(昆明理工大学 冶金与能源工程学院，昆明 650093)
摘 要: 利用高温下金属硫酸盐易结晶沉淀的化学原理，开展了水热结晶脱镁行为研究，研究了初始Zn2+浓度、反应温度、反应时间、初始 浓度、初始硫酸浓度对水热结晶脱镁过程的影响规律。结果表明：在初始Zn2+和Mg2+浓度分别为120 g/L和25 g/L、反应温度为200 ℃、反应时间3 h、初始 浓度为145 g/L、初始硫酸浓度为5×10-4 g/L的条件下，镁以MgSO4？6H2O的形式结晶析出，其脱出率可达到94.42%。升高反应温度以及初始 和Mg2+的浓度、延长结晶时间均有利于提高镁的结晶脱出率。受同离子效应影响，当Zn2+浓度由0增大至120 g/L可有效降低Mg2+的结晶析出温度，并使Mg2+的结晶脱出率增大40%以上，相近的ZnSO4？xH2O和MgSO4？xH2O微观结构抑制了水热条件下MgSO4？6H2O向MgSO4？H2O的转变。受初始硫酸浓度及溶液中 电离平衡引起 和H+浓度变化的影响，Mg2+的结晶析出率随初始硫酸浓度的升高先增大后减小。水热结晶除镁法可实现湿法炼锌含镁硫酸锌溶液中Mg2+的清洁高效脱出。
关键字: 湿法炼锌；水热法；除镁；结晶；结晶脱出率
（Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, China）
Abstract:The hydrothermal crystallization of magnesium sulfate was studied by using the chemical principle of easy crystallization precipitation of metal sulfate in high temperature. The effect of initial concentration of Zn2+, reaction temperature, reaction time, initial concentration of and initial concentration of sulfuric acid on hydrothermal crystallization process of de-magnesia was studied. The results show that, under the conditions of initial Zn2+ and Mg2+ concentrations of 120 g/L and 25 g/L, reaction temperature of 200 ℃, reaction time of 3h, and initial concentration of 145 g/L, magnesium is crystallized out in the form of MgSO4？6H2O, with release rate of 94.42%. Increasing the reaction temperature and the initial concentration of and Mg2+, and prolonging the crystallization time are beneficial to improving the crystallization rate of magnesium. Under the influence of the same ion effect, when the concentration of Zn2+ increases from 0 to 120 g/L, the crystallization temperature of Mg2+ can be effectively reduced and the crystallization rate of Mg2+ increases by more than 40%. The similar microstructures of ZnSO4？xH2O and MgSO4？xH2O prevent the transformation of MgSO4？6H2O into MgSO4？H2O under hydrothermal conditions. Under the influence of the initial sulfuric acid concentration and the concentration changes of and H+ caused by the equilibrium of ionization in the solution, the crystallization rate of Mg2+ first increases and then decreases with the increase of the initial sulfuric acid concentration. The hydrothermal crystallization method of magnesium removal can realize the clean and efficient removal of Mg2+ from zinc sulphate solution containing magnesium.
Key words: zinc hydrometallurgy; hydrothermal process; magnesium removal; crystallization; crystallization removal rate
