C1aL13 Copper
Key Words
Chalcopyrite- copper ore consisting of copper iron sulphide.
Chalcosine - another copper ore, mostly copper sulphide.
Concentration - how much material there is in a given volume.
Good conductor - electricity and heat can pass easily.
Leaching - slow dissolving of a mineral into water..
Low grade ore - ore where the principal mineral is found in low concentration, so there is a lot of waste rock.
Unreactive - does not readily react.
Grade E
Copper is another transition metal, with an atomic number of 29 and mass number of 64. Its properties are:
- Hard
- Dense;
- Good electrical and thermal conductor;
- Unreactive;
- High melting point.
It is extracted as two ores, chalcopyrite and chalcosine. These are quarried in open cast mines.
Grade C
To extract the copper, the chalcosine ore is heated with oxygen to give copper oxide and sulphur dioxide. The copper oxide is then heated with more copper sulphide to give copper metal and sulphur dioxide.
copper sulphide + oxygen ® copper oxide + sulphur dioxide
2Cu2S + 3O2 ® 2Cu2O + 2SO2
Copper oxide + cupper sulphide ® copper + sulphur dioxide
2Cu2O + Cu2S ® 6Cu + SO2
The concentration of the mineral is not high, so there is a lot of waste rock. The particles of chalcosine are separated from the rock by floatation, where the bits of rock go to the bottom of a tank full of water and detergent, while the chalcosine particles float to the top.
As well as the environmental impact of an open cast mine, there is also the pollution caused by the water and detergent. Also sulphur dioxide is a nasty gas that causes choking and inflammation of the airways, as well as acid rain.
It is possible to extract copper from low grade ores (where the concentration of copper is low) by soaking the rock with water, so that the copper compounds leach out. The copper is removed from the leachate (leached out solution) by electrolysis.
Grade A
The alloy between copper and tin is bronze.
The alloy between copper and zinc is brass.