(a) Distinguish between ‘roasting’ and ‘calcination’. Which of these two is used for sulphide ores and why? (b) Write a chemical equation to illustrate the use of aluminium for joining cracked railway lines. (c) Name the anode, the cathode and the electrolyte used in the electrolytic refining of impure copper.




Roasting is a step of the processing of certain ores. More specifically, roasting is a metallurgical process involving gas–solid reactions at elevated temperatures with the goal of purifying the metal component.

calcination is heating to high temperature in air or oxygen.