Composition and method for retarding the setting of cements

Claim 2

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.

Claim 3

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.

Claim 4

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.

Claim 5

A composition according to claim 2, wherein said retarding agent consists essentially of, in percent by weight: ______________________________________ CaF.sub.2 55 - 60 Ca.sub.3 (PO.sub.4).sub.2 8 - 10 CaSO.sub.4 6 - 7 SiO.sub.2 15 - 20 Mg.sub.3 (PO.sub.4).sub.2 1 - 1.2 CaCl.sub.2 0.3 - 0.5 Fe.sub.2 O.sub.3 1.5 - 2 Al.sub.2 O.sub.3 3.5 - 4.5 Na.sub.2 O 0.3 - 0.7 K.sub.2 O 0.3 - 0.7 Rare earth 0 - 0.2. ______________________________________

Claim 6

A composition according to claim 2, said retarding agent being present in amount of 1-3% by weight.

Claim 7

A composition according to claim 1, said cement being a Portland cement, and further comprising sufficient sand, gravel or crushed stone to constitute concrete upon setting.

Claim 8

A composition according to claim 1, said cement being a mixture of Portland cement and slag cement, and further comprising sufficient sand, gravel or crushed stone to constitute concrete upon setting.

Claim 9

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.

Claim 10

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.

Claim 11

A method according to claim 7, wherein said water is saline water.

Claim 12

A method according to claim 7, wherein the mixing is conducted at about 15°-45° C.

Claim 13

A method according to claim 7, wherein the retarding agent is a brown free-flowing powder derived from the production of hydrochloric acid with raw phosphate and separation of the impurities precipitated when preneutralizing the attack liquor.