Optimization of the process for preparing active magnesium hydroxide from magnesium chloride hexahydrate of bittern

Raw material preparation and pretreatment:

First, the washed raw materials were dried at 105℃ to constant weight and crushed to -120 µm for subsequent calcination.

Calcination process optimization:

The pretreated raw materials were calcined in the temperature range of 400-800℃ and kept at different temperatures for 10, 30, 60 and 90 minutes to prepare MgO with different activities.

Preparation of active magnesium hydroxide:

Using anhydrous ethanol as a dispersant, the particle size and specific surface area of MgO particles were measured by a laser particle size analyzer, and then MOC slurry was prepared according to the molar ratio of active MgO:MgCl2:H2O of 5:1:13, and its coagulation time was measured.

Preparation of magnesium chloride solution:

A specific concentration of MgCl2 solution was prepared by H2O and MgCl2, and its concentration was expressed in degrees Baume.

Preparation and performance characterization of MOC specimens:

Using the calcined products at different temperatures as raw materials, MOC slurry is prepared according to the designed raw material molar ratio, and injected into the mold. After 24 hours of curing, it is demolded and continued to be cured to different ages.

Preparation method of magnesium hydroxide:

Introducing two methods for preparing magnesium hydroxide, the lime milk method and the sodium hydroxide method, which have important applications in the preparation of flame retardants.

Preparation of magnesium hydroxide by hydrothermal method:

The process of preparing magnesium hydroxide by hydrothermal method using the magnesium chloride content in bittern, a byproduct of salt production, is discussed. This method has potential in the preparation of flame retardants.

Market application prospects:

Active magnesium hydroxide has broad market prospects due to its application in the field of flame retardancy, especially in the context of the rapid development of the plastics industry, the demand for non-toxic, smoke-suppressing and thermally stable magnesium hydroxide flame retardants is growing.

By optimizing the preparation process of bittern magnesium chloride hexahydrate, active magnesium hydroxide can be effectively prepared. This material has important application value and market potential in the field of flame retardants.