PRODUCTION OF CEMENT CLINKER Russian patent published in 2015 - IPC C04B7/44 C01F7/38 

FIELD: process engineering.

SUBSTANCE: invention relates to industrial production of cement, particularly, to production of cement clinker from high-alumina ash-and-slag wastes of electric power stations and can be used in processing of ash dumps of Ekibastuz Hydroelectric Power Station. Proposed process comprises classification and magnetic separation of stock mix containing ash-and-slag wastes of coal power stations, preparation of alumina concentrate, mixing is with limestone and annealing. It differs from known processes in that during first stage after extraction of magnetic fraction from stock mix, the residue is processed with alkali to complete leaching. Obtained alumina concentrate is sintered with limestone at 1150-1200°C to get the cake. The latter is processed with soda solution to leach sodium aluminate while sodium silicate solution is processed with carbonic acid to get amorphous alumina. Obtained sodium carbonate solution is processed with lime. At second stage obtained solid phase is sintered with limestone at 1400-1450°C to get cement clinker. Note here that cement clinker chemical composition is corrected at mixing and sintering of belite slime with limestone. Sodium aluminate solution formed at leaching of alumina silicate cake with limestone is used for production of alumina.

EFFECT: non-polluting process, increased output.