Preparation Technology Of Activity Fiberlike Magnesium Hydroxide In Alcohol Solution

In the experiment, MgCl2·6H2O and NH3·H2O were reaction in methanol solution topreparation of high yield fibrous basic magnesium chloride. The result show that, more than double offibrous basic magnesium chloride can be obtained than that of water as solvent. Then the basicmagnesium chloride obtained in the above was reaction with sodium hydroxide to preparation offibrous magnesium hydroxide. The product was modificated with suitable surfactant in order to obtainan active fibrous magnesium hydroxide.In this experiment, the mixed solvent of methanol and water, MgCl2·6H2O and ammoniumhydroxide were used to prepare fibrous Mg2(OH)3Cl·4H2O. The morphology and yield ofMg2(OH)3Cl·4H2O was affected by many factors. The influence of concentration of methanol andMgCl2; the molar ratio of MgCl2and NH3·H2O; reaction and ageing temperature was studied.Based on the test result of XRD, SEM and TG/DTG, the best technology which optimized byorthogonal method are as fellows: the methanol concentration is25.0%, the molar ratio of MgCl2and NH3·H2O is3.0:1, the concentration of MgCl2is4.0mol L-1, the reaction temperature is25℃,and ageing temperature is50℃. The fibrous Mg2(OH)3Cl·4H2O were about0.3μm in diameterand50μm in length, with an aspect ratio no less than100. The yield of basic magnesium chlorideis13.13%, nearly double than reaction in water. It showed that methanol-water system is aneffective medium for producing high yield of basic magnesium chloride.In this experiment, fibrous magnesium hydroxide was produced by selecting basicmagnesium chloride and sodium hydroxide as initial materials, in the presence of ethanolsolvent. The influence of material mole ratio, ethanol concentration, reaction temperature andconcentration of basic magnesium chloride were thoroughly studied, and the morphology andstructure of the product were characterized by SEM and XRD. The results showed that in thepresence of80%ethanol solvent, magnesium hydroxide fiber can be obtained in1.5h, whenmole ratio of sodium hydroxide and basic magnesium chloride is2.0:1, concentration ofbasic magnesium chloride is0.30mol L-1, and temperature at50℃. fibrous magnesiumhydroxide was obtained in1.5h. The yield was100%。In the process of surface modification of fibrous magnesium hydroxide, the influence of kindand amount of modifier, modifying temperature, reaction time and concentration of magnesiumhydroxide were studied. The result shows that,5%added of sodium stearate is the moreappropriate modifier to modified fibrous magnesium hydroxide. When the concentration ofmagnesium hydroxide was2%, the reactants was reacted in50℃for1.5h. We can get activatedfibrous magnesium hydroxide, the activation index was99.12%.