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.     

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…     

镁离子浓度对氧化亚铁硫杆菌生长动力学的影响

在氧化亚铁硫杆菌(T.f)培养过程中其他营养物质足量的情况下,通过考察不同初始Mg2+浓度对氧化亚铁硫杆菌(T.f)生长活性的影响,得到在不同Mg2+浓度下细菌的生长曲线。结果表明:T.f对Mg2+具有一定的耐受能力;当培养基中ρ(Mg2+)≤10 g/L时,Mg2+对细菌生长活性影响很小;其ρ(Mg2+)为15 g/L时,Mg2+开始产生延迟效应,抑制细菌生长;ρ(Mg2+)为20 g/L时,细菌生长完全受到抑制。同时利用基于存在非竞争性抑制的Monod方程,建立了T.f在高Mg2+浓度下的生长动力学方程模型,确定在不同条件下细菌生长动力学参数,包括最大比生长速率μmax、Monod常数Km及镁离子抑制常数KI。利用correl系数工具分析细菌比生长速率的实验值和模拟值之间的相关系数为0.973,表明该动力学方程能较好地描述Mg2+浓度对氧化亚铁硫杆菌生长的影响。     

绢云母对黄铜矿微生物浸出的影响

采用以Acidithiobacillus ferrooxidans为主的混合菌,研究绢云母对微生物浸出黄铜矿的影响。结果表明,铜的浸出率随着绢云母粒度的减小而增加,随着绢云母质量分数的增加而呈先升高后降低的趋势。在添加粒度为-33μm、质量分数为5.0%的绢云母时,铜的最高浸出率为54.88%,比不添加绢云母时的铜浸出率提高了约12%,表明绢云母能促进黄铜矿的微生物浸出。绢云母的加入可使浸出体系pH值降低,最终pH值低于1.22。在浸出过程中,新生成的物质主要是铵黄铁矾,它覆盖于黄铜矿的表面,对微生物浸出铜有一定的阻碍作用。     

Behavior of Fe and S in bioleaching of pentlandite

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

Microcalorimetric studies of interaction between extracellular polymeric substance and sulfide minerals

Extracellular polymeric substance（EPS） seem to be important for bioleaching. For better control of the processes, the function of EPS of leaching bacteria is of crucial importance. Microcalorimetric measurement was used to study the three simulative components of EPS. The attachment of L-cysteine increases with its increasing concentration, which is Langmuir monomolecular layer adsorption. The attachment of glucose on pyrite is similar to mannose, which is not Langmuir monomolecular layer but multilayer adsorption. The results prove that the EPS mediates attachment and reacts with the sulphide surface and results in changed chemical properties of the mineral surface. It provides a new method to study the interaction between EPS and sulfide minerals.     

氨基酸复配酸洗缓蚀剂的研究

目的氨基酸对环境无毒无害,生产成本低,可生物降解且水溶性较高,是一种极具发展潜力的新型绿色酸洗缓蚀剂。探究在盐酸介质中,氨基酸及复配缓蚀剂对Q235钢的缓蚀作用。方法采用失重法,利用电子分析天平精确称量浸入腐蚀介质前后金属试样的质量来确定金属的腐蚀速率。研究了L-半胱氨酸及其复配缓蚀剂在1 mol/L盐酸介质中对Q235钢的缓蚀性能,借助等温吸附模型对其缓蚀机理进行了探讨。结果单独使用L-半胱氨酸缓蚀效率较低。当质量浓度为800 mg/L时,L-半胱氨酸的缓蚀效率达到最大值,为65.57%。复配合成缓蚀剂能降低经济成本,并提高缓蚀效率。通过三元复配实验得出L-半光氨酸、KI和抗坏血酸的最佳复配比,当L-半胱氨酸、KI、抗坏血酸的质量浓度分别为20、30、250 mg/L时,其缓蚀效率可达96.37%,且成本较低,是较理想的复配缓蚀剂。复配缓蚀剂在Q235钢表面的吸附符合Langmuir吸附等温模型。结论在盐酸介质中,L-半胱氨酸三元复配缓蚀剂整体用量适中,价格合理,证明复配缓蚀剂是一种能够得到良好应用的绿色缓蚀剂。     

诱变对新菌株Leptospirillum ferriphilum YXW及浸出金矿的影响

通过稀释分离方法从江西德兴铜矿矿山废水中富集而来的混合菌中分离得到菌株 Leptospirillum ferriphilum YXW,再利用超声波、紫外线和微波对其进行诱变,筛选出更高效的细菌用于金矿的浸出。生理生化特性实验显示,菌株YXW为极端化能自养型细菌,最佳的生长条件为温度40°C,pH=1.5。诱变后,细菌浓度分别可达到9×109(超声波)、8.4×109(紫外线)和4.3×108 mL?1(微波),与原始菌相比,分别提高了291%、265%和87%。微波和紫外诱变后,细菌总蛋白活性升高,而超声诱变后,细菌总蛋白活性降低。诱变对细菌浸出金矿的影响由大到小的排列顺序是微波、紫外线、超声波。在金矿浸出过程中,微波诱变后的细菌具有最好的浸出效果。浸出10 d后,As和Fe的浸出率分别高出原始菌19.6%和17.7%。结果表明,诱变对细菌浸出金矿效果的提高,可能不在于细菌浓度的增大,而是取决于细菌总蛋白活性的提高。     

Feasibility study on heap bioleaching of chalcopyrite

Bioleaching of chalcopyrite often encountered the formation of passivation layer, which inhibited the leaching process and resulted in a low leaching rate. This inhibitory effect can be eliminated by thermophilic biole- aching. The industrial test of BioCOP technology based on thermophiles was successfully completed, which confirmed the feasibility of chalcopyrite bioleaching. However, industrial leaching rate of chalcopyrite heap bioleaching is lower. This paper described the development status and industrial test of chalcopyrite heap bioleaching technology. The reasons for the lower efficiency of chalcopyrite heap bioleaching were analyzed. The strategies for successful chalcopyrite heap bioleaching were proposed.     

Thermodynamic properties of bioleaching liquid mixtures with and without mesophilic bacteria at different temperatures

In this work, low-grade copper sulfide mine has been treated by the bioleaching process using native cultures of Acidithiobacillus ferrooxidans. The bioleaching experiments were carried out in shake flasks at pH 2.0, 180 r·min-1 and 30°C for mesophilic bacteria. The conductivity of copper bioleaching liquid was determined by the electric conductivity method at temperatures ranging from 298 K to 313 K. The ionic activity coefficients were estimated using Debye-Hücker and Osager-Falkenlagen equations. Meanwhile, the effects of temperature and concentration on the mean ionic activity co efficients were discussed. The relative partial molar free energies, enthalpies and entropies of copper leaching solution at above experimental temperatures were calculated The behaviors of change of relative partial molar quantities were dis cussed on the basis of electrolytic solution theory. Simultaneously, the thermodynamic characters of bioleaching solution with and without mesophilic bacteria were compared. The existence of mesophilic bacteria changed the Fe3 /Fe2 ratio, which resulted in the difference of ionic interaction. The experimental data show that the determination of the thermody namic properties during the bioleaching processes should be important     

黄铁矿、单质硫、亚铁离子对浸矿微生物产生胞外多聚物的影响(英文)

嗜酸浸矿微生物产生的胞外多聚物(EPS)在酸性矿坑水的产生和硫化矿的浸出过程中,有着非常重要的影响,胞外多聚物(EPS)介导细胞与能源物质的接触,对有机薄膜的形成和细菌与基础物之间的相互作用起着重要的作用。对7株浸矿菌在不同能源培养物下产生的EPS的量以及EPS的化学成分进行研究,发现EPS含有化学成分糖、蛋白质、糖醛酸等,细菌的种类和能源物质对EPS的量和成分有很大影响。结果表明,以黄铜矿为能源物质的细菌产生的EPS要比以单质硫和亚铁为能源物质产生的EPS量多,EPS含量最高为(159.43±3.93)mg/g,是由Leptospirillum ferriphilum CBCBSUCSU208015在黄铁矿为能源物质下产生的。     

黄铁矿微生物浸出体系中的表面热力学和扩展DLVO理论

根据Young s方程的推导公式结合接触角的测定结果计算黄铁矿和氧化亚铁硫杆菌的表面能参数。结果表明,氧化亚铁硫杆菌的表面能明显高于黄铁矿的表面能。应用热力学计算氧化亚铁硫杆菌在黄铁矿表面吸附的自由能,发现其吸附自由能为正值,无法解释氧化亚铁硫杆菌在黄铁矿表面的吸附现象,而通过扩展DLVO理论建立的Lifshitz-van der Waals(LW)、Lewis acid-base(AB)和静电(EL)作用自由能与作用距离(d)之间的势能曲线,能够准确的预言氧化亚铁硫杆菌在黄铁矿表面的吸附现象。     

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.     

Control of redox potential by oxygen limitation in selective bioleaching of chalcocite and pyrite

Based on the bioleaching mechanism and electrochemical studies of metal sulfides, the dissolution rates of chalcocite and pyrite are controlled by redox potentials. Experiment on the bioleaching of chalcocite and pyrite under constant redox potential by sparging with nitrogen gas was demonstrated. By leaching at low and constant redox potential（〈760 mV, vs SHE）, copper recoveries of 90 %–98 % are achieved, which are 10 times more than iron recoveries. The iron-oxidizing bacterial populations are observed to continue to reduce under oxygen limitation conditions, but the Acidithiobacillus that have only sulfur-oxidizing capabilities are an attractive alternative for redox-controlled bioleaching of chalcocite.Thus, the described redox control technique might be one of the effective approaches to balance acid and iron in Zijinshan copper bio-heap leaching practice.     

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.     

古菌生物浸出黄铜矿过程中的表观硫氧化活性表征

对4株纯的极端嗜热古菌及它们的混合菌在生物浸出黄铜矿过程中的硫氧化活性进行对比研究。结果表明,混合菌比纯菌拥有更高的硫氧化活性,它大幅度促进黄铜矿浸出率的提高。表征嗜热古菌硫氧化活性的参数值通常受很多因素的影响,以致在不同的硫氧化菌和不同的条件下生物浸出黄铜矿时,这些参数很难准确地反映出相应的硫氧化活性。因此,期待找到一种能有效表征浸矿菌硫氧化活性的方法。     

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.     

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...     

高效浸矿混合菌种的筛选及其在浸矿过程中的微生物群落结构演变

为了筛选可高效浸出低品位硫化矿的混合菌株,从10个典型的硫化矿矿区的酸性矿坑水中分离富集到混合菌株。以浸出率作为筛选的主要标准,筛选后的高效菌株,利用群落基因组芯片分析混合菌群的组成和过程变化。浸矿持续进行24d后,采集自江西德兴银山铅锌矿的混合菌浸出率最高,为68.89%。群落基因组芯片结果表明银山菌群包含9种菌,可被分为6类,在浸出过程中群落始终在变化。该研究为加速浸出和了解浸出过程中群落演替提供了一个较好的方法。     

Comparative study on bioleaching of two different types of low-grade copper tailings by mixed moderate thermophiles

The bioleaching of two different types of low-grade copper tailings, acid-leaching tailings (ALT) and copper flotation tailings (CFT) by mixed moderate thermophiles, and the variation of mineralogical and microbiological characteristics during their dissolution processes were comparatively investigated. Results showed that bioleaching behaviors of the two types of tailings were significantly different. In ALT bioleaching, lower redox potential, higher [Fe³⁺]/[Fe²⁺] ratio and higher cell density in solution were obtained. These resulted in higher total copper, primary copper sulfide and secondary copper sulfide extractions, compared with CFT bioleaching. X-ray diffraction analysis suggested that gypsum and some metal organic complexes were detected in CFT bioleaching, which could cause the sluggish oxidation of sulphide minerals. The shifts of microbial community in the leachates and leaching residues varied greatly between ALT and CFT bioleaching. The percentage of iron-oxidizing bacteria in ALT bioleaching was higher than that of CFT, but the sulfur-oxidizing bacteria percentage was the opposite. The archaeon F. thermophilum L1 was detected in ALT but not in CFT.