Granularity-controllable magnesium hydroxide reaction crystallization apparatus and process

Abstract

The invention discloses a granularity-controllable magnesium hydroxide reaction crystallization apparatus and process. The reaction crystallization apparatus consists of a reaction crystallizer (1), a conveying pump (2) and a pipeline (3). The reaction crystallizer (1) comprises a jacket-type kettle body (4), a guide barrel (5), a longitudinal separation plate (6), a stirring paddle (7), an electric stirrer (8), a magnesium chloride feeding pipe (9), a sodium hydroxide feeding pipe (10), a feed distributor (11), a magnesium hydroxide discharging pipe (12) and a magnesium hydroxide feeding pipe (13). The invention also provides the magnesium hydroxide reaction crystallization process. By utilizing the apparatus and the process provided by the invention, the granularity-controllable production of the magnesium hydroxide can be realized, the magnesium hydroxide with different granularities can be prepared, and the requirements of different users on the granularity of a magnesium hydroxide product can be met. The granularity-controllable magnesium hydroxide reaction crystallization apparatus and process have the advantages of flexibility and adjustability in product granularity and narrow granularity distribution.

Description

technical field [0001] The invention belongs to the technical field of inorganic chemical industry, and relates to a reaction crystallization device and process of magnesium hydroxide with controllable particle size, in particular to a reaction crystallization device and process for synthesizing magnesium hydroxide with different particle sizes by using magnesium chloride and sodium hydroxide as raw materials. Background technique [0002] Magnesium hydroxide is an important multifunctional inorganic powder material, which can be used as a green inorganic flame retardant, flue gas desulfurizer, acid waste water neutralizer, water heavy metal remover, etc. It is used as an anti-acid in the pharmaceutical industry agents, laxatives; [0003] At present, the main production methods of magnesium hydroxide products include two categories, one is to use natural brucite to directly produce magnesium hydroxide through crushing and removing impurities; the other is to produce magnesi...

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Problems solved by technology

The product obtained by the ammonia method has high purity and large particle size, but there are air and water pollution in the production process, and the ammonia distillation operation is complicated and the cost is high.

The sodium hydroxide method can produce high-purity magnesium hydroxide products. If combined with the combined alkali production process, zero discharge of wastewater can be achieved and production costs can be effectively reduced; however, due to the strong alkalinity of sodium hydroxide, the reaction rate is too fast, The crystallization process is difficult to control, resulting in problems such as small particle size, wide particle size distribution, and difficulty in filtration and washing of the product obtained by reaction crystallization;

[0005] Chinese patent CN103043689A reports a device and process for preparing magnesium hydroxide by sodium hydroxide method. The supergravity reaction device is used to prepare nanoscale magnesium hydroxide products. The advantage of this method is that magnesium hydroxide products of 7-17 nanometers can be obtained , but the particle size of the product is too small, it is difficult to filter, and the specific surface area is large. It is used as a flame retardant in a small amount, and the power consumption in the production process is high.

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