Treatment of ore

Claim 1

A PROCESS FOR THE EXTRACTION OF NICKEL AND COBALT VALUES FROM MAYARI-TYPE LATERITIC IRON ORE CONTAINING UP TO ABOUT 1.07% BY WEIGHT NICKEL, UP TO ABOUT 0.15% BY WEIGHT COBALT AND UP TO ABOUT 53% BY WEIGHT IRON BY THE STEPS OF (1) SULFATIZING, (2) ROASTING, (3) LEACHING, AND (4) SEPARATING, WHICH COMPRISES (1) IN THE SULFATIZING STEP, CONTACTING THE ORE WITH SULFUR TRIOXIDE-CONTAINING GAS CONSISTING IN PART OF GAS FROM SAID ROASTING STEP AND IN PART OF MAKE-UP SULFUR TRIOXIDE GAS, TO FORM THE SULFATES OF IRON, NICKEL, COBALT, CHROMIUM, MANGANESE, ALUMINUM AND SILICON, (2) IN THE ROASTING STEP, HEATING SAID SULFATIZED MASS AT A TEMPERATURE FROM ABOUT 500*C. TO ABOUT 620*C. FOR FROM 1/12 TO 3 HOURS TO CONVERT THE FERRIC SULFATE TO INSOLUBLE FERRIC OXIDE WHILE CONTINOUSLY FEEDING THE SULFUR TRIOXIDE EVOLVED TO SAID SULFATIZING STEP, (3) IN THE LEACHING STEP, LEACHING THE ROASTED PRODUCT WITH AN AQUEOUS LEACH SOLUTION, THE PH OF SAID LEACH SOLUTION BEING SO ADJUSTED THAT THE PREGNANT LEACH SOLUTION LEAVING THE LEACHING STEP HAS A PH OF FROM 2.5 TO 4.5, AND (4) IN THE SEPARATING STEP, SEPARATING THE INSOLUBLE FERRIC OXIDE FROM THE SUBSTANCES IN SOLUTION.