硫化矿细菌浸出机理及协同作用研究现状

细菌浸出作为一种经济、环保的处理技术,广泛应用于金属硫化物的金属提取和预处理过程中。为进一步理解细菌在硫化物浸出过程中的作用,详细阐述了细菌在浸出过程中的作用机理及其在矿物表面的作用机制,系统描述了金属硫化物溶解的硫代硫酸盐与多硫化合物途径。同时,还重点介绍了常见浸矿细菌的生存环境,并对不同种类浸矿细菌之间的协同作用进行了分析。     

铜镍多金属硫化矿生物浸出研究现状及进展

铜镍多金属硫化矿是目前产镍的主要矿物,这些含镍硫化矿物很容易被细菌侵蚀,对于生物浸出铜镍硫化矿,许多学者已经开展了广泛的研究,并实现了规模化的工业实践。介绍了铜镍多金属硫化矿的主要矿床类型、分布规律和矿物组成特征,并从矿物晶体结构、热力学、电化学等多个方面分析了铜镍硫化矿中主要矿物物化性质的差异,总结了铜镍硫化矿生物浸出研究的现状。当前,生物浸出铜镍多金属硫化矿还有很多机制和工艺上的问题有待进一步解决:高性能浸铜、浸镍菌种的选育驯化;浸出铜镍硫化矿过程的微观机制分析以及常规生物浸出工艺存在的各种问题。未来铜镍矿生物浸出的发展趋势主要有3方面:高效菌种选育、微观机制研究、新工艺开发。对于常规生物浸出铜镍硫化矿工艺,所得浸出液成分复杂,杂质含量较高,给萃取分离工作带来了困难,本文提出了复杂铜镍硫化矿生物选择性浸出的新思路,有助于解决复杂生物浸出液中有价金属的高效分离。目前,该工艺还处在实验阶段,要实现其工业化应用还需要更广泛的基础理论研究和工艺实践。     

难处理硫化矿生物湿法冶金研究进展Ⅱ氧化机制、强化细菌浸出与生物反应器设计

着重评述了难处理硫化矿的矿物结构、性质及表面特征与各种电化学因素、细菌氧化机制与难处理硫化矿细菌强化浸出、浸矿基因工程菌以及生物反应器等方面的研究进展。指出缩短生物氧化周期长是细菌强化氧化研究的核心；将细菌繁殖和矿物氧化两个过程分开进行的“分离器-发生器”设备设计，是一值得推广的高效生物反应器。     

生物冶金中浸矿微生物的研究现状

总结了国内外主要浸矿微生物种类,分析了嗜中温细菌、中度嗜热细菌、中度嗜热古生菌和极端嗜热古生菌等嗜酸菌种及嗜碱菌种的生存习性、培养特点和浸矿能力,评述了浸矿微生物的物理、化学及生物改良方法的特点和适用性,以及多种菌属联合浸出、异养微生物浸出和浸矿生物反应器等高效强化浸出方法。     

我国铜矿微生物浸出技术的研究进展

回顾了我国微生物浸出技术发展的历史进程, 总结了我国开展生物浸铜技术的探索与应用进程, 介绍了紫金山铜矿、德兴铜矿两个典型的生物浸铜案例; 探讨了浸矿细菌分离、鉴定与富集, 生物浸出机理与界面反应, 浸出体系多级渗流行为, 孔隙结构重构与定量化, 浸出体系多场耦合与过程模拟, 电子废弃物中的铜金属回收领域的主要进展.最后, 结合生物浸铜技术的当前进展, 阐述了生物浸铜技术面临的环保、安全等方面的挑战与未来发展趋势, 为今后该领域的研究提供良好借鉴.      

加压湿法冶金处理含铂族金属铜镍硫化矿的应用及研究进展

近年来，加压湿法冶金应用于处理重有色金属硫化矿发展迅速，在环境保护及强化金属提取方面显示了明显的优越性。本文以加压湿法冶金处理含铂族铜镍硫化矿过程中铂族金属的行为为主线，介绍了该领域的最新研究进展。分别简要评述了加压氨浸、加压酸浸、加压碱浸和加压氰化等过程所适应的物料特性、工艺特征和生产实践。对铂族金属在加压浸出过程中的行为进行了讨论。     

温度和液固比对某铀矿生物浸出的影响

铀矿生物浸出过程中,浸矿微生物（氧化亚铁硫杆菌）对温度和液固比等环境因素较为敏感。基于铀矿生物浸出溶浸液中酸碱度、氧化还原电位(Eh)、铁离子浓度的变化和铀浸出率的差异,研究温度和液固比对南方某铀矿生物浸出的影响。结果表明,在温度为30 ℃和液固比为20的条件下,铀矿微生物浸出效果最佳,铀浸出率分别高达为96.15%和97.02%。因此,在生物浸出过程中,可以控制浸出体系温度和液固比,为浸矿细菌提供最适宜生长环境,以强化铀矿的生物浸出。研究结果为南方某铀矿工业生产提供重要参数和理论依据。     

生物氧化浸矿反应器的研究进展

生物氧化浸出技术工业应用和发展将过程工程的研究和高效生物浸矿反应器的研制推上一个重要位置。综合分析了搅拌槽式和气升式这两种工业常用生物浸出反应器,指出其不完全适用于生物氧化浸矿,评述了近十年来生物氧化浸矿反应器的现状和发展趋势,总结了反应器设计的一般指导原则,介绍了几种最具开发潜力的反应器。     

硫化铜矿强化浸出研究进展

综述了硫化铜矿强化浸出的研究进展,针对铜的强化浸出过程,介绍了多种可能的强化浸出的方法,其中包括氯介质浸出、生物浸出以及添加辅助剂对硫化矿浸出过程的影响。重点阐述了生物强化浸出黄铜矿的研究。指出采用添加活性炭强化生物浸出黄铜矿能够克服浸出过程中存在的钝化现象,是解决黄铜矿浸出速度缓慢最有发展前景的方法。     

紫金山铜矿生物浸出过程酸平衡分析研究

生物浸出过程中, 矿石溶解、环境蒸发和工程渗漏等因素都会导致酸的消耗; 同时, 高铁的水解反应、矿石中某些金属硫化物(如黄铁矿)在细菌浸出时均会产酸, 此外, 萃余液还会带入一定量的酸.酸的产耗平衡问题不仅与矿物的氧化分解及浸出率息息相关, 还会影响浸矿细菌的生长繁殖以及后续萃取与电沉积工艺的进行.针对紫金山铜矿生物浸出过程, 考察各种矿物的产耗酸的情况, 并模拟特定的工业环境和工艺条件, 进行酸平衡理论分析和计算.通过工业实践, 发现浸出1 t矿石, 产酸量为13.589 kg, 耗酸量为10.597 kg, 从而得到酸过剩量为2.992 kg·t-1矿石.     

硫酸渣脱硫制备高品质铁精矿研究进展

利用硫酸渣脱硫制备高品质铁精矿具有良好的的工业利用价值,不仅可以解决烧渣的综合利用问题,而且可以解决其对环境影响的问题.本文系统介绍了硫酸渣脱硫制备高品质铁精矿的脱硫技术方法、工艺流程及最新研究进展.硫酸渣脱硫方法主要有化学法、联合法和生物法.化学法主要包括酸浸、碱浸,联合法可分为碱浸-酸浸、浮选-磁选、重选-浮选、磁化焙烧-磁选等联合工艺方法.比较了这些方法的工艺路线及存在的优缺点,提出了生物法具有良好的工业应用前景,展望了该方法未来的研究方向为:高效脱硫菌种的选育,生物脱硫液的循环使用,硫酸渣生物脱硫协同回收有价金属,生物脱硫过程基础理论及工程化技术研究等.      

A Visual Insight into the Oxidation of Sulfide Minerals During Bioleaching and Chemical Leaching of a Complex Ore

A scanning electron microscope (SEM) study was performed to provide a visual insight into the oxidation patterns of sulfide minerals during chemical and bacterial leaching of a complex ore for 3 days. The mineral grains were studied under SEM before and after bacterial and chemical leaching with or without the addition of ferrous iron to generate ferric iron in situ by bacteria or chemical oxidant (MnO₂). Both mesophilic and moderately thermophilic cultures of bacteria were used in bioleaching tests. A limited oxidation of sphalerite and pyrite, similar to those in acid leaching (control), was observed to occur when no ferrous iron was added. However, the initial addition of ferrous iron into bioleaching media was shown to significantly improve the oxidation of sphalerite and pyrite. Galena was readily oxidized in the presence or absence of bacteria. Sphalerite was oxidized more extensively/selectively than chalcopyrite and pyrite, consistent with their respective nobility/electrochemical activity. Provided that chemical/biological oxidation of sphalerite was intensive, a sulfur-rich layer appeared to form on mineral surface. But, no such layer on pyrite surfaces was discernable. Supplementary bioleaching data were also provided to support SEM observations and to further elucidate the bioleaching characteristics of these sulfide phases. It can be inferred from this study that the oxidation of sulfides proceeds most discernibly via “indirect mechanism” and the generation of ferric iron by bacteria in sufficient quantity is essential for the effective oxidation of sulfide minerals.     

Electrochemical bioleaching of high grade chalcopyrite flotation concentrates in a stirred bioreactor

The main objective of this study is to improve the basic understanding of electrochemical bioleaching as an advanced hydrometallurgical process suitable for the treatment of high grade complex sulfide ores and to use this understanding for analyzing the potential of this process for copper recovery from high grade chalcopyrite ores and flotation concentrates. Using a typical flotation concentrate from the Sarcheshmeh copper processing complex (located in the south-east of Iran) and mixed mesophilic as well as moderately thermophilic microorganisms, leaching experiments were performed in a stirred bioreactor. The emphasis was given on the comparison between the results of bioleaching and that of electrochemical bioleaching tests. From the results of this study, it can be pointed out that compared to the conventional bioleaching; the electrochemical bioleaching of chalcopyrite flotation concentrate leads to about 35% more copper recovery. It seems that the main reason for increasing copper recovery by electrochemical bioleaching is the control of redox potential between 400 and 425 mV. Under this condition, the precipitation of iron oxy-hydroxides on the surface of chalcopyrite, which can act as a diffusion barrier and prevents chalcopyrite dissolution, is significantly reduced. This leads to a higher electrochemical reduction of chalcopyrite and its improved dissolution.     

细菌接种量对铀生物浸出的影响

以某难处理铀矿石为原料,开展了不同细菌接种量对铀生物浸出的影响研究。在相同浸出条件下,经84h浸出,5%、10%、20%和30%细菌接种量的铀浸出率分别为50.46%、56.42%、62.38%和67.05%,细菌接种量越大,铀浸出率也越高。在铀矿生物浸出工艺中,可以通过控制细菌接种量来获得适宜的浸铀效率。     

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。     

Issues in Bioleaching: To Inoculate or not to Inoculate

Abstract

Two active bioleaching microbial strains were isolated from a zinc mineral sample. These bacteria isolates were grown on media containing sulfur or iron and reintroduced, individually or in combination, to the original mineral sample in controlled shake-flask bioleaching experiments. Uninoculated controls were included but no attempt was made to sterilize the solid material. On the contrary, growth of the same indigenous microorganisms was encouraged in the control flasks. Zinc was leached from both inoculated and uninoculated mineral at the same rate. The only difference was that the lag times before onset of leaching were shorter if active bacteria were present from the very beginning. In all cases, zinc was leached preferentially over iron. This difference was even more pronounced on leaching by sulfur-grown bacteria which did not extract iron to the same degree as iron-grown bacteria. When total leaching times required for 100% zinc extraction were compared, no statistically significant difference was observed between the inoculated and uninoculated tests. This conclusion may have some bearing on experimental and process design, when decisions must be made on whether to stimulate leaching by addition of extraneous bacteria or by fostering the proliferation of indigenous microorganisms.     

锌的生物浸出技术现状及研究进展

锌是现代工业所必需的有色金属,属于很重要的战略资源,其在世界所有金属产量中排名第四,仅次于铁、铝和铜。随着低品位难处理锌资源的种类和产量的不断增加,以及湿法冶金技术的不断发展,锌的生物浸出技术得到了研究人员的广泛关注,并展示出了良好的潜在应用前景。本文首先较为详细的介绍了含锌资源的矿物特征,并对其生物可浸性进行了分析。其次,对目前锌的生物浸出体系,所用浸矿菌种,浸出过程所涉及的电化学、热力学、动力学以及浸出机理进行了归纳总结;接着,对锌的生物浸出技术现状和工艺新进展进行了阐述。最后,展望了锌的生物浸出工艺的发展趋势及后续的研究热点。研究表明高效浸锌菌种的选育驯化、与之相匹配的工艺及装备研发,是锌的生物浸出当今研究热点及未来发展方向。      

Bacterial leaching of low-grade ZnS concentrate using indigenous mesophilic and thermophilic strains

In this study low-grade sphalerite has been treated by the bioleaching process using native cultures of Acidithiobacillus ferrooxidans and Sulfobacillus thermosulfido-oxidans in order to determine the ability of these bacteria to the leaching of zinc. The effects of bacterial strain, pH, temperature, pulp density, iron precipitation, and initial concentration of ferric iron on the zinc leaching were evaluated. The bioleaching experiments were carried out in shake flasks at pH 1.5, 180 rpm, 33 °C and 60 °C for mesophilic and thermophilic bacteria, respectively. Compared with the use of laboratory reference strains or control conditions, zinc recovery from the respective concentrate was greater when native isolates were employed. The experimental data show that the selection of the suitable pH and temperature during the bioleaching processes would be important. The results indicate that the increase in pulp density generates a decrease in the dissolved zinc concentration. The maximum zinc extraction reached was 87% using native thermophile S. thermosulfido-oxidans culture after 30 days.     

Bacterial Leaching of Metals from Tannery Sludge by Indigenous Sulphur-Oxidizing Bacteria—Effect of Sludge Solids Concentration

An investigation on the effect of sludge solids concentration on bioleaching of Cr(III) and other metals from tannery sludge by indigenous sulphur-oxidizing bacteria was carried out. The sludge solids concentrations ranged from 13 to 60 g/L. The concentration of elemental sulphur was fixed at 30 g/L. The results showed that the lowest pH reached after 25 days of bioleaching at all studied sludge solids concentration was about 1.3. The optimum sludge solids concentration for maximum metal leaching from tannery sludge was 40 g/L and about 87% of Cr(III), 73% of Al, 72% of Fe, 62% of Mg, and 73% of Zn could be leached in this case. During bioleaching, the concentrations of total and volatile suspended solids of the tannery sludge significantly decreased. The sulphur-oxidizing bacteria could tolerate a Cr(III) concentration as high as 5,930 mg/L at pH 1.3. The leaching efficiencies of Cr(III), Al, and Fe for both chemical leaching and bioleaching of tannery sludge were similar at pH 1.3. The leaching efficiency of Ca, Mg, and Zn in both leaching processes were identical for pH values in the range of 1.3 to 3.0.