电镀污泥水热合成复合铁氧体与回收铜试验研究

Hydrothermal synthesis of compound ferrite and reclamation of copper from electroplating sludge

以电镀污泥为原料,在温度为200℃、晶化时间为4h的条件下研究水热法合成复合铁氧体.结果表明,通过投加氯化高铁和沉淀剂可将电镀污泥中的Zn、Fe、Cr和Ni固化、稳定在铁氧体晶格之中;X射线衍射分析表明,此复合铁氧体主要为Ni/Zn铁氧体.通过选择NH4HCO3作为沉淀剂,可将电镀污泥中的氢氧化铜络合生成[Cu(NH3)4]2+,铜萃取率可达80%以上;并可通过调节含铜分离液的pH值在5.4～6.4,生成碱式氯化铜转入固相,铜回收率在98%以上.复合铁氧体的磁性较强,分散性好,粒度分布均匀,且重金属浸出毒性低于美国TCLP(Toxic Characteristic Leaching Procedure)的毒性鉴别标准值.因此,水热法合成复合铁氧体是实现电镀污泥资源化与自净化的有效途径.

The hydrothermal synthesis of compound ferrite from electroplating sludge was investigated at a temperature of 200℃ and with a holding time of g h. The heavy metals from electroplating sludge were solidified and stabilized into the inert compound ferrite by adding iron trichloride and a precipitator. Ni-Zn ferrite, the main solid phase material in the hydrothermal synthesis, was identified by X-ray diffraction. The copper in the sludge precipitated in the form of [ Cu（NH3 ）4 ] 2^＋ when ammonium bicarbonate was added, and over 80% of the copper was thus extracted from the sludge. Over 98% of the [ Cu （NH3 ）4 ] 2^＋ reacted to form Cu2 Cl（OH） 3, when the pH of the separated supernatant liquor was adjusted to between 5. g and 6. g. The compound ferrite had good magnetism, was a weakly agglomerated and equably distributed powder, and its leaching concentration of heavy metals was lower than the regulatory limit in the Toxic Characteristic Leaching Procedure （TCLP） of the EPA. Therefore, hydrothermal synthesis of compound ferrite is a feasible method of recycling and purifying electroplating sludge.