Method and equipment for evaporative crystallization of aluminium chloride

Abstract

The invention discloses a method and equipment for evaporative crystallization of aluminium chloride and belongs to the field of the chemical industry. The method adopts a multiple-effect evaporation process for evaporative crystallization of the aluminium chloride, and the processes of washing and acid removal are added in the conveying process of secondary steam after a former-effect separating chamber and before a latter-effect heating chamber, wherein the used washing liquid is alkaline liquid with the temperature and the pressure the same as those of the secondary steam. In separation, a multiple-evaporating-chamber evaporation mode is adopted, and in heating, a serial multi-tube-pass heating mode is adopted. The multiple-evaporating-chamber and multiple-evaporating-chamber modes mean that two or more than two evaporating chambers and tube passes are arranged, and in the equipment, a washing tower containing the alkaline liquid with the temperature and the pressure the same as those of the secondary steam in the former-effect separating chamber is arranged on a pipeline between the former-effect separating chamber and the latter-effect heating chamber in a communicating manner. The separating chamber is of a multi-chamber structure, the heating chamber is a multi-tube-pass heating chamber, multiple evaporating chambers of the separating chamber are respectively communicated with multiple tube passes of the heating chamber, and the upper parts of the multiple evaporating chambers of the separating chamber are respectively communicated with the washing tower by pipelines. The method and equipment have the advantages that the hydrogen chloride volatilizing in the process of evaporative crystallization of the aluminium chloride can be prevented from corroding the equipment and polluting the environment, the efficiency of evaporation and concentration is improved, the volume and the occupied area of the equipment are reduced and the investment is reduced.

Description

technical field [0001] The invention relates to a chemical process, in particular to an evaporation crystallization process in the production of aluminum chloride. Background technique [0002] The chemical formula of aluminum chloride is AlCl 3 , the industrial product of aluminum chloride is a colorless transparent crystal or white and slightly yellowish crystalline powder. Aluminum chloride easily absorbs moisture in the air and partially hydrates to release hydrogen chloride to form acid mist. [0003] At present, the production of aluminum chloride generally adopts one-step acid-dissolving method to produce alumina. In the production process of aluminum chloride, the raw material liquid of aluminum chloride needs to be evaporated and concentrated. Most of the current evaporation and concentration processes use multiple Generally, the evaporation process of aluminum chloride is carried out in this way: first, the raw material liquid of aluminum chloride is pumped from ...

AI Technical Summary

Problems solved by technology

The secondary steam containing hydrogen chloride is very corrosive to equipment and pipelines. The current production process not only affects the service life of the equipment and increases equipment investment, but also the secondary steam discharged will pollute the environment and make the operating environment of workers harsh.

[0006] In addition, because the material handling capacity of the general evaporation process in the industry is very large, the general evaporation equipment is relatively large, but the equipment processing capacity is relatively small, and the equipment production capacity is not large.

Images