ANS:D - fertiliser

The maximum consumption of limestone is in the cement industry. Limestone is a key raw material used in the production of cement. It is primarily composed of calcium carbonate and serves as a source of calcium in the cement manufacturing process. Limestone is crushed and ground into a fine powder, known as raw meal, which is then heated in a kiln along with other materials to produce clinker. The clinker is then ground with gypsum to produce cement. The cement industry is the largest consumer of limestone globally, accounting for a significant portion of limestone mining and quarrying activities. Limestone is essential for the production of Portland cement, which is the most widely used type of cement in construction and infrastructure projects worldwide. Therefore, the maximum consumption of limestone occurs in the cement industry.