Thermodynamic properties of evaporative crystallization of high-salt wastewater

High-salt wastewater requires a lot of energy during the evaporative crystallization process, and this energy consumption increases with the width of the metastable zone. In order to reduce the width of the metastable zone, this paper investigates the influence of cooling rate, pH, stirring rate and iron ion addition on the width of the metastable zone of sulphate in the CLT acidic aqueous solution system. The saturation and supersaturation at the onset of nucleation are determined by the conductivity method. The results show that the best crystal promotion is achieved at a cooling rate of 0.2 °C/min, a pH value of 3 and a stirring rate of 200 r/min. The iron ions, which promotes the crystallization but reduces the purity, should be replaced by crystal seeds. This study can provide reference for improving efficiency and saving energy during the evaporative crystallization of high-salt wastewater.