摘要
针对钕铁硼废料中金属离子浸出成本高、污染大的问题,采用电化学阳极氧化技术直接浸出钕铁硼废料中的钕和铁元素。研究电解时间、电压、电解质浓度、温度和pH值等条件对浸出速率的影响,通过扫描电镜(SEM)、X射线能谱仪(EDS)和X射线衍射仪(XRD)分析产物微观结构和组成。结果表明,随着电解质浓度、温度和电压增加,浸出速率增大,电解时间和pH值对浸出速率无明显影响,但过低的pH值会降低回收率。最合适浸出条件为:电压2.5 V,温度25℃,电解液浓度为0.2 mol·L^(-1)的硫酸钠溶液,此时浸出速率为2.88 mg·min^(-1),Fe和Nd的回收率分别为96.1%和94.6%,每千克钕铁硼能耗为1.74 kW·h,回收产物为疏松多孔的氢氧化物。与现有浸出工艺相比,该工艺操作简单,能耗低,无需使用强酸,是一项绿色环保的钕铁硼浸出工艺。
Electrochemical anodic oxidation technology was used to leaching Nd and Fe directly from NdFeB wastes in order to overcome high cost and pollution during metal ion leaching from NdFeB wastes.Effects of electrolytic time,voltage,electrolyte concentration,temperature and pH value on leaching rates were studied.The microstructure and composition of the products were analyzed by scanning electron microscopy(SEM),X-ray energy dispersive spectroscopy(EDS)and X-ray diffractometer(XRD).The results show that the leaching rate increases with the increase of electrolyte concentration,temperature and voltage.The electrolytic time and pH value have no obvious effect on the leaching rate,but too low pH value reduces recovery rate.The optimal leaching conditions were:voltage 2.5 V,temperature 25℃ and 0.2 mol·L^(-1) sodium sulfate solution.Under these conditions,the leaching rate was 2.88 mg·min^(-1),the recovery rates of Fe and Nd were 96.1% and 94.6%,respectively,and energy consumption per kilogram of NdFeB was 1.74 kW·h.The obtained product was porous hydroxid.Hence,it is an environmental friendly method for leaching NdFeB waste magnets with simple operation,low energy consumption and using no strong acid compared with the existing leaching processes.
作者
周利娜
苏志伟
肖成梁
李中坚
杨彬
雷乐成
张兴旺
ZHOU Li-na;SU Zhi-wei;XIAO Cheng-liang;LI Zhong-jian;YANG Bin;LEI Le-cheng;ZHANG Xing-wang(College of Chemical and Biological Engineering,Zhejiang University,Hangzhou 310027,China;Institute of Zhejiang University-Quzhou,Quzhou 324000,China)
出处
《高校化学工程学报》
EI
CAS
CSCD
北大核心
2022年第4期603-609,共7页
Journal of Chemical Engineering of Chinese Universities
基金
国家自然科学基金(21776248)。
关键词
阳极氧化
钕铁硼废料
稀土
浸出
anodic oxidation
NdFeB waste
rare earth
leaching
