METHOD OF PRODUCING PORTLAND CEMENT Russian patent published in 2021 - IPC C04B7/04 

FIELD: chemistry.

SUBSTANCE: invention relates to production of hydraulic binder materials based on mineral base, particularly, to production of portland cements. Method involves burning Portland cement raw meal in a reducing atmosphere and subsequent grinding Portland cement clinker to a specific surface S_ss= 2800–3000 cm²/g with the addition of gypsum, is not greater than 3.5 % SO₃. To form reducing medium inside clinker capsules during firing raw mixture coke additives are introduced into it in range of 3.5–4 wt. % over the weight of the crude mixture based on coke contained in the ash-slag wastes, which are an integral part of the components of the crude mixture of portland cement. Reduction gas medium formation during clinker annealing is controlled by air excess ratio of 1.05–1.10, annealing is carried out at temperature of 1450 °C for 30 minutes, rapid cooling of cement clinker is carried out in an aerated air-water medium.

EFFECT: higher activity of cement, reduced consumption of process fuel and electric power, improved grinding capacity of cement clinker, increased service life of lining.

1 cl, 1 tbl