Acidithiobacillus ferrooxidans对软锰矿浸出的影响

利用循环伏安、交流阻抗谱和极化曲线研究了Acidithiobacillus ferrooxidans对软锰矿在模拟浸出溶液(9K基础培养基, A.ferrooxidans, Fe (Ⅲ), A.ferrooxidans+Fe (Ⅲ))中电化学腐蚀行为的影响; 利用模拟有菌/无菌浸出溶液中钝化膜的Mott-Schottky理论比较了有无细菌存在情况下形成的钝化膜的优劣性.结果表明, A.ferrooxidans促进MnO₂/Mn2+氧化还原转化, 催化MnO₂/Mn (OH)₂电极反应; 加速软锰矿/溶液界面电子交换, 无铁存在时A.ferrooxidans使电荷转移内阻降低34%, 比含Fe (Ⅲ)无菌体系低11%;引起软锰矿电极极化, 增强其氧化活性; 加速MnO₂向MnO·OH转化及其产物扩散.A.ferrooxidans与软锰矿作用更倾向于间接作用机理.在选取的各模拟电解液(pH值为2.0)中, 0.2~0.4 V区间内软锰矿形成耗尽层, 在模拟浸出溶液中形成的钝化膜都表现出p-n-p-n型半导体性能.在选取的0.2 V极化电位下, 无铁时引入A.ferrooxidans使膜中的施主/受主密度减少, 细菌含有多种基团参与半导体/溶液界面电子转移反应, 接受界面间自由电子或填充空穴, 促使软锰矿与溶液界面物质交换变频繁; 含铁溶液中加入A.ferrooxidans使得钝化膜受主/施主密度增大, A.ferrooxidans降低了膜的耐腐蚀性, 因而促进软锰矿浸出.      

铝离子对氧化亚铁硫杆菌活性及浸出黄铜矿的影响

以氧化亚铁硫杆菌(Acidthiobacillus ferrooxidans,At.f)为研究对象,研究了铝离子浓度对黄铜矿浸出体系At.f菌氧化活性、黄铜矿表面吸附细菌数量以及铜浸出率的影响,并对其之间内在联系进行了考察。研究结果表明,浸出体系铝离子浓度在所研究的0~20 g·L~(-1)范围内,对细菌氧化活性的影响有明显差异。铝离子浓度为1 g·L~(-1)时,细菌氧化活性最好,浸出15 d后,体系氧化还原电位便可由381 mV升高到588 mV左右,Fe~(2+)氧化率达到98.49%,体系pH值由2.11下降到1.44;超过1 g·L~(-1)后,细菌氧化活性逐渐降低,Fe~(2+)氧化率下降,铝离子浓度为20 g·L~(-1)时,浸出45 d后,体系氧化还原电位仅为400 mV左右,Fe~(2+)氧化率也仅为40%左右。矿物表面吸附细菌数量、浸出体系铜浸出率均随铝离子浓度增加先升高后降低,铝离子浓度为15 g·L~(-1)时,浸出体系铜离子浸出率最高,可达71.39%,矿物表面吸附细菌数量也最多,表明铜浸出率与矿物表面吸附细菌数量正相关。     

嗜酸氧化亚铁硫杆菌的分离鉴定及对废胎面胶的脱硫再生

从河北兴隆某硫铁矿筛选到一株硫杆菌YT-1,经理化性能和16S rDNA序列分析鉴定为嗜酸氧化亚铁硫杆菌(At.ferrooxidans YT-1),研究了该菌对废胎面胶(GTR)的脱硫再生作用.研究结果表明,三元共混物丁苯橡胶(SBR)/炭黑(CB)/再生GTR比SBR/CB/未再生GTR拉伸强度和断裂伸长率分别提高了5.3%和11.1%;X射线光电能谱检测表明SBR/CB/再生GTR表面硫元素质量分数降低13.92%,且峰位往高氧化态偏移0.2 eV,说明再生GTR表面硫元素被氧化;共混胶断裂面扫描电子显微镜显示再生GTR与SBR/CB基体粘合性能显著提高,说明再生GTR表面硫交联键被打断.     

极端嗜热硫杆菌浸出黄铁矿

为了探讨极端嗜热菌在高铁、高酸和高温条件下生物脱硫的可行性,采用从腾冲热海酸性温泉分离出的一株新型极端嗜热硫杆菌开展了四组不同初始pH值条件下的黄铁矿生物柱浸实验.该菌株能耐受pH值为0.58、全铁质量浓度为38.9 g·L-1的高酸高铁环境,同时维持580~640 mV的较低电位.初始pH值为2时,浸出28 d后黄铁矿浸出率达到最高为17.8%.生物浸出时,菌株生长依次表现出较明显的迟缓期、对数期和稳定期,且降低初始pH值会延长其到达稳定期的时间.此外,70℃高温和全铁质量浓度为38.9 g·L-1的高铁体系能促进生成黄钾铁矾和少量单质硫沉淀,而菌株能在pH值小于0.9时将大部分S0氧化为SO₄2-.      

用嗜酸氧化亚铁硫杆菌(Acidithiobacillus ferrooxidans)从硅酸盐-磷灰石矿石中溶解铀

Abhilash S．Singh等研究了印度低品位硅酸盐-磷灰石铀矿石的生物浸出。矿石中含0．024％U3O8和10．6％铁及少量贱金属。用采自矿山的用于产生氧化剂铁离子的富含嗜酸氧化亚铁硫杆菌（Acidithiobacillus ferrooxidans（A.ferrooxidans））的菌液提取铀。     

高砷高硫难处理金精矿生物预氧化—氰化炭浸提金试验研究

研究了采用生物预氧化—氰化炭浸工艺从广西某高砷高硫难处理金精矿中提取金,考察了矿浆浓度、体系pH、氧化时间、溶氧量对金浸出率的影响。试验结果表明:采用生物预氧化—氰化炭浸工艺,金浸出率由直接氰化浸出时的16.35%提高到77.78%,浸出效果较好。     

影响嗜酸氧化亚铁硫杆菌生长及生物浸出效率的研究进展

介绍了嗜酸氧化亚铁硫杆菌(acidithiobacillus ferrooxidans,以下简称A.f菌)在生物提铜过程中的生长及影响其活性的常见因素,阐述了生物浸出体系中黄钾铁矾类物质、溴代阻燃剂、重金属离子、阴离子等对生物浸出过程的抑制作用,分析了各因素对生物浸出效果的抑制机制及解除措施,在此基础上,分析了电磁场、催化剂、表面活性剂等对生物浸出的促进作用,以期促进生物冶金技术在电子废弃物金属资源化领域的进一步应用与发展。     

难浸高硫金精矿细菌预氧化--氰化浸出试验研究

针对甘肃亚特含高硫难浸金精矿开展了生物预氧化-氰化浸出试验研究,考察了细菌预氧化过程中矿浆浓度、pH值、反应温度、磨矿细度和氧化时间等参数条件对浸出的影响,并对氧化后液进行回用处理。结果表明,在矿浆浓度为16%、pH值为1.2~1.4、反应温度为40℃、磨矿细度＜0.043 mm占94.8%以上以及氧化时间为8 d的条件下,采用细菌预氧化处理技术对矿样进行处理,硫氧化率达86.0%,金浸出率由直接氰化浸出率的23.4%提高到92.6%。     

高硫高粘土含砷含碳卡林型金精矿生物预氧化研究

针对低品位高硫高粘土含砷含碳卡林型金精矿矿石性质特殊,直接氰化金浸出率仅为10.01%,且常规生物预氧化方法无法有效脱除金精矿中的硫、砷等有害杂质,开展了分步生物预氧化试验研究。通过充气搅拌浸出条件试验,考察了磨矿细度、接种量和矿浆浓度对预氧化效果的影响,结果表明三者均对预氧化效果影响很大。当工艺参数为:浸矿温度45℃,磨矿细度-37μm占90%,矿浆浓度10%,接种量10%,搅拌速度120 r·min-1,浸矿体系2 L,采用分步预氧化方法,共氧化9 d,金精矿中硫、砷脱除率分别可达82.96%和92.01%,后续金的氰化浸出率为79.91%。预氧化渣XRD图谱,SEM分析以及氰化试验表明,金精矿中有机碳物质具有严重劫金作用,同时预氧化5~9 d期间黄铁矿表面形成的大量黄钾铁矾膜对后续金的氰化浸出也具有严重的抑制作用。     

外源硫和Fe~(3+)对低硫铀矿生物浸出的影响

针对铁、硫含量较低的铀矿,采用外源添加不同浓度的Fe~(3+)及单质硫的方法强化铀矿生物浸出,研究外源Fe~(3+)、单质硫对浸出体系中pH、氧化还原电位值Eh、铁离子浓度、铀浓度的影响。结果表明,Fe~(3+)初始浓度分别为0、1、2、3和4g/L时,铀浸出率分别为81.85%、92.61%、89.15%、86.28%和86.09%,Fe~(3+)浓度为1g/L时浸出铀浓度最大,不同初始浓度的Fe~(3+)对铀矿浸出具有显著影响。在2g/L Fe~(3+)体系中,添加2g/L单质硫与未添加单质硫相比,pH上升较慢,铀浸出率提高1.63个百分点;SEM-EDS分析表明,与原矿相比,铁体系中矿物表面粗糙且矿石结构疏散,矿石颗粒比表面积增加,浸出渣样中伴随黄钾铁矾等沉淀的产生,添加2g/L单质硫的体系中黄钾铁矾显著降低。     

Raman characterization of secondary minerals formed during chalcopyrite leaching with Acidithiobacillus ferrooxidans

Chalcopyrite passivation greatly reduces the yields from leaching and bioleaching but the problem has not been successfully resolved. Passivation involves the formation of a layer of secondary minerals on chalcopyrite surface, which becomes a diffusion barrier to fluxes of reactants and products. This study aims to identify secondary minerals formed during chalcopyrite passivation in the presence of iron- and sulfur-oxidizing bacteria (Acidithiobacillus ferrooxidans) in mineral salts solution. The minerals were characterized with X-ray diffraction, Fourier transform-infrared spectroscopy, and Raman spectroscopy. Potassium jarosite was the initial product covering chalcopyrite grains, followed by the formation of ammonio-jarosite. Covellite and elemental sulfur were also detected in the passivation layer. The results suggest that passivation may be reduced by controlling jarosite precipitation and prior acclimatization of bacteria to oxidize CuS and elemental S in the presence of ferrous and ferric iron.     

辉钼矿生物浸出研究进展

简要回顾了国内外钼矿生物浸出的发展历程,总结了钼矿生物浸出率低的原因。对钼矿生物浸出中的关键问题,即辉钼矿的可浸性、钼矿浸出的菌种、生物浸出的作用机理、钼离子对菌种生长的影响和沉淀对浸出的抑制作用作了探讨。此外,提出了浸矿菌种基因改良、多级生物反应器浸出和浸出体系溶液电位调控等辉钼矿生物高效浸出方法。     

黄铁矿促进黄铜矿微生物浸出影响因素

采用摇瓶实验,以氧化亚铁硫杆菌(Acidithiobacillus ferrooxidans,At.f)浸出黄铁矿-黄铜矿,重点研究了基础培养基、矿物配比和粒度组成等因素的影响.黄铁矿能促进黄铜矿的微生物浸出,以采用无Fe 9K培养基效果较好,它对应铜浸出率是9K培养基的1.68倍;采用宽粒级矿物时铜浸出效果较好,且铜浸出率与黄铁矿和黄铜矿的质量比有关,当质量比为2:2时铜浸出率最高可达45.58%;黄铁矿含量大小是影响铜浸出率高低的实质,当质量比小于等于5:2时以At.f菌的氧化作用为主,当质量比为10:2时以硫化矿间的原电池效应为主.浸渣的X射线衍射分析表明,采用无Fe 9K培养基时浸渣中生成的钝化物黄钾铁矾较少,故黄铁矿可以很好地替代9K培养基中的FeSO₄,并能与黄铜矿形成原电池效应,从而促进铜的浸出.      

Bioleaching of Rare Metals from Manganese Nodules by Thiobacillus Ferrooxidans

Manganese nodules, which constitute a potential future resource of rare metals, are composed mainly of oxides of manganese and iron, with various metals such as copper, nickel, and cobalt. Although physical and chemical processes have been developed for extracting the rare metals from manganese nodules, another possible process is the leaching of metals by microbial means.

This paper describes leaching of raw manganese nodules by sulfurous acid and sulfuric acid which are biologically produced by oxidation of elemental sulfur by Thiobacillus ferrooxidans. The bioleaching behavior of each metal from nodules was measured at 30°C and pH 2 in a well-mixed batch reactor. The metal content of the nodules used in this work was 0.29% Cu, 0.49% Ni, 0.27% Co, 16% Fe and 17% Mn by weights. For both the microbial system and the control culture containing no T.ferrooxidans, copper and nickel exhibited close to 100% leaching in two weeks and less than 5% for iron and manganese. On the other hand, leaching of cobalt was markedly accelerated in the microbial system reaching 50% in two weeks compared with the sterile control. The bioleaching rate of cobalt was enhanced as the initial sulfur-liquid loading ratio became higher, but is was practically independent of the nodule size which was less than 330 mesh. Moreover, there was an optimal relation between the bioleaching rate and the initial cell concentration, and the addition of T.ferrooxidans cells in excess of the optimal concentration resulted in a decrease in the leaching rate of cobalt.     

高碱脉石低品位铜镍复合矿的诱变细菌浸出

金川低品位铜镍复合矿为高碱脉石的氧化—硫化混和矿 ,矿区无土著浸矿细菌。采用经诱变改良的外源混合T .f浸矿菌和控制矿浆 pH(<4 ) ,有效地浸出了该复合矿中的镍和铜 ;控制矿浆pH在细菌生长最适的范围内 ,钙、镁实际耗酸分别只占其总含量的 2 2 %～32 % ;铜、镍在不同浸出阶段表现为相反的浸出行为 ,酸浸时铜优先被浸出 ,菌浸时镍优先被浸出 ;渣样分析表明硫化镍、硫化铜的浸出机制为间接作用。物相分析表明这些浸出行为与浸出对象的赋存状态有关。     

氧化亚铁硫杆菌及中度嗜热菌的紫外诱变对黄铜矿的浸出

利用紫外线对氧化亚铁硫杆菌和采自酸性温泉水的中度嗜热菌进行诱变,对黄铜矿浸出。诱变后菌活性分别提高40.6%和35.9%,浸出率分别提高了36.6%和23.5%,并对这两种菌混合后浸出做了探讨。     

Chemical and electrochemical basis of bioleaching processes

The bioleaching of sulfide minerals involves electrochemical and chemical reactions of the mineral with the leach liquor and the extra-cellular polysaccharide layers on the microorganisms. The microorganisms derive energy by oxidising the sulfur moiety and ferrous iron, which can be interpreted using electrochemistry and chemiosmotic theory. Recently, significant advances have been made in understanding the mechanism by which the bioleaching of sulfide minerals occurs. Kinetic models based on the proposed mechanism are being used successfully to predict the performance of continuous bioleach reactors. The measurement of oxygen and carbon dioxide consumption rates together with the measurement of redox potentials has led to this further elucidation of the mechanism of bioleaching of sulfide minerals and enabled the kinetics of the sub-processes involved to be determined separately. It has been shown that bioleaching involves at least three important sub-processes, viz., attack of the sulfide mineral, microbial oxidation of ferrous iron and some sulfur moiety. The overall process occurs via one of two pathways depending on the nature of the sulfide mineral, a pathway via thiosulfate resulting in sulfate being formed or a polythionate pathway resulting in the formation of elemental sulfur. For the case of pyrite, the primary attack of the sulfide mineral is a chemical ferric leach producing ferrous iron. The role of the bacteria is to re-oxidise the ferrous iron back to the ferric form and maintain a high redox potential as well as oxidising the elemental sulfur that is formed in some cases. The first two sub-processes of chemical ferric reaction with the mineral and bacterial oxidation of the ferrous iron are linked by the redox potential. The sub-processes are in equilibrium when the rate of iron turnover between the mineral and the bacteria is balanced. Rate equations based on redox potential or ferric/ferrous-iron ratio have been used to describe the kinetics of these sub-processes. The kinetics have been described as a function of the ferric/ferrous-iron ratio or redox potential which enables the interactions of the two sub-processes to be linked at a particular redox potential through the rate of ferrous iron turn-over. The use of these models in predicting bioleach behaviour for pyrite is presented and discussed. The model is able to predict which bacterial species will predominate at a particular redox potential in the presence of a particular mineral, and which mineral will be preferentially leached. The leach rate and steady state redox potential can be predicted from the bacterial to mineral ratio. The implications of this model on bioleach reactor design and operation are discussed. Research on the chemistry and electrochemistry of the ferric leaching of sulfide minerals and an electrochemical mechanism for ferrous iron oxidation based on chemiosmotic theory will be presented and reviewed.     

Microbiological leaching of copper from lead mattes

The possibility of recovering copper from lead blast furnace mattes by bioleaching, using bacteria of the genus Thiobacillus ferrooxidans, has been studied. In this paper, the influence of certain variables on the dissolution rate and the adaptation period of the bacteria have been evaluated, including energy source, nutrient, type of matte, type of stirring, pulp density, and particle size. In addition, the influence of bioleaching for different periods of time, as a preparatory stage before chemical or biological leaching of the matte, was studied. The optimum conditions for recovery are achieved by way of the two-stage bioleaching process. The degradation of the solid caused by bacterial activity during the first stage is the reason for the high recovery during the second stage.     

生物浸矿的电化学催化

生物浸矿由于其浸出速率很低而使其实际应用受到了严重限制。金属硫化物的生物浸出过程实质上是电子得失的电化学氧化还原过程,因此利用电化学原理可强化金属硫化物的生物浸出。介绍了不同矿物间组成的腐蚀电极、金属离子催化、外国电位（流）等强化生物浸矿的电化学方法,同时分析了细菌的作用和其所受到的影响,探讨了各种方法强化生物浸矿的机理。