脱硫石膏中无机杂质对制备碳酸钙及其活性的影响

Inorganic Impurity on Preparation of Calcium Carbonate and Its Active Influence Oriented from Desulfurization Gypsum

为了达到烟气脱硫石膏减量化处理,建立其资源化利用方法,在考虑到烟气脱硫石膏来源复杂性的基础上,分别考察了金属离子(如Mg2+,Fe3+)和非金属离子(如F-)对利用碳酸铵转化烟气脱硫石膏,制备碳酸钙粉末的影响。结果表明,F-,Mg2+,Fe3+等离子对脱硫石膏转化率有不同程度影响,但转化率均能达到70%以上,转化固体产物为较纯碳酸钙粉末。其中随着阳离子Mg2+,Fe3+含量增加,转化率下降;F-的水解作用以及络合物的生成将对转化率造成复杂影响,0.5 wt%为最优的含量。转化产物经其吸收活性测试,其活度比天然石灰石略低,到达脱硫剂基本要求,但需注意杂质离子的积累效应。碳酸铵转化烟气脱硫石膏方法可制备微细碳酸钙粉末,是一种循环利用烟气脱硫石膏的有效途径。

To reduce gypsum produced from wet flue gas desulfurization（WFGD）process and to establish a resource approach to utilize desulfurization gypsum,the effect of metal ion such as Mg2＋,Fe3＋ and nonmetallic ion such as F-on productivity of calcium carbonate prepared from desulfurization gypsum was investigated,taking into consideration of complex composition of desulfurization gypsum.Results showed that the ions such as F-,Mg2＋,Fe3＋ affect conversion of desulfurization gypsum to different extents,with conversion rate more than 70% and pure calcium carbonate as obtained solid powder.As cationic Mg2＋,Fe3＋ content increased,the conversion rate decreased.Both hydrolysis of F-and formation of the complicates conversion affected the conversion,with F-0.5 wt% as the optimal content for conversion.It is verified that the solid product obtained has the potential activity to be recycled as desulfurization absorbent though impurities should be paid attentions.Conversion of desulfurization gypsum to calcium carbonate powder by ammonia carbonate is an effective method to recycle desulfurization gypsum.