| [Visitor (111.55.*.*)]answers [Chinese ] | Time :2024-03-27 | (1) Mix fly ash with a mass ratio of 1:5~40 with water, stirring speed 50~400rpm, stirring 0.5~12h; After standing, the supernatant was taken and the suspended particulate matter was removed by filtration to prepare the leaching solution; Among them, the free calcium oxide content in fly ash is 1.70~3.40%, and the calcium ion concentration in the leaching solution is 640~1500mg/L;
(2) After anaerobic digestion of municipal sludge, the supernatant is taken and filtered to remove suspended particulate matter and acidified with acidification, and the pH value of the solution is adjusted to 3.5~4.2 pretreatment;
(3) according to the initial reaction calcium-phosphorus molar ratio of 0.5~3.3:1 mixed with the leaching solution of step (1) and the digestive juice after pretreatment of step (2); The alkali solution was added to adjust the pH value of the reaction to 7.5~11.0, and the calcium phosphate salt precipitate was obtained by stirring the reaction for 5~120min.
(4) The temperature is controlled at 103~105 °C, and the calcium phosphate precipitate in step (3) is dried. |
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