METHOD FOR PROCESSING SYNNYRITE TO OBTAIN POTASSIUM FERTILIZERS AND ALUMINA Russian patent published in 2024 - IPC C22B3/12 C22B1/16 C01F7/38 

FIELD: chemistry.

SUBSTANCE: invention relates to chemical processing of high-potassium aluminosilicate mineral raw material - synnyrite to obtain potassium carbonate and sulphate, aluminium hydroxide, and alumina. Method includes preparation of initial raw material, its sintering with additives of alkali and alkali-earth metals, leaching of sinter with recycled alkaline solutions, precipitation and filtration of silicon-containing precipitate, precipitation of aluminium hydroxide from alkaline solutions, obtaining potassium carbonate and sulphate from solutions. Limestone and potassium carbonate are used as an additive during sintering. Sintering is performed at 1200–1300 °C. Cake is leached with an alkaline solution with concentration of caustic alkali (K₂O) to 4–105 g/l at a ratio of S:L = 1:(2.5–4.0) and temperature of 60–90 °C. After that, desiliconisation of the obtained solution is carried out. Obtained silicon-containing precipitate after filtration is decomposed with potash solutions with concentration of carbon dioxide (K₂O) of 120–360 g/l. Carbonisation is carried out to content of Al₂O₃ in solution of 7–25 g/l. Aluminium hydroxide is precipitated, followed by obtaining solutions of potassium carbonate and potassium sulphate. Aluminium hydroxide precipitate is calcined to obtain alumina.

EFFECT: simple technology of processing synnyrite with production of alumina, potassium sulphate, potassium carbonate.

7 cl, 1 dwg, 11 tbl, 2 ex