Inco roast-reduction smelting of nickel concentrate

CIM Bulletin, Vol. 87, No. 981, 1994

C. Diaz, B.R. Conard and C.E. O'Neill, Inco Limited, J. Roy Gordon Research Laboratory, and A.D. Dalvi, Inco Exploration and Technical Services Inc.

Roast-reduction smelting (RRS) of nickel concentrate, combined with flash smelting of copper concentrate, was one of the process options that Inco considered as a means of meeting its 1994 sulphur dioxide abatement target at its Copper Cliff operations. RRS involves deep roasting the nickel concentrate in fluid bed roasters. The roaster off-gas is treated in a sulphuric acid plant, and the low sulphur calcine is reduction smelted with coke in an electric furnace to yield a sulphur-de}lCient matte. The latter material is converted to Bessemer matte in Peirce-Smith converters, with minimal evolution of sulphur dioxide, and the converter slag is reverted to the electric furnace. Excellent nickel and cobalt recoveries obtained. This paper discusses the development of RRS, including extensive commercial scale testing at Inco's Thompson Smelter, and its key operating parameters.
Mots Clés: Metallurgy, Roast-reduction smelting, Nickel concentrate.