Sodium arsenate, the main component of arsenic‐containing solid waste pollutants, causes serious environmental health threats. Crystallization is one of the effective methods for separating and purifying sodium arsenate from arsenic‐alkali residue lixivium. However, the crystallization process is limited for its low observability and the lack of separation and purification data. In this work, a laser detection system with a magnetic field generator was designed, and the solubility, metastable zone width, interfacial tension, interfacial entropy factor, crystal nucleation, and growth rate of sodium arsenate were investigated in a constant composition environment. The results showed that the solubility, metastable zone width, interfacial tension, and interfacial entropy factor decreases with the presence of a magnetic field. The magnetic field shortened the crystallization induction time and changed the nucleation and growth rate of sodium arsenate. Under the magnetic field, the nucleation rate increased from 2.43 × 10¹⁶ to 8.98 × 10¹⁷ (s m³)⁻¹, and the growth rate decreased from 4.94 × 10⁻⁸ to 2.73 × 10⁻⁸ (s m³)⁻¹, the growth mechanism of sodium arsenate as a continuous growth mode was unchanged. In addition, the X‐ray diffraction and infrared showed that the crystal structure of sodium arsenate is unaffected by the magnetic field, indicating that the enhancement of the crystallization process of sodium arsenate with the magnetic field could be a feasible method in engineering application.

中文翻译：

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磁场对砷酸钠亚稳区宽度和结晶成核动力学的影响

砷酸钠是含砷固体废物污染物的主要成分，对环境健康构成严重威胁。结晶是从砷碱残液浸提液中分离纯化砷酸钠的有效方法之一。然而，结晶过程由于其低可观察性以及缺乏分离和纯化数据而受到限制。在这项工作中，设计了一个带有磁场发生器的激光检测系统，并研究了在恒定组成环境下的溶解度，亚稳态区宽度，界面张力，界面熵因子，晶体成核作用和砷酸钠的生长速率。结果表明，溶解度，亚稳区宽度，界面张力和界面熵因子随磁场的存在而降低。磁场缩短了结晶诱导时间，改变了砷酸钠的形核和生长速率。在磁场下，成核速率从2.43×10增加¹⁶至8.98×10 ¹⁷（s m ³）^-1，且生长速率从4.94×10 ^-8降至2.73×10 ^-8（s m ³）^-1，砷酸钠作为连续生长方式的生长机理未改变。另外，X射线衍射和红外光谱表明砷酸钠的晶体结构不受磁场的影响，表明砷化钠的结晶过程随磁场的增强可能是工程应用中的一种可行方法。