METHOD OF PRODUCING CEMENT ON BELITE CLINKER AND SLOW-CURING CEMENT OBTAINED ON ITS BASIS Russian patent published in 2020 - IPC C04B7/02 C04B7/24 C04B7/36 C04B7/38 C04B7/42 C04B7/44 C04B7/52 

FIELD: chemistry.

SUBSTANCE: disclosed group of inventions relates to a method of producing slow-setting cement and cement produced on its basis. Method involves preparation of a crude mixture containing carbonate component in amount of 89.2–90.2 wt% and clay component in amount of 1.1–1.2 wt %, primary combined grinding of carbonate component and clay component in wet self-grinding mill to obtain coarse sludge, fine grinding of coarse sludge in tube mills together with ferruginous additives in amount of 2.5–2.6 wt%. Fine grinding is carried out until residue on sieve No. 008 – 7.0±2.0 %, on sieve No. 020 – 3.0±1.0 %. Then, the sludge is mixed and corrected in the sludge basins by adding the alumina component in amount of 1.1–1.2 wt% and silica component in amount of 4.8–6.0 wt%. Sludge is calcined in a rotary furnace by heating it to 1,350 °C with further cooling and obtaining belite clinker. Obtained clinker is milled together with gypsum in amount of 5.8–7.0 wt% and mineral additives in amount of 1–5.9 wt%. Of fine powder to a specific surface of 3,200±200 cm²/g and a residue on sieve No. 008 1±0.5 %. Cement has the following composition, wt%: SiO₂ 21.4–22.6; Al₂O₃ 4–4.7; Fe₂O₃ 4–4.84; CaO 60–61.8; SO₃ 2.4–3.5, percentage of other impurities 1.2–1.4, MgO, R₂O(K₂O, Na₂O) – balance.

EFFECT: creation of cement with slow and more uniform kinetics of set of compression and flexural strength at all stages of hardening, low early strength, which reduces risk of defects in structure of concrete; besides, proposed method provides reduction of slurry burning temperature to 1,350 °C, which increases service life of furnace lining and its ability to counteract both high temperatures and chemical action of clinker melt on refractories.

10 cl, 11 tbl, 3 ex, 3 dwg