it affects the flotation behavior of the mineral. Conventionally, in the flotation process for Cu sulphide ores, the degree of ore floatabilities varies depending on the mineral phase such as chalcopyrite, bornite, or chalcocite. Therefore, mineral surfaces are treated with activators and depressants to control the floatability of target minerals and obtain high recovery performance. There are lots of flotation reagents which have many effects on ores depending on ore characteristics and conditioning methods. For example, sodium hydrosulphide (NaHS) as activator is known to have the effect of resulfurizing and activating oxidized surface of chalcocite and bornite. On the other hand, NaHS is reported to depress chalcopyrite floatability. In this study, the evaluation of mineral surfaces was conducted to predict flotation behavior. Activation of Cu minerals (chalcocite, bornite, and chalcopyrite) by NaHS was experimented. The three Cu minerals were treated in two steps. Firstly, they were oxidized in the drying oven. Secondly, they were treated with NaHS solution. After each treatment step, each mineral was measured by contact angle apparatus then analyzed by X-ray photoelectron spectroscopy (XPS). The results of surface characteristics after oxidation and NaHS treatment were utilized to accomplish the study’s objective. INTRODUCTIONCopper sulfide minerals such as chalcocite (Cu2S), bornite (Cu5FeS4), chalcopyrite (CuFeS2) are well-known abundant copper-containing minerals. Generally, these minerals are recovered and concentrated via collector flotation. In flotation, the wettability of the mineral surface is an important factor in its recovery. When the surface is hydrophobic, the mineral has high floatability and when the surface is hydrophilic, it has low floatability. Usually, Cu sulfide minerals have high floatability. However when their surfaces are oxidized, their floatability becomes lower in flotation. In this case of surface oxidation occurrence, activators are added before flotation to modify the surface property of the Cu sulfide minerals so that they can be floated at a certain flotation condition. Sodium hydrosulfide, NaHS, is known as one of the activators. Zhao et al. (2018) reported that NaHS is often used as sulfurizer for oxidized sulfide minerals (Becker et al., 2014, Clark et al., 2000, Newell et al., 2006, 2007, Newell and Bradshaw, 2007). Although the floatability of Cu sulfide minerals was raised by adding NaHS generally, the results of this flotation study showed that the flotation behaviors of mixed chalcocite, bornite, and chalcopyrite were different. Therefore, it was considered that NaHS works differently for each mineral."

Jan 1, 2018

By Ö. Genç

In this paper, full-scale mill data collected from three different circuit configurations in cement plants demonstrated the size reduction performance of dry ball mills in relation with the ball size classification achieved by the classifying liners used in the grinding compartments. Findings indicated that, breakage rates at the last 2 ~ 4 meters of the mill are not sufficient to give reasonable size reduction ratios for the production of fines. Application of only damming rings without classifying liners resulted in inverse ball size classification which lead to reduction in size reduction performance thus specific breakage rates.

Jan 1, 2014

By Güven Önal, Zeki Dogan, Neset Acarkan

In this study, it was aimed to produce glass sand with less than 0.15% Fe2O3 for window glass manufacture and glass ware grade with less than 0.05% Fe2O3 from Yalõköy sand dunes having 0.48% Fe2O3. In order to reduce the iron content of the Yalõköy sand dune, magnetic separation, flotation, scrubbing, H2SO4 leaching and drying were used. The optimum iron removal was achieved by H2SO4 baking at 150oC and 8 kg/t acid consumption. In this way, sand concentrate was obtained with 0.04% Fe2O3 and sand recovery 95%.

Jan 1, 2003

By Y. Q. He

The methodology of active pulsing air separation is a new method for dry material classification. Especially, it is suitable to electronic scraps disposal and re-utilization. By studying the difference of drag coefficients of the particles moving through areas of varying Reynolds numbers, and considering the extra-mass forces acting on the particles in the active pulsing air field, models of the dynamic motion which particles follow were developed. A computer simulation was prepared that showed the traces of particles with different densities and/or diameters, but similar aerodynamic characteristics, as they moved through the turbulent flow, to modify and define the parameters of the models. The simulation was found to predict the observed results with artificial tracing spheres being separated by the laboratory equipment. The separation performance, as being affected by the particles, nature, the air velocity, the pulsing frequency and the air pattern, is discussed. In general, lower density particles are more responsive to variations in airflow velocity. In addition, an industrial scale active pulsing air separator was designed, and it provides a new and efficient method for resource re-utilization in China.

Jan 1, 2014

In this study, selective flocculating of diaspore using anion macromolecular reagent as flocculant was tested to separate diaspore from alum-silicate minerals. Firstly, the effect of pH on settling behavior of diaspore and kaolinite dispersions has been investigated. The results show that the maximum settling speed of diaspore and kaolinite appeared re-spectively at pH7 and pH3.33 which is close to the point of zero charge (PZC) of diaspore (6.8) and kaolinite(3.5). This result is in well agreement with the double electric layer theory. Secondly, the settling behavior of diaspore and kaolinite particles in different anion flocculant solution have been researched. The results indicate that flocculant solution concentration significantly affect the selectivity and the flocculating performance of anion molecular. In high concentration solution, both diaspore and kaolinite have faster settling rate compared to blank solution. How-ever, in low concentration solution, the anion macromolecular can enhance the settling rate of diaspore remarkably but has no apparent effect on the settling rate of kaolinite. This result suggests that the tested anion flocculant is a promising reagent for de-silica of diasporic bauxite. Lastly, FTIR method was employed to probe the adsorption mechanism of flocculant on diaspore and kaolinite. The results reveal that there are anion flocculant characteristic bands on the spectra of diaspore but no obvious characteristic bands of flocculant on the FTIR spectrum of kaolinite. This result is in good correspondence with settling test.

Jan 1, 2014

By S. L. Gubin, T. V. Ignatova, A. V. Levshin, D. O. Sharkovsky

"Flotation process applied for concentration of unoxidized ferruginous quartzites by PJSC Mikhailovsky GOK (MGOK) is based on wet magnetic separation of strong magnetic minerals. However quality of the resulting concentrate (Fe65-66%) is insufficient for production of metallics. Quality upgrade of magnetite concentrate via flotation has been implemented by MGOK to produce premium quality magnetite concentrate.Flotation is a challenging process due to sensitivity to varied amounts of reagents, fine and coarse mineral ratio, particle contact (retention) time and temperature of feed. Tomah’s PA-14 reagent (USA) has proven efficient for application in flotation of MGOK’s magnetite concentrate.Objective of this work is to select and prove applicability of selective agents for flotation upgrade of magnetite iron ore concentrate.Series of flotation tests has been carried out with application of new highly selective collecting agents produced by Akzo Nobel (Sweden), Clariant (Germany) as well as Akzo Nobel’s and Tomah’s cationic collector mix to improve performance efficiency of flotation process. Tomah’s flotation agents and Akzo Nobel’s Lilaflotproved to be the most effective for purposes of concentrate quality upgrade to Fe69.0% via flotation.Testing Method: Following scientific research methods were applied for testwork: system analysis, mathematical statistics, observation, comparison, trial (experiment).To determine key process factors a series of pilot tests was carried out. Most of the testwork was performed by PJSC Mikhailovsky GOK’s Central Process Laboratory.Work Results:-optimized flotation performance modes were defined to ensure production of three types of low-silica concentrate, i.e. containing SiO25%, SiO24% and below SiO23% by weight. Most efficient selective agents applicable for flotation have been defined. Mixture of higher aliphatic amines has proven to intensify selective flotation of quartz. It enables higher yield of chamber product maintaining desired quality of concentrate.Achieved process operation and performance factors have been revaluated.Value for Advancement and Expansion of Mineral Processing:Flotation of concentrate has enabled expansion of PJSC Mikhailovsky GOK’s production capacity, improved production quality, helped to maintain sustainability and competitive advantage of the company."

Jan 1, 2018

By Chi Zhang, Junyi Wu

"With the increasing popularity of lithium cobalt oxide in lithium ion battery industry, which is driven by new energy vehicle and mobile device applications, the demand of cobalt is also growing rapidly in recent years. There is a significant trend of increasing investment on cobalt capacity in China, and the automation renovation is considered as an option of improving production efficiency. This study aimed at evaluating the practicability of stainless permanent cathode blank and automatic stripping process in cobalt electrowinning process. The purpose is to replace the old starter sheet process in cobalt electrowinning, which so far was used by most of cobalt refineries in China, but very labor intensive and exposed operators to serious aerosols that contained both cobalt and acid. In the old starter sheet process, the initial cobalt starter sheet is produced onto a plate made of titanium, while the titanium cathode blank and hanger bar fit the critical corrosive environment but is lack of mechanical strength for automatic production which has been mature in copper electrowinning process. To evaluate the proper materials instead of titanium, the coupon corrosion tests with different raw materials including 316L and other stainless steel grades were held for several months in production environment at a cobalt tank house in China. Following the comparison between titanium and other tested materials, a pilot production test in a cobalt tank house is also on-going.INTRODUCTION Cobalt has been known in early China and used in pottery glazes, and the ancient Greeks and Romans used its compounds to make colored glass since long time ago. The blue on the colored porcelain from the Tang Dynasty in China was also due to the presence of cobalt compounds. The word cobalt is known being derived from the German kobalt, from kobold meaning ""goblin"", because the cobalt-bearing blue ore, CoAsS, was called kobaltin in Europe in the Middle Ages, it may have been thought to be harmful to the health of the miners because of arsenic in the ores."

Jan 1, 2018

By Magnus Evertsson, Rebecka Stomvall, Josefine Berntsson

"Understanding the effect of particle shape on dry rheology is considered to be an important aspect in order to replace natural sand used in concrete with manufactured sand. Crushed particles from solid rock are normally less rounded and have less equally shaped dimensions compared to natural sand. Thus, the flowability and workability of the concrete will be different. In previous research, it has been demonstrated how different crushing techniques affects the shape of the particles. In many cases it is believed that Vertical Shaft Impact (VSI) technology is a way forward to replace natural sand. To be able to study the effect of VSI at the smaller fractions (63-2000 µm) sufficient measurements methods to determine particle shape are required. Optical tools to analyze the aggregates would make it possible to study a large amount of particles at small fractions. The determination of particle shape of aggregates is challenging since the shape is highly irregular and the size span of particles are very large. This study aim to evaluate one of the available optical tools, the Camsizer, for digital imaging determination of shape and size distribution. The available default shape parameters of the Camsizer are studied to understand the meaning of the parameters and their suitability for determining the quality of manufactured sand. To evaluate the capacity to determine particle shape, tests are made with 35 different materials. The results are compared with the dry rheology measured with the standardized "flow cone" test. Dependence has been previously proven between particle shape and the mass flow rate in the cone. Three different shape parameters, aspect ratio, sphericity and symmetry, are studied with the Camsizer and the results are compared with the mass flow rates in the cone. The results indicate a strong linear relationship between the optical parameters and the flow cone test."

Jan 1, 2014

By Rong Fan, Andrea Gerson

"The small recovery of Ag, often in the order of 50%, by traditional flotation and leaching process strategies is closely related to the complicated and heterogeneous nature of Ag-bearing minerals with Ag typically being associated with numerous minerals within any given ore-body. Moreover, grain sizes may be extremely fine with micron-scale common. In order to design cost-effective Ag-bearing mineral flotation and leach recovery strategies it is firstly necessary to characterise the speciation of Ag and its correlation with other elements, e.g., Cu, As and Sb, within the ore matrix and process streams. The traditional QEM-SCAN analytical approach can prove problematic for some mineralogies due to difficulties in recognising degrees of crystallinity, polymorphs, complex solid solution series, high value trace element mineralogy, very fine grained materials; and the requirement for a comprehensive data base. Moreover, there is difficulty ‘seeing’ either surface films or surface contaminants which can both lead to poor flotation performance. There is therefore clearly a need to develop confirmatory and complementary approaches when these uncertainties arise. Synchrotron X-ray microprobe analysis provides a powerful tool for the mineralogical characterisation of finely segregated heterogeneous Ag-containing materials. These measurements enable comprehensive characterisation of the Ag-bearing components using synchrotron microprobe X-ray fluorescence mapping (µ-XFM), X-ray diffraction (µ-XRD) and X-ray absorption spectroscopy (µ-XAS). Further analytical strength is provided by principal component analysis of laboratory ToF-SIMS data which enables the statistical identification of correlated surface species enabling examination of surface chemical characteristics responsible for mis-reporting of Ag containing components within flotation streams. We describe the application of these techniques to a selected Ag-containing feed and tail and demonstrate how these compliment and extend traditional analytical methodologies."

Jan 1, 2014

By John Ralston, Jona Addai-Mensah, Patience Mpofu

The flocculation and dewatering behaviour of kaolinite (non swelling) and smectite (swelling) clay dispersions has been investigated using hydrolysable metal ions Mn(II) and Ca(II) and anionic polyacrylamide-acrylate copolymer (PAM) at pH 7.5 and 10.5. A pH-dependent, specific metal ion adsorption behaviour, accompanied by a marked reduction in particle zeta potential and slurry shear yield stress, was observed to have a profound influence on the colloid stability of both types of clays. Due to the differences in the cation exchange capacity, the smectite clay dispersion required a higher amount of metal ions than kaolinite dispersion to produce similar effects. The adsorption density of the anionic PAM at the negatively charged clay particle surfaces correlated well with metal ion hydrolysis and adsorption behaviour, all of which had a strong effect on slurry settling rate and extent of consolidation. At pH 7.5 where Mn(II) ions hydrolyse, metal ion and flocculant adsorption densities were both greater in the presence of Mn(II) than Ca(II) ions. At pH 10.5, however, where Ca(II) ions begins to hydrolyse, higher adsorption densities were observed for Ca(II) ions in comparison with Mn(II) ions, as the latter hydrolysed completely and precipitated. The metal ion mediated flocculant adsorption led to improved hydrogen bond driven particle bridging and facilitated charge neutralisation flocculation mechanisms which significantly enhanced the dewaterability of both clay dispersions.

Jan 1, 2003

By A. Javadi

"Our recent studies revealed that the sulfide minerals in contact with water during grinding produced hydrogen peroxide (H2O2) where the amount of H2O2 production by the minerals found to be in the order of pyrite > chalcopyrite > sphalerite > galena. The H2O2 effect on the oxidation of pulp components and its influence on the concentrate grade and recovery in flotation have been studied and the results have been presented and discussed in this paper. Studies have also been carried out to build correlation between percentage of pyrite in the concentrate, grinding conditions and concentration of OH•/H2O2 in the pulp and as well of controlling the formation of these species through known chemical means for depressing the generation of the oxidant. Flotation tests using a complex sulfide ore with the same reagent scheme that is being used at Bama concentrator in Iran but with the addition i) Na2S reductant and ii) inorganic (EDTA) and organic (TETA) surface modifiers, during grinding stage have been performed to judge the beneficial or detrimental role of H2O2 on the selective flotation of sulfides. The results demonstrate that the selectivity of metal sulfides against pyrite increases with increasing generation of H2O2 in the pulp liquid.INTRODUCTIONOur recent studies have illustrated the formation of hydrogen peroxide (H2O2) by metal-sulphides during grinding in the presence and absence of oxygen (Javadi Nooshabadi & Hanumantha Rao, 2013a; Javadi Nooshabadi & Hanumantha Rao, 2013b; Javadi Nooshabadi & Hanumantha Rao, 2013c; Javadi Nooshabadi & Hanumantha Rao, 2014). In the absence of oxygen, it was found that pyrite surface is catalytically active and able to breakdown water molecules to form OH• free radical and thereby deriving oxygen in the formation of H2O2 from water molecules. The in-situ formation of H2O2 and its influence on sulphide flotation has not been addressed yet. The presence of strong H2O2 oxidant in the pulp liquid and its selective oxidation of pyrite would be beneficial in depressing pyrite flotation. Therefore, it is important to build correlation between percentage of pyrite in the concentrate, grinding conditions and concentration of OH•/H2O2 in the pulp as well as to study possible ways of flexibly controlling the formation of these species through known chemical means for depressing the generation of the oxidant."

Jan 1, 2018

By J. Yianatos

The cleaning circuit operation and its effect on the plant metallurgical performance, was characterized at Los Pelambres concentrator, Chile. Experimental data from columns, scavenger and regrinding stages was evaluated. Each stage was characterized by size fractions, and the interaction between stages (columns, scavenger, regrinding) as well as the effect that circulating loads had. The approach for describing the flotation equipment operation (cells and columns) considered the collection and froth zones separately. This methodology allows for the identification of the impact that particle size distribution has on the actual collection and froth transport processes, independently. In this way the effect of regrinding on flotation recovery and grade can be related to the corresponding operating variables, e.g. pulp flowrate, air flowrate, pulp level and pulp density, among others. The effect of gangue entrainment was considered using an empirical dimensionless correlation. The interaction between the circulating load and the overall performance of cleaning circuit was evaluated. The circulating load was defined as the ratio between the solid flowrate of scavenger concentrate over rougher concentrate. It was found that the overall cleaning flotation circuit (column-scavenger) can operate at a relatively high and constant recovery for a wide range of mineral treatment. This is possible when the scavenger has the capacity for compensating the decrease in column recovery at larger circulating loads. Under the condition of high overall cleaning recovery, the rougher stage closely represents the plant recovery. However, at large mineral treatment conditions, the design characteristics (e.g. concentrate transport channel capacity and transfer boxes) as well as instrumentation, control facilities and operation, became bottle-necked. A simulator was developed using empirical models for each stage (column, scavenger and regrinding) in order to evaluate proper operational strategies for cleaning flotation circuits Keywords: flotation, cleaning, regrinding, Vertimill, simulation.

Sep 1, 2012

By X. L. Song

A large amount of tailings in concentrators bring a series of problems to the environment and society. It is significant to reclaim the huge tailings and reuse them in industries in order to utilize mineral resources adequately. Primarily Lead-Zinc tailings with a certain quality of clay and feldspar were used to produce ceramic tiles by sintering method under specific technical conditions. By testing the properties of the ceramic tiles, it was shown that the amount of Lead-Zinc tailing used in the tiles was 60%~70%, and the mechanics properties were good. The optimum proportion parameters were Lead-Zinc tailing 60%, clay 35%, feldspar 5%, and the maximum flexural strength of tiles was up to 38.2MPa when it was sintered at 1090? for 30min. Its flexural strength, water absorption and thermal shock resistance reached the State Standard of GB/T4100.4. The product is suitable to be used in pavements and paths of parks.

Jan 1, 2014

By G. J. Feng

Based on detailed theoretical analysis of coarse floatation and three-phase froth, a laboratory system which contains a new type of froth floatation equipment is established. Through water experiment, the relationship among floatation dynamics parameters of the equipment is studied and the best work parameters are educed too. Based on all of above, Slurry test is carried out in a copper concentration plant. Granule between 0.28~0.45mm can be reclaimed successfully. The slurry test proves that to separate coarse minerals in froth floatation equipment is a kind of effective method, it is well worth to make a further study.

Jan 1, 2014

By S. Narra

Converting biomass into valuable fuel requires various preprocessing of the raw materials. Biomass densification is one of the conversion processes for its utilization. The aim of densification is to produce biomass pellets, which can withstand regular handling stresses and exhibit high densities with uniform size and shape. Physical properties, such as the particle size distribution after comminution is of highest importance for the binding mechanisms in the pelletisation process. Durability and strength of the pellets play an important role indicating the ability to withstand handling stresses. Particle size distributions of the cereal straws (Rye and Wheat) after specific comminution and liberation processes have been carried out with the help of three different image analysis (Microscope, Camsizer and Fibreshape). The durability of the pellets have been investigated as specified in the standards (ASAE standard S269.4) with a quadratic crate and the strength of the pellets with compression and tension testing machine (Zwick Roell type: ZMART.PRO). The particles size results showed differences in both length and width after different comminution processing. An exact comparison between the particle size analyses with the three different image analyses was not possible. The particle size distribution and the different comminution processes displayed influences on the durability and strength of the produced pellets. The particle size distribution displayed approximately 40 % of fines and 60 % of fibers. The particle size distribution displayed a direct relation to the durability of the pellets. Further durability and strength of the pellets displayed a good correlation.

Sep 1, 2012

By K. D. Mehta

Copper concentrate containing complex sulphides of Cu-Ni with 14.13% Cu and 10.04% Ni besides impurities such as 0.33% Co and 0.71% Mo, is not acceptable to the copper smelters due to the smelting problems. Selective bioleaching of nickel from the concentrate can be considered an an option to make it suitable for copper smelter. Effect of elemental sulphur and pyrite on the bioleaching of Ni and Co has been investigated using a mixed culture of Acidithiobacillus ferrooxidans (A.f.) and Acidithiobacillus thiooxidans (A.t.). Parameters such as pH, temperature, particles, size etc. were optimised to understand the role of additives in the bioleaching. With 2% S at 308K, 2.0 pH, 5% pulp density and 200µm size particles while shaking at 100 rpm, 79% Ni, 41% Co and 5% Cu were bioleached as compared to the leaching of 81% Ni and 45% Co in presence of 10 wt% pyrite in 60 days; 27% Ni, 24% Co and 4% Cu were recovered in sterile experiment. The selective dissolution of nickel and cobalt as compared to copper may be explained by galvanic interaction between chalcopyrite: pentlandite / pyrrhotite. Bioleaching was facilitated by strong oxidizing conditions due to higher Fe3+/Fe2+ ratio/redox potential (ESCE) as a result of improved interaction of minerals through biooxidation of sulphur and accelerated galvanic interaction by pyrite. The mechanism of selective leaching of Ni and Co was established by XRD phase identification.

Sep 1, 2012

By M. Alvarez-Silva

The control of the amount of chromite reporting to the concentrate during the flotation of UG2 ore is of critical importance since its presence affects the downstream smelting process. It is generally reported that the main mechanism responsible for chromite recovery is through entrainment. This is reflected in analyzing the solids and water recoveries. These in turn are strongly dependent on the froth phase. In the present investigation a laboratory scale column flotation cell was used to investigate the role of the froth phase in the flotation of UG2 ore. Such a device is superior to a standard batch cell since it operates at steady state in open circuit and also allows for a greater degree of flexibility in terms of froth heights. The mass of solids and water recovered in the concentrate as well as chromite (Cr2O3) recovery by size class was determined as a function of froth height, superficial gas velocity and depressant dosage. The results showed that depressants had little effect on chromite recovery but increased the grade due to the depression of gangue minerals. A 60cm froth height always resulted in slightly lower solids, water and chromite recovery than for 30cm. Typically only 20-25 % of solids reaching the pulp-froth interface reached the launder. The relationship between solids and water recovery for a wide range of conditions indicated that chromite is mostly recovered by entrainment. Keywords: UG2 ore, column flotation cell

Sep 1, 2012