| 摘要 |
In a method of making a metal oxide modified Ca3(Po4)2, at least one metal is dissolved in H3Po4, the resulting solution of metal phosphate is added to an agitated aqueous slurry of Ca(OH)2 at a rate such that the slurry remains alkaline and the CaO/P2o5 ratio is between 1,18:1 and 1,9:1 and the phosphate is precipitated while dispersing oxide of the metal on it followed by removal of the phosphate from water and drying. The dissolved metal may be above (e.g. Fe, Co, Zn, Ni and Pb) or below (e.g. Cu and Ag) hydrogen in the electrochemical series and an oxidizing agent, e.g. tho- or t-butyl perbenzoate may be added to the H3Po4, e.g. when iron is dissolved in H3Po4 the added oxidizing agent is Cr2O3 and when nickel is dissolved in H3Po4 the added oxidizing agent is HNO3. Prior to drying an alkaline potassium compound is added to the precipitated product, pellets are formed from the dried product which are subsequently calcined in an atmosphere of steam. The Ca3 (Po4)2 may have an oxide of either Cu or Fe dispersed therethrough together with an alkaline potassium compound. Specified compositions include (1) 10-50% Fe2O3, 0-50% Cr2O3 and 5-20% of an alkaline potassium compound on Ca3(Po4)2; (2) 2-20% of CuO, 0-5% NiO and 0-15% of an alkaline potassium compound on Ca3(Po4)2; (3) 18% Fe2O3, 2% Cr2O3, 12% KOH and 68% Ca3(Po4)2; (4) 20% Fe2O3 3% Cr2O3, 10% KOH and 67% Ca3(Po4)2; (5) 26% Fe2O3, 4% Cr2O3, 12% KOH and 58% Ca3(Po4)2 and (6) 12% CuO, 0,5% NiO, 5,5% KOH and 82% Ca3(Po4)2. Other examples are given. Regeneration of such compositions is effected by oxidation.
|
