METHOD FOR PRODUCING MAGNESIUM FROM SERPENTINITE Russian patent published in 2005 - IPC

FIELD: non-ferrous metallurgy, namely production of magnesium from magnesium containing raw material, for example from serpentinite and further electrolysis of prepared chlorine-magnesium raw material.

SUBSTANCE: method comprises steps of disintegrating waste material; leaching concentrated hydrochloric acid for preparing chlorine-magnesium solution; separating solution and deposit; cleaning and concentrating solution; charging waste electrolyte for producing synthetic carnallite; performing multi-stage dehydration of it for preparing dehydrated chlorine-magnesium raw material for electrolysis; performing electrolysis for producing magnesium, chlorine and electrolyte; conversion of chlorine for producing hydrogen chloride and feeding it to stage for preparing raw material for electrolysis and for producing hydrochloric acid; returning electrolyte to step for preparing raw material for electrolysis; after cleaning and concentrating chlorine-magnesium solution separating it by two parts; feeding one part of solution for producing synthetic carnallite and treating other part by means of solution of soda ash; separating; feeding deposit in the form of hydrocarbonate paste to purification and concentration of chlorine-magnesium solution and feeding mother liquor for preparing merchant products. Relation of part of solution fed for preparing hydrocarbonate paste to other part fed for synthesis of carnallite is in range 1 : (0.7 -7.0). Part of hydrocarbonate paste is fed to step for scrubbing exhaust gases. Treatment by means of solution of soda ash is realized at temperature 70 - 95 C. Concentration of solution of soda ash is sustained in range 100 - 400 g/l. Hydrocarbonate paste contains magnesium carbonate, 27 -30%; magnesium hydroxide, 6 -8%; sodium chloride, 12 - 14% and water, 50%. Mother liquor is fed for production of crystalline sodium chloride.

EFFECT: lowered costs of reagents for purifying chlorine-magnesium solution, enhanced degree of purification of magnesium chloride, production of new types of merchant products.

7 cl, 1 ex