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Advantages and disadvantages of the process of preparing magnesium hydroxide by brine lime method

Hebei Messi Biology Co., Ltd. stated that it is not easy to produce products that meet quality requirements through the interaction of bittern and milk of lime. If the reaction conditions are not well controlled, colloidal precipitation is likely to occur. The sedimentation rate is very slow, and there are many entrained impurities, which requires repeated use of water. Washing consumes a lot of water. To solve this problem, the circulating seed method can be adopted, that is, a part of magnesium hydroxide or magnesium oxide is first added as a seed crystal during the precipitation reaction to make the magnesium hydroxide precipitated particles larger, making it easier to precipitate, filter, and wash.

Magnesium hydroxide for coating

Controlling the addition speed of milk of lime to fully react with calcium hydroxide and magnesium chloride can avoid unreacted calcium hydroxide impurities contained in the magnesium hydroxide precipitation, which not only causes a waste of raw materials, but also reduces the quality of the product magnesium hydroxide. In order to improve the yield and quality of magnesium salts, it is necessary to control the pH of the solution during precipitation. The higher the pH, the more complete the precipitation of magnesium hydroxide, and the less boron impurities will be adsorbed at high pH. Comprehensive consideration, under the conditions of solution pH greater than 10.5 and maintaining a high magnesium recovery rate, magnesium hydroxide is easy to settle, filter and wash. The milk of lime method adds the process of removing calcium and reducing boron, so although the cost of raw materials is lower, the total production cost is still higher.

Hebei Messi Biology Co., Ltd. stated that dolomite milk prepared by calcining dolomite and adding water instead of quicklime milk can make full use of the magnesium oxide in dolomite, and the magnesium hydroxide generated in the original dolomite milk naturally acts as a crystal seed. It is beneficial to precipitation, filtration and washing, and accordingly reduces production costs. Therefore, it is more economical to use this method in areas rich in dolomite.

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