Hydraulic cements
AssigneeThe Associated Portland Cement Manufacturers Limited
InventorsRansom James Murray, Arthur William Brown
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Abstract
A method of making a special high strength cement of the Portland type containing alite of improved hydraulic activity, wherein argillaceous and calcareous materials are combined to form clinker by heating in a kiln and the resulting clinker is ground to form a cement, comprising the step of introducing into the kiln a combination of mineralizers which contains fluorine and sulphur, provided that an alkali metal compound which can be a component of the aforesaid combination of mineralizers is included in the combination of mineralizers at least when the condition that the lime saturation factor be at least 0.98 and the silica ratio be at least 4 is not met.
Claims30
In a method of making a high strength cement of the Portland type wherein argillaceous and calcareous materials are combined to form clinker by heating in a kiln and the resulting clinker is ground to form a cement, the improvement wherein the hydraulic activity attributable to the alite content is improved by introducing into the kiln a combination of mineralisers which contains fluorine and sulphur in which the mineralisers contain 0.1 to 2.0 percent fluorine by weight and 1 to 10 percent SO.sub.3 by weight based on the clinker, provided that an alkali metal compound which can be a component of the aforesaid combination of mineralisers is included so that at least 0.5 percent sulphate is retained in the clinker as alkali metal sulphate at least when the condition that the lime saturation factor be at least 0.98 and the silica ratio be at least 4 is not met.
The method of obtaining a cement clinker containing at least 65% by weight alite, which comprises the steps of:
- a. forming a Portland cement raw feed mix;
- b. thermally converting said raw feed mix to clinker in the presence of mineralisers which contain an alkali metal, fluorine and sulphur, said mineralisers being present in amount sufficient to provide from 0.1-2.0% fluorine and 1-10% SO.sub.3 by weight based on the clinker;
- and
- c. recovering a clinker containing at least 0.5% CO.sub.3 combined with said alkali metal.
Dependencies are inferred from the claim text.