Sulphide ores containing less electropositive metals such as Cu, Hg, Pb, and others are heated in the presence of air in the auto reduction process. It is done to convert the ore into sulphate or oxide, which then interacts with the residual sulphate ore in the absence of air to produce sulphur dioxide, a less electropositive metal and a gas.
In basic terms, the auto reduction method is utilised in the manufacturing of less electropositive metals such as Cu, Hg, and Pb, among others.Auto reduction process is a widely used industrial process of metal extraction from minerals or ores especially for less electropositive metals like copper (Cu), lead (Pb), mercury (Hg) etc.
