| 简介 |
FIELD : manufacture of building materials; production of high-early-strength cement and concrete.
SUBSTANCE : high-early-strength Portland cement is produced on basis of calcination of cement raw mix till sintering; cement raw mix contains carbonate, aluminosilicate and ferrous components; it also includes sodium and potassium oxides and sulfuric anhydride; calcination is followed by joint grinding of clinker thus obtained in tubular mill; clinker contains free CaO and free sulfates of alkaline and alkaline-earth metals; water and gypsum component are also introduced; raw mix contains SO3 at mole ratio of R2O=Na2O+0.658K2O to SO3= 1.34-1.7 and additionally it contains calcium fluoride at mole ratio of R2O to fluorine-ion F equal to 1.3-2.9; clinker thus obtained contains the following components, mass-% : free Cao, 0.25-1.5; free sulfates of alkaline and alkaline-earth metals, 0.3-1.2; alumina modulus 1.3-1.7; Portland cement contains 0.15-0.3 mass-% of water; grinding is continued till clinker part of Portland cement contains, mass-% : 4CaO.0.5R2O.0.9 (AlxFey)2O3.1.1SO3.(8-12)H2O, where R-Na and/or K at x/y from 1.3 : 1 to 2 : 1 - 0.15-1.8 and Al(OH)3-zFz.SiO(OH)2 at z+0.5-2.5 - 0.1-0.6. Raw mix contains, mass-% : SO3, 0.25-1.2 and calcium fluoride in terms of F, 0.15-0.4; clinker contains from 0.01 to 0.3 mass-% of free calcium sulfate. Raw mix contains SO3 in form of sulfates of alkaline and alkaline-earth metals and calcium fluoride in form of fluorite or its ore containing no less than 20 mass-% of fluorite. Portland cement clinker contains, mass-% : tricalcium silicate, 55-75; dicalcium silicate, 3-22; tricalcium aluminate and/or its alkaline derivative, 2-13; fluorine mayenite, 2.5-10; calcium alumoferite 2CaO.(Al2O3)x.(Fe2O3)1-x, where x>0 and >1, 0.5-14; the remainder being free CaO and sulfates of alkaline and alkaline-earth metals. Mineral forming promoter is additionally introduced into raw mix. Criterion of optimal its content is appearance of 3CaO.SiO2 cellular microstructure in clinker. During calcination, content of fluxes in raw mix is controlled. Use may be made of any gypsum component. During grinding, active mineral additive or standard Portland cement clinker or 0.05-0.4% (of mass of Portland cement) of different intensifying agents may be introduced. During grinding, standard Portland cement clinker is additionally introduced or Portland cement on base of standard clinker is introduced at mass ratio of 5 : 1 to 1 : 1. Expanding additive in the amount of 7-15 mass-% is additionally introduced into Portland cement. Water may be introduced into tubular mill by different methods. Method of production of concrete includes mixing of Portland cement with water and fillers, forming this mix and holding it till hardening at temperature of 1-45C and moisture content of 70-100% during 5-24 hours or under conditions of heat and moisture treatment at temperature of 50-85C during 1.5-5.5h.
EFFECT : reduced consumption of fuel; reduced power requirements; increased productivity of furnaces and cement mills; reduced shrinkage; enhanced strength of mixes and concrete.
23 cl, 3 tbl, 2 ex |
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