A. A. Baikov Institute of Metallurgy and Materials Science of Russian Academy of Sciences, Moscow, Russia

N. V. Serova, Senior Researcher
M. P. Lysykh, Researcher
T. V. Olyunina, Deputy Senior Researcher, e-mail: toliun@yandex.ru
A. G. Kitay, Leading Researcher

“Norilsk Nickel” MMC, Norilsk, Russia

V. T. Dyachenko, Head of Administratiion of Idustrial and Engineering Development

This article gives the research results of autoclave leaching of the oxidized nickel ore of a Buruktalsky deposit. Researchings were held in the laboratory conditions with using an autoclave with 1 dm³ capacity. An elementary sulfur and oxygen were applied during the leaching instead of a sulfuric acid. In comparison with a sulphuric acid technology, the leaching parameters were reduced. At the temperature by 200–220 ^oС and general pressure nearby 0,8 MPа, the extraction of nickel in solution was 90–96.5%, and the extraction of cobalt was 96–98%. Thus, the concentration of a free sulfuric acid in a final solution was 90–140 g/dm³. Usage of this solution as recirculated in the process of atmospheric ore leaching at the temperature by 95–100 ^oС, allowed to reduce the concentration of a sulfuric acid to 19–22 g/dm³ and to raise the concentration of useful components in a solution. The phase concentrations of the oxidized nickel ore and leaching products were investigated by methods of X-ray analysis. The significant content of smectites is the peculiarity of this ore of mixed silicate and ferruginous type. It is probably due to some toughening of leaching conditions in comparison with a processing of other samples of blended type ores. A quartz and various basic sulphates (generally — jarosite and sodium rock alum), were discovered as the basic phases in solid residues from leaching. The residues of initial ore phases were present in the cakes in appreciable quantities. The cakes were formed during the atmospheric leaching. In the case if the sodium sulphite is not added in the initial pulp, the final cakes contain nontronite and, in smaller quantities, chlorite and bowlingite. There was conjectured an influence of a peculiarities of a crystalline structure of smectites on a change of a leaching mode. The cited data allows to consider that the developed way of autoclave leaching of oxidized nickel ores with usage of an elemental sulfur, can compete with the sulphuric acid autoclave leaching because of the comparative cheapness of the basic reagent and more lower values of the technological parametres of the process.

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