为实现铁资源高效回收，以CaO为改质剂、空气为氧化剂，改质熔融氧化处理镍渣，分析了反应前后渣样的物相组成及组织形貌，考察了反应后氧化渣样中元素的分布情况，测定了不同碱度下磁铁矿相的结晶量和颗粒尺寸，分析了碱度对磁铁矿相析出长大过程的影响. 结果表明，原渣中的铁主要赋存于铁橄榄石相及铁镁橄榄石相中，改质可将渣中Fe, Ni, Co, Cu元素在磁铁矿相中富集，适宜的碱度有利于磁铁矿相析出与长大，碱度为0.6时渣中铁以磁铁矿相形式析出，呈颗粒状，结晶量最大，为36.4%，颗粒平均粒径大于50 ?m，分布较均匀.

In order to recycle iron resources in nickel slag via modified molten oxidation used CaO as modifier under air atmosphere, the phase composition and microstructure of original and modified nickel slag, the distribution of elements was investigated, and the precipitation quantity and grain size of magnetite at various basicities were characterized, and the effect of basicity on the precipitation and growth in nickel slag were studied. The results showed that the iron element exists as fayalite and hortonolite. Fe, Ni, Co, Cu are simultaneously concentrated in magnetite phase during molten oxidation process In addition, the precipitation and growth of magnetite phase are affected significantly by slag basicity. When the basicity is about 0.6, iron is precipitated as magnetite with uniform distribution, and its precipitation quantity reaches a maximum value of 36.4%, the average size of larger than 50 ?m and distribution uniform.