Preparation process of high-purity magnesium hydroxide: optimization and application of microcrystalline magnesite hydration technology

Microcrystalline magnesite, as an important natural mineral resource, has great potential in the preparation of high-purity magnesium hydroxide. Through the study of fine hydration process, magnesium hydroxide products with good performance can be obtained, which are widely used in flame retardants, medicine, environmental protection materials and other fields.

Raw material preparation and calcination

Microcrystalline magnesite is first calcined at high temperature, usually at 900℃ to 920℃ for several hours to produce light-burned magnesium oxide (MgO). Calcination conditions have a decisive influence on the purity and structure of the product.

The importance of particle size control

The particle size of light-burned magnesium oxide directly affects the hydration efficiency and product quality. Crushing to a particle size of 1mm or finer can increase the surface area of the material and promote the hydration reaction.

Precise control of the hydration process

Hydration agents (such as NH₄Cl, MgCl₂·6H₂O, etc.) may be added to light-burned magnesium oxide powder during the hydration process to promote the formation of magnesium hydroxide. Hydration conditions, including temperature, stirring time, solid-liquid ratio and amount of hydrating agent added, play a key role in product purity and crystal morphology.

Key steps of impurity removal and purification

The hydrated product needs to be washed, filtered, dried and other steps to remove impurities. In some studies, a burning step is also included to remove adsorbed water and impurities by high temperature treatment (such as 1100°C) to further increase the MgO content.

Methods for performance evaluation

The purity, grain size, shape and distribution of the final product are characterized and evaluated by chemical analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM) and other means.

The hydration process of microcrystalline magnesite to prepare high-purity magnesium hydroxide is a systematic project involving multiple links such as raw material pretreatment, hydration condition control, impurity removal and purification, and product performance optimization. By continuously optimizing these process conditions, high-purity magnesium hydroxide that meets specific application requirements can be obtained.