CALCIUM SULPHATE-BASED PRODUCTS HAVING ENHANCED WATER RESISTANCE

摘要

A water-resistant calcium sulphate based body comprises a matrix of crystalline calcium sulphate anhydrite, crystals of the matrix being connected to one another by water-resistant phosphate bonding zones, optionally also containing aluminium. The body can be produced by impregnating a porous calcium sulphate with a source of phosphate ions (optionally containing aluminium), and then calcining. Alternatively, a paste comprising calcium sulphate and a source of phosphate ions (optionally containing aluminium) is heated or compressed to form a 'green body' and then calcined to produce the body.