The Central Glass & Ceramic Research Institute, Calcutta has developed a new technique of sinterin for the production of High Alumina Cements : 45- 50%, 65-66% and 72-78% alumina types that can be used for making castable for recommended maximum service temperature ranging from 1300o-1800o C. The new process has certain advantages such as low temperature of sintering, minimising the use of high cost infra- structural facilities, low cost of production. The technology is also suitable for and adaptable by the medium scale, the small scale and the mini scale sector of the industries. The quality of the cement produced by this process are comparable to the similar types of cements being imported from abroad and satisfy IS or other specification.

PROCESS

The synthetic high alumina cements are manufactured from indigenous raw materials such as bauxite/ technical or hydrated alumina and limestone or calcite with minor addition of other ingredients by a comparable low temperature of sintering i.e. 1300- 1350oC, 1400-1450oC and 1400-1500oC after usual conventional processing like crushing, grinding, vibro milling with/ without water, dewatering, drying, fiiring, fine grinding of cement sinters/ melt to cement fineness, sieving, demagnetising etc for yielding 45-50%, 65-66% and 72-78% Al2O3 - type cement respectively.

The production of cements can be easily taken up be existing refractory/ ceramics/ cement manufacturing units with/ without addition of a few equipment and machinery (all are indigenously available).