Describe the process of extracting metals from their ores, specifically focusing on the steps involved for moderately reactive metals.

Moderately reactive metals like zinc, iron, and lead are usually found as sulphides or carbonates in their ores. The extraction process typically involves: 1. Concentration of the ore. 2. Conversion of sulphide ores to oxides by roasting (heating in air). 3. Conversion of carbonate ores to oxides by calcination (heating in limited air). 4. Reduction of the metal oxides to the metal using a reducing agent like carbon. For example, ZnO + C → Zn + CO.