• 关键词：脱硫浆液  脱硫石膏  汞

• 基金项目：国家重点基础研究发展计划项目(No.2013BC430005);国家高技术研究发展计划项目(No.2011AA060801)

• 潘杰
• 上海交通大学环境科学与工程学院, 上海 200240

• 晏乃强
• 上海交通大学环境科学与工程学院, 上海 200240

• 瞿赞
• 上海交通大学环境科学与工程学院, 上海 200240

• 徐浩淼
• 上海交通大学环境科学与工程学院, 上海 200240

• 马永鹏
• 上海交通大学环境科学与工程学院, 上海 200240

• 陈万苗
• 上海交通大学环境科学与工程学院, 上海 200240

• 黄文君
• 上海交通大学环境科学与工程学院, 上海 200240

• 赵松建
• 上海交通大学环境科学与工程学院, 上海 200240

• 摘要：燃煤烟气湿法脱硫石膏中汞的大量富集限制了其应用范围且容易产生汞的二次逃逸问题.因此,本文对脱硫浆液中的汞在固相石膏的迁移转化规律进行了模拟研究,考察了不同操作条件和离子浓度的影响,探求汞进入石膏的量和形态的变化趋势.同时考察了温度、pH、石膏老化时间和结晶方式等对汞与石膏结合特性的影响,并对机理进行了探讨.结果表明,当液相汞浓度从0.16 mg·L^-1增加到2.67 mg·L^-1时,进入石膏的汞含量相应从0.38 mg·kg^-1增加到4.17 mg·kg^-1,但其占液相总汞的比例却呈先下降后不变的趋势.当石膏浆液浓度从1%增加到20%时,由液相进入石膏中的汞比例不断上升,但石膏汞含量却不断下降.基于实验结果推测汞与石膏结合的两种方式:石膏的内部包裹作用和石膏的表面吸附作用.另外,酸根离子浓度会改变浆液中游离汞的含量,从而影响石膏中汞的富集量:Cl^-和NO₃^-对汞进入石膏有抑制作用,而SO₄^2-的存在会起到促进作用;铁、铝阳离子的存在会促进汞进入石膏,钙、镁阳离子对汞的富集基本无影响.

• Abstract：The mercury enrichment limits the application of coal-fired flue gas wet desulphurization gypsum which is also prone to mercury secondary escape problems. In order to seek the trend of amount and speciation for mercury into gypsum in desulphurization slurry, the effects of operating conditions and ions in slurry were investigated, thus providing theoretical basis on the disciplines of migration and transformation of mercury on gypsum crystallization.This study also investigated the operating conditions of temperature, pH, gypsum aging time, and way of gypsum crystallization. Our results showed that mercury content in gypsum increased from 0.38 mg·kg^-1 to 4.17 mg·kg^-1 as liquid mercury concentration increased from 0.16 mg·L^-1 to 2.67 mg·L^-1, while mercury enrichment ratio first decreased and then remained unchanged with addition of more mercury. When desulfurization slurry concentration increased from 1% to 20%, mercury transfer ratio increased as well, however mercury content in gypsum deceased. The reason was that mercury in gypsum presented in two ways: the interior wrap of gypsum and surface adsorption equilibrium. Acid radical anions influenced mercury content by changing concentration of free mercury ion in the slurry. Cl^- and NO₃^- had an inhibition effect, while SO₄^2- promoted mercury content first and then inhibited. Iron and aluminum promoted gypsum mercury level which may be associated with flocculation, or iron/aluminum complex form of mercury. Calcium and magnesium had no significant effect.

• Key words：desulfurization slurry  desulfurization gypsum  mercury (Hg)

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