The invention discloses a method for preparing
anthraquinone. The method comprises procedures of condensation,
hydrolysis, cycle closure,
dilution procedures, mother liquid retreatment procedures andwaste
sulfuric acid retreatment procedures. A simple process is adopted, circulation is achieved, waste is turned into wealth, commercial chemical raw materials are respectively recycled from waste aluminum
salt water and waste
sulfuric acid water, the comprehensive preparation cost is greatly reduced, and the environment
pollution is reduced.
Wastewater with an aluminum salt is generated in the
hydrolysis procedure, that is, a mother liquid, the mother liquid contains a certain amount of o-benzoylbenzoic acid, after improvement of the
hydrolysis procedure, unseparated o-benzoylbenzoic acid ina lower layer of the mother liquid can be separated, the yield of the
anthraquinone can be increased, the purity of a composite water purifier in the mother liquid can be improved, and the compositewater purifier is free of impure color. In addition, the
turbidity removal capability of the composite water purifier prepared by using the method is remarkably improved.