[Microbiological leaching of zinc and lead ores of the Tekeli deposit].

In certain regions of the West Tekeli lead-zinc ore deposti, the number of Thiobacillus ferrooxidans cells reaches 10(6) per 1 ml of ore water. Spontaneous bacterial leaching of sulphide ore is confirmed by an increase in the concentration of ferric iron and zinc in ore water. As a result of this leaching, up to 40 per cent of zinc and 60 per cent of lead have been leached from lead-zinc ore within 271-286 days. Bacterial leaching of lead intermediate products has shown that the maximum rate of galenite oxidation is reached at 50--65 degrees C and the content of Fe3+ in a solvent being above 20 g per litre. Microbiological leaching can be used for selective extraction of zinc and lead. Zinc dissolves directly in the leaching bacterial solution while lead remains in the precipitate and is then dissolved under the action of concentrated NaCl solutions.