From Salt Lake Industrial Byproduct Manufacture Flame-retardant Magnesium Hydroxide,

Magnesium hydroxide is one of the most promising flame retardant without halogen. In the experiment, byproduct comprising of magnesium hydroxide from salt lake industry is used as raw material.It is purified by hydrothermal method,then the surface of magnesium hydroxide is modified with stearic acide .The products through hydrothermal treatment are characterized by means of by means of X-ray diffraction,Laser particle size analyzer and scanning electron microscope.Firstly the fire resistant mechanism of magnesium hydroxide and its preparation are discussed. Rusults indicate that higher purified product is possible to be obtained after hydrothermal method in theory. The causes of agglomeration are also analyzed, several effective methods of eliminating agglomeration are presented,and the technological flow of ultras-hydroxide magnesium is decided according to the principal.Secondly the technics condition of magnesium hydroxide preparation from the salt lake industry material is discussed through lots of experiments.The optimum experimental conditions during of the preparation of magnesium hydroxide through hydrothermal method are explored. The result indicate that the concentration of sodium hydroxide is 2.0mol/L,the hydrothermal temperature is 180°C , the hydrothermal time is 4h.The result shows that the mean particle size of the magnesium hydroxide is 5μm. The percentage of particle size less than 9.289μm exceeds 90%.The samples assume that the shape of platelet is slice and it belongs to the hexagonal crystalline system. The purity of the sample exceeds 97%.Finally the purified magnesium hydroxide is modified with stearic acid. The result demonstrates that the optimum experiment conditions are: the dosage of stearic acid is 4%,the modification time is 30minute,and the modification temperature is 90℃ .The study discover the active index is 97% after surface modification,and indicate the magnesium hydroxide of polarity is changed from hydrophilicity to hydrophobicity,and the result is good.To some extent,the study is benefit to develop salt lake industry.