Comprehensive treatment technology of waste aluminum ash

Abstract

The invention relates to a comprehensive treatment technology of waste aluminum ash, and concretely relates to processes for producing aluminum hydroxide from the waste aluminum ash, producing refractory materials through utilizing waste residues, and producing ammonium chloride through utilizing wastewater and an exhaust gas. The technology is characterized in that a sodium aluminate solution and a plaster are generated through dissolving out the aluminum ash by a cycle alkaline solution having a high concentration Na2Ok 220g / l at a temperature of above 260DEG C under a pressure of above 60kg / cm<3>; the aluminum ash is washed with water to remove most chlorides before the dissolving-out of the aluminum ash by the cycle alkali solution, and the obtained washing solution is used for absorbing ammonia generated in the dissolving-out process; and the plaster generated by the aluminum ash is used for producing refractory bricks or castable materials. A large amount of ammonia is contained in the waste aluminum ash, and ammonium chloride is prepared through recovering the ammonia with a salt washing solution in a cycle mode, so the ammonia pollution is eliminated, and products are prepared from the ammonia. The sodium aluminate solution undergoes crystal seed decomposition to generate an aluminum hydroxide fire retardant and a decomposition mother solution, and the aluminum ash is dissolved after the decomposition mother solution evaporates.

Description

technical field [0001] The invention relates to a comprehensive treatment process of waste aluminum ash, in particular to a process for producing aluminum hydroxide flame retardant from waste aluminum ash, producing refractory materials by using waste residue, and producing ammonium chloride by using waste water and waste gas. Background technique [0002] Waste aluminum ash is mainly generated in the process of producing aluminum by molten salt electrolysis of alumina. A certain amount of aluminum slag will be produced due to reasons such as carrying operation and measuring equipment, anode replacement, aluminum tapping, ingot casting, and electrolytic cell overhaul. Generally, 30-50 kg of aluminum slag and aluminum ash are produced for every ton of aluminum produced. In recent years, my country's aluminum production capacity and output have increased significantly. In 2010, the aluminum output exceeded 15 million tons, and 450,000 to 750,000 tons of aluminum ash were produ...

AI Technical Summary

Problems solved by technology

It only mentioned the use of evaporation to extract chlorides, and did not further consider the method of using chloride solutions to absorb exhaust gas