[Role of microorganisms in the destruction of spodumene].

A broad spectrum of microorganisms has been shown to be involved in the destruction of spodumene, a typical mineral of lithium pegmatites. The following microorganisms are most active: the microscopic fungi Penicillium notatum and Aspergillus niger, the thiobacilli Thiobacillus thiooxidans, and the so-called "silicate" slime forming bacterium Bacillus micilaginosus n. sp. siliceus. Spodumene destruction is accompanied with lithium, aluminium and silicon being transferred into solution. The activity of this process depends on the microbial species, the pH of the medium, and some other factors. Lithium and aluminium are extracted best of all at acid pH values whereas silicon at alkaline pH values. Possible mechanisms for spodumene destruction by microorganisms are discussed.