kalsiumoksidin

Kalsiumoksidin, known in English as calcium oxide (CaO), is a white to grayish solid that is highly basic and reactive. It is produced by calcination, the thermal decomposition of limestone (CaCO3) at temperatures around 900–1000°C, which releases carbon dioxide.

Calcium oxide readily reacts with water in a strongly exothermic reaction to form calcium hydroxide (slaked lime, Ca(OH)2). In water, CaO has limited solubility and rapidly hydrates, creating alkaline conditions that can be detected with limewater. It reacts with acids to form corresponding calcium salts and water. The compound is corrosive to skin, eyes, and mucous membranes, and inhalation of dust can irritate the respiratory tract.

Storage and handling require dryness and airtight containment to prevent premature hydration. It should be kept away from moisture and incompatible substances, with appropriate personal protective equipment during handling.

Uses of calcium oxide are widespread. In metallurgy, it serves as a flux in steelmaking to remove silica and alumina. In construction, it is a key ingredient in the production of cement and lime mortars. It is employed in water and wastewater treatment to raise pH and neutralize acidity, and in agriculture as a liming agent to improve soil structure and supply calcium. It also has applications in chemical synthesis and environmental remediation, where controlled neutralization is needed.

Calcium oxide is often contrasted with calcium hydroxide, its hydrated form, which is less reactive and more soluble. Both substances are central to lime-based processes in industry, agriculture, and environmental management.