METHOD OF PRODUCING WOLLASTONITE Russian patent published in 2016 - IPC C01B33/24 C30B7/10 C30B29/34 C30B29/62 B82B3/00 B82Y40/00 

FIELD: chemistry.

SUBSTANCE: invention relates to processing of calcium- and silicon-containing industrial wastes from boron production (borogypsum) and can be used in production of needle wollastonite for use in non-ferrous metallurgy, in tyre, asbestos-cement and paint industry, in production of ceramics. Wollastonite is produced by hydrothermal action on calcium- and silica-containing technogenic raw material with alkali metal hydroxide, followed by separation, drying and thermal treatment of formed precipitate with calcium hydromonosilicate, wherein calcium- and silica-containing material used is borogypsum, alkali metal hydroxide is added in stoichiometric amount based on reaction equation of formation of calcium hydromonosilicate in concentration, providing ratio of solid and liquid phases S:L=1:(7-10), wherein reaction is carried out in an autoclave at temperature of 210-225 °C and pressure of 20-23 atm, separated calcium hydromonosilicate is washed with water at 60-70 °C and dried at 80-90 °C for 4 hours, thermal treatment is carried out at 850-1,000 °C for 1-2 hours.

EFFECT: technical result is simplification and high environmental safety of method with simultaneous reduction of cost due to minimisation of labour input and costs for preparation of initial components.

1 cl, 8 dwg, 2 ex