直接还原-渣金熔分法回收钕铁硼废料

Recycling NdFeB Scrap by Direct Reduction and Melting Separation

采用直接还原-渣金熔分法回收稀土钕铁硼废料中铁合金和稀土氧化物渣。将废料以一定质量比配加到铁精矿粉中,在反应罐直接还原,物料中金属铁和钴的氧化物Fe O、Co O被还原为金属单质Fe和Co,Al、Mn、RE等活性金属被氧化为Al2O3、Mn O、RE2O3;海绵铁渣金熔分中,呈单质态的元素Fe、Co形成合金,呈氧化态的稀土氧化物与铁精矿中的脉石形成REO-Si O2-Al2O3熔渣,渣中稀土氧化物含量达到48.42%,具有很高的再利用价值。对熔分渣进行熔化性温度、扫描电镜和能谱微区成分分析及X射线衍射结构分析。分析表明,熔渣的流动性良好,当废料配入比大于15%时,熔渣的软化熔融温度区间变窄;渣中的稀土以氧化物和铝酸盐的形式存在,形成树枝状晶体。

This paper mainly describes how to recycle metallic iron and rare earth oxide from Nd-Fe-B scrap by direct reduction and melting separation by mixing a certain quantity ratio of Nd-Fe-B scrap with iron concentrate powder in retort to promote direct reduction,Fe O,Co O in the mixture are reduced to elements Fe and Co while other active metallic elements like Al,Mn,RE and etc are changed into oxidation state as Al2O3,Mn O and RE2O3. Then during melting separation of spongy iron,the elements like Fe and Co transform to alloy,and the rest oxidized substance is formed into REO-Si O2-Al2O3 slag with gangue in iron concentrate powder. As the rare earth oxide content reaches 48. 42%,the slag has a high recycling value.Based on data from comparing the smelting temperature and scanning electron microscope,and EDS micro- area composition analysis,as well as X- ray diffraction structural analysis,the results show that the slag has sound mobility while the softening- melting temperature ranges become narrow when the mix ratio of scrap is above 15%,and that rare earth in slag exists in the form of oxide and aluminate to become dendrites.