Preparation and characteristic research of anhydrous magnesium chloride with dehydrated ammonium carnallite①
来源期刊：中南大学学报(英文版)2006年第4期
论文作者：周宁波 陈白珍 何新快 李义兵
文章页码：373 - 378
Key words：dehydrated ammonium carnallite; ammonia; gas-solid reaction; anhydrous magnesium chloride; preparation; characterization
Abstract: Taking the saline lake bischofite and NH4Cl that was removed with the ammonia method and continuously followed by filtration as raw materials with a molar ratio of 1∶1 of MgCl2to NH4Cl, ammonium carnallite was synthesized. And then the ammonium carnallite was dehydrated to some extent at 160℃for 4 h. Ammonium carnallite reacted with ammonia at 240℃for 150 min and the ammonation ammonium carnallite was produced. Finally, the ammonation ammonium carnallite was calcined at 750℃into anhydrous magnesium chloride containing only 0.1%(mass fraction) of MgO. On the other hand, dehydrated ammonium carnallite was mixed with the solid ammonium chloride at mass ratio 1∶4 at high temperature and with the differential pressure of NH3 above 30.5kPa. The dehydrated ammonium carnallite of mixture was dehydrated at 410℃, and then calcined at 700℃into anhydrous magnesium chloride with only 0.087%(mass fraction) of MgO. X-ray diffraction and electron microscopy analysis results prove that anhydrous magnesium chloride obtained by both methods hasn t mixed phases, the particle is large and even has good dispersion, which is suitable for preparation of metal magnesium in the electrolysis.
