| 盐湖老卤动态变温分离高纯结晶硫酸镁 |
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| 引用本文： | 高姣丽,李恩泽,康锦,成怀刚.盐湖老卤动态变温分离高纯结晶硫酸镁[J].化工学报,2021,72(6):3022-3030. |
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| 作者姓名： | 高姣丽 李恩泽 康锦 成怀刚 |
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| 作者单位： | 山西大学资源与环境工程研究所，山西 太原 030000 |
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| 基金项目： | 国家自然科学基金项目(U20A20149);山西省“三晋英才”支持计划(2018030140) |
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| 摘 要： | 盐湖老卤中镁资源储量丰富，现阶段的初级利用形式主要是提取结晶氯化镁。为提高过程效益，提出了兑卤及变温直接分离高纯结晶硫酸镁的方案，并分别考察MgSO4饱和卤水、MgSO4-NaCl共饱和卤水、MgSO4-NaCl-MgCl2共饱和卤水在非平衡动态降温过程中硫酸镁晶体微观形貌的变化以及降温速率对晶体形貌的影响。结果表明，MgSO4饱和卤水非平衡动态降温过程中晶体形成的速率与降温速率有关，在-1.02℃/min的降温速率下，MgSO4饱和卤水降温30 min后即可形成径向约1300 μm的MgSO4·7H2O晶体；但是，当卤水中存在NaCl时，最终的晶体形式为MgSO4·6H2O，且多为不规则的块状；卤水中的MgCl2能促使晶体形成棱柱状的MgSO4·6H2O。在NaCl和MgCl2的作用下，MgSO4-NaCl-MgCl2共饱和卤水降温15 h后可以析出完整晶型的高纯结晶硫酸镁。
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| 关 键 词： | 硫酸镁 盐湖老卤 结晶 分离 显微结构 |
| 收稿时间： | 2020-12-01 |
Separation of high purity magnesium sulfate hydrates from salt lake tail brine in a dynamic temperature-changing process |
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| GAO Jiaoli,LI Enze,KANG Jin,CHENG Huaigang.Separation of high purity magnesium sulfate hydrates from salt lake tail brine in a dynamic temperature-changing process[J].Journal of Chemical Industry and Engineering(China),2021,72(6):3022-3030. |
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| Authors: | GAO Jiaoli LI Enze KANG Jin CHENG Huaigang |
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| Affiliation: | Institute of Resources and Environmental Engineering, Shanxi University, Taiyuan 030000, Shanxi, China |
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| Abstract: | There are abundant magnesium resources in salt lake brine, and the primary utilization form at present is mainly to extract crystalline magnesium chloride. In order to improve the efficiency of the process, the scheme of directly separating high-purity crystalline magnesium sulfate by adding brine and changing temperature was put forward in this paper, and the changes of magnesium sulfate crystal micro-morphology and the influence of cooling rate on crystal morphology during the non-equilibrium dynamic cooling process of MgSO4 saturated brine, MgSO4-NaCl co-saturated brine and MgSO4-NaCl-MgCl2 co-saturated brine were investigated. The results show that the rate of crystal formation in the non-equilibrium dynamic cooling process of MgSO4 saturated brine is related to the cooling rate. At the cooling rate of -1.02℃/min, MgSO4 saturated brine can form MgSO4·7H2O crystal with a radial diameter of about 1300 μm after cooling for 30 min. However, when NaCl exists in brine, the final crystal form is MgSO4·6H2O, and most of them are irregular blocks. MgCl2 in brine can promote the crystal to form prismatic MgSO4·6H2O. Under the action of NaCl and MgCl2, MgSO4-NaCl-MgCl2 co-saturated brine can precipitate a complete crystal form of high-purity crystalline magnesium sulfate after cooling for 15 h. It is assumed that the initial crystal nucleus determines the crystal form, but the interference of Na+ on crystal growth makes the crystals diversified in morphology. |
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| Keywords: | magnesium sulfate salt lake tail brine crystallization separation microstructure |
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