Wet-process harmless treatment method for electrolytic bath overhaul residue

Abstract

The invention discloses a wet-process harmless treatment method for electrolytic bath overhaul residue. The wet-process harmless treatment method for electrolytic bath overhaul residue comprises a cyanogen removal process and a fluorine removal process, wherein in order to enable cyanides in the overhaul residue to react with hypochlorite released by bleaching powder in water as soon as possible while being dissolved in water, in the cyanogen removal process, the overhaul residue is premixed with the bleaching powder to shorten a reaction time, a pH value is controlled to be between 9 and 12, a reaction temperature is not greater than 50 degrees, and an available chlorine content of the bleaching powder is not less than 28%; and in the fluorine removal process, calcium hydroxide needs to be added at first, and then hydrochloric acid is added, and after a fluorine removal agent (calcium hydroxide) is added, the final pH value of reaction solution is controlled to be 6-7, and the content of Ca(OH)2 in the industrial calcium hydroxide is not less than 92%. The wet-process harmless treatment method for electrolytic bath overhaul residue, which is disclosed by the invention, belongs to solid waste treatment projects; the technical scheme is advanced and reasonable, low in investment, and high in implementation property; the purpose of harmless treatment for overhaul residue of enterprises is effectively solved; the treated overhaul residue is finally produced into cement bricks, and cannot generate any waste water and waste residue; and resource realization is effectively realized, and good economic benefits and social benefits are achieved.

Description

Technical field: [0001] The invention relates to a method for treating harmful substances, in particular to a method for harmless treatment of slag from overhaul of an electrolytic cell by wet method, and belongs to the technical field of metallurgical environmental protection removal of harmful substances. Background technique: [0002] Since 2010, my country has become the world's largest aluminum producer. With the increase of my country's aluminum production, the overhaul slag produced by electrolytic cells has also increased year by year. Normally, about 30-50kg of overhaul slag is discharged for every ton of raw aluminum produced. At present, the cumulative discharge of overhaul slag in my country has reached more than 5 million tons, and the discharge rate is increasing at a rate of 250,000 to 300,000 tons per year. In the overhaul slag, carbonaceous materials account for about 37%, fluoride salts account for about 30%, other substances are mainly nepheline, β-alumin...

AI Technical Summary

Problems solved by technology

[0003] The overhaul slag of the electrolytic cell is very harmful to the ecological environment, mainly manifested in: it has great harm to the growth of animals and plants, and causes the animal bones / plant tissues to become black and necrotic; it affects the agricultural ecological balance and reduces the yield of crops; High levels of soluble fluoride and cyanide pollute ground and surface water with rainwater; under humid conditions release harmful gases that pollute the atmosphere