Carbonyl treatment of nickelcontaining laterite ores

Claim 1

THE IMPROVED PROCESS FOR THE TREATMENT OF LATERITIC MINERAL MATERIAL OF THE SILICATE TYPE CONTAINING SMALL AMOUNTS OF NICKEL AND LARGER AMOUNTS OF IRON WHICH COMPRISES SUBJECTING SAID LATERIC MINERAL MATERIAL TO A FIRST STAGE REDUCING TREATMENT AT RELATIVELY LOW TEMPERATURES OF ABOUT 750*F. TO ABOUT 1100*F. IN THE PRESENCE OF A RELATIVELY WEAK REDUCING GAS CONTAINING REDUCING AND OXIDIZING COMPONENTS IN THE RATIO OF ABOUT 0.5:1 TO ABOUT 1:1 BY VOLUME TO PRODUCE METALLIC NICKEL AND A SMALLER AMOUNT OF METALLIC IRON, PASSING CARBON MONOXIDE AT SUBSTANTIALLY ATMOSPHERIC PRESSURE IN CONTACT WITH THE REDUCED LATERITIC MINERAL MATERIAL TO PRODUCE NICKEL CRBONYL AND SMALLER AMOUNTS OF IRON CARBONYL, WITHDRAWING SAID NICKEL CARBONYL AND IRON CARBONLY FROM THE TREATED LATERITIC MINERAL MATERIAL, SUBJECTING SAID TREATED LATERITIC MINERAL MATERIAL TO A SECOND STAGE REDUCING TREATMENT AT RELATIVELY HIGH TEMPERATURES OF ABOUT 1300* F. TO ABOUT 1600*F. IN THE PRESENCE OF WEAK REDUCING GAS CONTAINING REDUCING AND OXIDIZING COMPONENTS IN THE RATIO OF ABOUT 0.5:1 TO ABOUT 1:1 BY VOLUME TO PRODUCE FURTHER AMOUNTS OF METALLIC NICKEL AND SMALLER AMOUNTS OF METALLIC IRON, PASSING CARBON MONOXIDE AT SUBSTANTIALLY ATMOSPHERIC PRESSURE IN CONTACT WITH THE TREATED LATERITIC MINERAL MATERIAL TO PRODUCE NICKEL CRBONYL AND SMALLER AMOUNTS OF IRON CARBONYL AND WITHDRAWING SAID NICKEL CARBONYL AND IRON CARBONYL FROM SAID ORE, TO EFFECT A HIGHER NICKEL EXTRACTION THAN WOULD NORMALLY BE OBTAINED WITH AN EXTRACTION PROCESS COMPRISING EITHER A ONE STAGE REDUCTION-CARBONYL EXTRACTION OR A REPETION OF THE REDUCTION-CARBONYL EXTRACTION.