AN IMPROVED PROCESS FOR THE MANUFACTURE OF SYNTHETIC CRYOLITE USING SODIUM FLUOSILICATE AND SODIUM CARBONATE

摘要

An improved process for the manufacture of synthetic cryolite from sodium fluo silicate comprising the steps of, heating an aqueous slurry of sodium fluo silicate to 80 -90 degree C reacting the same with sodium carbonate solution, removing the precipitated silica, reacting the filtrate containing sodium fluoride with aluminum sulfate solution, filtering the precipitated cryolite followed by washing with water, drying and calcimining the same, characterized in that the filtrate containing sodium fluoride is divided into foists and second portions comprising 80% and 20% by volume and the first portion is made to react with aqueous aluminum sulfate initially, followed by addition of the second portion to the reaction mixture to complete the reaction.