Impinging-stream-based continuous magnesium hydroxide production process

Abstract

The invention discloses an impinging-stream-based continuous magnesium hydroxide production process, and relates to a magnesium hydroxide production process. The process comprises the steps that a magnesium salt and precipitant with certain concentration serve as raw materials, an impinging stream reactor is adopted, in the impinging stream reactor, the magnesium salt and the precipitant react at20-90 DEG C, magnesium hydroxide precipitates are generated, the obtained precipitates are aged at 50-120 DEG C for 1-10 hours, then filtering and drying are conducted, and a magnesium hydroxide product is finally obtained. Auxiliary equipment of the process comprises a raw material storage tank, a pump, a flowmeter, a filter, an ageing tank, a dryer and the like. Accordingly, the impinging streamreactor is adopted, the magnesium salt and the precipitant serve as the raw materials, and the magnesium hydroxide product which is high in dispersion, small in specific surface area, uniform in particle size and consistent in crystal form can be obtained. By means of the continuous magnesium hydroxide production process, the materials are mixed rapidly, the reaction is efficient, and residence time distribution is narrow. The process flow is short, the equipment is less, and the product quality is good and stable.

Description

technical field [0001] The invention relates to a magnesium hydroxide production process, in particular to a continuous magnesium hydroxide production process based on impinging flow. Background technique [0002] As a "green" inorganic flame retardant, magnesium hydroxide is more stable at high temperature and has better smoke suppression ability, and its indicators are better than aluminum hydroxide flame retardant. With the development of the global flame retardant product market showing the trend of non-halogenation, low hazard and low smoke, the market application prospect of flame retardant magnesium hydroxide is very broad. [0003] At present, the methods for preparing magnesium hydroxide are mainly chemical precipitation method and natural brucite processing method (physical pulverization). The properties (physical properties and chemical composition content) of the two types of magnesium hydroxide products are different, the use effects are different, and the mark...

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Problems solved by technology

When the reaction is carried out in the traditional batch stirred reactor, the concentration of the reactants in the reaction system is constantly changing, resulting in that the magnesium hydroxide prepared by the ammonia water method in the batch reactor is mostly amorphous, and this magnesium hydroxide product is used in polymer materials. The dispersibility and compatibility are poor, so it is difficult to be directly used in polymer materials for flame retardant

However, when the precipitation reaction is carried out in a continuous stirred tank reactor (similar to a fully mixed flow reactor), although the concentration of the reactants in the reactor is constant, due to the high degree of back mixing in the reactor, the material has a residence time distribution. , will also lead to inconsistency in product appearance, thus limiting the direct use of the magnesium hydroxide product produced as a flame retardant

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