Process for manufacturing rapid hardening portland cement clinker
AssigneeOnoda Cement Co., Ltd.
InventorsShigejiro Mori, Hiroshi Uchikawa, Shunichiro Uchida
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Abstract
A process for manufacturing a rapid hardening portland cement clinker containing a calcium halo-aluminate having the formula; 11CaO.7Al.sub.2 O.sub.3.CaX.sub.2, in which X is a halogen, characterized by adding at least one sulfur compound selected from calcium sulfate, calcium sulfite and calcium sulfide to the mixed raw materials comprising mainly an aluminous material, a calcareous material, a silicious material, an iron source and a halogen source, and burning the obtained mixture in an oxidizing temperature.
Claims9
A process for manufacturing rapid hardening portland cement which comprises adding calcium sulfate hemihydrate and anhydrite to a clinker containing 10 - 70% by weight of 11CaO.7Al.sub.2 O.sub.3.CaX.sub.2, wherein X is a halogen, 15 - 60% by weight of 3CaO.SiO.sub.2 and less than 1% by weight of free CaO which clinker is prepared by adding 0.5 - 4.5% by weight based on SO.sub.3 of at least one sulfur compound selected from the group consisting of calcium sulfate, calcium sulfite and calcium sulfide to mixed raw materials which comprise an aluminous material, a calcareous material, a siliceous material, an iron source and a halogen source;
- and burning the obtained mixture at the temperature of 1265.degree. - 1400.degree. C in an oxidizing atmosphere, wherein said calcium sulfate hemihydrate and anhydrite are added in an amount such that the weight ratio of Al.sub.2 O.sub.3 /SO.sub.3 in the cement is present in a range of 0.7 - 1.8.
Dependencies are inferred from the claim text.