选择性还原钕铁硼废料中铁的试验研究

基于稀土氧化物和铁氧化物还原性的差异,在高温管式炉中开展了CO选择性还原钕铁硼废料中铁的试验研究,考察了还原温度、还原时间、物料粒度和CO流量对铁还原率的影响。结果表明:钕铁硼废料中铁还原率受还原温度和还原时间影响最大,受CO流量影响次之,受物料粒度影响最小;在物料粒度为0.040 mm～0.045 mm、还原温度为1 273 K、还原时间为50 min、CO流量为300 mL/min的条件下,铁还原率达86.23%,产物以金属铁为主,少量以FeNdO₃形式与稀土共存。研究结果为钕铁硼废料中稀土和铁的综合回收提供理论支撑。

Experimental Research on Selective Reduction of Iron in NdFeB Scrap

Based on the difference reduction properties of rare earth oxide and iron oxide, experimental research on selective reduction of iron in NdFeB scrap using CO was carried out in a high-temperature tubular furnace. And the effect of reduction temperature, reduction time, particle size and CO flow rate on the iron reduction rate were investigated. Results showed that the reduction rate of iron in NdFeB scrap was most affected by reduction temperature and reduction time, followed by CO flow rate, and least affected by particle size. Under the conditions of particle size of 0.040 mm-0.045 mm, reduction temperature of 1 273 K, reduction time of 50 min and CO flow rate of 300 mL/min, the iron reduction degree was up to 86.23%. The reduction products were mainly composed of metallic iron, a small amount of iron element which coexisted with rare earth in the form of FeNdO₃. This will provide theoretical supports for the comprehensive recovery of rare earth and iron in NdFeB scrap.