电镀污泥的铁氧体化研究

Study on ferrite process of electroplating sludge

采用酸浸-铁氧体化-毒性浸出分析工艺实现电镀污泥的资源化。对电镀污泥中重金属的硫酸浸出工艺进行了研究,考查了液固比、时间、温度的影响。结果表明:在液固质量比为5∶1,时间为60 min,温度为25℃时,污泥中重金属的浸出率最佳。向重金属浸出液中加入硫酸亚铁,通入空气,控制pH值和温度条件下制备铁氧体材料,结果表明:在pH为9,铁和其他重金属M的摩尔比为8∶1,温度为80℃,时间为120 min的条件下,所得铁氧体结构稳定,滤液中重金属的浓度最低,远低于国家规定的一级排放标准值,可安全排放。对硫酸浸出残渣和铁氧体进行毒性浸出分析,结果均低于TCLP毒性鉴别标准值,已达到无害化,残渣可安全填埋,铁氧体可作为工业产品应用。

Acid leaching-ferrite process-toxicity characteristic leaching procedure technique is studied to realize resource utilization of electroplating sludge.The influences of liquid-solid ratio,leaching time and reaction temperature on the sulfuric acid leaching of heavy metal elements from electroplating sludge are studied.The optimal leaching rate of heavy metal elements from electroplating sludge can be achieved under the following conditions：5∶1 mass ratio of liquid and solid,60 minutes of leaching time and 25℃ of temperature.The ferrites with the leaching liquids as the raw materials is prepared by adding ferrous sulfate,bubbled air,control of pH and temperature.The results show that when pH is 9,the Fe/M molar ratio is 8∶ 1,temperature is 80℃,and the reaction time is 120 minutes,the stable ferrites can be obtained.The concentration of copper in the filtrate is lowest,which is far lower than the national emission standard.The filtrate can be discharged without further treatment.The Toxicity Characteristic Leaching Procedure of the acid leaching residues and ferrites are detected.It is found that the leaching concentrations of heavy metals are lower than the regulatory limit in the Toxicity Characteristic Leaching Procedure and reach the harmless standard.The residues can be landfilled safely and ferrites can be used as industry products.