kalsiumsulfaatidihydraatti

Kalsiumsulfaatidihydraatti, known in English as calcium sulfate dihydrate, is an inorganic compound with the formula CaSO₄·2H₂O. It is obtained naturally as the mineral gypsum and can also be produced synthhetically by reacting calcium carbonate or calcium oxide with sulfuric acid in the presence of water. The chemical is a white, crystalline solid that is slightly soluble in water, forming a clear solution at a concentration of about 2.4 g per litre at 25 °C. It exists in a number of hydrated forms; the dihydrate is the most common and commercially significant phase.

The compound has widespread industrial and commercial applications. In the construction industry, calcium sulfate dihydrate is used as a set hardening agent in plaster, as a binder in plasterboard, and as a supplementary cementitious material that contributes to the durability and strength of concrete. In agriculture, it serves as a soil amendment to improve drainage and to provide calcium and sulfur nutrients to crops. In the art world, gypsum plaster is a traditional medium for sculptures and architectural stucco. The compound is also employed in the manufacturing of drywall, as a component of certain medical casts, and as a filler in the production of plastics and rubber.

Because calcium sulfate dihydrate can readily absorb water, it is sometimes called “drywall gypsum” when used for wallboard, yet in other contexts it is viewed as a softening or desiccant agent. It is generally regarded as safe for industrial use; however, dust exposure during processing can cause respiratory irritation, and the compound may form hazardous waste streams if improperly disposed. Environmental concerns primarily relate to water runoff from gypsum-based materials, which may introduce calcium and sulfate ions into aquatic ecosystems. Management practices typically involve careful handling and containment to mitigate these impacts.