Composition and method for retarding the setting of cements
AssigneesChemical Development Corporation, Tessenderlo Chemie S.A.
InventorsJean H. Buchet, Fernand Peerts
Life of this patent
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Abstract
A retarding agent for cement consists essentially of in percent by weight: ______________________________________ CaF.sub.2 50 - 65 Ca.sub.3 (PO.sub.4).sub.2 7 - 12 CaSO.sub.4 5 - 7.5 SiO.sub.2 10 - 20 Fe.sub.2 O.sub.3 1 - 2 Al.sub.2 O.sub.3 1 - 5, ______________________________________ this retarding agent is preferably the insoluble residue by-product obtained by dissolving raw phosphate with an inorganic acid. It retards the setting of cement at high ambient temperatures, and can be used as well with sea water or with fresh water in the making of concrete and the like.
Claims10
A composition comprising:
- a. a cement selected from the group consisting of Portland cement, slag cement and mixtures thereof;
- b. a retarding agent in an amount relative to the cement contained in the final composition of 0.5-5% by weight, said retarding agent consisting essentially of, in percent by weight:
- ______________________________________ CaF.sub.2 50 - 65 Ca.sub.3 (PO.sub.4).sub.2 7 - 12 CaSO.sub.4 5 - 7.5 SiO.sub.2 10 - 20 Fe.sub.2 O.sub.3 1 - 2 Al.sub.2 O.sub.3 1 - 5, ______________________________________ said retarding agent being the insoluble residue by-product obtained by dissolving raw phosphate with hydrochloric, nitric or phosphoric acid.
A composition comprising:
- a. a cement selected from the group consisting of Portland cement, slag cement and mixtures thereof;
- b. a retarding agent in an amount relative to the cement contained in the final composition of 0.5-5% by weight, said retarding agent consisting essentially of, in percent by weight:
- ______________________________________ CaF.sub.2 50 - 65 Ca.sub.3 (PO.sub.4).sub.2 7 - 12 CaSO.sub.4 5 - 7.5 SiO.sub.2 10 - 20 Fe.sub.2 O.sub.3 1 - 2 Al.sub.2 O.sub.3 3 - 5 Mg.sub.3 (PO.sub.4).sub.2 0 - 2 CaCl.sub.2 0 - 0.5 Na.sub.2 O 0 - 1 K.sub.2 O 0 - 1 Rare earth 0 - 0.2, ______________________________________
- wherein the retarding agent is a brown free-flowing powder derived from the reaction of hydrochloric acid with raw phosphate and separation of the impurities precipitated when preneutralizing the attack liquor.
In a method of making concrete comprising mixing Portland cement with mineral aggregate and water, the improvement wherein a retarding agent is mixed into the concrete, said retarding agent being added in set retarding amounts and consisting essentially of, in weight percent:
- ______________________________________ CaF.sub.2 50 - 65 Ca.sub.3 (PO.sub.4).sub.2 7 - 12 CaSO.sub.4 5 - 7.5 SiO.sub.2 10 - 20 Fe.sub.2 O.sub.3 1 - 2 Al.sub.2 O.sub.3 3 - 5 Mg.sub.3 (PO.sub.4).sub.2 0 - 2 CaCl.sub.2 0 - 0.5 Na.sub.2 O 0 - 1 K.sub.2 O 0 - 1 Rare earth 0 - 0.2 ______________________________________
- said retarding agent being the insoluble residue by-product obtained by dissolving raw phosphate with hydrochloric, nitric or phosphoric acid.
Dependencies are inferred from the claim text.