湿法脱硫浆液中Hg<sup>2+</sup>的还原机制研究

湿法脱硫浆液中Hg²⁺的还原机制研究

摘要: 针对燃煤电厂湿法脱硫浆液中Hg²⁺易被还原的特性，研究Hg²⁺在模拟湿法脱硫系统中的迁移机制，考察了浆液温度、pH值以及SO₃^2-、Cl^-、Ca²⁺、Mg²⁺浓度等因素对Hg²⁺还原性能的影响。结果表明，Hg²⁺还原率随着浆液中SO₃^2-浓度的增大而降低；pH值对Hg²⁺的还原呈先增加后降低的趋势，在pH值为5.5时还原率最高；温度的升高不利于浆液中稳定的二价汞盐络合物存在，导致Hg²⁺还原率增加；Ca²⁺、Mg²⁺以及Cl^-浓度的增加有利于形成稳定化合物，从而抑制Hg²⁺的还原。

Abstract: Given the easy reduction of Hg²⁺ in wet desulfurization slurry in a power plant, migration mechanism of Hg²⁺ in a simulated system was studied. Influences of several experimental parameters including slurry temperature, pH value and concentrations of SO₃^2-, Cl^-, Ca²⁺ and Mg²⁺ were investigated separately. The results indicate that the increase of SO₃^2- concentration lowers the reduction rate of Hg²⁺, while the rise of slurry temperature leads to an opposite result. The effect of pH value shows a trend of first increase and then decrease, and reaches the highest reduction rate at pH value of 5.5. Moreover, the rise of Ca²⁺, Mg²⁺ and Cl^- concentrations could inhibit the reduction of Hg²⁺.