Question

(2) Name the three processes involved in the extraction of lead from Galena.

Answer 1

The extraction of lead from galena (PbS) involves the following three processes:

1. Ore Concentration (Beneficiation): Galena ore is first crushed and ground to liberate the lead-containing mineral from the impurities. The process of ore concentration involves using various methods such as froth flotation, gravity separation, or magnetic separation to concentrate the lead minerals, leaving behind the gangue (unwanted material).

2. Roasting: The concentrated galena is then subjected to the roasting process. Roasting involves heating the concentrated ore in the presence of air to convert the lead sulfide (PbS) into lead oxide (PbO) and sulfur dioxide gas (SO2). The chemical reaction is represented as:

`\[ 2PbS + 3O_2 \rightarrow 2PbO + 2SO_2 \]`

3. Smelting: The roasted ore, now in the form of lead oxide, is further processed through smelting. In this step, the lead oxide is reduced with carbon (coke) to produce metallic lead. The overall reaction is:

`\[ 2PbO + C \rightarrow 2Pb + CO_2 \]`

These processes collectively allow the extraction of lead from galena, providing a pathway to obtain metallic lead from its sulfide ore.