1. Oxidizing Roasting: This involves heating the material in the presence of excess oxygen. It is commonly used to convert sulfide ores to oxides. 2. Reducing Roasting: This involves heating the material in a reducing atmosphere, such as hydrogen or carbon monoxide, to remove oxygen and form the elemental metal. 3. Sulfating Roasting: This type involves adding sulfuric acid or sulfating agents, producing sulfates that are easier to process. 4. Chloridizing Roasting: This involves adding chlorine or chloridizing agents to convert oxides into chlorides.
