PREPARATION OF HIGH PURITY SILICA

摘要

A method of producing high purity silica containing less than 2 ppm iron oxides and less than 50 ppm alumina from particulate silica or quartz concentrates containing both surface and occluded mineral impurities wherein the concentrate is agitated with an aqueous solution containing 3-20% by weight hydrofluoric acid at a temperature between 50.degree.C and the boiling point of the solution. The impurities dissolve at a greater rate than the silica and can be washed away or separated as a slime.