水氯镁石复盐法脱水工艺

Dehydration of Bischofite for Anhydrous Magnesium Chloride Preparation by Hydrated Double Salt Method

用烧瓶蒸馏装置模拟固定床脱水设备,研究用苯胺盐酸盐作脱水剂的复盐法将水氯镁石(MgCl2.6H2O)脱水制备无水氯化镁(MgCl2)的过程,考察复盐配料比例、保护气含水浓度、热解温度、热解时间等因素对所制备无水氯化镁产品中氧化镁和水分含量的影响,优化用固定床脱水工艺条件。结果表明,完全脱水和脱苯胺盐酸盐的最佳温度和时间分别是300℃与25～30 min和320～350℃与10～20min。最佳配料摩尔比C6H5NH2.HCl∶MgCl2.6H2O为1.1∶1.0。在最佳条件下,可得到合格的无水氯化镁产品MgCl298%～98.6%,MgO 0.03%～0.38%,苯胺盐酸盐0.10%～0.12%,水分0.60%～0.81%。

The process for dehydration of bischofite（MgCl2·6H2O） to prepare anhydrous magnesium chloride（MgCl2） with the thermal decomposition of a hydrated double salt is investigated by simulating fixed bed equipment for dehydration with the distilling flask system.The effects of the ratios of aniline hydrochloride（C6H5NH2·HCl） to bischofite,temperature and time of dehydration and thermal decomposition,the concentration of H2O in protection-gas against dehydration on the content of MgO and H2O in the products are described.The technical parameters are optimized.The results show that the optimal temperature and time are 300 ℃ and 25~30 min for the complete removal of H2O,and 320~350 ℃ and 10~20 min for the complete removal of C6H5NH2·HCl,respectively.The optimalmol ratio of C6H5NH2·HCl to MgCl2·6H2O is 1.1∶1.0.Under the optimal condition,the prepared product,anhydrous magnesium chloride,is desired,containing MgCl2 98%~98.6%,MgO 0.03%~0.38%,C6H5NH2·HCl 0.10%~0.12% and H2O 0.60%~0.81%.