电解锰废渣中可溶性Mn^(2+)固化的影响因素

Influence factors of curing soluble Mn^(2+) in electrolytic manganese residue

电解锰废渣年产量大,污染物种类多,渣库管理相对落后。在长期风雨侵蚀下,导致大量可溶Mn^(2+)的转移并进入外环境,污染周边土壤及水体等,存在巨大的潜在安全隐患。为了解决锰渣的污染问题,以生石灰为固化剂,通过正交实验和单因素优化实验,考察了生石灰添加量、液固比、反应温度及反应时间对锰渣中可溶性Mn^(2+)固化效果的影响。结果表明,生石灰添加量对可溶性Mn^(2+)固化的影响较大,当生石灰添加量为5 g、液固比为7∶1、反应时间为10 h、常温反应条件时固化效果最好,可溶性Mn^(2+)固化率达98.10%,残余Mn^(2+)质量浓度为1.01 mg/L,符合GB 8978—1996的排放要求。

China＇s annual output of electrolytic manganese residue（ EMR） has been very huge,which contains many kinds of pollutants. China＇s management on EMR impoundment has remained relative backward. EMR has often been exposed to wind and rain for a long time,which results in the migration of a large amount of soluble Mn^2＋into outer environment,polluting nearby soil and water.It has a huge potential environmental risk.In order to solve pollution problem caused by EMR,quick lime is selected as curing agent. Influences of quick lime dosage,the ratio of liquid to solid,reaction temperature and reaction time on the curing effects of soluble Mn^2＋in EMR are studied through orthogonal and single-factor experiments.The results show that the dosage of quick lime has a great effect on the curing effect. The best curing effect is gained under the optimal conditions that quick lime dosage is 5 g,the ratio of liquid to solid being 7 ∶1,reaction time 10 h at ordinary temperature. The curing rate of soluble Mn^2＋reach 98. 10% and the remaining concentration of soluble Mn^2＋is 1. 01 mg·L^（-1）,which meets the discharge standard GB 8978—1996.