A. V. Topchiev Institute of Petrochemical Synthesis (Russian Academy of Sciences), Moscow, Russia:

K. L. Zanaveskin, Senior Researcher, e-mail: zakon82@mail.ru
G. S. Dmitriev, Senior Researcher, e-mail: dmitriev.gs@mail.ru
L. N. Zanaveskin, Head of a Sector, e-mail: zanaveskin@ips.ac.ru

Scientific-Research Physical and Chemical Institute named after L. Ya. Karpov, Obninsk, Russia:

A. N. Maslennikov, Junior Researcher, e-mail: anmaslennikoff@gmail.com

This article shows the results of experimental researches, aimed at the definition of the peculiarities of processing of quartz-leucoxene concentrate (Yaregskoe deposit) by autoclave leaching. Leaching was carried out using sodium hydroxide water solution in laboratory autoclave at the temperatures of 180–200 ^оС, and the ratio L:S = 3–4 ml/g. Slime fraction may be formed as a result of autoclave concentrate leaching. The basic reason of slime formation are the concurrent reactions of alkaline interconnection both with mineral impurities, and with ore component in concentrate. Besides the main reaction of quartz interconnection with alkali, the concurrent reactions may flow in leaching process, leading to formation of sodalite, magnetite, sodium titanate, titanic acid and molengrafite. Control of formation of titanium-containing impurities, changing the leaching process conditions, leads to the definition of sodalite content only by initial aluminium oxide concentration. Experiments showed that sodalite is the undesirable impurity, decreasing the fractional conversion of TiO₂ into TiCl₄. During the chlorination process, sodalite is transformed into alumosilicic spinel, inert to chlorine impact, and is cumulated in reaction area. By its cumulation, spinel covers the concentrate particles uniformly, complicating the reagent supply to the TiO₂ surface. As a result, chlorination process is almost stopped, and TiO₂ conversion is 88.7%. Processing of autoclave concentrate by 0.1 mole/l solution of HCl makes possible the sodalite removing. Experiments showed that obtained product is suitable for processing on TiCl₄.

Investigation was carried out due to the grant of Russian Scientific Fund (project No. 15-13-00171).

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