METHOD FOR PROCESSING SYNNYRITE INTO POTASSIUM, MAGNESIUM SULPHATES AND ALUMINA Russian patent published in 2021 - IPC C22B3/08 C22B3/22 C01D5/02 C01F5/40 C01F7/26 C01F7/32 C01F7/76 C01B33/12 

FIELD: metallurgy.

SUBSTANCE: invention relates to nonferrous metallurgy and can be used in production of alumina and potassium sulfate from a high-potassium aluminosilicate raw material - synnyrite (K₂O 19 to 21%). The method for producing potassium sulfate and alumina from synnyrite includes thermal treatment, decomposition of activated synnyrite with sulfuric acid, separation of alum solution from insoluble residue, crystallisation of alum from the sulfuric acid solution and sintering of the obtained alum with potash followed by processing thereof into potassium sulfate and alumina, wherein the initial synnyrite prior to acid decomposition is mixed with one of the magnesium-containing natural raw additives: dolomite CaMg(CO₃)₂, or magnesite MgCO₃, or brucite Mg(OH)₂ at a mass ratio of 2:1, and sintered at a temperature of 1100 to 1150°C, and after sulfuric acid decomposition, along with potassium alum, a magnesium component in form of magnesium sulfate hexahydrate MgSO₄•6H₂O is isolated from the solution by evaporation.

EFFECT: increased efficiency of complex processing of synnyrite due to the use of the main acid-resistant minerals of the raw material (microcline, orthoclase) at the stage of thermochemical decomposition as a raw additive - one of the cheap natural magnesium compounds selected from dolomite CaMg(CO₃)₂, or magnesite MgCO₃, or brucite Mg(OH)₂, at a mass ratio between synnyrite and the additive equal to 2:1 leading to decreased temperature of the thermal processing by 150 to 200°C resulting in acid-soluble compounds; the technical result additionally consists in increased product range: in addition to potassium sulfate and alumina, magnesium from all the described additives in the process of sulfuric acid decomposition of activated synnyrite can be isolated into magnesium sulfate as an additional product.

1 cl, 5 dwg, 2 ex