Study On The Preparation Of Series Magnesium Hydroxide From The Serpentine

Study on the process of the purified of raw magnesium sulfate from the sulfuric acid leaching filtrate of serpentine for preparing purified magnesium sulfate . Study on the technological conditions for the preparation of magnesium hydroxide from the purified magnesium sulfate hy the single factor experiment. Results showed that the better technological conditions as following: the concentration of magnesium 1.25-1.65moL/L , the proportion of ammonia to magnesium 6:1(mole), reaction temperature 40~50℃ , reaction time 15~20 minutes , the quality of production has hee reached HG/T3607-2000. The nanometer magnesium hydroxide can obtained by the concentration of magnesium more than 2moL/L , the proportion of ammonia to magnesium 6:1(mole), reaction temperature 50℃. The nanometer magnesium hydroxide of different morphology can acquired by adding non-ionic surface active agent. The traditional process of the preparation for the magnesium hydroxide flame-retardant has some faults, for examples, the process long, higher cost and lower product .Based the faults and the rich of mine with multitudinous magnesium sulfate in Anhui province . The one-step process was put forward to prepare nanometer magnesium hydroxide f lame-retardant. The conditions are mild. Results of the single factor experiment showed that the better technological conditions as following: the adding of multiplicity surface active agent 5-10mL/L , reaction treatment time 3. 0~4. 0 hours , ageing time more than 4. 0 hours and the multipl icity surface active agent is better than single surface active agent. The measurement results of XRD and TEM indicate that (1)the diffraction intensity of (101) direction is higher than (001) direction (2) its shape is acicular with a diameter of 5~10nm, length-to-diameter ratio more than 20 (3) a strain in (101) direction less than 3×10-3 and the specific area (BET) not more than 20 m2/g.