Explanation
Option (a) is incorrect: Saltpetre (Potassium nitrate) is not used in steel production. It is used in the production of fertilizers, rocket propellants, fireworks, and tree stump removal.
Option (b) is incorrect: Rock phosphate is used in the production of fertilizers, not in steel production. It is primarily a source of phosphorus.
Option (c) is correct: Coking coal is crucial for steel production. It is used in the process of converting iron ore into iron and then into steel. India has limited reserves of high-quality coking coal, and more than 60% of the coking coal requirement of the domestic steel industry is met through imports.
Coking coal is a key ingredient in the blast furnace process for making steel. It is used to convert iron ore into molten iron, which is then further processed into steel. Coking coal, or metallurgical coal, is special because it produces coke, an essential ingredient in steelmaking. It has high carbon content, low impurities, and unique properties like plasticity and swelling when heated, forming a strong, porous structure needed in blast furnaces. It’s rarer and more expensive than thermal coal, with major reserves in Australia, China, and the USA. India has limited reserves (mainly in Jharkhand, Odisha, and Chhattisgarh) and is a major importer to meet steel industry demands.