Liquid additive for intergrinding cement
AssigneeW. R. Grace & Co.-Conn.
InventorsLeslie A. Jardine, Charles R. Cornman, Vijay Gupta, Byong-Wa Chun
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Abstract
Exemplary compositions and methods for reducing hexavalent chromium in cementitious compositions involve the use of a liquid additive composition, comprising stannous chloride. Along with the stannous chloride may be used at least one co-additive comprising an antioxidant, oxygen scavenger, or mixture thereof, and/or at least one agent comprising a cement grinding aid, cement quality improver, or mixture thereof.
Claims24
A method for reducing hexavalent chromium in cementitious compositions, comprising:
- grinding cement clinker to produce Portland cement;
- introducing to said cement clinker, before or during the grinding thereof, a liquid additive composition comprising stannous chloride present in an amount not less than 20 percent and not greater 95 percent based on total weight of the liquid additive composition,
- said liquid additive composition further comprising a co-additive selected from the group consisting of an antioxidant and an oxygen scavenger, or mixtures thereof said co-additive being present within said liquid additive composition in a stannous chloride:co-additive ratio of not less than 99.5:0.5 and not greater than 20:80;
- said stannous chloride being added to said cement clinker at a rate no less than 0.001 and no greater than 5.0 percent based on weight of said cement clinker.
A method for reducing hexavalent chromium in cementitious compositions, comprising:
- grinding cement clinker to produce Portland cement;
- and
- introducing to said cement clinker, before or during the intergrinding thereof, a liquid additive composition comprising stannous chloride and a co-additive, agent, or mixture thereof;
- said coadditive being selected from the group consisting of an antioxidant and oxygen scavenger or mixtures thereof;
- and
- said agent being selected from the group consisting of a cement grinding aid and cement quality improver.
Dependencies are inferred from the claim text.