Method of manufacture of high purity sodium aluminate

Claim 1

THE PROCESS OF PRODUCTING SODIUM ALUMINATE FROM BAUXITE WHICH COMPRISES THE STEPS OF HEATING A 45% TO 70% BY WEIGHT SOLUTION OF SODIUM HYDROXIDE TO A TEMPERATURE OF AT LEAST 275*F., ADDING THERETO WITH AGITATION A BAUXITE WHICH CONTAINS AT LEAST 57% BY WEIGHT OF ALUMINA TO PRODUCE A REACTION MASS HAVING A NA2O TO AL2O3 RATIO BETWEEN 1.11:1 TO 1.25:1, CONTINUING THE PROCESS WHEREBY THE ALUMINA PRESENT IN THE BAUXITE IS SUBSTANTIALLY CONVERTED TO SODIUM ALUMINATE AND THE INSOLUBLE IMPURITIES CONTAINED IN THE BAUXITE ARE UNIFORMLY SUSPENDED THROUGHOUT THE REACTION MASS, SAID ALUMINATE LIQOUR HAVING A SPECIFIC GRAVITY OF BETWEEN 1.600 AND 1.850, DILUTING TO SPECIFIC GRAVITY BETWEEN 1.300 AND 1.500, FILTERING THE DILUTED LIQUOR IN THE PRESENCE OF NOT MORE THAN 1% BY WEIGHT OF CARBON FILTER AID AT A PRESSURE OF AT LEAST 25 POUNDS PER SQUARE INCH GAUGE, DISCARDING NOT MORE THAN THE FIRST 5% OF FILTRATE AND ADDING TO THE FILTERED LIQUOR BETWEEN .1% AND 1.5% BY WEIGHT OF AN INORGANIC BLEACH FROM THE GROUP CONSISTING OF ALKALI METAL HYPOCHLORITE, CHLORINE, AND HYDROGEN PEROXIDE AND THEN DRYING THE PRODUCT.