Calcium carbonate is used in the purification and separation of iron from its ore. â¶ It is often used in swimming pools for maintaining the alkalinity of water and countervailing acidic properties of the disinfectant. â¶ As it is heavy, calcium carbonate increases the density of drilling fluids and helps in controlling the down hole pressure. Hence it is widely used in the oil industry. It is also added to drilling fluids as a formation bridging and filter-cake sealing agent. â¶ Calcium carbonate is also used in industries like paint, plastic, rubber, ceramic, cement, glass, steel, oil refining, and in biorock creation for mariculture of sea organisms. â¶ The decomposition of calcium carbonate gives carbon dioxide and lime, which is of use in the glass, steel, and paper industries. â¶ Calcium carbonate is the most preferred mineral in the paper industry, used for filling and coating paper. â¶ It is used as a filler in sealants and adhesives. Calcium carbonate is also used in the production of mortar which is utilized for making concrete blocks, bonding bricks, rubber compounds, tiles, etc. Uses in Agriculture â¶ Calcium carbonate is a primary component of garden lime, also known as agricultural lime, which is used for neutralizing acidic soil and to enhance soil quality. â¶ Garden lime when added to soil, acts as a rich source of calcium for plants and increases the pH and water-retaining capacity of acidic soils.