PROCESS FOR MAKING NON-POROUS MICRON-SIZED HIGH PURITY SILICA

摘要

A process for making non-porous, dense, silica partices having a diameter of about 3 to 1000 microns, a nitrogen B.E.T. surface area less than about 1 m2/g, a total impurity content of less than about 50 ppm and a metal impurity content content of less than about 15 ppm from an aqueous dispersion of fumed silica. The particles are converted into porous particles and sintered in an atmosphere having a water partial pressure of from about 0.2 to about 0.8 atmosphere for temperatures below about 1200 DEG C.