1. IN A PROCESS FOR BRIGHTENING DISCOLORED CLAY WHICH COMPRISES PULPING THE CLAY WITH WATER, DISPERSING THE PULP BY ADDITION OF SODIUM SILICATE THERETON, AND SUBJECTING THE DISPERSED PULP TO FROTH FLOTATION IN THE PRESENCE OF AN ANIONIC FLOTATION REAGENT IN AN ALKALINE FLOTATION CIRCUIT, THE IMPROVEMENT WHICH COMPRISES INCORPORATING A WATER-SOLUBLE POLYVALENT METAL SALT INTO A DILUTE AQUEOUS SOLUTION OF THE SODIUM SILICATE CLAY DISPERSANT BEFORE THE SODIUM SILICATE IS INCORPORATED INTO THE CLAY PULP, THE AMOUNT OF POLYVALENT SALT BEING SUFFICIENT TO FORM A STABLE HYDROSOL WITH SAID DILUTE SODIUM SILICATE.