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以磷尾矿经硝酸复合溶剂酸解、除铁等纯化过程得到的镁源为原料,采用碱性沉淀剂制备氢氧化镁。探讨了不同沉淀剂、沉淀剂滴加速度、沉淀温度、陈化时间对产品纯度及回收率的影响。实验结果表明,当选择氨水为沉淀剂,滴加氨水使溶液pH达到11.5,滴加速度为1.5 m L/min,沉淀反应温度为45℃,陈化时间为120 min,在此条件下镁回收率为89.86%,产品Mg(OH)2纯度为90.43%。并用XRD、粒度分析仪和SEM分别对产物的成分、粒度分布以及形貌特征进行分析,测试表明,产品粒度均匀,呈片状。
Magnesium source obtained from phosphoric tailings by nitric acid compound solvent acid hydrolysis, iron removal and other purification processes is used as raw material, and alkaline precipitant is used to prepare magnesium hydroxide. The effects of different precipitating agents, precipitating agent dropping rate, precipitation temperature and aging time on product purity and recovery were discussed. The experimental results show that when ammonia is selected as the precipitating agent, ammonia solution is added dropwise to make the solution pH reach 11.5, the dropping rate is 1.5 m L / min, the precipitation reaction temperature is 45 ℃ and the aging time is 120 min. Under these conditions, the magnesium recovery Is 89.86%, the purity of product Mg (OH) 2 is 90.43%. The composition, particle size distribution and morphology of the product were analyzed by XRD, SEM and SEM respectively. The results showed that the product had uniform particle size and flaky shape.