Effect of Cu~(2+)ions on bioleaching of marmatite

The effect of Cu~(2+)ions on bioleaching of marmatite was investigated through shake leaching experiments.The bacteria inoculated are a mixed culture ofAcidithiobacillus ferrooxidans,Acidithiobacillus thiooxidans and Lepthospirillum ferrooxidans.The results show that zinc is selectively leached,and the addition of appropriate content of Cu~(2+)ions has positive effect on the bioleaching of marmatite.SEM and EDX analyses of the leaching residue reveal that a product layer composed of iron sulfide, element...     

Effect of Cu ions on bioleaching of marmatite

The effect of Cu^2＋ ions on bioleaching of marmatite was investigated through shake leaching experiments. The bacteria inoculated are a mixed culture ofAcidithiobacillusferrooxidans, Acidithiobacillus thiooxidans and Lepthospirillumferrooxidans. The results show that zinc is selectively leached, and the addition of appropriate content of Cu^2＋ ions has positive effect on the bioleaching of marmatite. SEM and EDX analyses of the leaching residue reveal that a product layer composed of iron sulfide, elemental sulfur and jarosite forms on the mineral surface. The biooxidation of elemental sulfur is catalyzed by the Cu^2＋ ions, which eliminate the barrier to bioleaching of marmatite and keep low pH value. With the addition of 0.5 g/L Cu^2＋ ions, the maximum zinc extraction rate reaches 73% after 23 d at the temperature of 30 ℃ with the pulp density of 10%, while that of iron is only about 10%.     

Bioleaching of marmatite flotation concentrate by Acidithiobacillus ferrooxidans and Leptospirillum f errooxidans

Bioleaching of marmatite flotation concentrate by Acidithiobacillus ferrooxidans and Leptospirillum ferrooxidans was investigated at 35℃, the initial pH value of 2.0 on an orbital shaker with 160 min^-1 over a period of 10 days. Experimental results indicate that the adapted strains increase markedly the dissolution rate and the leac-hing ratio of marmatite. Pulp density also affects the bioleaching of marmatite. Massive elemental sulfur and jarosite form during the leaching process in the systems inoculating the adapted strains in pure and mixed cultures;and acid product is enhanced, which decreases the pH below to 2.0 in latter leaching period. Marmatite preferentially dis-solves during the bacterial leaching of complex sulfides. Compared with the pure cultures of original and adapted strains, the adapted strains of Acidithiobacillus ferrooxidans and Leptospirillum ferrooxidans in mixed cultures are more efficient in the oxidation of marmatite.     

Marmatite bioleaching with moderately thermoacidophilic bacterial strain and mineral analyses of solid residues

The bioleaching of a marmatite flotation concentrate with a moderately thermoacidophilic iron-oxidizing bacterial strain （MLY） is influenced significantly by temperature, pH, particle size, pulp density of ores and bacterial strains. Under such leaching conditions as the initial pH value of 1.5, temperature of 50℃, pulp density of 5%, particle size less than 35.5μm （over 90%） and inoculating the adapted strains of MLY, the leached Zn is over 95% after 10 d of bioleaching. SEM observations show the cell attachment and the surface features of solid residues under different leaching conditions. XRD and EDX analyses show that a mass of elemental sulfur form during the bioleaching process. The technological feasibility of a microbiological process using MLY for extracting zinc from the marmatite concentrate is demonstrated.     

Single and cooperative bioleaching of sphalerite by two kinds of bacteria —— Acidithiobacillus ferriooxidans and Acidithiobacillus thiooxidans

A cooperative bioleaching （Acidithiobacillus ferriooxidans and Acidithiobacillus thiooxidans） and single bioleaching （Acidithiobacillus ferriooxidans or Acidithiobacillus thiooxidans） of sphalerite were investigated by X-ray diffractometry, energy dispersive spectrography and scanning electron microscopy. The experimental results show that the leaching rate of zinc in the mixed culture is higher than that in pure culture and the sterile control. In these processes, two kinds of bacteria perform different functions and play a cooperative role during leaching of sphalerite. The bioleaching action carded out by Acidithiobacillus ferriooxidans （.4. ferriooxidans） is not directly performed through Fe^2＋ but Fe^3＋, and its role is to oxidize Fe^2＋ to Fe ^3＋ and maintain a high redox potential. Moreover, the addition of an appropriate concentration of ferric iron to the leaching systems is beneficial to zinc dissolution. In the leaching systems without Acidithiobacillus thiooxidans （.A. thiooxidans）, elemental sulfur layers are formed on mineral surface during the dissolution of zinc and block continuous leaching. Acidithiobacillus thiooxidans, however, eliminate the passivation and cause the bioleaching process to continue in the leaching systems. At the same time, protons from the bacterial oxidization of the elemental sulfur layers also accelerate the leaching of zinc.     

Elective culture of bacteria used in bioleaching on pyrrhotite

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Bioleaching of chalcopyrite by pure and mixed culture

The bioleaching of chalcopyrite in shake flasks was investigated by using pure Acidithiobacillusferrooxidans and mixed culture isolated from the acid mine drainage in Yushui and Dabaoshan Copper Mine in China, marked as YS and DB, respectively. The mixed culture consisted mainly of Acidithiobacillus fOrrooxidans, Acidithiobacillus thiooxidans, and Leptospirillum spp. （Leptospirillum ferriphilum and Leptospirillum ferrooxians）. The results show that the mixed culture is more efficient than the pure Acidithiobacillus ferrooxidans because of the presence of the sulfur-oxidizing cultures that positively increase the dissolution rate and the recovery of copper from chalcopyrite. The pH value decreases with the decrease of chalcopyrite leaching rate, because of the formation ofjarosite as a passivation layer on the mineral surface during bioleaching. In the bioleaching using the mixed culture, low pH is got from the sulfur oxidizing inhibiting, the formation ofjarosite. The copper extraction reaches 46.27% in mixed culture and 30.37% in pure Acidithiobacillusferrooxidans after leaching for 75 d.     

Isolation and characterization of acidophilic bacterium from Gaofeng Mine in China

An acidophilic, chemolithotrophic and ferrous oxidizing bacterium strain GF was isolated from the acid mine drainage （AMD） of Gaofeng Mine, Guangxi Province, China using 9K enrichment medium, and then purified on solid ferrous-agarose medium. The physiological experiments show that it can use ferrous or sulfur as sole energy and a low level （0.1%, w/v） of peptone can accelerate the growth of the isolated strain. The optimum pH and temperature for growth are 2.0 and 30 ℃, respectively. The isolated strain shares 99.64% identities of 16S rRNA gene with the type strain Acidthiobacillusferrooxidans ATCC 23270 and 100% identities of iro gene （CDS） with A.ferrooxidans strain Fe-1. These results show that the strain can be considered as A cidthiobacillus ferrooxidans. Because of the high activity of oxidizing ferrous and sulfide mineral, strain GF was used in bioleaching of marmatite. The Zn concentration is 0.273 g/L under the steriled control and 7.30 g/L with adapted GF strain incubated after 29 d in leaching marmatite. The isolated strain GF can be used to leach marmatite in industry application.     

元素硫对黄铜矿生物浸出行为及群落结构的影响(英文)

研究3种典型铁/硫代谢菌—Acidithiobacillus ferrooxidans,Leptospirillum ferriphilum及Acidithiobacillus thiooxidans混合浸出黄铜矿过程中铁/硫氧化活性、群落结构(PCR-RFLP)的变化,以及不同浓度的元素硫对其影响。结果发现,加入3.193g/L元素硫能促进细菌的表观硫氧化活性,改变浸矿体系的群落结构,并进一步影响钝化层的形成、金属离子的溶出,其浸出率(71%)较未添加硫的(67%)有一定程度的提高。而过量的元素硫会抑制铜的浸出(浸出率44%)。     

Bioleaching of pyrite by A. ferrooxidans and L. ferriphilum

Pyrite oxidation rates were examined under various conditions in the presence of A.ferrooxidans and L.ferriphilum,in which different pulp concentration,inoculation amount,external addition of Fe3+ and initial pH value were performed.It is found that A.ferrooxidans and L.ferriphilum show similar behaviors in the bioleaching process.The increasing pulp concentration decreases the leaching rate of iron,and external addition of high concentration Fe3+ is also adverse to leaching pyrite.The increased inoculation amount and high initial pH value are beneficial to leaching pyrite,and these changed conditions bring more obvious effects on leaching pyrite by L.ferriphilum than by A.ferrooxidans.The results also show that adjusting the pH values in leaching process baffles leaching pyrite due to the formed jarosite.Jarosite formed in leaching process was observed using XRD,SEM and energy spectrum analysis,and a considerable amount of debris with a crystalline morphology is present on the surface of pyrite.The results imply that the indirect action is more important for bioleaching pyrite.     

金属离子强化铁闪锌矿浮选精矿的生物浸出

考察了金属离子Cu2 、Fe3 和Fe2 等对铁闪锌矿浮选精矿生物浸出的影响,并与无菌条件下对铁闪锌矿浸出的影响进行比较.结果表明:Cu2 、Fe3 和Fe2 等金属离子在一定浓度范围内都可以促进铁闪锌矿的生物浸出;在无菌条件下,除Fe2 外,Cu2 和Fe3 离子仍对铁闪锌矿溶解有一定的促进作用.电化学测试和X射线衍射分析表明:添加Cu2 和Fe3 等离子将影响铁闪锌矿电极发生的电化学反应和浸渣组成;添加Cu2 离子可取代矿物基质晶格中的Zn而生成CuS沉淀,并与锌矿产生原电池效应而促进浸出过程;Fe3 和Fe2 两种离子强化铁闪锌矿生物浸出的机理本质上一致,均可以提高浸出液中氧化剂浓度和促进细菌生长与生物活性.     

Effect of technological factors on bacterial leaching of low-grade Ni-Cu sulfide ore

1　ＩＮＴＲＯＤＵＣＴＩＯＮＢａｃｔｅｒｉａｌｌｅａｃｈｉｎｇｗｉｔｈａｕｔｏｔｒｏｐｈｉｃｂａｃｔｅｒｉａ ,ｓｕｃｈａｓＴｈｉｏｂａｃｉｌｌｕｓｆｅｒｒｏｏｘｉｄａｎｓ (Ｔ .ｆ.) ,ｈａｓｂｅｅｎｅｘｔｅｎｄｅｄｔｏｓｏｍｅｐｏｌｙｍｅｔａｌｌｉｃｓｕｌｆｉｄｅｏｒｅｓ[1] .ＡｆｅｗｏｆｐａｐｅｒｓｏｎｂｉｏｌｅａｃｈｉｎｇｏｆＮｉ Ｃｕｓｕｌｆｉｄｅｏｒｅｗｅｒｅｐｕｂｌｉｓｈｅｄ .Ｔｏｒｍａ[2 ] ｒｅｐｏｒｔｅｄｔｈａｔｔｈｅｌｅａｃｈｅｄＮｉ,ＣｕａｎｄＣｏｗｅｒｅａｌｌｏｖｅｒ 6 0 %ｉｎ 10ｄ…     

Behavior of Fe and S in bioleaching of pentlandite

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

Microbial leaching of marmatite by Acidithiobacillusferrooxidans and Acidithiobacillus thiooxidans

1 Introduction Microbial leaching of metals from sulfide minerals has been practiced over hundreds of years without realizing that microorganisms were involved. Copper, zinc, gold, etc can be recovered from sulfide ores by microbial leaching[1?5]. Zinc s…     

Relatedness between catalytic effect of activated carbon and passivation phenomenon during chalcopyrite bioleaching by mixed thermophilic Archaea culture at 65 °C

The relatedness between catalytic effect of activated carbon and passivation phenomenon during chalcopyrite bioleaching by mixed thermophilic Archaea culture (Acidianus brierleyi, Metallosphaera sedula, Acidianus manzaensis and Sulfolobus metallicus) at 65 °C was studied. Leaching experiments showed that the addition of activated carbon could significantly promote the dissolution of chalcopyrite for both bioleaching and chemical leaching. The results of synchrotron-based X-ray diffraction, iron L-edge and sulfur K-edge X-ray absorption near edge structure spectroscopy indicated that activated carbon could change the transition path of electrons through galvanic interactions to form more readily dissolved secondary mineral chalcocite at a low redox potential (<400 mV) and then enhanced the copper dissolution. Jarosite accumulated immediately in the initial stage of bioleaching with activated carbon but copper dissolution was not hindered. However, much jarosite precipitated on the surface of chalcopyrite in the late stage of bioleaching, which might account for the decrease of copper dissolution rate. More elemental sulfur (S⁰) was also detected with additional activated carbon but the mixed thermophilic Archaea culture had a great sulfur oxidation activity, thus S⁰ was eliminated and seemed to have no significant influence on the dissolution of chalcopyrite.     

Bioleaching of chalcopyrite with Acidianus manzaensis YN25 under contact and non-contact conditions

In order to investigate the contributions of contact and non-contact cells of Acidianus manzaensis(A.manzaensis) YN25 to the bioleaching of chalcopyrite,three experiments were carried out in the modified shake flasks.The redox potential,pH,cell density,copper and iron ions in the solution were monitored,and the morphological feature and chemical composition of the leached residues were analyzed.The highest leaching efficiency of Cu and Fe was reached in the experiment where the A.manzaensis YN25 could contact the surface of the chalcopyrite.There was no precipitation of jarosite in the leached residues of three experiments,but there was elemental sulfur in the leached residues when the cells could not contact the chalcopyrite.From these results,it is apparent that the leaching of the chalcopyrite is the cooperative action of the contact and non-contact A.manzaensis YN25.     

嗜酸兼性异养菌Acidiphilium sp.DX1-1的分离、特征及其浸矿行为(英文)

研究了一株源自江西德兴铜矿矿区的中温嗜酸兼性异养菌Acidiphilium sp.DX1-1的分离、鉴定、特征及其浸矿行为。菌株Acidiphilium sp.DX1-1为短杆状革兰氏阴性菌,最适合的生长温度为30℃,最适合的生长pH约为3.5。该菌株具有广泛的底物利用特性,可以利用有机物进行异养生长并在细胞内积累聚羟基丁酸酯,也可以利用单质硫、三价铁等无机物进行自养生长。系统发育分析表明DX1-1属于Acidiphilium属,与Acidiphilium cryptum and Acidiphilium multivorum的同源性大于99%。在铁闪锌矿生物浸出过程中,Acidiphilium sp.DX1-1表现出极强的浸矿能力,其作用不仅仅是之前报道的作为其他自养嗜酸浸矿细菌的辅助者。在初始pH3.5时,DX1-1能够在一个月内单独地浸出铁闪锌矿中40%的锌。该浸出率高于它与A.ferrooxidans混合以及A.ferrooxidans单独浸出铁闪锌矿(初始pH均为2.0)的浸出率。     

Effect of two kinds of amino-acids on bioleaching metal sulfide

By adding suitable amount of amino acid L-cysteine to acidic solution in contact with sphalerite or pyrite,the activity of Thiobacillus Ferrooxidans is largely enhanced. But, at comparable higher concentration of L-cysteine, a deleterious effect on bacterial activity was found, which can be due to the toxic effect of this amino acid at higher concentrations to microbes. The addition of L-methionine would be great inhibition to the bioleaching no matter how much it was applied, which indicates that L-methionine is harmful for bioleaching. The quite different effect on bioleaching between L-cysteine and L-methionine lies in that L-cysteine has a SH group which is useful in helping metal sulfide bioleaching by Thiobacillus ferrooxidans.     

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...     

碳质金矿的碳质物及生物氧化预处理研究现状

碳质金矿是一种重要的难处理金矿。研究发现,其碳质物主要包括元素碳、有机酸和烃类物质。在氰化浸金过程中碳质物可通过类活性炭的吸附方式将已溶解的金劫走。目前,已有的预处理方法主要有高温焙烧法、生物氧化法、化学氧化法、竞争吸附法、覆盖抑制法、微波加热法。生物氧化法因具有条件温和、流程简单、能耗低、环境友好等优点得以迅速发展。与生物氧化预处理有关的微生物主要有氧化亚铁硫杆菌、氧化硫硫杆菌、氧化亚铁钩端螺旋菌等化能无机自养菌。有关黄孢原毛平革菌、假单胞菌、多毛链霉菌在碳质物降解和钝化方面的研究也已展开。最后,分析了该技术存在的问题,并对其应用前景进行了展望。