1, Use dolomite as raw material to prepare magnesium hydroxide whiskers. Hebei Messi Biology Co., Ltd. stated that dolomite is used as raw material and is calcined to obtain dolomitic lime. After digestion and multi-stage carbonation treatment, the calcium carbonate precipitate is removed by filtration to obtain a heavy magnesium [Mg(HCO3)2] aqueous solution. The concentration is adjusted and combined with Ammonia water reaction, and then hydrothermal treatment, surface modification and other processes are carried out to obtain magnesium hydroxide whisker products with good flame retardant properties and low cost.
Principle: After dolomite is calcined at high temperature and then subjected to multi-stage treatment to obtain a magnesium hydroxide sample, the preparation process can be expressed by the following reaction equation: synthesis and hydrothermal treatment in an autoclave, Mg(OH)2 precipitates into crystal grains during this process It continues to grow and gradually transforms into crystals with a smaller specific surface area and a fibrous structure. Advantages: The production process is relatively simple, and the process conditions are easy to control. The raw materials are conveniently sourced and easy to purchase. The utilization rate of raw materials is high, and by-products such as light calcium carbonate can be recycled. The mother liquor can be recovered and the ammonia water can be recycled.
2, Use serpentine as raw material to prepare magnesium hydroxide whiskers. Use sulfuric acid to decompose serpentine, and the acid leaching liquid crystallizes at normal pressure and room temperature to obtain crude magnesium sulfate. After impurity removal and purification, a refined magnesium sulfate solution is obtained. Use this refined magnesium sulfate solution and ammonia water as raw materials, add surfactant, and react at 40°C for 0.5h to prepare magnesium hydroxide whiskers.
Principle: The acid leaching solution of varenite is crystallized under normal pressure and room temperature to obtain a refined magnesium sulfate solution after impurity removal and purification from crude magnesium sulfate. Surfactant is added under appropriate conditions and precipitated with ammonia water to obtain magnesium hydroxide. Advantages: The reaction conditions of this method are mild, and the reaction raw materials are cheap and easy to obtain.
3, Prepare magnesium hydroxide whiskers using Qinghai chlorite mixture as raw material. Hebei Messi Biology Co., Ltd. stated that it uses Qinghai magnesia as raw material, uses sodium hydroxide solution containing a certain amount of organic solvent as precipitant, and uses microwave-hydrothermal method to produce hydrogen with good crystal shape, good dispersion and high purity. Magnesium oxide whisker products.
Principle: Using the Qinghai Dongtai hydrochlorite mixture as the raw material, and sodium hydroxide containing a certain amount of organic solvent as the precipitant, certain molecules or ions in the reaction system are easily adsorbed on the designated crystal faces, changing the development of the crystal faces. , using microwaves and organic solvents simultaneously in the hydrothermal method can produce magnesium hydroxide samples with special shapes. Advantages: Microwave-hydrothermal method is used to produce magnesium hydroxide whisker products with good crystal shape, good dispersion and high purity, with a yield of 80%. The production process has low cost and high efficiency.