When organic matter, especially sodium oxalate (NaCO), accumulates to a certain extent, it will seriously affect the alumina production process in the refinery and therefore urgently needs to be removed. This work attempts to illuminate the benefits of ultrasonic intensification of the crystallization process of NaCO, taking the alumina refinery waste liquor, i.e., flat plate washing liquor, as a case study. The effects of different operating parameters (seed crystal addition amount, caustic soda concentration, reaction time, ultrasonic power) on the crystallization behavior and yield are discussed, and it is found that ultrasonic can increase the NaCO removal rate to 70.4%. The addition of ultrasonic promotes the morphological evolution of NaCO and is of great significance to the optimization of the components of the precipitated NaCO. Specifically, the proportion of NaCO in the crystallized product reaches 64% with conventional conditions, while it reaches 77% with ultrasonic conditions. Therefore, ultrasonic can greatly reduce the alkali loss caused by the crystallization process of NaCO in flat plate washing liquor, which has great economic benefits.

中文翻译：

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超声增强活性晶种在氧化铝精炼废液脱除草酸钠中的应用


当有机物特别是草酸钠（NaCO）积累到一定程度时，将严重影响精炼厂的氧化铝生产过程，因此迫切需要去除。本工作试图以氧化铝精炼废液（即平板洗涤液）为例，阐明超声波强化 Na2CO3 结晶过程的好处。讨论了不同操作参数（晶种添加量、烧碱浓度、反应时间、超声功率）对结晶行为和产率的影响，发现超声可以将NaCO去除率提高到70.4%。超声波的加入促进了NaCO的形态演化，对于沉淀NaCO的成分优化具有重要意义。具体而言，常规条件下结晶产物中Na2CO3的比例达到64%，而超声条件下结晶产物中Na2CO3的比例达到77%。因此，超声波可以大大减少平板洗板液中NaCO结晶过程造成的碱损失，具有很大的经济效益。