Extraction of metals from the concentrated ore have 2 stages:-
a. Calcination: It is the process in which the ore is heated in the absence of air at a temperature below its melting point so that the moisture content of ore, volatile impurities, bio substances, etc. can be removed. Along with this, metal carbonates and hydroxides are converted into its oxide.
b. Roasting: It is the process in which the ore is heated in the presence of air at a temperature below its melting point so that the moisture content of ore, sulfur, phosphorous, etc, are converted into its oxide and can be removed. Sulfide ores also get converted into oxides.