SEGREGATION ROASTING OF NICKEL OXIDE ORE.

Ten years of research in segregation roasting of nickel oxide ore has now reached the stage of successful conclusion of several months of pilot plant tests in a 1 ton per hour unit. Nickel oxide ore from the Philippines has been calcined and segregated using CaCl//2 and Coke as additions. Metallic concentrate containing over 60% has been collected by magnetic separation for a total Ni recovery of over 92%. As the process is kept below 950 degree C compared to over 1600 degree C for the smelting alternative a total of 30% energy saving are anticipated for a fullscale plant. The process also gives a great flexibility to the ore chemistry, particularly the basicity. The process uses a new invention, namely a mechanical kiln in which heat is generated within the material to be treated. The 1 ton per hour kiln has an inner diameter of 3. 5m and an inner length of 3. 8m.