石灰乳中和模拟酸性废水形成的二水硫酸钙的晶粒形貌与粒度分布  

Morphology and Size Distribution of Calcium Sulfate Dihydrate Crystals Precipitated from Simulated Acidic Wastewater by Lime

作　　者：邓立聪[1,2] 张亦飞[1] 陈芳芳[1] 张懿[1] 

机构地区：[1]中国科学院过程工程研究所绿色过程与工程重点实验室,湿法冶金清洁生产技术国家工程实验室,北京100190 [2]中国科学院研究生院,北京100049

出　　处：《过程工程学报》2012年第2期259-264,共6页The Chinese Journal of Process Engineering

基　　金：国家高技术研究发展计划(863)基金资助项目(编号:2011AA060701);国家水体污染控制与治理科技重大专项基金资助项目(编号:2009ZX07529-005)

摘　　要：实验研究了各工艺参数及废水中Mg2+与Fe3+主要杂质离子对石灰乳中和模拟酸性废水形成的二水硫酸钙晶体形貌与大小的影响.结果表明,反应温度是主要影响因素,当其从25℃提高至70℃时,硫酸钙晶体形貌从片状和针状向棒状转变;而搅拌转速、石灰乳浓度、石灰乳加入速度对结晶过程的影响较不明显.废水中Mg2+和Fe3+离子对硫酸钙晶体生长有抑制作用,浓度越大,抑制作用越强,Mg2+浓度达1945mg/L时晶体由片状转变为棒状.石灰乳二段中和模拟工业酸性重金属废水,得到团聚的针状硫酸钙晶体,废水达标排放.The effects of process parameters and addition of Mg2＋ and Fe3＋ ions on the morphology and size distribution of calcium sulfate dihydrate （gypsum） particles produced by the reactive crystallization between simulated acidic wastewater and lime were investigated. Compared with the stirring speed, addition rate of lime slurry and concentration of Ca（OH）2, reaction temperature significantly affected the morphology and particle size distribution of calcium sulfate dihydrate. The morphology of precipitated crystals evolved from platelet-like and needle-like shapes to rod-like shape when the temperature increased from 25 to 70℃. And the crystallization of gypsum slowed significantly in the presence of Mg2＋ and Fe3＋ ions in the solution. Moreover, the morphology of gypsum was transformed from platelet-like to rod-like shape with over 1945 mg/L Mg2＋ concentration in the solution. The simulated industrial acidic wastewater containing heavy metals was efficiently purified by the two-stage neutralization technology, and highly agglomerated gypsum precipitates with rod-like shape were obtained.

关 键 词：反应结晶 硫酸废水 石灰乳 二水硫酸钙 

分 类 号：X703.1[环境科学与工程—环境工程]