High iron oxide hydraulic cement
AssigneeThe Reagents of the University of California
InventorPovindar K. Mehta
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Abstract
Hydraulic cements having higher (about 5%) iron-oxide content and lower (43-57%) than the usual calcium-oxide content of Portland cements are disclosed. These high iron-oxide cements have normal setting times, but high early strengths that develop without resorting to fine grinding or steam curing. The cements can be produced with considerably less expenditure of energy than required for conventional Portland cements due to lower burning temperatures and reduction in the amount of calcium-oxide which requires the greatest energy input for preparation of the cements.
Claims9
High iron-oxide hydraulic cement compositions comprising from about 15 to about 65% by weight tetracalcium aluminoferrite, from about 10 to about 20% by weight tetracalcium trialuminosulfate, and from about 10 to about 15% by weight calcium sulfate.
A method for producing high iron-oxide hydraulic cement clinker comprising mixing predetermined amounts of iron-oxide, aluminum-oxide, calcium oxide, and sulfate raw materials, subjecting said raw materials to a heat treatment at temperatures of about 2,200.degree.-2,300.degree. F. for a period of time sufficient to form clinkers comprising an admixture of from about 15 to about 65% tetracalcium aluminoferrite, from about 10 to about 20% tetracalcium trialuminosulfate, and from about 10 to about 15% calcium sulfate, and thereafter cooling the clinker.
A method for reducing the energy required to produce an hydraulic cement clinker comprising reducing the amount of CaO required in the cement composition and replacing the reduced amount of CaO with additional amounts of iron-oxide, alumina and sulfate in the form of tetracalcium aluminoferrite tetracalcium trialuminosulfate and calcium sulfate.
Dependencies are inferred from the claim text.