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

• 批准号: 532307-2018
• 负责人: Ghahreman, AhmadA
• 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: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=761103
• 关键词: step; acidic; gold; bioleaching; use

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.

低级硫化物金矿石的常规黄金提取过程是在低pH下堆放矿石，借助细菌氧化硫化物，然后洗涤固体，最后用含有氰化物的含有溶液将黄金浸入氰化物中的盐。该过程具有环境和成本劣势，因为在堆操作中的氰化物的应用具有环境后果，并且在硫化物氧化后，堆pH值为酸性，并且需要用石灰中和以将pH提高到所需的pH值，即pH值。 9.5至10.5。氰化物使用的石灰成本和环境问题是该标准过程的主要挑战。在此，一方面建议在酸性pH中同时进行硫化物氧化和金浸出。在此提出的过程中，用通常的细菌氧化了硫化物矿物质，但此外，在堆中使用硫氰酸盐产生细菌，以产生硫氰酸酯作为酸性pH中的黄金浸出的硫氰酸酯。该过程将减少植物的石灰消耗（整个过程将在酸性pH下进行），并消除氰化物的使用。硫氰酸酯的毒性比氰化物少200倍，因此使其在黄金恢复方面更具吸引力。通过这个项目，将培训一名博士生。