Converting Minerals to Metals - Mining and the Environment: From Ore to Metal - page 252

TABLE 6.1
The Main Technologies to Turn Copper Concentrates into Pure Metal - In an age when some of today's
most powerful industries scarcely existed three decades ago, the extractive metal industry is the 'Grand Old Man' of modern economy

Year Method Technology

1865 Electrolytic (Electro) Refining Patent (Elkington)

1907 Froth Flotation Australian Patent (Potter)

1909 Converting Patent (Pierce & Smith)

1940s Solvent Extraction - SX/EW Uranium Purification

1949 Flash Smelting First Outokumpu Furnace

Source:
Dresher 2001

FIGURE 6.2
Increase of Copper Content through
Smelting and Electro-Refi ning

Mining

Ore

2%

To be amenable directly for smelting
ores must contain copper minerals
in sulphide the form. Only high-grade
ores in form of concentrates can be
economically smelted.

Grinding

Concentrating

25%

Roasting

Smelting

60%

Conversion

99%

Anode Casting

Electro Refining
99.99%

We will illustrate the pyrometallurgical process using the example of converting chal-
copyrite (CuFeS 2 ) to copper. From the formula, it is clear that iron and sulphur have to
be removed in order to produce copper which is the purpose of smelting ore. The iron is
removed from the furnace as slag, the sulphur in the form of sulphur dioxide is processed
into sulphuric acid. The copper leaves the smelter in anode form - 99 percent pure. Anode
copper is further processed in an electrolytic refinery where impurities are removed,
upgrading the purity to 99.99 percent ( Figure 6.2) .

Flotation

To be amenable for smelting, copper minerals must be sulphides, such as chalcocite (Cu 2 S),
chalcopyrite (CuFeS 2 ) and covellite (CuS). Because of the high energy requirements only

To be amenable for smelting,
copper minerals must be sulphides.