Copper Sulfide Ore Research Articles

Oxidative weathering of a copper sulphide ore and its influence on pulp chemistry and flotation

The influence of grinding chemistry on the flotation behaviour of sulphides minerals has been widely studied. However, its influence on partially oxidised sulphide ores is not well documented. Various oxidation events can affect a sulphide ore, either during in situ weathering of an ore body or during the different extraction and processing stages (mining operations, stockpiling, crushing, milling and flotation). In this study, a hypogene copper sulphide ore was artificially oxidised to various lengths of time by percolating a small quantity of acidic ferric sulphate solution inoculated with a mixed bacterial culture through packed columns. For each time interval a series of grinding-flotation tests using different grinding media alloys was completed. The grinding and flotation chemistry were compared and linked to the flotation behaviour of the ore samples.The results reveal that as oxidation progressed the copper metallurgy deteriorated. However, the deleterious effects of oxidation could be partially overcome through the application of the right grinding chemistry.

Primary copper sulfides bioleaching vs. chloride leaching: Advantages and drawbacks

Currently the vast majority of the world's copper is obtained through sulfide mineral processing. Primary copper sulfides are the most economically relevant due to their abundance. Therefore, several technologies have been developed in order to achieve an efficient copper extraction from these types of copper sulfides. Among these developments, the hydrometallurgical options of bioleaching as well as chemical chloride leaching are prevailing for copper sulfides due to their good results at lab, pilot and industrial scale. However, comparisons are not available among technologies due to differences in scale and mineral/ore used in different studies. In this work, we have compared bioleaching and chemical chloride leaching technologies (including sulfuric acid-sodium chloride ore pre-treatment) for a mainly primary copper sulfide ore. This comparative analysis showed first that bioleaching and chemical chloride leaching work at completely different range of redox potential as expected. Hydrometallurgical iron balances indicated that chloride leaching and bioleaching have comparable iron recovery levels. Copper balances showed that bioleaching is significantly more advantageous than chemical chloride treatments in terms of leaching kinetics and final copper recovery. These advantages were correlated to different primary copper sulfides leaching mechanisms that are taking place during bioleaching. Altogether, these results showed major advantages of bioleaching over chloride chemical leaching for the industrial low-grade primary copper sulfide ores treatment.

A study on selective flotation in low and high pyritic copper sulphide ores

ABSTRACTThe effect of chemical reagent configurations was investigated on two different copper sulphide ore types, including high and low pyritic feeds. Three different combinations of collectors as isopropyl-n-ethyl thionocarbamate (C-4132), mixture of mercaptobenzothiazole and butyl sodium dithiphosphate (Flomin 7240) and sodium isopropyl xanthate (Z11) were used in flotation experiments. Solely using C-4132 was selected as the best pattern for both feed types with regard to achieving the highest copper grade and the lowest iron recovery. However, the selectivity index (SI) results showed that the combination of Z11+F7240 provides the highest selectivity of chalcopyrite against pyrite in either low or high pyritic ores.

Study of eight Albanian-Dalmatian axes (XIII-XII B.C.) and six celts (XI-X B.C.) found in northern Albania, by μ-XRF, OM, SEM-EDS

Albania lies in the southeast part of Europe, in the Balkan Peninsula and one of its northern oldest city is Shkodra. This study includes eight Albanian-Dalmatian axes (XIII-XII B.C.) and six celts (XI-X B.C.), found in Shkodra's suburbs. Their elemental composition is analyzed with X ray fluorescence spectroscopy (XRF), the axes' microstructure together with the corrosion products are observed using reflected and polarized optical microscopy (OM). Finally the microstructure as well as the composition of various phases are studied with scanning electron microscopy - energy dispersive spectroscopy (SEM-EDS). All axes result copper-tin alloys associated with elements such as Pb, Fe, Ni and As. The Albanian-Dalmatian axes may have been used as monetary tools while the celts may have served as working tools. Several phases in the microstructure suggest the possibility of sulphide copper ore usage.

Mesophilic inoculation enhances primary and secondary copper sulfide bioleaching altering the microbial & mineralogical ore dynamics

Bioleaching involves a chemical-microbial-driven dynamic process of oxidation and dissolution, as well as formation of surface secondary phases that change the copper sulfide exposure/occlusion profiles. This dynamic process determines the kinetics of copper sulfides bioleaching. Former studies have shown the microbiological dynamics of bioleaching solutions, but few have focused attention at the ore surface, while most mineralogical studies have been done with pure copper sulfide species under controlled conditions. In this work we aim to unravel the link between the microbiology and the mineralogy during bioleaching, and to determine the effect of mesophilic inoculation of a mainly primary copper sulfide ore. State of art molecular microbial community analysis showed that microbial dynamics in the leaching solutions is not representative of the bioleaching process since it differs significantly from the one established at the ore surface. Moreover, a single mesophilic inoculation permanently alters the microbial dynamics, both in the leachate and the ore surface, generating a major and fast alteration of the primary copper sulfide minerals chalcopyrite (CuFeS2) and bornite (Cu5FeS4), as well as the transient formation of covellite (CuS), which was the unique secondary phase detected by advanced mineralogical analysis. Overall, mesophilic inoculation significantly enhanced copper recovery from a low-grade primary copper sulfide ore by means of alteration of the microbial and mineralogical dynamics.

Covellite CuS as a matrix for “invisible” gold: X-ray spectroscopic study of the chemical state of Cu and Au in synthetic minerals

Geological processes leading to formation of sulfide ores often result in precipitation of gold-bearing sulfides which can contain high concentrations of this metal in “invisible” (or “refractory”) state. Covellite (CuS) is ubiquitous mineral in many types of the ore deposits, and numerous studies of the natural ores show that covellite can contain high concentrations of Au. At the same time, Au-bearing covellite withstands cooling in contrast to other minerals of the Cu–Fe–S system (chalcocite, bornite, chalcopyrite), where Au exsolves at low temperatures. This makes covellite a convenient model system for investigation of the chemical state (local environment and valence) of the “invisible” Au in copper-sulfide ores (copper-porphyry, epithermal, volcanogenic massive sulfide, SEDEX deposits). Therefore, it is necessary to determine the location of Au in the covellite matrix as it will have important implications for the methods employed by mineral processing industry to extract Au from sulfide ores. Here we investigate the chemical state of Cu and Au in synthetic covellite containing up to 0.3wt.% of Au in the “invisible” state. The covellite crystals were synthesized by hydrothermal and salt flux methods. Formation of the chemically bound Au is indicated by strong dependence of the concentration of Au in covellite on the sulfur fugacity in the experimental system (d(log C(Au))/d(log f(S2))∼0.65). The Au concentration of covellite grows with increasing temperature from 400 to 450°C, whereas further temperature increase to 500°C has only minor effect. The synthesized minerals were studied using X-ray absorption fine structure spectroscopy (XAFS) in high energy resolution fluorescence detection (HERFD) mode. Ab initio simulations of Cu K edge XANES spectra show that the Cu oxidation state in two structural positions in covellite (tetrahedral and triangular coordination with S atoms) is identical: the total loss of electronic charge for the 3d shell is ∼0.3 for both positions of Cu. This result is confirmed by theoretical analysis of electron density performed using quantum theory of atoms in molecules (QTAIM). Modeling of the Au L3 edge EXAFS/XANES spectra showed that Au in covellite exists in the form of the isomorphous solid solution formed by substitution for Cu atoms in triangular coordination with the Me–S distance in the first coordination shell increased by 0.18Å relative to the pure CuS structure. The “formal” oxidation state of Au in covellite is +1. The Bader partial atomic charge for Au in covellite is lower than the charge of Cu (+0.2e vs. +0.5e) indicating that the degree of covalency for the Au-bearing covellite is higher than that of pure CuS. The analysis of electronic density of states shows that this structural position of Au results in strong interactions between hybridized Au s,p,d, S p, and Cu p,d orbitals. Such chemical bonding of Au to S and Cu can result in the formation of Au-bearing solid solution with other minerals in the Cu–Fe–S system.

Characterization of microbial community in industrial bioleaching heap of copper sulfide ore at Monywa mine, Myanmar

Microbial communities and activities in multi-lift bioleaching heap of copper sulfide ore were investigated at Monywa copper mine, Myanmar. The high-throughput sequencing method revealed a microbial community dominated by archaeal Ferroplasma (about 70%), rather than more commonly reported genera of Acidithiobacillus and Leptospirillum (together about 25% in Monywa heap). Multi-lift stacking operation without heap aeration resulted in low oxygen concentrations in the heaps (leachate oxygen concentration of 0.35mgL−1 to 0.68mgL−1). Therefore, low oxygen concentrations, high organic matter concentrations and moderate temperature in the heaps favored the growth of versatile Ferroplasma which can both undergo autotrophic and heterotrophic growth. Total cell number in the irrigation solution and leachate was in the range of 4.86–8.80×106mL−1, and the detected microbes in ore residues and leaching solutions were mainly those with iron-oxidizing ability. Their iron-oxidizing rate showed highest at the temperature of 35°C, while in heaps may be limited by the low oxygen supply. Monywa bioleaching system with the above mentioned microbial community and activity formed a leaching solution of low redox potential, resulting in appropriate pyrite oxidation during chalcocite dissolution, thus helped maintain relatively stable acid and iron concentration in the cycling leaching solution. This study explained the formation of the microbial community and activity in Monywa heap leaching, linking to its heap physical and chemical conditions, and suggested that the role of Ferroplasma in bioleaching system may have been overlooked previously, especially in oxygen-limited bioleaching heaps.

The bioleaching potential of a bacterial consortium

This work presents the molecular foundation of a consortium of five efficient bacteria strains isolated from copper mines currently used in state of the art industrial-scale biotechnology. The strains Acidithiobacillus thiooxidans Licanantay, Acidiphilium multivorum Yenapatur, Leptospirillum ferriphilum Pañiwe, Acidithiobacillus ferrooxidans Wenelen and Sulfobacillus thermosulfidooxidans Cutipay were selected for genome sequencing based on metal tolerance, oxidation activity and bioleaching of copper efficiency. An integrated model of metabolic pathways representing the bioleaching capability of this consortium was generated. Results revealed that greater efficiency in copper recovery may be explained by the higher functional potential of L. ferriphilum Pañiwe and At. thiooxidans Licanantay to oxidize iron and reduced inorganic sulfur compounds. The consortium had a greater capacity to resist copper, arsenic and chloride ion compared to previously described biomining strains. Specialization and particular components in these bacteria provided the consortium a greater ability to bioleach copper sulfide ores.

Chalcopyrite and pyrite floatabilities in the presence of sodium sulfide and sodium metabisulfite in a high pyritic copper complex ore

ABSTRACTOne of the principal problems in flotation of copper complex ores is the presence of pyrite and copper-activated pyrite in moderately alkaline pHs. Misreported pyrite into copper concentrates dramatically declines copper grade and its recovery. In this study, the effect of sodium sulfide, sodium metabisulfite (SMBS), and their dosages (100, 200, 300, and 400 g/t) were investigated on chalcopyrite and pyrite floatabilities in a high pyritic copper sulfide ore. Furthermore, the role of particle size distribution (PSD) in three different levels (i.e., d70, d75, and d80 of passing 75 µm) was evaluated by a series of batch flotation experiments. It was revealed that using 200 g/t SMBS provides not only the highest and the lowest chalcopyrite and pyrite recoveries, but also the maximum and minimum copper and iron grades. Pyrite recovery was sharply increased by the addition of sodium sulfide in light of sodium sulfide-induced collectorless flotation; however, it showed a very weak effect on chalcopyrite floatability. In addition, the highest and lowest chalcopyrite and pyrite recoveries were, respectively, identified when d75 equaled to 70% 75 µm. In other words, for the high pyritic copper ore type, it is feasible to achieve the highest chalcopyrite recovery consuming the lowest grinding energy.

Influence of flotation cell volume and solids mass on kinetics of sulfide ore flotation

The paper presents studies on the influence of flotation cell capacity and mass of solids in the suspension on the flotation kinetics of sulfide copper ore. A sample of copper ore that was collected from the Polkowice Mine of KGHM Polska Miedz S.A. in Poland was used in the experiments. It was determined that neither the volume of flotation cell nor the mass of solids had influence on the type of kinetics equation of flotation. Copper-bearing minerals floated according to the second-order equation, while the remaining components according to the first-order equation. The kinetic rate constants and maximum recovery of the studied components decreased with increasing solids mass in the flotation cell, regardless of the capacity of the cell. The best results were obtained for tests using a 1.0 dm3 cell, while the less favorable kinetics results were observed in the test with the smallest cell of 0.75 dm3 volume. The obtained results can be helpful in choosing the most appropriate methodology of upgrading the sulfide copper ore from Poland in order to obtain the best kinetics results.

Evaluation of bioleaching column test of sulphide copper ore and copper concentrate using preconditioned surface

Bacterial activity can be related to the presence of Fe+3 in the solution, which drives copper oxidation during the secondary copper low grade sulfide ore leaching process. The present work evaluates improvements in kinetics of leaching when ferroxidans are preconditioned in an inert surface helping to build a biofilm which improves metabolism of the colony. The present work shows evaluation using laboratory columns to perform bioleaching during a 30 days period under three conditions: a base column with no inert surface, a column with loofa available for bacterial growth and conditioning, and finally a column with the loofa surface ground and distributed in the column among the particles.

Gold mineral flotation versus preparation conditions in a complexing agent belonging to dithiazinanes

To gain the efficient and optimized application of agents MTH and ETH belonging to dithiazinanes to float gold from complex ores the investigation was undertaken on complexing conditions in water environment and at pyrite surface with manually attached gold (FeS2Au) prior to flotation tests. The microscopic and spectral analysis of (FeS2Au) surface after contact with MTH and ETH show the presence of organic S- and N-containing compounds. It is found that selective gold recovery from a gold-bearing material in flotation with MTH and ETH is conditioned by a number of factors that accelerate formation of poorly soluble compounds at the surface of gold particles. The analysis includes the contact time, optimal medium alkalinity, formation of an oxidized film at Au0 particle surface, introduction of modifying agents as additional ligands as well as mechano-chemical acceleration of the complexing. Mechano-chemical treatment with feeding a low soluble agent into a mill before flotation of copper-sulfide gold-bearing ore enabled to higher gold recovery into rough and intermediate flotation concentrates by 15.9 and 4% respectively. In this case Au content in tailings was lowered by 0.15 g/t as compared to flotation experiments with butyl xanthate and its combinations with ETH.

Microbial & Mineralogical Dynamics during Copper Sulfides Bioleaching, the Search for the Missing Link

Bioleaching involves a chemical-microbial-driven dynamic process of oxidation and dissolution, as well as precipitation and formation of surface secondary phases that change the copper sulfide exposure/occlusion profiles. This dynamic process determines the kinetics of copper sulfides bioleaching. Former studies have shown the microbiological dynamics of the leaching solutions, and most mineralogical studies have been done with pure copper sulfide species under controlled conditions. In this work we aim to unravel the link between the microbiology and the mineralogy during the bioleaching of a mainly primary copper sulfide ore through the determination of the surface microbial and mineralogical variations in time applying process conditions. The results showed that the microbial dynamics in the leaching solutions is not representative of the bioleaching process since it differs significantly from the one established at the ore surface. Moreover, a major and fast alteration of the primary copper sulfide minerals chalcopyrite (CuFeS2) and bornite (Cu5FeS4) was observed, having as the major bioleaching intermediate the formation of covellite (CuS). When the ore was subjected to a mesophilic inoculation, the microbial dynamics was modified, significantly changing the mineralogical dynamics of these primary sulfides and enhancing the overall kinetics of copper recovery.

Bioleaching vs. Chloride Leaching: Real Advantages and Drawbacks for Primary Sulfides

Currently the vast majority of the world’s copper is obtained through sulfide mineral processing. Among the copper sulfides, chalcopyrite is the most economically relevant due to its abundance. Therefore, several technologies have been developed in order to achieve an efficient copper extraction from copper sulfides. Among these developments, the hydrometallurgical options of bioleaching as well as chemical chloride leaching are prevailing for secondary copper sulfides due to their good results at lab, pilot and industrial scale. Examples such as the Bacterial Thin-Layer technology developed by Minera Pudahuel in the ́80s (CL Patent 32025), as well as the Cuprochlor® process developed by Minera Michilla (CL Patent 45163), coming to the more recent “Heap leaching method” (US Patent WO2014030048A1) and the mixed version of the “Chloride method for bioleaching” patented by BHP Billiton (US Patent WO2012001501A1), are some examples that are currently being extended to the efficient copper extraction from chalcopyrite. In this work, we have compared at lab-scale BioSigma’s bioleaching technology and the industrial state-of-art chloride leaching for a mainly chalcopyritic copper sulfide ore. The metallurgical and microbial results, and the economical evaluation and comparative analysis clearly show that bioleaching presents several advantages compared to chloride leaching, being the biotechnological option more cost-effective and therefore industrially applicable.

Primary Copper Ore Leaching by Leaching Solution Adjusted Oxidation-Reduction Potential in Column

Copper ore is classified into three groups; primary copper sulfide, copper oxide and secondary copper sulfide. Leaching copper from primary copper sulfide, such as chalcopyrite, with sulfuric acid takes longer time than from copper oxide and secondary copper sulfide. As such, an oxidant is required to extract copper from chalcopyrite. In this study, column leaching tests were carried out using primary copper sulfide ores produced in an iron oxide copper gold (IOCG) deposit and rich in iron in coparison to porphyry copper ores. The columns of 10 cm diameter and 100 cm long had a double tube structure so that the column temperature can be kept at desired temperature by circulating warm water in the outer tube. The oxidation-reduction potential (ORP) of the leaching solutions were adjustedto 400, 450 and 500 mV vs Ag/AgCl. The column leaching test using just pH 2.0 sulfuric acid without adjustment of ORP at 45 °C got a copper recovery rate of 37 % in 400 days. On the other hand, with ORP adjusted leaching solutions of pH 2.0 sulfuric acid containing 500 mg/L Fe, the copper recovery rate reached up to 87 % in 400 days.In addition, it was necessary to keep the temperature above 45 oC to enhance copper leaching by ORP adjusted leaching solution. The result of the column leaching test at room temperature (around 30 °C) using ORP adjusted leaching solution shows that the recovery rate of copper is lower than the result at 45 °C. The ORP adjustment of leaching solution is effective for leaching copper from primary copper sulfide ore, however, the leaching temperature needs to be kept above 45 °C. As a result, it makes clear that copper leaching is enhanced by utilization of ORP adjusted leaching solutions and suggests that the solution ORP control is important to the application of bioleaching.

Bioleaching of Copper Sulphide Ore by a Microbial Consortium Isolated from Acid Mine Drainage: Influence of [Fe<sup>2+</sup>

Peru is mining country with a great diversity of mineral resource. The high grade ores are declining, and there is a need to implement new techniques for recycling metals (Cu, Au, Zn, Pb, etc) from low-grade ores. In order to answer this question, the bioleaching of copper from sulphide ore (FeS2 45.30%, CuFeS2 1.90%, ZnS 8.90%, FeAsS 13.12%, PbS 3.69%) was evaluated with different concentrations of Fe2+ using an iron-oxidizing native microbial consortium.The samples were collected from drainage acid mine (4100 m.a.s.l.) located in the south of Huancavelica region and the sample of ore from middle Huaraz region (3200 m.a.s.l.). Microorganisms were isolated in 9k medium at pH 1.8, 22oC. Bioleaching test were performed in two consecutive steps to 150 rpm at 22oC, monitoring pH, ORP (mV). Assays varying the concentration of Fe2+ (0 mM – 53 mM) were performed with a pulp density of 1% and 2% at each step, and with an inoculum 10% (v/v) to a microbial concentration of 108 cel/mL.We isolated a microbial consortium after 8 weeks with presence of bacteria Acidithiobacillus ferrooxidans-like. In assays, copper was solubilized. The microbial concentration in the tests was (2x107- 4x107cel/mL). In the first stage, the test with 21 mM Fe2+ recovered 62% copper. In the next step, with the bacterial concentration of the first step, bioleaching time is reduced by 22% for copper recovery (63%) in absence of Fe2+.With these data, we observed that the addition of iron is not necessary in a stage adaptation when the mineral contain iron.

Pressure oxidation leaching of an enargite concentrate in the presence of polytetrafluoroethylene beads

Polytetrafluoroethylene (PTFE) is a promising additive in medium-temperature pressure oxidation leaching of high sulfide copper ores. In this article, we present a systematic study on the performance of pressure oxidation leaching of an enargite concentrate in the presence of PTFE beads. The effects of various leaching conditions, including leaching solution composition, temperature, oxygen overpressure, initial pulp density, and an addition of varying amounts of PTFE beads, on copper leaching kinetics have been systematically investigated. Our results show that, with the use of PTFE beads, the rate of leaching and ultimate extraction of copper can be significantly enhanced, over the temperature range of 150–210°C and an oxygen overpressure range of 50–120psi, compared to otherwise similar conditions without the addition of PTFE beads. Results of analysis of the surface adsorbates on the PTFE beads suggest that, during the initial stages of leaching, PTFE beads capture hydrophobic sulfide minerals on their surface. Leaching of the minerals then progresses on the surface of the beads, producing elemental sulfur. The molten sulfur is partially drawn away from the mineral/electrolyte interface to the PTFE surface, mitigating the agglomeration of the mineral particles and facilitating their further oxidation. In addition, the PTFE beads have been found to be highly reusable with identical performance maintained for at least 6cycles of leaching experiments without the need of any special surface regeneration treatment. Arsenic deportment was tracked by XRD and ICP-MS analysis of both the resulting leaching solution and residue. The majority of arsenic (about 96%) was converted to a stable solid scorodite product, thus facilitating its safe disposal.

Bioleaching of fluoride-bearing secondary copper sulphides: Column experiments with Acidithiobacillus ferrooxidans

Bioleaching is a mature technology, which is widely employed commercially in the leaching of low-grade secondary copper sulphide ores. In this work, the bioleaching potential of a low-grade (marginal) ore with a significant content of fluoride was assessed. Small columns were inoculated with a strain of At. ferrooxidans, at 30°C, and resulted in copper extractions above 89%, in 255days. The dissolution of fluorite from the gangue minerals accounted for up to 2.5g/L fluoride in solution, which affected bioleaching shortly after column inoculation. However, both the released of aluminium from the ore and ferric iron production by the bacteria reduced fluoride toxicity. A fluoride-toxicity parameter (η) was proposed to represent the mass ratio between total fluoride, total aluminium and total ferric iron concentrations in the system. Low values of the η parameter resulted from high ferric iron and aluminium concentrations and implied in large bacterial population in the systems. Thus, the presence of fluoride-bearing minerals in the ore may be an important issue, but the content of both cations should be also considered. Despite the absence of ferric iron and a high fluoride concentration prior to first solution bleeding, the η parameter was lower than 0.3 in the column containing an external aluminium source. In this condition, as the aluminium content surpassed that of fluoride the bacterial population reached 107cells/mL and enabled copper bioleaching.

Well-controlled column bioleaching of a low-grade copper ore by a novel equipment

For the low-grade copper sulfide ores with 0.99% of copper, of which 41.5% was primary copper sulfide, and 54.5% was secondary copper sulfide, well-controlled column bioleaching on a novel equipment was carried out to investigate the optimal conditions of pre-leaching, particle sizes of ores, temperature, spray intensity and strain consortium. Results show that copper extraction of 91.11% can be obtained after 90 d with the optimal pH value of pre-leaching of 0.8; the pH values of pre-leaching significantly affect the final copper extractions. Copper extractions of 93.11%, 91.04% and 80.45% can be obtained for the bioleaching of ores with particles size of 5–8 mm, 5–15 mm and 5–20 mm, respectively. Copper extractions are 83.77% and 91.02% for bioleaching under the conditions of room temperature and 35 oC. Copper extractions are 77.25%, 85.45% and 91.12% for the bioleaching when flow rate of spray was 5 L/(h·m2), 10 L/(h·m2) and 15 L/(h·m2), respectively. Additionally, the strain consortium C3 is the best among the four strain consortia in bioleaching. By considering the energy consumption, the optimal conditions of bioleaching in this work are determined as pH of pre-leaching of 0.8, particles size of 5–15 mm, temperature of 35 °C, spray intensity of 15 L/(h·m2), and strain consortium C3.

Investigating the first-order flotation kinetics models for Sarcheshmeh copper sulfide ore

This study was performed in two phases of work. In the first stage, four conventional first-order flotation kinetics models were fitted to the measured recoveries data and the best model were selected. In the second stage, influence of pH, solid concentration, water chemistry and the amount of collector dosage were investigated on kinetics parameters including flotation rate constant and ultimate recovery. The results indicated that that perfectly mixed reactor model and Kelsall model gave the best and the weakest fit to the experimental data, respectively. It was observed that flotation rate constant and ultimate recovery were strongly affected by chemical factors investigated especially water quality. The flotation rate constant decreased with increasing the solids content, while ultimate recovery increased to certain value and thereafter reduced. It was also found that the most values of flotation rate constant and ultimate recovery obtained in dosage of collector are 30 and 40g/t, respectively.