A method of bleaching kaolin and other minerals using sodium dithionite

摘要

A method for brightening kaolin clays and other minerals by combining an aqueous solution of sodium borohydride and sodium hydroxide with an aqueous solution of sodium bisulfite, in a chemical mixer to form sodium dithionite (hydrosulfite) and adding the output of the chemical mixer to the slurry of kaolin clays wherein the ratio of (moles bisulfite - moles hydroxide)/moles borohydride is no more than 7.8.