What is Pyrometallurgy and hydrometallurgy?

Pyrometallurgy extracts a metal at high temperature, by reduction of its oxide in a furnace. Hydrometallurgy extracts it from an aqueous solution. Their usual steps are roasting (heating a sulfide ore in air to turn it into an oxide, $\ce{2ZnS + 3O2 -> 2ZnO + 2SO2}$), leaching (dissolving the metal’s compound, often in sulfuric acid, $\ce{ZnO + 2H+ -> Zn^2+ + H2O}$), purification of the solution, for instance by cementation (reduction of the ions of a nobler metal by a powder of a less noble one, $\ce{Cu^2+ + Zn -> Cu + Zn^2+}$), and the recovery of the metal, often by electrolysis.