Smelting, Refining and their Products

The product of flotation is called 'concentrate'. It is passed on to the smelter and, after further processing, refining is done in great batteries of electrolytic tanks. Some indication of the scale on which these operations are conducted is given by the great size of the reverberatory smelting furnaces and the impressive extent of some of the larger tank-houses. A large modern reverberatory may be a single chamber 130 ft. long, 25ft. wide, and 12 ft. high. This will smelt 1,000 tons per day of concentrate or calcine, and in some cases much more; and it does this continuously for over a year before it need be emptied and relined with refractory bricks. A typical tank-house contains a large number of concrete tanks, each carrying about thirty-six pairs of impure copper slabs which are the anodes, and thinner sheets of pure copper; it is on the faces of the latter that additional pure copper is deposited as the anodes are electrolytically decomposed. A large tank-house may contain 1,500 tanks, requiring perhaps 100,000 anodes and cathodes. All this represents a tremendous advance from the techniques used at Swansea only a hundred years ago!

The final products of smelting and electrolytic refining are cathodes, cast often in the form of copper wirebars and cakes.* The casting are subsequently worked in various ways into wrought forms. Re-melted cathodes may also be cast into ingot bars suitable for the preparation of alloys.

* See CDA Publication No. 52, Introduction to Copper.