红土镍矿电炉还原炼镍铁合金的研究进展

RESEARCH PROGRESS ON THE PRODUCTION OF FERRONICKEL ALLOY BY ELECTRIC FURNACE REDUCTION FROM LATERITIC NICKEL ORE

综述了我国红土镍矿电炉还原炼镍铁的研究进展,重点总结了炼镍铁的机理与研究现状,分析了该技术的难点及其发展趋势。结果表明:红土镍矿中各氧化物的还原先后顺序为NiO>NiFe2O4>Fe2O3>SiO2>MgO。SiO2/MgO在1.6～2.8,FeO含量在20%～30%时,渣与金属密度差异大,且具有良好的流动性,有利于渣与金属分离,提高镍的直收率。渣型对脱硫影响也较大,在碱性渣范围内适当提高炉渣碱度,有利于炉渣脱硫,但是碱度过大会导致渣黏度变大而对脱硫不利。采用电炉还原熔炼工艺生产镍铁具有流程短、镍铁品位易控、金属回收率高的优点,但对于强化冶炼过程、提高作业效率、进一步提高镍铁合金的金属镍含量等问题还有待在生产实践中继续摸索解决。

The latest progress on the production of ferronickel alloy by electric furnace reduction from laterite was tentatively reviewed, which focused on the mechanisms and current research status of ferronickel production and analyzed the technical difficulty and developing direction. Results showed that the sequence of reduction for ox ides in laterite is NiO 〉 NiFe204 〉 Fe203 〉 SiO2 〉 MgO. Slag and metal could be separated easily while great densi ty difference exists between them, which is also of good fluidity and beneficial for the separation of furnace slag thus enhance the direct recovery of nickel when the SiO2/MgO ratio is between 1.6 2.8 and FeO content between 20% 30%. Slag type has large influence on desulfurization of slag. Within a range of suitable alkalescency of slag, it is beneficial for desulfurization when increase the alkalinity properly, however, it is not beneficial for desulfuriza tion while excessive alkalinity due to high viscosity. Ferronickel production by electric furnace reduction is of some advantages such as short process, easily controlled ferronickel grade and high direct recovery of nickel, however, there is still lots of work need to be done in production practice to intensify the smelting process, such as promote the efficiency of production and increase the content of nickel in ferronickel.