利用湿法烟气脱硫中间产物亚硫酸钙（CaSO₃）和氯碱工业副产物芒硝和废硫酸制备高浓度亚硫酸氢钠（NaHSO₃）溶液,以简化亚硫酸氢钠溶液的后续处理工序并降低能耗。以亚硫酸氢钠溶液质量浓度为考察指标,采用两步法制备高浓度的亚硫酸氢钠。首先考察亚硫酸钙加入量、反应温度、反应时间、亚硫酸钙悬浮液质量分数等因素对第一步制备的低浓度亚硫酸氢钠溶液质量浓度的影响。其次考察第一步制备的低浓度亚硫酸氢钠溶液质量浓度对第二步制备的高浓度亚硫酸氢钠溶液质量浓度的影响。研究结果表明,实验中当亚硫酸钙加入量为0.068 mol、反应温度为13 ℃、反应时间为30 min、亚硫酸钙悬浮液质量分数为25%时,第一步制备的低浓度亚硫酸氢钠溶液质量浓度达到198.2 g/L;当第一步制备的低浓度亚硫酸氢钠溶液质量浓度为170 g/L时,第二步制备的高浓度亚硫酸氢钠溶液质量浓度达到264.2 g/L。采用两步法制备高浓度的亚硫酸氢钠溶液,节省了蒸发能源,具有显著的经济效益,为亚硫酸钙的利用提供了一条可行的路径。

The high-concentration NaHSO₃ solution was prepared by using wet flue gas desulfurization intermediate product CaSO₃,chlor-alkali industrial by-products Na₂SO₄ and waste sulfuric acid via two-step method.This method can simplify the subsequent treatment process and reduce energy consumption of the traditional preparation process of NaHSO₃ solution.The concentration of NaHSO₃ was selected as a major indicator to guide experiments to prepare a high concentration NaHSO₃ solution by two-step method.Firstly,the effects of CaSO₃ amount,reaction temperature,reaction time and mass fraction of CaSO₃ suspension on the concentration of dilute NaHSO₃ were investigated.Secondly,the effect of dilute NaHSO₃ concentration on the high concentration NaHSO₃ solution was investigated.The results showed that when the amount of CaSO₃ was 0.068 mol,the reaction temperature was 13 ℃,reaction time was 30 min and the mass fraction of CaSO₃ solution was 25% in the experiment,the diluted NaHSO₃ solution with 198.2 g/L can be prepared.When the mass concentration of diluted NaHSO₃ solution was 170 g/L,the mass concentration of high concentration NaHSO₃ solution can reached 270.4 g/L,which was close to saturation.This two-step method for preparation of high concentrated NaHSO₃ solution not only saves energy,but also provides a feasible path for the utilization of CaSO₃,which can brings a significant financial benefit.