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

Nepheline ores are one of the most important types of aluminium raw materials in Russia. Together with aluminium, they contain gallium, which demand in semiconductor electronics increases annually. During the sintering processing of nephelines, gallium is concentrated in potash mother liquors. At the same time, their aluminium content is by more than 50 times higher than gallium content. Liquid extraction by nitrogen-containing chelating phenol-type extractants can be an efficient method of separation of these metals. During the researches, the extractants N-(2-hydroxy-5-nonylbenzyl)-β, β-dihydroxyethylamine (NBEA-0) and N-(2-hydroxy-5-nonylbenzyl)-β-hydroxyethylmethylamine (NBEA-2) were used in octane mixture with 25% (vol.) of octanol. The following values were defined:
– optimal equilibrium achieving time is 15 minutes;
– potassium carbonate content in solution is 300–350 g/l;
– optimal concentration of sodium hydroxide in solution is 4–4.5 mole/l.
According to these conditions, the metal:reagent ratio in extractable complex is 1:1.
Authors offer the following aluminium extraction equation: [Al(OH)₄]^– + HR_(o) = RAl(OH)_{2 (o)} + OH^– + H₂O, where HR is NBEA-0/NBEA-2. Aluminium re-extraction was offered to carry out by 2.5 mole/l alkaline solutions. Aluminium extraction is higher, using NBEA-0 than NBEA-2 as extractant. Regularities of gallium and aluminium extraction were compared for the purpose of selection of optimal parameters for their extraction from combined potash clay mother liquors.

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