Bacterial succession in bioheap leaching

Bioheap leaching of secondary copper ores is applied commercially at operations in Chile, Australia, and Myanmar. Bioheap leaching of sulfidic refractory gold ores has been demonstrated at large scale. There is limited comprehension of what actually occurs microbiologically in full-scale bioheap operations, despite the commercial achievement of copper ore bioheap leaching and the anticipated technical and commercial success of gold ore bioheap leaching. Copper bioheaps are typically inoculated with the bacteria contained in the raffinate or intermediate leach solution, whereas, sulfidic refractory gold ore bioheaps can be inoculated with bacteria developed in a separate reactor. Chemical and physical conditions within bioheaps change radically from the time the bioheap is stacked and inoculated until bioleaching is completed. Redox, acidity, temperature, oxygen and solution chemistry conditions vary widely during the oxidation period. Such conditions likely select for microorganisms or may, in fact, effect a succession of organisms in portions of the bioheap. Bioheap solutions are recycled and constituent build-up over time also affects the microbiology. Organic entrapment in the raffinate from the solvent extraction circuit may influence microbial activity. Heterotrophic microorganisms may also play some role in bioheap leaching. Understanding the microbiology of bioheaps is key to advancing commercial bioheap applications. Such knowledge will increase the ore types as well as the diversity of mineral deposits that can be processed by bioheap technology. It will also enable better control of conditions to improve leach rates, metal recoveries and costs. This paper briefly explains commercial practices, describes chemical, physical and microbiological monitoring of bioheaps, considers conditions that control microbial populations in bioheaps, and examines the types of ore deposits that could be bioleached, if the microbiology was elucidated.     

黄铜矿的湿法冶金工艺研究进展

介绍了黄铜矿湿法冶金的最新进展及工艺特性，探讨了黄铜矿湿法冶金的发展前景。Dynatec加煤粉流程和CESL二段浸出流程很好地解决了中温压力氧化酸浸过程中单质硫的影响，对材质的耐腐蚀性要求低，在低能耗下获得了高的浸出效果，对于主要分布于黄铜矿中的含金铜精矿，可获得很高的金回收率。Intec和Hydro Copper工艺在常压低温氯化介质中很好地浸出黄铜矿精矿，并能同时回收伴生的贵金属．生产的中间产品铜粉可直接加工高附加值产品，能耗低，回收率高，是复杂铜精矿湿法冶金的途径．Geocoat工艺的诞生使得高品位黄铜矿精矿大规模高温细菌氧化浸出成为现实，它克服了细菌浸出对设备要求高的缺点，利用堆浸的优势，以低的运行成本获取高的黄铜矿浸出率。     

Impact of Biotechnology on Metal Extractions

The present article provides information on the application of biotechnology in the valorization of mineral resources. Biohydrometallurgy is relatively a recent development but already employed in the copper, uranium and in a limited extent in precious metal processing industries. The basic principles of bioleaching and the mechanisms of bacterial action are discussed and specific examples are given for the biohydrometallurgy of the elements. An extended treatment of microbial activity is given with regard to gold and silver recoveries from ores and leach solutions, as well as for the desulfurization of coal, to represent tendencies of most active research areas. The article discusses also the biosorption processes and gives a short review of efforts devoted to biogenetic engineering of leaching organisms.     

含铜金矿生物浸出渣铜品位对氰化提金的影响

对紫金山低品位含铜金矿进行生物浸出—介质转换—氰化提金摇瓶试验,考察不同生物浸出周期铜的浸出率以及生物浸出渣中铜的品位对后续氰化提金的影响。结果表明,生物浸出12d,含铜金矿中73%的铜溶出,浸出渣铜品位降至0.096%。生物浸出渣铜品位对氰化浸出有显著影响,随着铜品位的升高,氰化钠耗量、氰化过程铜的浸出率以及贵液铜浓度均升高。为降低铜对氰化提金的影响,生物浸出渣中铜的品位应降至0.1%以下。     

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.      

Aqueous Pressure Oxidation of Minerals - A Salient Development in Hydrometallurgy

Aqueous pressure oxidation has been developed to a viable technology. It has found extensive commercial applications in mineral industry. Numerous pressure processing plants have been constructed worldwide for production of nickel, cobalt, copper and zinc from ores, concentrates and other metallurgical intermediates or secondary materials and for pretreatment of gold refractory ores. Successful operation of these plants provides hydrometallurgy with experience and confidence for its potential development and applications. This paper is intended to review the development and applications of pressure oxidation technology and the chemistry involved as well.     

金矿非氰化浸金研究进展

随着易处理金矿石资源枯竭,含砷、含碳、高硫、超细颗粒金矿石已成为金矿开采的重点,这些难处理金矿通过常规氰化浸金等方法浸出效果差,由于氰化物有剧毒,会危害人体健康,并严重污染生态环境。非氰化法浸金因具有环保、浸出速率快、效率高等优点受到了广泛关注。在综述了硫代硫酸盐法、甘氨酸法、卤素法、石硫合剂法、碘化焙烧工艺、硫脲浸出法和非水溶液浸金7种非氰浸金方法的浸金原理及其在难处理金矿方面的最新研究进展的基础上,讨论了非氰浸金方法存在的浸出剂昂贵、浸出液中金回收困难、浸出体系复杂、浸出剂性质不稳定及消耗量大等问题,并对非氰浸金技术的发展方向进行了展望。      

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。      

复杂难处理金矿石预处理工艺研究现状及进展

复杂难处理金矿石中因金被硫化矿物或脉石矿物所包裹等导致浸出过程中金浸出率低,而预处理工艺可以有效打开金的包裹,使金解离裸露,从而提高金综合回收率。介绍了5种主要的预处理工艺,包括超细磨工艺、焙烧氧化工艺、热压氧化工艺、生物氧化工艺及化学氧化工艺,阐述了各工艺的基本原理、工艺流程、研究进展及工业应用情况,并对各工艺的优缺点进行了分析比较,旨在为复杂难处理金矿石提金提供理论依据和技术参考。     

难浸金矿石的预处理──Ⅱ．焙烧－氰化法提取金的研究

随着金矿的普遍开采应用，从难浸金矿石中提取金越来越引起国内外的广泛重视。前不久中国黄金总公司科技处的赴美考察［１］足以说明在我国已经把注意力转移到这一领域中来。难处理金矿石中的金是以微粒或亚微粒状被矿石中的其它成分所包裹，因而在漫取前要给矿石施以预处理。本文对河南某地的难浸金矿石进行了氧化焙烧－氰化物提取的研究。主要研究了焙烧条件与浸取率的关系。实验证明：在氧化剂参与下进行焙烧，用氰化钠提取，可以获得９６％以上的提取率。     

黄铜矿生物浸出中钝化现象研究进展

随着矿产资源的日益贫化，传统的矿物加工及其后续的火法冶炼技术在处理矿物时存在不少弊端，生物浸出技术以其反应温和、对环境友好、能耗低、流程短等优点被各国广泛研究。常温生物堆浸技术业已在硫化铜矿（次生）的开采中实现大规模商业化应用，效果良好。但是，在铜资源主体一黄铜矿的生物浸出研究中，研究者发现常温菌难以获得较高的浸出速率，即所谓的钝化现象，以黄钾铁矾钝化，硫层钝化，多硫化物钝化3种现象最为普遍。为了防止黄铜矿生物浸出过程中钝化现象的产生，提出了Ag^＋催化、Fe^2＋和Cu^2＋催化、嗜热嗜酸菌浸出等有效措施。本文介绍了国内外生物湿法冶金工作者在黄铜矿生物浸出过程中钝化方面的研究进展。     

含铜难处理金矿石混合氯浸试验研究

某难处理金矿石中含有大量铜,如果直接氰化浸出,除了消耗大量氰化物外,还会在金表面形成一层薄膜,减慢金的溶解速度,金回收率低于30%;如果预氧化处理后再氰化提金,操作复杂、过程冗长、有污染、成本高,而且回收率并无实质性提高。为提高金回收率,降低生产成本,试验将该难处理金矿石破碎细磨后采用低浓度的NH4Cl和氨水混合浸出,利用氯离子与金形成稳定的配合物进行提金,矿石中的铜离子起氧化作用,促进金的反应,金浸出率可达87%以上。该方法无需进行预氧化处理,避免添加有毒有害药剂,消除对环境的污染。     

生物-化学两级循环反应器预处理坪定难处理金矿石

试验研究了矿石粒度、温度、Fe^3＋浓度等因素对生物-化学两级循环反应器预处理甘肃坪定难处理金矿石效果的影响。试验研究结果表明：在70℃、Fe^3＋质量浓度为6g/L（6K）、矿石粒度-74μm的条件下,该矿石经生物-化学两级循环反应器氧化预处理72h后,砷的浸出率可达到17．7％以上;预处理5d后的氧化矿样金的氰化浸出率高达91．76％。而用传统生物氧化法预处理10d,金的氰化浸出率为80．31％。试验结果还显示,温度的升高、Fe^3＋浓度的增加,可促进化学反应器中Fe^3＋对矿物的氧化,且矿石的粒度细预处理效果好。     

难处理含铜金矿石预处理与浸出技术现状及进展

对难处理含铜金矿石的各种预处理技术的特点、适应性和应用情况进行了分析和探讨；对难处理含铜金矿石浸出工艺的现状及进展进行了阐述；同时对难处理含铜金矿石预处理及浸出技术的发展方向提出了自己的观点。     

铜的生物湿法冶金在德兴铜矿的应用

结合德兴铜矿堆浸厂的生产与研究情况,分析了采用细菌浸出－萃取－电积工艺生产铜过程中存在的问题并提出了解决方法,探讨了该工艺的发展方向与前景。     

The effect of preferential flow on extraction and surface morphology of copper sulphides during heap leaching

Despite the commercial achievement of heap leaching of some copper, gold, zinc, and nickel minerals, there is limited comprehension of the flow pattern within the heap. Several field investigations have suggested that bypassing of ore by leaching solution is a common phenomenon, and the leaching process was significantly influenced by it. The extraction and surface morphology of low-grade copper sulphides under the condition of preferential flow was investigated in this paper. The experiment result, conducted within a novel bioleaching apparatus, shown that majority of acid was consumed by alkaline gangue and matrix, so the concentration of Cu²⁺ and total Fe increased slightly at the initial leaching stage. The ore extraction decreased with the increasing of its location depth, for instance, the ore extractions of the top and bottom region were 29% and 2% respectively. Preferential flow happened within the fine region due to the low irrigation employed by this experiment, and the extraction of fine ores was larger than that of coarse ores. The SEM images showed that the surface of top ores within the column was degraded seriously, but the middle and bottom ores were attacked slightly. Plenty of cracks were observed on the bottom ore surface due to the precipitation layer of sulfur and jarosite.     

含锑难处理金矿臭氧氧化预处理工艺研究

为解决含锑金精矿难处理的问题,对某含锑金矿进行臭氧氧化浸出锑的实验研究。实验结果表明,氧化浸出优化工艺参数：温度75 ℃,HCl浓度4.5 mol/L,浸出时间4 h,液固比10∶1,臭氧浓度121.9 g/L。在此条件下,锑的浸出率为98.13%,硫的浸出率为43.52%。经过臭氧氧化浸出处理后,矿物中的金得以在渣中富集。对原矿和浸锑渣进行硫脲浸金试验,金浸出率分别为12.36%和70.17%,表明预处理取得一定效果,实现了含锑难处理金矿中锑和金的综合回收。研究结果能为臭氧氧化浸出辉锑矿和含锑难处理金矿预处理提供理论指导。     

含锑难处理金精矿加压氧化法制备焦锑酸钠的工艺研究

锑及其化合物是重要的战略物资,焦锑酸钠被广泛应用于玻璃行业。锑金矿是难处理金矿的一种,直接氰化浸出时金的浸出率极低,需要进行预处理后才能提取金。针对某矿山含锑较低的难处理金精矿的特点,并结合目前难处理金矿的各种预处理方法的优缺点,研究确定了该类难处理金精矿适宜采用先回收锑再回收金的思路,即以含锑难处理金矿为原料,采用硫化钠浸出法优先分离锑,使锑以硫代亚锑酸钠形式进入滤液,然后采用加压氧化新工艺以焦锑酸钠产品的形式回收锑,氧化后的滤液经过净化和浓缩结晶后产出硫代硫酸钠产品,脱除锑后的浸出渣用细菌氧化预处理,最后用氰化法从细菌氧化渣中提取金,从而实现难处理金精矿中锑、硫、金的综合回收。     

难处理硫化矿生物湿法冶金研究进展（Ⅰ）微生物氧化工艺技术研究

生物湿法冶金技术与传统矿业氧化工艺相比，成本低、无污染，具有广阔的工业应用前景。本文着重评述了国内外在浸矿微生物、培养基的优化、细菌的接种量、温度、酸度、矿石粒度、矿浆浓度、浸出液中As(Ⅲ)和As(Ⅴ)浓度等方面的研究进展。     

微生物浸矿强化技术研究进展

介绍了微生物浸矿强化技术在浸矿菌株驯化、生物反应器研制及浸矿过程方面的应用状况及研究进展,指出了今后的研究方向。