Process for the treatment of lateritic ores to obtain cobalt and nickel values

Claim 1

A PROCESS FOR THE TREATMENT OF A NICKEL BEARING OXIDIZED ORE WHICH CONTAINS NICKEL, COBALT, AT LEAST ABOUT 25% IRON BY WEIGHT AND AT LEAST ONE OTHER METAL SELECTED FROM THE GROUP CONSISTING OF MAGNESIUM, MANGANESE, ALUMINUM AND CHROMIUM WHICH COMPRISES THE STEPS OF: (A) DISPERSING SAID NICKEL BEARING ORE PARTICLES IN WATER TO FORM A SLURRY; (B) MIXING SULPHURIC ACID WITH SAID SLURRY IN AMOUNT AT LEAST SUFFICIENT TO COMBINE WITH THE CONTAINED NICKEL, COBALT, MANGANESE AND MAGNESIUM VALUES BUT LESS THAN THAT REQUIRED TO COMBINE WITH ALL THE CONTAINED FERROUS AND NONFERROUS METAL VALUES AS SULPHATES; (C) HEATING THE SULPHURIC ACID TREATED ORE PARTICLES IN AN OXIDIZING ATMOSPHERE AT A TEMPERATURE WITHIN THE RANGE OF FROM ABOUT 600*C. TO ABOUT 700*C.; (D) CONTINUING THE HEATING STEP UNTIL THE WEIGHT RATIO OF WATER SOLUBLE IRON TO WATER SOLUBLE NICKEL CONTAINED IN THE ORE PARTICLES IS IN THE RANGE OF 5:1 TO 1:1; (E) LEACHING THE ORE PARTICLES FROM THE HEATING STEP WITH WATER TO EXTRACT AND DISSOLVE NICKEL AND COBALT VALUES; (F) SEPARATING UNDISSOLVED RESIDUE FROM THE LEACH SOLUTION; (G) REACTING THE LEACH SOLUTION WITH A SULPHIDIZING AGENT TO CONVERT DISSOLVED NICKEL AND COBALT VALUES TO AND PRECIPITATE THEM FROM THE SOLUTION AT SULPHIDES; AND (H) SEPARATING PRECIPITATED NICKEL AND COBALT SULPHIDES FROM THE SOLUTION.