Research On Hydration Preparation Of Fire-Retardant Level Magnesium Hydrate From Magnesium Oxide

China is rich in magnesium resources, especially in the western salt lakes. However, for a long time by the technical and economic condition constraints, in the Salt Lake resource development, do not form the industrial chain of utilization of magnesium resources. Salt lake magnesium resources are not being rational use of, every year, hundreds of tons of magnesium chloride has been rescheduled back to Salt Lake, forms the "magnesium erisis". How to use the salt lake magnesium resources became an urgent problem.Magnesium hydroxide as an important inorganic compounds, with the advantages of non-toxic, harmless and non-volatile, shows excellent performance in many respects, widely used in flame retardants, wastewater treatment, flue gas desulfurization and the food industry. Magnesium oxide was prepared by pyrolysis of bischofite, using the magnesium oxide as raw material for preparation of magnesium hydroxide. The effects of reaction time, reaction temperature, liquid to solid ratio and stirring rate on the hydration of magnesium oxide were investigated by means of single factor test and orthogonal test. The optimal hydration condition are determined through test. The experiment results showed that the order of the factors is temperature, time, liquid to solid ratio, the optimal condition of magnesium oxide hydration as follows:temperature is80℃, time is12h, liquid to solid ratio of water and magnesium oxide is8:1, the stirring rate is300r/min.Then the magnesium hydroxide after preparation was modified with sodium dodecyl sulfonate and other three surface modifiers, The experimental results demonstrate that the optimum modifying additive is sodium dodecyl sulfonate, the optimum experiment condition is as follows:the dosage of sodium dodecyl sulfonate is4%, the modification temperature is70℃, the modification time is1h.Research on the dynamics of the hydration of magnesium oxide, The hydration curves of40℃,60℃,800℃are gotten by experiments and the reaction rate constant under different temperatures could be calculated. Then according to Arrhenius equation the hydration activity energy of magnesium oxide is calculated. The experimental results show that the magnesium oxide hydration reaction can be used equation a=1-exp (-kt), the reaction rate constants of40℃,60℃,80℃were0.9709,3.4215,4.4468, activity energy of magnesium oxide is about43.7KJ/mol. The hydration of magnesium oxide is controlled by chemical reaction.