News & Events
Bioleaching of precious metals from solid waste
Speaker(s): Dr Gayathri Natarajan (SCELSE)
When: 01 October 2015 - 01 October 2015 (9:30)
Where: SBS Classroom 4 (Level 1)
Type: Seminars


Bacteria play a vital role in leaching metals from rocks, ores and metal bearing wastes. Their mining methods are not offensive to the environment as most other pyrometallurgical and hydrometallurgical techniques, which may use explosives, toxic chemicals and high temperatures. Biomining offers significant advantages over conventional chemical processes by its ability to extract metals from low-quality ores and by being safer, simpler in operation, less energy intensive, and requiring low capital and operating cost. Furthermore, the release of toxic gases and chemicals are much lower in bioleaching, thus making it an environmentally friendly process. Such benefits have seen biomining grow apace as a viable alternative to mainstream mineral refinement with 25% of the world's present copper production, worth more than $1 billion annually being biomined.

With growing importance, biomining/bioleaching has progressed to recovery of precious metals from secondary ores and industrial wastes. Many industries such as photographic and electronics firms, jewelry makers, mining companies, and foundries discard about 100 million dollars worth of gold, silver, and other metals into waste streams each year. In addition to precious metal recovery, toxic heavy metals such as lead, cadmium and mercury need to be removed for pollution control and environmental protection from metal containing solid wastes such as electronic waste, fly ash, battery waste and spent catalyst. Application of bioleaching process for precious metal recovery from solid waste, mainly electronic waste, mechanisms involved and challenges in advancing biohydrometallurgy will be discussed in this presentation.