Bioleaching of Nickel Ores with Moderate Acidophiles
Tech Area / Field
8 Project completed
Senior Project Manager
Melnikov V G
Institute of Biochemistry and Physiology of Microorganisms, Russia, Moscow reg., Puschino
- Natural Resources Canada / Mining and Mineral Sciences Laboratories, Canada, ON, Ottawa
Project summaryThe largest supplier of nickel is Canada with a huge deposit of mixed nickel and copper sulphide in Sudbury, Ontario. Other countries with substantial nickel production are Russia, Australia, New Caledonia and South Africa.
Russia produces nickel, making it the world's 14th largest nickel producer. Norilsk Nickel contains approximately 78% of Russia’s nickel reserves, which are made up primarily of sulphidic and lateritic ores. Norilsk currently controls more than 20% of the global nickel market and the company produces 91% of Russia's nickel. During 2005 total nickel production was 243 thousand metric tons, maintaining the Company’s 2004 production level. MMC Norilsk Nickel announced that 2006 nickel production is to increase to an estimated 243 to 248 thousand metric tons (http://www.nornik.ru/en).
LME Official Price for March 2006 was up to 14,910.00 US$/t of nickel.
Sulphidic ores are primarily located at Norilsk’s operations in Siberia (85%) and the Kola Peninsula (15%) with minor lateritic ores being produced from the Urals.
There is a well known technology called hydrometallurgy or bioleaching of metals. This biotechnology permits to extract metals from poor ores in a cheap way – by application of thionic bacteria (thiobacilli). The thionic bacteria degrade metal-containing minerals via oxidation of mineral sulphides into sulphuric acid, thus, they extract metals from the minerals into the solution.
The method can be applied with minimal human staff. It used to be applied not to mines only but also to the mine burrows or to rocks with trace content of expensive metals (for example, uranium). However, industrial application of the technology is related with serious problems: i) some ores contains chemical elements (Cu, Ni, and others that can inhibit classic thionic bacteria which are strong Acidophiles (Acidithiobacillus ferroxidans, A.thiooxidans and Leptospirillum ferroxidans), ii) these bacteria suffer from a short-term life as a result of change of pH via reaction with surrounding minerals.
Application of bioleaching can allow increased nickel production by treating very poor ores or mine dumps. The Russian and, possible, Canadian companies could expand areas of their activity with this method.
The project aims to develop or improve the bioleaching technology for its application to poor grade ores in Russia, Canada and to provide these joint results for third parties.
The nickel bioleaching process needs new bacterial strains, which shall be resistant to nickel metals and, as well, be able to degrade mineral sulphides with continuous and stable acidification. The Russian team has got experience in isolation of different strains and in bioleaching of concrete and steel with moderate Acidophile and suggests to isolate and select strains of moderate Acidophiles which could degrade nickel sulphides with acidification, however, could survive and work under conditions of the pH neutralizing produced with natural mineral surrounding.
The proposal research work plan involves the isolation of a bacterial strain or a consortium of strains that can be utilised in bioleaching of low-grade nickel sulphide ores. The investigations include:
- Isolation of industrial strains with emphasis on acid-producing bacteria growing under moderate acid and/or neutral conditions from samples of ores and/or existing mine tailing sites located both in Canada and Russia and provided via professional Canadian geologists.
- Development of appropriate technology with determination of main affecting factors regulating processes of chemical and biological nickel leaching in heaps (ore composition, mineral crystal structure, mechanical structure of rocks, toxicity of heavy metals, acidity, temperature, aeration, mixing, relation of solid: liquid phases, solution composition, bacteria selection).
Expected results and profits are: i) New industrial strains. ii) New patents. iii) New approach in bioleaching.
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