Synthesis of β-wollastonite on the basis of silica formed from silicate layers of serpentine

Two-stage method for synthesis of β-wollastonite via reaction of calcium hydroxide and silica formed from silicate layers of serpentine and calcination of the resulting compounds was examined. It was found that the specific structural features of the silica used for this purpose make it possible to avoid a many hours’ autoclave treatment and obtain such amorphous calcium hydro- and hydroxo-silicates that are converted under annealing, beginning at 800–810°C, to β-wollastonite by mixing a suspension of Ca(OH)2, SiO2, and H2O heated to its boiling point under atmospheric pressure. The optimal synthesis parameters, molar ratio of the starting substances and agitation duration, are determined.