Method for using aluminum ash to prepare aluminum polychlorid and co-produce calcium fluoride

Abstract

The invention discloses a method for using aluminum ash to prepare aluminum polychlorid and co-produce calcium fluoride. The method comprises the steps that filtrate and a filter cake are obtained through catalytic hydrolysis, filtration and washing of aluminum ash, and a fluorine rich solution is obtained through multiple recycling of the filtrate; an aluminum rich solution, washing liquid and acidolysis residue are obtained through acidolysis, filtration and washing of the filter cake; calcium fluoride and denitration ammonium hydroxide are prepared through precipitation and filtration of the fluorine rich solution; an aluminum polychlorid water purifying agent is prepared through polymerization mediation of the aluminum rich solution obtained through acidolysis, and a fireproof materialis prepared through drying and sintering of acidolysis residue. The method disclosed by the invention achieves thorough hydrolysis of aluminum nitride and directional enrichment and separation of impurity ions, the ammonia-nitrogen content of the aluminum polychlorid is low, the quality is high, the performance indexes are completely superior to the requirement of GB / T22627-2014 standard, the calcium fluoride purity is high, and the aluminum polychlorid can replace industrial calcium floride. The method solves the problem of safe treatment of aluminum ash, and achieves resource utilization, and the environmental, economical and social benefits are outstanding.

Description

technical field [0001] The invention relates to the field of hazardous waste safe disposal, resource utilization and sewage treatment, in particular to a new method for preparing polyaluminum chloride and co-producing calcium fluoride by using aluminum ash. Background technique [0002] Aluminum ash is a hazardous waste produced by aluminum electrolysis, aluminum processing and aluminum recycling industries, with an annual emission of more than 4 million tons. The electrolytic aluminum industry produces about 10-50kg of aluminum ash for every 1 ton of aluminum produced. Because the primary aluminum ash contains more than 40% elemental aluminum, the elemental aluminum in it can be recovered through frying ash treatment, and the secondary aluminum ash with a smaller particle size cannot be recycled due to the low content of elemental aluminum. Secondary aluminum ash contains aluminum nitride and fluoride, and direct discharge will cause serious water, soil, and air pollution. ...

AI Technical Summary

Problems solved by technology

Because the primary aluminum ash contains more than 40% elemental aluminum, the elemental aluminum in it can be recovered after frying ash. The secondary aluminum ash with a smaller particle size cannot be recycled due to the low content of elemental aluminum.

Secondary aluminum ash contains aluminum nitride and fluoride, and direct discharge will cause serious water, soil, and air pollution

Although the method disclosed above realizes the deep hydrolysis of aluminum nitride, it does not consider the direction of fluoride, resulting in the purified aluminum ash is still a hazardous waste, and neither of them has formed a systematic process, only for certain characteristics of aluminum ash Components are utilized as resources, resulting in secondary waste residue / waste water, and continuous operation has not yet been realized

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