Process for treating aluminous ores

Claim 1

IN A CONTINUOUS BAYER TYPE PROCESS FOR THE RECOVERY OF ALUMINA VALUES FROM IT ORES WHICH INCLUDES DIGESTION AND CLARIFICATION STEPS, THE METHOD OF TREATING AN ORE CON TAINING ITS ALUMINA VALUES AT LEAST PREDOMINANTLY AS TRIHYDRATE ALUMINA AND AN ORE CONTAINING AT LEAST A PORTION OF ITS ALUMINA VALUES AS MONOHYDRATE ALUMINA TO PRODUCE A GREEN CAUSTIC ALUMINATE LIQUOR HAVING AN ALUMINATO-CAUSTIC RATIO BETWEEN ABOUT .62 AND .65 DURING SAID CLARIFICATION STEP, COMPRISING CHARGING SAID MONOHYDRATE ALUMINA CONTAINING ORE TO SPENT CAUSTIC ALUMINATE LIQUOR IN AN AMOUNT SUFFICIENT TO PRODUCE A RATIO OF A/C BETWEEN ABOUT .54 AND .60 WHEN SUBSTANTIALLY ALL OF THE AVAILABLE ALUMINA OF SAID ORE IS DISSOLVED THEREIN AND DIGESTING SAID ORE THEREIN TO DISSOLVE SUBSTANTIALLY ALL OF SAID AVAILABLE ALUMINA UNDER TEMPERATURE CONDITIONS BETWEEN ABOUT 385 AND 400*F. AND CAUSTIC SODA CONCENTRATION CONDITIONS BETWEEN ABOUT 170 AND 270 GRAMS PER LITER, SEPARATELY CHARGING SAID TRIHYDRATE ALUMINA CONTAINING ORE TO A SEPARATE PORTION OF SPENT CAUSTIC ALUMINATE LIQUOR IN AN AMOUNT SUFFICIENT TO PRODUCE A RATIO OF A/C BETWEEN ABOUT .68 AND .75 WHEN SUBSTANTIALLY ALL OF THE AVAILABLE TRIHYDRATE ALUMINA OF SAID ORE IS DISSOLVED THEREIN AND DIGESTING SAID ORE THEREIN TO DISSOLVE SUBSTANTIALLY ALL OF SAID AVAILABLE TRIHYDRATE ALUMINA UNDER TEMPERATURE CONDITIONS BETWEEN ABOUT 290 TO 300*F. AND CAUSTIC SODA CONDITIONS BETWEEN ABOUT 140 AND 200 GRAMS PER LITER, AND BLENDING THE EFFLUENT OF SAID MONOHYDRATE ALUMINA ORE DIGEST WITH THE EFFLUENT OF SAID TRIHYDRATE ALUMINA ORE DIGEST IN PROPORTIONS TO OBTAIN THE SAID FIRSTMENTIONED A/C RATIO PRIOR TO THE CLARIFICATION STEP.