Belgorkhimprom, JSC (Republic of Belarus):

Stromskiy А. S., Нead of Department, nito1@mail.ru

Turko М. R., Нead of Laboratory, tela7@bk.ru

Shemyakina М. G., Нead of Laboratory, gran10@tut.by

Molokovich S. О., Senior Reseacher, gran10@tut.by

Research Institute for Physical Chemical Problems of the Belarusian State University (Republic of Belarus):
Shablovskiy V. О., Нead of Laboratory, shablovski@bsu.by

The article presents the methods of calcium and magnesium impurity ions separation from dissolving liquor at Belaruskaliy halurgy plant (Republic of Belarus). The main methods of calcium and magnesium ions separation from concentrated potassium chloride solutions (ion exchange, adsorption, extraction, ultrafiltration, etc.) are considered. However, due to complexity of the above methods in process realization, precipitation techniques are most promising. Prospectivity of calcium and magnesium ions precipitation from potassium chloride solutions was assessed with a view of subsequent processing of forming sludge into marketable products. Precipitation conditions effects upon structure and properties of forming sludge are described, optimal conditions for formation of high-quality crystal sediments are reported. A method of calcium and magnesium impurity ions separation through salts crystallization in oversaturated solutions has been considered. It is shown, that with solution over-saturation increase, crystallization rate is increased, while with isothermal crystallization and continuous decrease of solution over-saturation, crystallization process rate is slowed down. Effects of impurities, present in solution or admixed by small dosages, upon crystallization process and crystal size, are considered. Two flow sheets for Са²⁺ and Mg²⁺ irons precipitation from recycled alkali liquor at a halurgy plant, providing for production of feed phosphates and magnesium hydroxide, as well as fertilizers, containing СaHPO₄ and Mg₃(PO₄)₂, are proposed.

1 Fedorov G. G., Shusser B. M., Vitina N. A. Inzhenernyye raschety pri galurgicheskoy pererabotke kaliynykh rud (Engineering analysis in the process of potassium ores chemical processing). Obzornaya informatsiya. Seriya «Kaliynaya promyshlennost» (Survey information. Series «Potassium industry»), Moscow, NIITEKHIM, 1985, 32 p.
2 Pozin M. Ye. Tekhnologiya mineralnykh soley (Mineral salts technology), Pt. 1. Leningrad, Khimiya, 1974, 792 p.