Converting Minerals to Metals - Mining and the Environment: From Ore to Metal - page 251

FIGURE 6.1
The Path of Copper from Mineral
to Pure Metal

Ore Mining

It is important to differentiate between
sulphide ore and leachable ore.
Generally sulphide ore is composed
of minerals containing copper, iron
and sulphur, hence the name sulphide.
Leachable ore is composed primarily
of minerals containing copper oxide.

Comminution

Concentrating

Leaching

Extraction

Roasting

Stripping

Smelting

Electrowinning

Conversion

Anode Casting

Electro-Refining

Final Copper
Cathodes

6.1 THE USE OF FIRE - PYROMETALLURGICAL MINERAL
PROCESSING ILLUSTRATED

In pyrometallurgy, concentrated copper ore is smelted and refined. The use of fire (pyro in
Greek) to extract metals pre-dates recorded history, and it remains the conventional and
most commonly used metallurgical process: reactions are faster at higher temperatures;
molten metals are easy to handle and alloy; reagents (fluxes) are cheap; the metal and
impurities separate easily; the precious metals stay with the primary metal; and the con-
centration of copper in a smelter is 20 times that in a hydrometallurgical process (Dresher
2001). Due to the high recovery rate the process remains especially attractive for high
grade ores when even a small increase in recovery results in a substantial increase in profit.
It would surprise most people, even those involved in the industry, that smelting and refin-
ing technologies were introduced on an industrial scale as early as 1865 ( Table 6.1 ) .

The use of fi re to extract metals
pre-dates recorded history, and
it remains the conventional
and most commonly used
metallurgical process.