In this experiment, the fibrous basic magnesium chloride (Mg2(OH)3cl · 4H2O) was prepared from MGCL2 · 6H2O and ammonia with methanol-water as the reaction solvent. By recycling the filtrate, the utilization ratio of magnesium is further improved. The fibrous Magnesium hydroxide was prepared by the reaction of fibrous basic magnesium chloride (Mg2(OH)3cl · 4H2O) with sodium hydroxide in ethanol-water system, and was modified with Surfactant, finally, a fibrous active Magnesium hydroxide with high surface activity and large aspect ratio was obtained. Fibrous basic magnesium chloride was prepared from mgcl2 · 6H2O and ammonia in methanol-water system.
The effects of methanol concentration, MGCL2/NH3 · H2O molar ratio, MGCL2 concentration, reaction temperature and aging temperature on the yield and morphology of basic magnesium chloride were studied. The optimum preparation conditions were as follows: methanol 25.0% , MGCL2: NH3 · H2O 3.0:1, mgcl24 mol · L -1, reaction temperature 25 ° C, aging temperature 50 ° C. The fibrous basic magnesium chloride with yield of 13.13% , length of 30-50μm, diameter of 0.3 μm, aspect ratio of 100 and molecular formula of MG2(OH)3cl · 4H2O was obtained. In the ethanol-water system, fibrous magnesium basic chloride (Mg2(OH)3cl · 4H2O) and sodium hydroxide were used as raw materials to prepare fibrous Magnesium hydroxide.
The effects of molar ratio of raw materials, ethanol concentration, reaction temperature and basic magnesium chloride slurry concentration on reaction time and Magnesium hydroxide morphology were studied. When the molar ratio of sodium hydroxide to basic magnesium chloride is 2.0:1, the solvent is 80% ethanol, the reaction temperature is 50 ° C, and the concentration of basic magnesium chloride is 0.30 mol · L-1, it only takes 1.5 H, the fibrous Magnesium hydroxide with a surface smooth, length 30-50μm, diameter 0.3 μm and aspect ratio greater than 100 can be obtained. The conversion rate was 100% .
In the process of surface modification of fibrous Magnesium hydroxide, the effects of modifier type, modifier dosage, modification temperature, Magnesium hydroxide slurry concentration and modification time on the modification effect were studied, the suitable modifier Sodium stearate was selected to modify the surface. The experimental results show that when the Sodium stearate dosage is 5% , the modified temperature is 50 ° C, the Magnesium hydroxide slurry concentration is 2% and the modified time is 1.5 H, the activity of the fibrous Magnesium hydroxide is 99.12% and the length is 30-50 μm, the diameter is about 0.3 μm, and the ratio of length to diameter is more than 100.
