|Cuprite||Cu2O||See question 2|
|Chalcocite||Cu2S||See question 2|
1. Place these products in the extraction process in ascending order of copper content.
- Cathode copper
- Anode copper
- Copper concentrate
- Fire refined copper
The correct order is:
- Ore (0.25 to 0.5% copper)
- Concentrate (30% copper)
- Matte (50-70% copper)
- Blister (98% copper)
- Fire refined (99% copper)
- Anode (99% copper)
- Cathode (99.99% copper)
2. Use a periodic table to find the atomic masses of the elements in cuprite and chalcocite. Then work out the percentage of copper in each mineral. Don’t forget to double the copper mass as it is Cu2.
The masses are:
Ar(Cu) = 64; Ar(O) = 16; Ar(S) = 32
The molar mass of Cu2O = 128 + 16 = 144
The percentage of copper in Cu2O is therefore 128/144 x 100 = 89%
The molar mass of Cu2S = 128 + 32 = 160
The percentage of copper in Cu2S is therefore 128/160 x 100 = 80%
3. Which of the minerals in the table are sulfides?
Chalcocite, bornite and chalcopyrite.
4. Why is sulfur dioxide scrubbed from the smelter flue gases?
The sulfur dioxide produces sulfuric acid in the acid plant. It would cause acid rain if released into the atmosphere as well as serious health risk to anyone living anywhere near the furnaces. The sulfuric acid has a high value because it is used to leach copper oxide ores.