This paper reports the solid-liquid phase equilibria of the CoSO-HO and CoSO-HSO-HO systems at low temperatures. Binary and ternary phase diagrams, including the stable solid phases CoSO·6HO and CoSO·7HO were established using experimental data and thermodynamic modeling applying the mixed-solvent electrolyte (MSE) model. The results showed that the addition of HSO shifts the eutectic temperature and concentration to lower values for cobalt sulfate and ice crystallization. The trends obtained from the experimental data and the modeling are consistent for the binary CoSO-HO system with good agreement, but the ternary CoSO-HSO-HO system shows some deviations. In general, the MSE model is shown to be reliable for inferring and establishing the phase diagram of the low-temperature system. The phase diagrams are helpful for designing the pathways of cooling crystallization and eutectic freeze crystallization and assessing the performance of the low-temperature crystallization process in the production of CoSO hydrates. In addition, some practical examples of cooling crystallization and eutectic freeze crystallization of CoSO solutions are provided.

中文翻译：

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通过冷却和共晶冷冻结晶回收 CoSO4·nH2O (n = 6,7) 的 CoSO4-H2O 和 CoSO4-H2SO4-H2O 体系的相图


本文报道了 CoSO-H2O 和 CoSO-HSO-H2O 体系在低温下的固液相平衡。使用实验数据和应用混合溶剂电解质（MSE）模型的热力学模型建立了二元和三元相图，包括稳定的固相CoSO·6HO和CoSO·7HO。结果表明，HSO 的添加使硫酸钴和冰结晶的共晶温度和浓度降低。对于二元CoSO4-H2O体系，实验数据和模型得到的趋势是一致的，具有良好的一致性，但三元CoSO4-HSO-HO体系表现出一些偏差。总的来说，MSE 模型对于推断和建立低温系统的相图是可靠的。相图有助于设计冷却结晶和共晶冷冻结晶的路径以及评估CoSO水合物生产中低温结晶工艺的性能。此外，还提供了一些CoSO溶液冷却结晶和共晶冷冻结晶的实例。