Study On Producing Process Of Magnesium Hydroxide And Calcium Carbonate By Dolomite

Dolomite is a non-metallic minerals calcium and magnesium compound, it is not onlyrich in natural resources and low prices. The new route for developing new processes haveimportant significant in the use of dolomite resources in China. The extensive mode ofproduction has not only led to the waste of a large number of quality resources, but alsocaused serious ecological problem and environmental pollution. The purpose of this workis the basis of the existing work on the development of appropriate technologies process,and can dovetail with existing technology. The process for production of magnesiumhydroxide and calcium carbonate old process of reform and innovation, trying to make thecurrent production situation has improved. This process of innovation is the process closed,without any waste of raw materials to maximize the extent of the dolomite use, fully solvethe pollution of traditional crafts.In this paper, dolomite and ammonium chloride was used as raw material,magnesium hydroxide was synthetized by precipitation method. Magnesium hydroxideand high purity calcium carbonate was produced by cyclic process technology. Themechanism for Preparation of magnesium hydroxide and Calcium carbonate was studed.The reaction conditions effecting on the quality of magnesium hydroxide and calciumcarbonate, such as hydration process, carbonization process, ammonia distillation processwas dicussed.The optimizing hydration conditions as fllow: hydration temperature100℃, solid/water ratio1:10, molar ratio1:2.3, Ammonium chloride concentration2.0mol· L-1, Thereaction temperature100℃, Aging time30min. The content of magnesium hydroxidereaches to98.61%and content of calcium oxide is less than0.2%. The content of calciumcarbonate reaches to99.61%. The total conten of other elements including iron,manganese, zinc, copper, aluminum etc is less than0.2%. The quality of products meetnational specifications.The phase structure, morphology of magnesium hydroxide, calcium carbonate werecharacterized by XRD, SEM, TGA etc.