The Preparation Process And Thermal Decomposition Kinetics Of Magnesium Hydroxide Sulfate Hydrate Whiskers From Mirabilite Associated With Bloedite

The salt lake of Gaxiongnor in Inner Mongolia is mirabilite associated withbloedite, the ultimate direction of mirabilite associated with bloedite is subjectto extracted sodium sulfate directly and it is difficult to solve the problem ofcomprehensive utilization to the associated mineral. This thesis presents theresearch on synthesizing magnesium hydroxide sulfate hydrate (MHSH)whiskers with special molecular structure and excellent flame retardantproperties, to increase the utilization and to find the way of improving thecomprehensive utilization to mirabilite associated with bloedite. Based onresearching the thermal decomposition property of MHSH whiskers, thethermostability and flame retardant properties was defined, and further to definethe scope of its application.With the mirabilite associated with bloedite of Gaxiongnor in InnerMongolia as the raw material, referring to the research of the previousexperience, separating the sodium sulfate and magnesium sulfate fromassociated mineral, the separated mother liquor was used for prepared MHSHwhiskers by one-step hydrothermal method. Using X-ray powder diffraction(XRD) to investigate phase constitution of products, microscope and Scanningelectron microscopes (SEM) were employed to observe the morphology of theproduct, Fourier infrared spectrum (FT-IR) and Thermogravimetry-differentialscanning calorimetry (TG-DSC) were adopted to define the functional groupsand characterization their thermal behavior of products. With adjusted the moleratio of magnesium sulfate and sodium hydrate, reaction time, reactiontemperature and the concentration of magnesium sulfate, it was to identify thephase constitution of products and determine the influence of the concentrationof magnesium sulfate to the morphology. The reasonable prepare processconditions: the mole ratio of magnesium sulfate and sodium hydrate at10:1, at190℃for5hours and the concentration of magnesium sulfate0.8mol/L. Adopting the Professor Tang’s temperature integral approximationanalyzed the mechanism of thermal decomposition of MHSH whiskers. To solvethermal decomposition dynamics parameters in these three steps reaction:thermal decomposition mechanism function, activation energy and thepre-exponential factor. It was confirmed that the chemical qualities of MHSHwhiskers were stable under546K, and when the temperature was up to546-837K,MHSH whiskers decomposed out vapor, therefore showed the flame-resistantand smoke suppression effect and MHSH whiskers has the significantflame-resistant effect to the polymers materials which decomposing-temperaturelies within500-800K. Aim to provide theoretical direction on the changes whenheated, thermal stability, service life and flame retardant of MHSH whiskers.