2004 年 16 巻 2 号 p. 66-70
In order to recover phosphorus from ash of sewage sludge, many studies are going under way. However, phosphates recovered from this sludge were mainly composed of aluminum phosphate. To promote the utilization of recovered aluminum phosphate, zeolite formation process was studied. Aluminum phosphate was mixed with silicon dioxide powder and sodium carbonate, and heated at 900°C for 2 hours. Aluminum phosphate reacted with silicon dioxide and sodium carbonate, under this condition zeolite like substance was formed. This zeolite like substance was recovered by addition of water for dissolving sodium phosphate formed in this reaction followed by solid-liquid separation. Sodium phosphate was recovered from filtrate by vaporization.