Ausmelt Smelting and Converting technology is also applicable to nickel sulphides and polymetallic nickel sulphides.

In a process similar to copper smelting, nickel sulphide concentrates are smelted in a continuous operation using Ausmelt Technology to produce a nickel matte. A range of matte grades can be achieved to maximise metal recovery and suit downstream process stages.

Nickel matte and slag are removed continuously as a mixed liquid from the Ausmelt smelter into a settling furnace for separation of the matte. The slag from the settling furnace typically contains 0.25% Ni.

Nickel Sulphides

Nickel Converters using Ausmelt Technology convert the smelted nickel matte to produce high grade matte containing ~70% Ni. Converting is a continuous, single stage operation that makes a high-grade matte product, tapped periodically from the furnace for conventional downstream electro-refining.

Ausmelt Technology is also applicable to the treatment of leach residues formed during the nickel electro-refining process. These residues contain significant levels of nickel and copper. In a process similar to sulphide smelting, Ni/Cu leach residues are smelted in an Ausmelt furnace to recover values to a matte product that is granulated and suitable for return to the nickel refinery. Depending on the copper content of leach residues, the matte produced can also be converted to blister copper or high-grade copper alloy in a second processing step.

The first of two Ausmelt converting furnaces to be constructed as part of the modernisation of Anglo Platinum's Rustenburg plant, South Africa is now in full operation, with the second now under design and construction. Ausmelt Nickel Converter technology is being used by Anglo Platinum to reduce overall plant SO2 and solid emissions by replacing the existing six Peirce Smith converters.

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