Dry and wet methods combined aluminum electrolysis flue gas deep treatment process

Abstract

A novel process for realizing deep treatment of electrolytic aluminum flue gas through combining a dry-wet method is characterized in that flue gas of each electrolytic cell is fully contacted with fresh alumina powder inside a VIR reactor; after fluorine is absorbed, the alumina powder and the flue gas enter an electrostatic dust collector so as to remove most alumina powder and alumina powder dust; waste gas enters an absorption tower of a wet system, and is in counter current contact with an absorption liquid so as to remove alumina powder, dust, hydrogen fluoride and sulfur dioxide in the waste gas; and the purified tail gas is exhausted into the atmosphere. The novel process has the advantages that the process turns the prior dry bag-type dust removal into electrostatic dust removal, thereby substantially reducing the investment of dry dust removal and the operating cost of the entire environmental protection system; then, wet treatment is adopted so as to reach the goal of deep treatment; meanwhile, SO2 with flue gas removed is absorbed, thereby greatly reducing the emission of pollutants during aluminum electrolysis; through the organic combination of the dry-wet technology, the process ensures that fluoride inside the wet system is directly synthesized into cryolite and is reclaimed, thereby solving the problems that the prior wet purification process needs to adopt a villaumite recovery device and that villaumite liquid wastes are difficult to treat.

Description

technical field [0001] The invention relates to a new process method used in the treatment of electrolytic aluminum flue gas in the production of electrolytic aluminum. Background technique [0002] During the production of electrolytic aluminum, aluminum fluoride and cryolite (Na 3 AlF 6 ), therefore, in addition to sulfur dioxide, dust and other pollutants, fluoride will also be produced in the waste gas emitted by aluminum electrolysis production. According to the recovery process and the equipment used, the traditional electrolytic aluminum flue gas purification and recovery can be divided into dry and wet methods. [0003] 1. Wet purification technology [0004] There are many methods for wet purification and recovery, such as washing with water, washing with alkaline water, washing with sea water, etc. The wash liquor is recovered through alkaline, ammonia and acid processes. Although the most simple and economical way to purify electrolytic aluminum flue gas is t...

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Problems solved by technology

[0019] The problem to be solved by the present invention is: to design a new process of combined dry and wet method for deep treatment of electrolytic aluminum flue gas, which can greatly improve the purification rate of electrolytic aluminum flue gas and solve the problem of SO 2 Problems of pollution discharge and fluoride recycling, thereby reducing environmental pollution and reducing operating costs

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