D. Serikbayev East Kazakhstan State Technical University, Ust-Kamenogorsk, Republic of Kazakhstan:

Zh. S. Onalbaeva, Doctoral Candidate, e-mail: zhanara-05@mail.ru
V. I. Samoylov, Assistant Professor
N. A. Kulenova, Head of a Chair “Chemistry, metallurgy and concentration”

N. A. Baygazova, Assistant Professor of a Chair “Information systems”

Ural Federal University named after the first President of Russia B. N. Yeltsin, Ekaterinburg, Russia:
V. I. Zelenin, Professor of a Chair “Rare Metals and Nanomaterials”

Nowadays, there are no industrial examples of combined decomposition of lithium minerals before their opening by sulfuric acid, in spite of the fact that such combined proces sing could significantly expand the raw materials base of hydrometallurgical lithium industries. In connection with this, there is an urgent issue to find the methods of combined processing of spodumene and lepidolite, providing the increasing of extraction of lithium to the level, required on these surfaces. With joint processing of lithium, spodumene and lepidolite minerals (chemically inert to sulfuric acid), there is foreseen the smelting of charge from spodumene and lepidolite concentrates and soda ash. This technology includes spodumene and lepidolite smelting with soda ash, water granulation of fusion cake, grinding of granulated fusion cake, sulfatization of grind fusion cake by sulfuric acid and water leaching of sulfates fusion cake, which provides the transition of lithium in water-soluble lithium sulfate, which is further used for production of marketable lithium carbonate. Almost whole amount of aluminium, potassium and sodium is transferred into solution in the time of granulate opening. Obtained cake contains up to 98.5% (wt.) of silica, which allows to use it further in liquid glass production. On the basis of research of kinetics of sulfuric acid extraction of lithium from spodumen-lepidolite mixture, activated by smelting with sodium carbonate, the apparent energy of activation of interaction of fusion cake-granulate with sulfuric acid was defined together with rate-limiting stage of this pro cess. Calculated value of apparent activation energy corresponds about the fact that the researched process is carried out in diffusion area. That's why, there can be made a supposition, that this process is limited by diffusion rate of acid molecules to response surface through the layer of formed reaction products. Established kinetic dependences make possible to optimize the technological modes of sulfuric acid opening of concentrates.

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