Spherical calcium silicate

Abstract

A spherical calcium silicate has d50 median particle size from 1 to 35 μm, oil absorption from 40 to 130 mL/100 g, sphericity factor (S80) at least about 0.80, BET surface area between 10-125 m2/g, and % CaO from 0.5-20 wt-%. The spherical calcium silicate are produced by (a) continuously feeding mineral acid and alkali metal silicate into a loop reaction zone having a liquid medium stream, with at least some mineral acid and alkali metal silicate reacting to form silica product; (b) continuously recirculating the liquid medium; (c) continuously discharging a portion of liquid medium with silica product; (d) filtrating and washing the liquid medium with silica product; (e) combining the filtercake of (d) with calcium hydroxide; (f) stirring combined filter cake and calcium hydroxide for 10 min to 180 min and (g) drying. The product can be used in dentifrice compositions, food mixtures, personal care applications and liquid coatings.

Dependencies are inferred from the claim text.