摘要：以轻烧镁粉为原料,氨水为沉淀剂,利用直接沉淀法合成"卡房"状高纯氢氧化镁粉体;通过单因素实验研究硫酸镁的浓度、反应温度、反应时间、氨水与镁离子的物质的量比和搅拌转速对氢氧化镁合成的影响,确定最佳反应条件;分别利用添加不同分散剂和水热法对制得样品进行改性;采用扫描电子显微镜、X射线衍射和X射线荧光对样品进行表征。结果表明:不同类型的分散剂均对氢氧化镁的改性效果不明显;水热法改性后氢氧化镁的结晶度等性质均有不同程度的改善,改性时添加浓度为6 mol/L的氢氧化钠效果最佳,可得极性弱、形貌规则、热稳定性良好、结晶度高的氢氧化镁粉体,其中氢氧化镁的质量分数大于99.94%,收率为87.92%。

关键词：氢氧化镁粉体；分散剂；水热法；氢氧化钠

Abstract： High purity and “card room” shape magnesium hydroxide powders were prepared by the method of direct precipitation with light calcined magnesium powders as raw materials and ammonia as precipitation agent. The effect of concentration of magnesium sulfate， reaction temperature， reaction time， ratio of ammonia to magnesium ion and whisking speed on synthesis of magnesium hydroxide was studied by the experiment of single factor， and the optimum experimental conditions were obtained. The prepared sample was modified respectively by the methods of adding different dispersants and hydrothermal. The sample was analyzed by SEM， XRD and XRF. The results show that multiple types of dispersants have little modification effect on magnesium hydroxide. The crystallinity and other properties of magnesium hydroxide after modification by hydrothermal are improved variously. Hydrothermal adding sodium hydroxide with concentration of 6 mol/L has the best effect， and the magnesium hydroxide powders with weak polarity， more regular morphology， good thermal stability and excellent crystallinity is obtained. The mass fraction of magnesium hydroxide is greater than 99.94% and the yield is 87.92%. 

Keywords: magnesium hydroxide powders； dispersant； hydrothermal method； sodium hydroxide