| 摘要 |
PROBLEM TO BE SOLVED: To obtain a slightly calcium leaching cement compsn. by adding one or more phosphoric acid compds. or fluorides to a cement material. SOLUTION: One or more phosphoric acid compds. or fluorides are added to a cement material. Calcium in the cement can be converted into a calcium phosphate compd. to suppress the formation of calcium hydroxide and to prevent the leaching of calcium ions from the cement and the ordinary cement is converted into the objective slightly calcium leaching cement compsn. In order to produce this compsn., one or more compds. selected from phosphates of alkali (alkaline earth) metals, their hydrates and aluminum phosphate or from fluorides of alkali (alkaline earth) metals, their hydrates and aluminum fluoride are added so that apatite, octacalcium phosphate or the like is formed in place of calcium hydroxide formed from calcium in Portland cement. |
