Calcium hydroxide is an inorganic compound with the formula Ca(OH)2. It is a colourless crystal or white powder. It is also known as hydrated lime or slaked lime. It has a boiling point of more than 1000oC and dissolves sparingly in water to give a highly alkaline solution of pH 12 to 13.

Manufacturing Process

Limestone undergoes thermal decomposition at high temperatures to form calcium oxide or burnt lime. Calcium oxide is treated or slaked with water to produce calcium hydroxide on a commercial scale: CaO + H2O → Ca(OH)2. The calcium oxide is broken down into fine particles of calcium hydroxide in the hydration reaction which occurs in a continuous hydrator. The particle sizes can then be modified through milling to ensure consistent particle size