电解锰废渣的浸出毒性及生石灰固化技术

A EMR SOLIDIFICATION TECHNOLOGY BASED ON QUICKLIME AND LEACHING TOXICITY

我国电解锰废渣产量大,污染物的浸出毒性较强。锰渣堆放方式粗放,渣库管理落后,且长期暴露在自然环境中,导致大量污染物迁移到周边的土壤及水体中。为了解决锰渣的无害化处理问题,在分析其浸出毒性的基础上,研究了生石灰固化技术对锰渣的浸出毒性的影响。结果表明:锰渣中的主要污染物为可溶性Mn^(2+)和NH_4^+-N,含量极高,严重超标;利用生石灰的吸附、包裹及化学反应作用,能有效将可溶性Mn^(2+)固化为难溶Mn O_2,同时将NH_4^+-N转化为气态NH_3,浸出液中污染物浓度均符合相关标准要求;当生石灰添加量为10%,锰渣含水率为27%,预搅拌时间40 min,预静置时间3 d,锰渣浸出液中可溶性Mn^(2+)浓度降为2.60 mg/L,固化率达99.8%,低于5.0 mg/L的标准限值;NH_4^+-N浓度降为21.23 mg/L,脱除率为96.73%,低于25 mg/L的标准限值。

The output of electrolytic manganese residue（EMR）was huge in China.Leaching solution of EMR was with great toxicity.While the piling method of EMR and management of tailing impoundment in China was comparatively backward.EMR was exposed to the natural environment in long-term.A large amount of pollutants easily migrated to the soil and water nearby.Leaching toxicity of EMR was analyzed,and influence of solidification technology on leaching toxicity of EMR was researched.The result showed that main pollutants were soluble Mn^（2＋） and NH_4~＋-N,whose concentration were high and seriously exceeded the standards limit.Soluble Mn^（2＋） was transformed to Mn O_2,an insoluble compound.Meanwhile,NH_4~＋-N was transformed into ammonia.Concentration of pollutants accorded with the relevant standards.The optimum codition was found as follows：quick lime amount of 10%,moisture content of 27%,pre-mixing time of 40 min,pre-reaction time of 3 d,then the concentration of soluble Mn^（2＋） was 2.60 mg/L,and NH_4~＋-N was 21.23 mg/L.Removal rate of soluble Mn^（2＋） and NH_4~＋-N were up to 99.8%and 96.73,respectively.