(1. 中南大学 冶金与环境学院，长沙 410083；
2. 中南大学 难冶有色金属资源高效利用国家工程实验室，长沙 410083)
摘 要: 应用Bromley方程，结合草酸钠溶解热力学理论及其在水溶液、氢氧化钠溶液中的溶解度数据，得出草酸钠的Bromley参数为-0.045，并以此为基础建立铝酸钠溶液中草酸钠的溶解度计算模型。应用该模型计算纯铝酸钠溶液体系中草酸钠的溶解度，结果与文献数据吻合较好。在此基础上，模拟计算了拜耳法氧化铝生产过程中草酸钠平衡浓度的变化规律。结果表明：碱浓度越高、温度越低、苛性比越高，铝酸钠溶液中草酸钠平衡浓度越低；铝酸钠溶液体系中，碳酸钠、硫酸钠对草酸钠溶解度的影响很小。这些结果可以解释草酸钠在生产氧化铝过程中的积累和析出规律，有助于生产过程铝酸钠溶液中草酸钠含量的控制。
关键字: 草酸钠；溶解度；计算模型；铝酸钠溶液
（1. School of Metallurgy and Environment, Central South University, Changsha 410083, China;
2. National Engineering Laboratory for Efficient Utilization of Refractory Non-ferrous Metals Resources,
Central South University, Changsha 410083, China）
Abstract:The calculation model of sodium oxalate’s solubility in sodium aluminate solution was established by Bromley equation with the solubility values of sodium oxalate in the aqueous and sodium hydroxide solution, and Bromley parameter of sodium oxalate calculated by this model is -0.045. Using this calculation model, the solubility values of sodium oxalate in sodium aluminate solution were calculated and a high degree of agreement can be reached compared with the data in literatures. On this basis, the equilibrium concentration values of sodium oxalate in Bayer liquors were calculated. The results show that, the higher the alkali concentration and caustic ratio are or the lower the temperature is, the lower the equilibrium concentration of sodium oxalate is. The concentration of sodium carbonate or sodium sulfate has little effect on the solubility of sodium oxalate. These results can explain the law of the accumulation and precipitation of sodium oxalate in alumina production process, and contribute to controlling the concentration of sodium oxalate in the process.
Key words: sodium oxalate; solubility; calculation model; sodium aluminate solution
