https://www.csacement.com/products/calcium-aluminate-cement.html Description of Calcium Aluminate Cement Calcium high temperature alumina cement, alumina cements or high alumina cements are obtained by the reaction at high temperature of lime (from limestone) and alumina (contained in natural minerals like bauxite). The aluminate cement obtained after cooling is a hard mineral: calcium aluminate clinker. Ground into a fine powder, the clinker becomes calcium aluminate cement (CAC) which forms a paste when mixed with water. The aluminate cement has the ability to harden very quickly: it forms a rigid solid within 24 hours.