烟气脱硫溶液中硫酸根的去除

Removal of SO_4^(2-) from Flue Gas Desulphurization Solution

分别采用石灰乳化学沉淀法和低温结晶法去除烟气脱硫溶液中的SO42-。实验结果表明:在室温、CaO溶液质量分数25%的条件下,石灰乳化学沉淀法对SO42-的去除率仅为59.51%,且向溶液中引入了Ca2+,产生的硫酸钙固体废物难以再生利用;采用低温结晶法处理烟气脱硫溶液,在结晶温度7℃、结晶时间3 h、NaOH加入量34.8 g/L的条件下,SO42-的去除率为82.04%、滤液中的ρ(Na+)为3.88 g/L。在现场工业应用试验中,采用低温结晶法去除烟气脱硫溶液中的SO42-,平均SO42-的去除率可达70.00%以上,滤液中的ρ(Na+)小于15.00 g/L。该法可有效抑制烟气脱硫溶液中SO42-含量的增加。

SO4^2-in flue gas desulfurization solution was removed by lime milk chemical precipitation and low temperature crystallization respectively.The experimental results show that：In the process of lime milk chemical precipitation,under the conditions of room temperature and CaO mass fraction of the addition solution 25%,the SO4^2-removal rate is 59.51%,and the solid waste calcium sulfate produced with the added Ca^2＋ is difficult to be reused; In the process of low temperature crystallization,under the conditions of crystallization temperature 7 ℃,crystallization time 3 h and NaOH dosage 34.8 g/L,the SO4^2-removal rate is 82.04%,the ρ（Na＋）in the filtrated liquid is 3.88 g/L.The low temperature crystallization process was applied in SO4^2-removal from flue gas desulfurization solution,the average SO4^2-removal rate is over 70.00%,and the ρ（Na＋）in filtrated liquid is less than 15.00 g/L.This process can effectively control the increasing of SO4^2-in flue gas desulfurization solution.