METHOD FOR OBTAINING WOLLASTONITE FROM SILICON-CONTAINING VEGETABLE RAW MATERIALS Russian patent published in 2022 - IPC C01B33/24 C09C1/28 C09C1/02 D21C1/06 

FIELD: painting and composite material production.

SUBSTANCE: invention can be used in the production of paint and composite materials. To obtain wollastonite, a solution containing sodium silicate and a solution of calcium chloride is brought into interaction with active stirring, the resulting precipitate containing calcium hydrous silicate and hydrated silica is separated, washed and dried. As a solution containing sodium silicate, an alkaline extract is used, obtained by processing crushed, dust-free, washed and air-dried rice straw with a 1M NaOH solution at 80-90°C for 60-80 minutes with the separation of unreacted solid fibrous straw residue. Calcium chloride is used in the form of a 5% solution, which is taken in the calculated amount, providing a molar ratio in the reaction mixture: Ca: Si=1:(1.0-2.0). The precipitate is calcined at a temperature of 900-1000°C for 1.0-1.5 hours to obtain wollastonite. The solid fibrous residue of rice straw, which has not reacted as a result of alkaline treatment, is sent for processing as a raw material for the production of cellulose materials.

EFFECT: invention makes it possible to obtain synthetic dispersed wollastonite from the waste of rice production for use as a pigment, increasing its reflectivity, whiteness and resistance to ultraviolet radiation.

3 cl, 2 ex, 4 dwg