Ca(OH)_2-CaCl_2沉淀法处理核工业高氟废水

Treatment of wastewater from nuclear industry by Ca(OH)_2-CaCl_2 precipitation process

为强化石灰沉淀法处理高氟废水时混合液的沉降性能,采用烧杯试验,分别考察了药剂投量、混凝剂投量、药剂投加顺序、原水F-浓度等因素对泥水分离性能的影响。研究表明,联合投加Ca(OH)_2和CaCl_2处理F-在5 000~10 000 mg/L的废水时,自絮凝会显著改善混合液沉降性能和出水浊度,而投加混凝剂的效果却有限。先Ca(OH)_2后CaCl_2的投加方式(二步法)比药剂同时投加(一步法)对沉降性能有较大的改善。运用分步加药法在中试规模的同程水平流斜板沉淀池实现了良好的固液分离效果。

In order to enhance the lime sedimentation performance of mixed liquid in the treatment of wastewater containing highly concentrated fluoride by lime precipitation process,beaker tests have been used for investigating the influences of factors,such as chemical agent dosages,coagulant dosage,dosing sequence of the chemical agents, F- concentration in raw water,etc. on the muddy/water separation performance,respectively. The research results show that when adding Ca（OH）2 and CaCl2 jointly for the treatment of F-（5 000-10 000 mg/L）in wastewater,the self- flocculation can obviously improve the sedimentation performance and effluent turbidity of the mixed liquid,but the effect of adding coagulant is limited. The sedimentation performance of the pattern of Ca（OH）2 first and CaCl2 last （two additions）can make greater improvement than that of the pattern of adding agent simultaneously（one addition）. Good solid/liquid separation effect can be achieved by a multi-step dosing method in a pilot-scale same-flow-path horizontal flow inclined board settling tank.