Influences of collector DLZ on chalcopyrite and pyrite flotation

The interaction mechanism of collector DLZ in the flotation process of chalcopyrite and pyrite was investigated through flotation experiments, zeta potential measurements and infrared spectrum analysis. Flotation test results indicate that DLZ is the selective collector of chalcopyrite. Especially, the recovery of chalcopyrite is higher than 90% in neutral and weak alkaline systems, while the recovery of pyrite is less than 10%. When using CaO as pH regulator, at pH=7-11, the floatability of pyrite is depressed and the recovery is less than 5%. Zeta potential analysis shows that the zeta potential of chalcopyrite decreases more obviously than that of pyrite after interaction with DLZ, confirming that collector DLZ shows selectivity to chalcopyrite and pyrite. And FT1R results reveal that the flotation selectivity of collector DLZ is due to chemical absorption onto chalcopyrite surface and only physical absorption onto pyrite surface.     

Mechanism of bioleaching chalcopyrite by Acidithiobacillus ferrooxidans in agar-simulated extracellular polymeric substances media

The mechanism of leaching chalcopyrite by Acidithiobacillus ferrooxidans (A. ferrooxidans) in agar-simulated extracellular polymeric substances (EPS) media was investigated. The results indicate that bacterial EPS can release H+ and concentrate Fe3+; Fe2+ is movable between agar-simulated EPS phase and bulk solution phase, but it is difficult for Fe3+ to move due to its hydroxylation and EPS complex action; A. ferrooxidans first prefer Fe2+ as energy to metabolize compared with chalcopyrite, and a suitable ...     

Comparison of microbial communities in three different mine drainages and their bioleaching efficiencies to low grade of chalcopyrite

Microbial community diversities in the drainage from three mines(Dexing Copper Mine,Qibaoshan Copper Mine and Yaogangxian Tungsten Mine,China)were analyzed using 16S rDNA PCR-RFLP approach.The efficiencies of chalcopyrite bioleaching were compared using enrichment of the three cultures.Phylogenetic analysis indicates that the dominant microorganisms are clustered with the Proteobacteria,the remaining is affiliated with Nitrospira,Acidobacteria and Actinobacteria.At the genus level,Acidithiobacillus is the dominant group in both YTW and QBS samples,while Spingomonas is dominant in YGX sample.Moreover,the principal component analysis(PCA)reveals that QBS and YTW have similar geochemical character and microbial communities.The results also show that pH value and tungsten concentration play a key role in microbial community distribution and relative abundance.The bioleaching efficiency of the enrichment cultures from YTW and QBS is similar.After 15 d,the bioleaching rates of low grade chalcopyrite(0.99%)are both up to 99.5% when using 10 g/L pulp density due to the similar microbial composition of YTW and QBS.Moreover,the leaching efficiencies of enrichment cultures containing multiple bioleaching microorganisms are higher than that of pure culture Acidithiobacillus ferrooxidans.     

Bioleaching of complex polymetallic sulfide ores by mixed culture

Bacterial leaching of single sulfide minerals and polymetallic sulfide ores was operated in shake flasks and small-scaled columns.The results show that bioleaching of jamesonite is not accessible,the iron extraction rate of pyrrhotite bioleaching reaches 98.2% after 26 d,and the zinc extraction rate of marmatite bioleaching reaches 92.3%,while the corresponding iron extraction reaches only 13.6% after 29 d.Pulp density has a significant effect on metal extraction of pyrrhotite and marmatite bioleaching.The corresponding metal extraction rate decreases with the increase of pulp density.For the polymetallic sulfide ores,zinc extraction of 97.1% is achieved after bioleaching in shake flasks for 10 d,while only 7.8% is obtained after bioleaching in small-scaled column.Analytical results of scanning electron microscopy（SEM） and energy dispersive X-ray analysis（EDX） reveal that large amount of calcium sulfate is formed on the mineral surface.     

Effect of organic depressant lignosulfonate calcium on separation of chalcopyrite from pyrite

In order to selectively separate chalcopyrite from pyrite, the effect of organic depressant lignosulfonate calcium (LSC) on the flotation separation of chalcopyrite from pyrite was investigated by flotation tests. The depression mechanism was studied by Fourier-transform-infrared (FTIR) analysis. The flotation tests of single mineral show that LSC can depress the flotation of pyrite in a certain pH range, but it has little effect on chalcopyrite flotation. Flotation separation of a mixture of chalcopyrite and pyrite can be completed to obtain a copper concentrate grade up to 24.73% with a recovery of 80.36%. IR analysis shows that LSC and butyl xanthate compete in absorption on pyrite surface, and there exists an LSC characteristic peak on pyrite surface. There is little adsorption of LSC on chalcopyrite.     

Efficacy of chalcopyrite bioleaching using a pure and a mixed bacterium

To determine the efficacy of chalcopyrite bioleaching using pure cultures of Thiobacillus ferrooxidans or Thiobacillus thiooxidans and a mixed culture composed of Thiobacillus ferrooxidans and Thiobacillus thiooxidans, experiments were carried out in shake flasks with [Fe~(2 )] 4 g.L~(-1) and S 1 g.L~(-1) at pH=1.80, 130 r/min and 30℃. The tests showed that the copper extraction in a mixed culture composed of Thiobacillus ferrooxidans and Thiobacillus thiooxidans is higher than that in a pure culture. On the other hand, an important potential of Thiobacillus thiooxidans to leaching chalcopyrite was indicated. Thiobacillus thiooxidans can prevent jarosites accumulating on the substrate and allow further copper to dissolute through the action of ferric ion. The selection of the suitable pH in a leaching solution would be significant. Thiobacillus thiooxidans and Thiobacillus ferrooxidans play an important role in the bioleaching process. Finally, the mechanism and the reason for iron precipitation were also discussed in detail.     

Bioleaching and electrochemical properties of chalcopyrite by pure and mixed culture of Leptospirillum ferriphilum and Acidthiobacillus thiooxidans

The bioleaching of chalcopyrite was investigated using a pure and mixed culture consisting of iron-oxidizing Leptospirillum ferriphilum (L. ferriphilum) and sulfur-oxidizing Acidthiobacillus thiooxidans (A. thiooxidans). The electrochemical tests were conducted to investigate the bioleaching behavior of chalcopyrite by various bacteria. Bioleaching efficiency of chalcopyrite in mixed culture is higher than that in the pure culture of L. ferriphilum alone. The iron-oxidizing L. ferriphilum plays a dominant role during bioleaching of chalcopyrite in the mixed culture of L. ferriphilum and A. thiooxidans. During bioleaching, certain values of redox potential are beneficial to the decomposition of chalcopyrite. Jarosite and sulfur are observed as products of bioleaching. The addition of A. thiooxidans during leaching by L. ferriphilum can change the electrochemical control steps of leaching. The corrosion current density is substantially promoted in the culture involving bacteria, especially in the mixed culture.     

Effect of L-cysteine on bioleaching of Ni-Cu sulphide by A.manzaensis

The effect of L-cysteine in different concentrations on the bioleaching of Ni-Cu sulfide was studied with an extremely thermophilic archaea, Acidianus manzaensis. It is found that adding certain amounts of L-cysteine to the bioleaching system of Ni-Cu sulfide largely enhances the leaching rate. X-ray diffraction (XRD) patterns show the change of bioleached solid residues and the effect of L-cysteine on the surface charges of minerals. Zeta potential and IR spectra of mineral surface show that the interaction between L-cysteine and mineral leads to the formation of metal complex, which is propitious to the bioleaching of Ni-Cu sulfide by Acidianus manzaensis.     

Mathematical model for coupled reactive flow and solute transport during heap bioleaching of copper sulfide

Based on the momentum and mass conservation equations, a comprehensive model of heap bioleaching process is developed to investigate the interaction between chemical reactions, solution flow, gas flow, and solute transport within the leaching system. The governing equations are solved numerically using the COMSOL Multiphysics software for the coupled reactive flow and solute transport at micro-scale, meso-scale and macro-scale levels. At or near the surface of ore particle, the acid concentration is relatively higher than that in the central area, while the concentration gradient decreases after 72 d of leaching. The flow simulation between ore particles by combining X-ray CT technology shows that the highest velocity in narrow pore reaches 0.375 m/s. The air velocity within the dump shows that the velocity near the top and side surface is relatively high, which leads to the high oxygen concentration in that area. The coupled heat transfer and liquid flow process shows that the solution can act as an effective remover from the heap, dropping the highest temperature from 60 to 38 °C. The reagent transfer coupled with solution flow is also analyzed. The results obtained allow us to obtain a better understanding of the fundamental physical phenomenon of the bioleaching process.     

Spontaneous combustion tendency of fresh and pre-oxidized sulfide ores简

Three representative sulfide ore samples were collected from typical metal mines,and their corresponding pre-oxidized products were obtained under nature environment.The thermal behaviors of each sample at heating rates of 5,10,15 and 20 °C/min in air flow from ambient temperature to 800 °C were studied by simultaneous thermal analysis and the TG/DSC curves before and after the pre-oxidation were compared.By the peak temperature of DTG curves,the whole reaction process for each sample was divided into different stages,and the apparent activation energies were calculated by the Ozawa-Flynn-Wall method.The results show that the reaction process of each sample after pre-oxidation is more complex,with quicker reaction rates,fewer heat production quantities,and higher or lower ignition-points.The apparent activation energies decrease from 364.017-474.228 kJ/mol to 244.523- 333.161 kJ/mol.Therefore,sulfide ores are more susceptible to spontaneous combustion after the pre-oxidation.     

Bioleaching of low-grade copper sulfide ores by Acidithiobacillus ferrooxidans and AcidithiobacillusThiooxidans简

The grown conditions of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans were investigated,and then experiments were conducted to research the bioleaching behaviors of crude ore of copper sulfide and hand-picked concentrates of chalcopyrite by Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans.The experimental results show that the bacteria grow best when the temperature is（30±1） °C and the pH value is 2.0.The bacteria concentration is 2.24×107 mL-1 in this condition.It is found that the copper extraction yield is affected by the inoculum size and the pulp density and the extraction yield increases as the inoculum size grows.The bioleaching rates reach their highest point in sulfide copper and chalcopyrite with a pulp density of 5% and 10%,respectively.Column flotation experiments of low-grade copper sulfide ores show that the bioleaching recovery reaches nearly 45% after 75 days.     

Structural,microstructural, and thermal characterizations of a chalcopyrite concentrate from the Singhbhum shear zone,India

The structural and morphological characterizations of a chalcopyrite concentrate, collected from the Indian Copper Complex, Ghatshila, India, were carried out by X-ray diffraction, scanning electron mi...     

Effects of bioleaching on the mechanical and chemical properties of waste rocks

Bioleaching processes cause dramatic changes in the mechanical and chemical properties of waste rocks,and play an important role in metal recovery and dump stability.This study focused on the characteristics of waste rocks subjected to bioleaching.A series of experiments were conducted to investigate the evolution of rock properties during the bioleaching process.Mechanical behaviors of the leached waste rocks,such as failure patterns,normal stress,shear strength,and cohesion were determined through mechanical tests.The results of SEM imaging show considerable differences in the surface morphology of leached rocks located at different parts of the dump.The mineralogical content of the leached rocks reflects the extent of dissolution and precipitation during bioleaching.The dump porosity and rock size change under the effect of dissolution,precipitation,and clay transportation.The particle size of the leached rocks decreased due to the loss of rock integrity and the conversion of dry precipitation into fine particles.     

黄铜矿生物浸出钝化及调控研究进展

综述了黄铜矿微生物浸出钝化作用和消除方法的研究现状和发展趋势,认为黄铜矿生物浸出的钝化作用主要有黄钾铁矾、硫及其多聚物、金属缺陷型硫化物和它们协同作用等。要提高黄铜矿生物浸出效果,必须削弱和消除钝化作用,主要的方法有物理法、化学法、生物法和复合法。但4种方法都还不成熟,要工业化应用,还需要大量的研究工作,同时提出从组合矿物对黄铜矿生物浸出钝化的影响开展研究工作,也许能取得突破性进展。     

硫化氢脱除以及物理场在该过程中的应用前景

硫化氢是普遍存在于煤气、天然气和化学原料的合成气等中的有害物质之一,它不仅影响后续加工过程,而且会造成环境污染。对可再生溶剂吸收脱硫、固定床吸收脱硫、膜分离方法脱硫、直接转化为硫脱硫和生物脱硫等五个方面,对脱硫方法的研究进展进行了简述。然后,对物理场脱硫进行了评述,分析了物理场在工业脱硫中的可行性和发展方向,指出将物理场脱硫与传统工艺结合,具有较为广阔的应用前景。     

热处理对高硫钢硫化物形态及性能的影响

研究淬回火热处理工艺对高硫钢的基体组织和硫化物形态的影响,分析了其力学性能和磨损性能。结果表明,热处理后高硫钢中硫化物主要为FeS,其形态趋于球化;淬火温度由880℃升至900℃,高硫钢的抗拉强度由460MPa提高到590MPa,伸长率由1．7％变化到3．0％,但其仍为脆性材料,这与组织中合有大量硫化物有关;由于硫化物的自润滑作用,热处理后高硫钢的耐磨性随连续磨损时间的延长而改善,并明显优于淬火后低温回火的GCr15钢。     

Influence of heavy metal stress on morphology and physiology of Penicillium chrysogenum during bioleaching process

In order to improve the efficiency of bioleaching heavy metal from the contaminated soil using Penicillium chrysogenum （P chrysogenum）, experiment was conducted to evaluate the influence of heavy metal stress on P. chrysogenum during bioleaching. The morphology and physiology of P chrysogenum were observed. Assuming that the heavy metals are all leached out from the experiment soil, heavy metals are added into the agar medium by simulating the heavy metal content in the soil. It is concluded that the survivable heavy metal contaminated soil mass range for P. chrysogenum is 2.5-5.0 g. As for biomass determination, the contaminated soil is added into the liquid medium directly. The soil mass that P.. chrysogenum can be survivable is in the range of 2.5-8.75 g. In this mass range, the biomass of P. chrysogenum is bigger than that of the control sample. 10 g soil mass is the threshold of the growth ofP chrysogenum. 102.2 mg/L gluconic acid, 156.4 mg/L oxalic acid, 191.6 mg/L pyruvic acid, 0.02 mg/L citric acid, 0.03 mg/L malic acid and 70.6 mg/L succinic acid are determined after 15 d bioleaching. The mycelium is broken into fragments, and heavy metals are adsorbed on the cell wall or transported into the cytoplasm during bioleaching. The GOD activity declines from 1.08 U/mL to 0.2 U/mL under 400 mg/L of multi-metal stress. The influence of Pb on GOD activity is bigger than that of Cr and Cd, and the GOD activity is not influenced apparently by Mn, Zn and Cu.     

五台山-恒山一带金、银多金属矿床同位素地球化学及其成矿模型

通过同位素地球化学研究，五台山—恒山—带金、银多金属矿床的硫源均来自深源；铅同位素组成表明成矿物质主要来自下地壳及地幔，但绿岩型金矿铅同位素变化较大，而燕山期次火山岩型金、银多金属矿床铅同位素较为集中；运移形成矿物的水源也有所不同，前者是以变质水为主(δ^18OH2O1.34％-12.55％,δD-22.287％—--177.36％)，后者则是以岩浆水及天水混合为主(δ^18OH2O多在-18．6‰～ 10．05‰，δD-68‰～-110‰)；碳氧同位素组成也揭示了前者以变质作用为主(δ^13C(PDB)-1.25‰～1.37‰，δ^18O(SMOW)11．4％～16．5％)，后者与花岗斑岩侵入有关(δ^13C(PDB)为-4．0‰～-9．2‰，δ^18O(SMOW)3．5‰～9．6‰)；两类矿床的锶同位素比值，也反映了与成矿作用有着密切关系的太古宙斜长角闪岩和燕山中期花岗斑岩均是壳幔混合产物，故可视为两类矿床有着内在成因联系；钐-钕同位素组成不仅获得相同结论，而且从εNd(0)和∫sm／Nd均是负值，推测属大陆地壳岩石，可能为O-C型绿岩地体的成矿背景，从而建立了五台热幔柱构造的成矿模型，试图指导找矿。     

Surface chemical study of the selective separation of chalcopyrite and marmatite

FCLS (Ferric Chromium Lignin Sulfonate) was used to aid the separation of chalcopyrite from marmatite. Flotation, adsorption and zeta-potential tests of treated marmatite and chalcopyrite were performed. The flotation of marmatite was strongly depressed, while that of chalcopyrite was only slightly depressed, over a wide range of pH values when FCLS was used as depressant in the presence of Butyl Xanthate (BX). The adsorption of BX onto chalcopyrite or marmatite takes place over a wide pH range. The adsorption density of BX on chalcopyrite and marmatite decreases as the pH increases. The adsorption density of FCLS onto marmatite is greater than the adsorption density onto chalcopyrite. The zeta potentials of chalcopyrite and marmatite become more negative due to the addition of xanthate and FCLS.