| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing an alumina hydrate pigment for recycling effectively an aluminum-containing waste liquid which is discharged from aluminum-related industries and contains multivalent anions, using the waste as the raw material. SOLUTION: In this preparation process of a porous alumina hydrate pigment from an aluminum-containing waste liquid, the alumina hydrate is synthesized by adding alternatively an aluminum-containing waste liquid containing multivalent anions an alkali to carry out pH swing between an acidic side and an alkaline side, and then the alumina hydrate is obtained by washing out and removing coexisting cations and anions. For the pH swings, the pH of the acidic side is 1-3 and that of the alkaline side is 8-10. The temperature for synthesis is 60-100°C, and the number of pH swings is 3-15. The retention time in the acidic side is 5-60 min and that in the alkaline side is 1-10 min. The retention time in the alkaline side is shorter than that in the acidic side. COPYRIGHT: (C)2004,JPO
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