1-step acidic gold bioleaching by the use of iron and sulfur oxidizing and thiocyanate (SCN) generating microorganisms

利用铁和硫氧化及硫氰酸盐 (SCN) 生成微生物进行 1 步酸性生物浸金

基本信息

批准号：
532307-2018
负责人：
Ghahreman, Ahmad
金额：
$ 1.92万
依托单位：
Queen's University
依托单位国家：
加拿大
项目类别：
Collaborative Research and Development Grants
财政年份：
2018
资助国家：
加拿大
起止时间：
2018-01-01 至 2019-12-31
项目状态：
已结题

来源：
https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=651763
关键词：
step acidic gold bioleaching use

项目摘要

The conventional gold extraction process from low grade sulphide gold ores is to heap leach the ore at low pH to oxidize sulphides with the help of bacteria, and then wash the solids and finally leach the heap with cyanide containing solution to leach gold into cyanide. The process has environmental and cost disadvantages as the cyanide application in the heap operation has environmental consequences, and also the heap pH is acidic after sulphide oxidation and will require neutralization with lime to increase the pH to the required level for gold cyanide leaching, i.e. pH 9.5 to 10.5. The lime cost and environmental issues of cyanide use are the main challenges with this standard process.****Here it is proposed to do both the sulfide oxidation and gold leaching in acidic pH in one step. In this proposed process, sulfide minerals are oxidized with the usual bacteria, but in addition, thiocyanate producing bacteria are used in the heap to produce thiocyanate as the lixiviant for gold leaching in acidic pH. The process will reduce the lime consumption of the plant (the whole process will be carried out at acidic pH) and will eliminate cyanide use. Thiocyanate is 200x less toxic than cyanide thus making it much more attractive for gold recovery. Through this project a PhD student will be trained.

从低品位硫化金矿石中提取金的传统工艺是在低pH值下堆浸矿石，借助细菌氧化硫化物，然后洗涤固体，最后用含氰化物的溶液浸出堆浸，将金浸出为氰化物。该工艺具有环境和成本方面的缺点，因为堆操作中氰化物的应用会对环境造成影响，而且硫化物氧化后堆的pH值呈酸性，需要用石灰中和以将pH值提高到氰化金浸出所需的水平，即pH值。 9.5 至 10.5。使用氰化物的石灰成本和环境问题是这一标准工艺的主要挑战。****这里建议在酸性 pH 值下一步进行硫化物氧化和金浸出。在这个提出的工艺中，硫化物矿物被普通细菌氧化，但此外，堆中使用产生硫氰酸盐的细菌来产生硫氰酸盐，作为酸性pH下金浸出的浸出剂。该工艺将减少工厂的石灰消耗（整个工艺将在酸性pH下进行），并消除氰化物的使用。硫氰酸盐的毒性比氰化物低 200 倍，因此对于黄金回收来说更具吸引力。通过该项目，将培训一名博士生。