The process of converting hydrated alumina into anhydrous alumina is known as .......

During which of the following processes is an ore converted into its oxide?

Given below are two statements:
Statement-$I$ : In the metallurgy process,sulphide ore is converted to oxide before reduction.
Statement-$II$ : Oxide ores in general are easier to reduce.
In the light of the above statements,choose the most appropriate answer from the options given below :

Heating of pyrites in air for oxidation of sulphur is called

The role of calcination in metallurgical operations is

Roasting involves