How will biomining be applied in future？

This paper reviews the current status of commercial biomining operations around the world, identifies factors that drive the selection of biomining as a processing technology, describes challenges to exploiting these innovations, and concludes with a discussion of biomining＇s future. Biomining is commercially applied using engineered dumps, heaps and stirred tanks. Overcoming the technical challenges of lowering costs, processing low-grade, low-quality and complex ores and utilizing existing capital investments at mines requires better understanding of microbial activities and innovative engineering. Surmounting biomining commercial challenges entails improved mining company/biomining innovator cooperation and intellectual property control.     

Bioleaching of marmatite in high concentration of iron

Bioleaching of marmatite with a culture of Thiobacillus ferrooxidans and Thiobacillus thiooxidans in high concentration of iron was studied,the results show that the zine leaching rate of the mixed culture is faster than that of the sole Thiobacillus ferrooxidans,the increasing iron concentration in leaching solution enhances the zine leaching rate.The SEM analysis indicates that the chemical leaching residues is covered with porous solid layer of elemental sulfur,while elemental sulfur is not found in the bacterial leaching residues.The primary role of bacteria in bioleaching of sphalerite is to oxidize the chemical leaching products of ferrous ion and elemental sulfur,thus the indirect mechanism prevails in the bioleaching of marmatite.     

Study on bioleaching of primary chalcopyrite ore with thermoacidophilic archae

A high temperature-tolerating thermoacidophilic archae （TA） was isolated from water samples collected from a hot sulfur-containing spring in the Yunnan Province, China, and was used in bioleaching experiments of a low-grade chalcopyrite ore. The TA grow at temperatures ranging from 40 to 80℃, with 65℃ being the optimum temperature, and at pH values of l.5 to 4.0, with an optimum pH value of 2.0. The bioleaching experiments of the chalcvpyrite ore were conducted in both laboratory batch bioreactors and leaching columns. The results obtained from the bioreactor experiments showed that the TA bioleaching rate of copper reached 97% for a 12-day leaching period, while the bioleaching rate was 32.43% for thiobacillus ferrooxidans （Tf） leaching for the same leaching time. In the case of column leaching, tests of a two-phase leaching （196 days）, that is, a two-month （56 days） Tf leaching in the first phase, followed by a 140-day TA leaching in the second phase were performed. The average leaching rate of copper achieved for the 140-day TA leaching was 195mg/（L.d）, while for the control experiments, it was as low as 78mg/（L .d） for the Tf leaching, indicating that the TA possesses a more powerful oxidizing ability to the chalcopyrite than Tf Therefore, it is suggested that the two-phase leaching process be applied to .for the heap leaching operations, whereas, the TA can be used in the second phase when the temperature inside the heap has increased, and the primary copper sulfide minerals have already been partially oxidized with Tf beforehand in the first phase.     

STUDY ON BIOLEACHING OF PRIMARY CHALCOPYRITE ORE WITH THERMOACIDOPHLIC ARCHAE

A high temperature-tolerating thermoacidophilic archae (TA) was isolated from water samples collected from a hot sulfur-containing spring in the Yunnan Province, China, and was used in bioleaching experiments of a low-grade chalcopyrite ore. The TA grow at temperatures ranging from 40 to 80℃, with 65℃ being the optimum temperature, and at pH values of 1.5 to 4.0, with an optimum pH value of 2.0. The bioleaching experiments of the chalcopyrite ore were conducted in both laboratory batch bioreactors and leaching columns. The results obtained from the bioreactor experiments showed that the TA bioleaching rate of copper reached 97% for a 12-day leaching period, while the bioleaching rate was 32.43% for thiobacillus ferrooxidans (Tf) leaching for the same leaching time. In the case of column leaching, tests of a two-phase leaching (196 days), that is,a two-month (56 days) Tf leaching in the first phase, followed by a 140-day TA leaching in the second phase were performed. The average leaching rate of copper achieved for the 140-day TA leaching was 195mg/(L· d), while for the control experiments, it was as low as 78mg/(L· d) for the Tf leaching, indicating that the TA possesses a more powerful oxidizing ability to the chalcopyrite than Tf. Therefore, it is suggested that the two-phase leaching process be applied to for the heap leaching operations, whereas, the TA can be used in the second phase when the temperature inside the heap has increased, and the primary copper sulfide minerals have already been partially oxidized with Tf beforehand in the first phase.     

Bioleaching of anilite by Acidithiobacillus ferrooxidans

In order to characterize the efficiency of copper bioleaching from anilite using pure cultures of Acidithiobacillus ferrooxidans in the absence and presence of ferrous sulphate,the experiments were carried out in shake flasks with or without 4 g/L ferrous sulphate(FeSO_4·7H_2O)at pH 2.0,150 r/min and 35℃.The tests show that Acidithiobacillus ferrooxidans is unable to attack anilite in iron-free 9K medium.Anilite is rapidly oxidized by bacterial leaching when ferrous sulphate is added.Chemical oxidation o...     

Catalytic effect of visible light and Cd2+ on chalcopyrite bioleaching

The effects of visible light and Cd²⁺ ion on chalcopyrite bioleaching in the presence of Acidithiobacillus ferrooxidans (A. ferrooxidans) were studied by scanning electron microscopy (SEM), synchrotron radiation X-ray diffraction (SR-XRD), and X-ray photoelectron spectroscopy (XPS). The results of bioleaching after 28 days showed that the copper dissolution increased by 4.96% with only visible light, the presence of Cd²⁺ alone exerted slight inhibition effect on chalcopyrite dissolution and the concentration of dissolved copper increased by 14.70% with visible light and 50 mg/L Cd²⁺. The results of chemical leaching showed that visible light can promote the circulation of iron. SEM results showed that Cd²⁺ promoted the attachment of A. ferrooxidans on chalcopyrite surface under visible light. SR-XRD and XPS results indicated that visible light and Cd²⁺ promoted chalcopyrite dissolution, but did not inhibit the formation of passivation. Finally, a model of synergistic catalysis mechanism of visible light and Cd²⁺ on chalcopyrite bioleaching was proposed.     

Bioleaching of refractory gold ore （ Ⅱ ）——Mechanism on bioleaching of arsenopyrite by Thiobacillus ferrooxidans

1　ＩＮＴＲＯＤＵＣＴＩＯＮＢｉｏｌｅａｃｈｉｎｇｐｒｏｃｅｓｓｅｓｈａｖｅｂｅｅｎｕｓｅｄｅｘｔｅｎｓｉｖｅｌｙｔｏｒｅｃｏｖｅｒｂａｓｅｍｅｔａｌｓ (ｍａｉｎｌｙｃｏｐｐｅｒ)ａｎｄｕｒａｎｉｕｍｆｒｏｍｌｏｗ ｇｒａｄｅｏｒｅｓａｎｄｍｏｒｅｒｅｃｅｎ     

原电池效应对混合硫化矿细菌浸出的影响

研究了黄铜矿与黄铁矿混合矿细菌浸出过程的原电池效应，提出了原电池效应模型。研究结果表明：当黄铜矿细菌浸出过程中加入黄铁矿及C时，浸出率大大提高，黄铜矿浸出30d，Cu浸出率可达40％；单一黄铁矿细菌浸出时，黄铁矿会被大量氧化分解，而当与黄铜矿混合浸出时，黄铜矿氧化加快，黄铁矿氧化速率降低；加入C及黄铁矿与黄铜矿混合时，由于接触电位的影响，黄铜矿氧化反应电流增大、反应起始电位负移，反应加尉，而黄铁矿的氧化反应受到抑制；混合矿浸出过程中，黄铜矿表面Cu含量较单一矿浸出时低得多，说明混合效应对浸出具有强化作用；黄铜矿中Cu浸出愈多，表面生成的元素硫愈多，黄铁矿细菌浸出时，表面不会有元素硫产生。     

多金属硫化精矿中铜、锌和铁的生物浸出(英文)

利用嗜温混合菌Acidithiobacillus ferrooxidans,Acidithiobacillus thiooxidans和Leptospirillum ferrooxidans对低品位复杂Cu-Zn-Pb-Fe-Ag-Au硫化精矿在曝气生物浸出反应器中进行生物浸出。该菌种为从塞尔维亚Bor地下铜矿的酸性溶液中筛选出一种嗜热嗜酸菌。营养液为p H 1.6的9K营养液。87%的矿物粒度大于10μm,矿浆密度为8%(w/v)。在测试条件下,锌、铜和铁的浸出率分别达到89%、83%和68%。动力学分析表明,浸出过程与Spencer-Topley模型相符,受局部反应扩散控制。     

Behavior of Fe and S in bioleaching of pentlandite

1　ＩＮＴＲＯＤＵＣＴＩＯＮＯｘｉｄｉｚｉｎｇｐｒｏｃｅｓｓｂｙａｕｔｏｔｒｏｐｈｉｃｂａｃｔｅｒｉａ ,ｓｕｃｈａｓＴｈｉｏｂａｃｉｌｌｕｓｆｅｒｒｏｏｘｉｄａｎｓ (Ｈｅｒｅｉｎｂｅｌｏｗｂｅａｂｂｒｅ ｖｉａｔｅｄｔｏＴ .ｆ .) ,ｈａｓｂｅｅｎｗｉｄｅｌｙ     

伊朗Kooshk铅-锌尾矿坝闪锌矿的生物浸出

将取自伊朗Yazd省Kooshk铅-锌尾矿坝的闪锌矿样进行生物浸出,并对比研究不同条件下的锌浸出率。Kooshk铅-锌尾矿坝含有3.64%锌、0.97%铅和24.18%铁。先将混合嗜温菌株、混合中度嗜热菌株进行摇瓶培养,然后在9K培养基中再次培养。在浸出闪锌矿的14 d 内,在有菌株的情况下,闪锌矿的浸出率达90%,而没有菌株的情况下,只有44%的闪锌矿被浸出。实验结果表明,在有菌株浸出的前10 d,有没有9K培养液对锌的浸出率有明显影响,但随后其差别不明显,到最后趋于相同。锌浸出率的提高与细菌菌落数和Fe3＋浓度的增加有关。中度嗜热菌浸取锌的动力学要求明显高于嗜温菌的,因此,在中度嗜热菌株存在的情况下,在低的氧化电位下闪锌矿优先于黄铁矿溶解而被浸出。     

Study on bioleaching of refractory gold ore (Ⅰ)──Mechanism on bioleaching of pyrite by Thiobacillus ferrooxidans

1　ＩＮＴＲＯＤＵＣＴＩＯＮＳｔｕｄｉｅｓｏｎｔｈｅｇｒｏｗｔｈ[1～ 3 ] ａｎｄａｐｐｌｉｃａｔｉｏｎｓ[4 ] ｏｆＴｈｉｏｂａｃｉｌｌｕｓｆｅｒｒｏｏｘｉｄａｎｓｈａｖｅｂｅｅｎｃａｒｒｉｅｄｏｕｔｂｙｍａｎｙｒｅｓｅａｒｃｈｅｒｓ ,ｓｉｎｃｅｉｔｉｓｏｎｅｏｆｔｈｅｍｏｓｔｉｍｐｏｒ ｔａｎｔｍｉｃｒｏ ｏｒｇａｎｉｓｍｓｆｏｒｔｈｅｒｅｃｏｖｅｒｙｏｆｓｏｍｅｍｅｔａｌｓｉｎｃｌｕｄｉｎｇｃｏｐｐｅｒａｎｄｕｒａｎｉｕｍｆｒｏｍｌｏｗ ｇｒａｄｅｏｒｅｓｉｎｉｎｄｕｓｔｒｉａｌｈｅａｐ ,ｄｕｍｐ ,…     

Effects of Acidiphilium cryptum on biosolubilization of rock phosphate in the presence of Acidithiobacillus ferrooxidans

The bioleaching of pyrite and biosolubilization of rock phosphate (RP) in 9K basal salts medium were compared by the following strains of an autotrophic acidophilic bacterium, Acidithiobacillus ferrooxidans, a heterotrophic acidophilic bacterium, Acidiphilium cryptum, and mixed culture of At. ferrooxidans and A. cryptum. The results show that A. cryptum is effective in enhancing the bioleaching of pyrite and biosolubilization of RP in the presence of At. ferrooxidans, although it could not oxidize pyrite and solubilize RP by itself. This effect is demonstrated experimentally that A. cryptum enhances a decrease in pH and an increase in redox potential, concentration of total soluble iron and planktonic part bacterial number in the broth during pyrite bioleaching processes by At. ferrooxidans. The mixed culture of At. ferrooxidans and A. cryptum leads to the most extensive soluble phosphate released at 30 °C. Pulp density exceeding 3% is shown to adversely influence the release of soluble phosphate by the consortium of At. ferrooxidans and A. cryptum. It is essential to add pyrite to the 9K basal salts medium for the biosolubilization of RP by the mixed culture of At. ferrooxidans and A. cryptum, and the percentage of soluble phosphate released is the greatest when the mass ratio of RP to pyrite is 1:2 or 1:3.     

低品位硫化铜矿细菌浸出

采用正交实验方法,考察了矿石粒度、矿浆含量、接种量对大冶露天矿石和井下矿石的摇瓶浸出过程的影响.结果表明:粒度对露天矿和井下矿的酸耗影响大,对井下矿的浸出率影响高度显著; 矿浆含量对酸耗影响大,对浸出率则不显著; 在接种的初期,接种量对酸耗与浸出率都有影响,2d后接种量的影响消失; 井下矿浸出的最优工艺条件为:粒度<0.154mm,矿浆含量10%,接种量10%; 露天矿浸出的最优工艺条件为:粒度<0.154mm,矿浆含量20%,接种量7.5%.     

Two-stage precipitation process of iron and arsenic from acid leaching solutions

A leaching process for base metals recovery often generates considerable amounts of impurities such as iron and arsenic into the solution. It is a challenge to separate the non-valuable metals into manageable and stable waste products for final disposal, without loosing the valuable constituents. Boliden Mineral AB has patented a two-stage precipitation process that gives a very clean iron-arsenic precipitate by a minimum of coprecipitation of base metals. The obtained product shows to have good sedimentation and filtration properties, which makes it easy to recover the iron-arsenic depleted solution by filtration and washing of the precipitate. Continuos bench scale tests have been done, showing the excellent results achieved by the two-stage precipitation process.     

硫铜钴矿生物浸出过程中细菌的作用及其溶解反应途径

研究硫铜钴矿生物浸出过程中细菌的作用及其溶解反应途径。结果表明,间接作用机制和接触作用机制均对硫铜钴矿生物浸出过程产生影响。当细菌吸附到矿物表面时,矿物溶解速率显著加快,说明浸出过程中接触作用机制对硫铜钴矿的溶解有重要影响。浸出过程中硫元素氧化价态的变化顺序为S?2→S0→S+4→S+6,并有单质硫沉淀在矿物表面,说明硫铜钴矿生物浸出过程按照多硫化物途径进行。硫铜钴矿表面被细菌严重腐蚀,出现许多大小不一的腐蚀坑洞,并有单质硫、硫酸盐及亚硫酸盐生成。这些氧化产物在矿物表面形成一层钝化层。     

Elective culture of bacteria used in bioleaching on pyrrhotite

1　ＩＮＴＲＯＤＵＣＴＩＯＮＢｉｏｈｙｄｒｏｍｅｔａｌｌｕｒｇｙｉｓｃｈａｒａｃｔｅｒｉｚｅｄｂｙｌｏｗｃｏｓｔ,ｓｈｏｒｔｆｌｏｗｓｈｅｅｔａｎｄｌｏｗｃｏｎｔａｍｉｎａｔｉｏｎ .Ｗｉｔｈｔｈｅｅｓｃａｌａｔ ｉｎｇｄｅｐｌｅｔｉｏｎｏｆｍｉｎｅｒａｌｓｏｕｒｃｅａｎｄｔｈｅｓｔｒｅｎｇｔｈｅｎｅｄｍｉｎｄｏｆｅｎｖｉｒｏｎｍｅｎｔａｌｃｏｎｓｅｒｖａｔｉｏｎ ,ｂｉｏｈｙｄｒｏｍｅｔａｌｌｕｒｇｙｐｒｅ ｓｅｎｔｓｍｏｒｅａｄｖａｎｔａｇｅｓｏｖｅｒｔｈｅｃｏｎｖｅｎｔｉｏｎａｌｍｅｔａｌｌｕｒｇ…     

Comparison on the leaching kinetics of chalcocite and pyrite with or without bacteria

The acid leaching, ferric leaching, and bioleaching of chalcocite and pyrite minerals were conducted in two sets of 3L stirred reactors. The dissolution rates of copper and iron were correlated with leaching conditions. In the acid leaching process, the dissolution rate of chalcocite was around 40wt.% while that of pyrite was less than 4%. In the ferric leaching process with high ferric concentration, only 10 wt.% of iron in pyrite was leached out at the same retention time though the copper recovery over 60 wt.% in chalcocite. For the bioleaching process, the chalcocite leaching rate was highly increased, nearly 90 wt.% of copper was leached out, and the iron dissolution of pyrite exceeded 70 wt.%. For the two minerals, the bioleaching shows the highest leaching rate compared with the acid leaching or ferric leaching. In uncontrolled bioleaching process, pyrite could be dissolved effectively. The experimental data were fitted to the shrinking core and particle model. The results show that in all the leaching tests, the chalcocite leaching was mainly controlled by diffusion, while for the pyrite leaching, chemical reaction is the main rate-determining step.     

Bacterial leaching of chalcopyrite and bornite with native bioleaching microorganism

A native mesophilic iron-oxidizing bacterium, Acidithiobacillus ferrooxidans, has been isolated （30 ℃） from a typical, lead-zinc concentrate of Dachang Mine in the region of Liuzhou located in the southwest of China. Two typical copper sulfide minerals, chalcopyrite and bornite, were from Meizhou Copper Mine in the region of Guangdong Province, China. Variation of pH and cell growth on time and effects of some factors such as temperature, inoculation cell number, and pulp density on the bioleaching of chalcopyrite and bornite were investigated. The results obtained from the bioleaching experiments indicate that the efficiency of copper extraction depends on all of the mentioned variables, especially the pulp density has more effect than the other factors on the microorganism. In addition, the results show that the maximum copper recovery was achieved using a mesophilic culture. The copper dissolution reached 51.34% for the chalcopyrite while it was 72.35% for the bornite at pH 2.0, initial Fe（ Ⅱ ） concentration 9 g/L and pulp density 5%, after 30 d.     

Photogenerated-hole scavenger for enhancing photocatalytic chalcopyrite bioleaching

The effects of photogenerated-hole scavengers (ascorbic acid, oxalic acid, humic acid and citric acid) on chalcopyrite bioleaching in the presence of visible light were studied using Acidithiobacillus ferrooxidans (A. ferrooxidans). Four sets of bioleaching experiments were performed: (1) visible light + 0 g/L scavenger, (2) visible light + 0.1 g/L of different scavenger (ascorbic acid, oxalic acid, humic acid and citric acid), (3) dark + 0.1 g/L of different scavenger (ascorbic acid, oxalic acid, humic acid and citric acid), and (4) dark + 0 g/L scavenger (control group). The results showed that ascorbic acid and oxalic acid could act as photogenerated-hole scavengers and significantly enhance chalcopyrite bioleaching under visible light. The dissolved copper in the light group without scavenger was only 18.7% higher than that of the control group. The copper extraction rates of the light groups with oxalic acid and ascorbic acid were respectively 30.1% and 32.5% higher than those of the control group. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) analyses indicated that ascorbic acid and oxalic acid as photogenerated-hole scavenger could capture photo-generated holes and inhibit jarosite formation on the chalcopyrite surface, thereby enhancing bioleaching of chalcopyrite under visible light.