All-Russian Scientific-Research Institute of Chemical Technologies (Moscow, Russia):

Koltsov V. Yu., Head of Department, Candidate of Engineering Sciences, e-mail: basilik@уandex.ru
Krinov D. I., Head of Laboratory, Candidate of Geological and Mineralogical Sciences
Kuznetsov I. V., Researcher

Heap leaching is one of the most economically efficient and localized methods of processing of various ores, including poor and off-balance uranium-containing ores. Together with this, the method is limited by the type of raw materials. For example, in the time of processing of clay raw materials, there appeared the problems, substantiated by colmatage (silting) of material, which leads to decreasing of water permeability of ore pile and extraction of leaching process. This article gives the results of researches, carried out on the sample of uranium-containing ore of Gornoe deposit both in laboratory, and in large scales. All-Russian Scientific-Research Institute of Chemical Technologies developed a method of preparation of ore material and heap leaching, which allows to decrease the time of standard raw materials leaching significantly. The method is concluded in grinding of initial material to defined coarseness and its pelletizing in sulfuric acid solution. At the same time, there happens the heterogenous chemical reaction in material layer with minimal rate of phases (close to stoichiometrically required rate). At the same time, sulfuric acid is a joining component in the pelletization time. During interconnection of acid with rock constituents, there are formed new compounds, which form stable water- and acid-resistant frame during the following aging of pellets. There is shown, that pelletization of ores with sulfuric acid significantly decreases the pile processing time and increases the metal extraction. For example, uranium extraction for rich radiometric separation product does not reach 50% even with the ratio of L:S = 5, when almost complete extraction for pelletized material with same composition has already been reached with the ratio of L : S = 1.5.

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