Which of the following processes is/are pyrometallurgical?
Smelting
Roasting
In the pyrometallurgical process, heat is used to remove impurities from the raw ore. In the given options smelting and roasting are pyrometallurgical processes. Electrolysis is the process of causing a chemical change using electricity; in metallurgy, electrolysis may be employes in different ways - like electrolytic reduction, electroplating, electrorefining etc.
On the other hand, leaching uses chemicals, usually at low temperatures, to selectively extract the metal component from its ore. This is part of hydrometallurgy and not pyrometallurgy.