Moscow State University of Fine Chemical Technologies named after M. V. Lomonosov, Moscow, Russia:

Ya. Yu. Ershova, Post-Graduate Student, e-mail: ershovajana@gmail.com
E. I. Lysakova, Assistant Professor
M. V. Tsygankova, Senior Researcher
A. M. Reznik, Professor

The main reserves of gallium in Russia belong to nepheline ores. An average grade of gallium is 23.6 g/t. Gallium is concentrated in potassium mother liquors during nepheline processing by sintering. Liquid extraction is a promising method of gallium extraction from potassium bittern (mother liquor) solutions. Extractants are nitrogen containing chelating phenol type compounds, namely: N-(2-hydroxy-5-nonylbenzil)-β, β-dihydrohyethilamine (NBEA-0) and N-(2-hydroxy-5-nonylbenzil)-β-dihydrohyethilmethilamine (NBEA-2), dissolved in the mixture, containing 75% of octane + 25% of octanol. The most efficient extraction parameters are 60 minutes of extraction time for both extractants, and 0.5 mol/l of alkaline concentration. Further increase of caustic alkalinity of solution leads to significant reduction of gallium distribution coefficient due to competitive extraction of alkali. There was found that increasing of K₂CO₃ concentration by more than 100 g/l leads to gallium extraction decrease. The most efficient concentration of extractants are 0.3 mol/l and more. The most appropriate solvents are the mixture of octane and 25% (vol.) of octanol. Taking into account the foregoing conditions, the (metal:extractant) correlation is 1:1. There was made a supposition that Ga is extracted according to the following equation:

[Ga(OH)₄]^– + HR_(o) = RGa(OH)_2(o) + OH^– + H₂O,

where HR — NBEA.

Authors made an offer to carry out gallium re-extraction using 3.5М concentration alkaline solutions. The results, obtained using NBEA-0 as extractant, are significantly better in comparison with NBEA-2.

This work was carried out within the State task of Ministry of Education and Science of Russian Federation.

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