镁质氧化镍矿非熔融金属化还原—磁选镍铁工业试验研究

Pilot-scale plant study on non-molten metalized reduction-magnetic separation for magnesium-rich nickel oxide ores to produce ferronickel concentrate

以代表性镁质氧化镍矿为研究对象,就前期课题组提出的氧化镍矿非熔融金属化还原—磁选生产镍铁精矿技术开展了半工业试验和工业试验研究.半工业试验在内径Φ=0.45 m,长度L=7.5 m的回转窑中进行,而工业试验在内径Φ=3.2 m,长度L=72 m的回转窑中进行.技术主要分为原料准备、非熔融态金属化还原、水淬/球磨及磁选分离等4个工序.半工业试验连续运行50 d,共处理镍矿20 t,可获得镍、铁品位分别为7.4%和69.6%的镍铁精矿,且镍、铁回收率高达91.3%和73.8%,渣含镍则低至0.16%.工业试验连续运行15 d,共处理镍矿8 000 t,取得了与半工业试验类似的结果,进一步验证了该新技术的可行性和稳定性.初步计算表明,吨镍铁精矿电耗约300 k Wh,折合吨干基矿电耗约55 k Wh.可见,文中提出的新技术能够实现镁质氧化镍矿在非熔融温度下充分金属化还原,达到富集镍和铁的目的.

In this study,semi-pilot and pilot scale tests were carried out to treat magnesium-rich low-nickel oxide ore,based on experimental results of non-molten state metalized reduction of nickel oxide ores followed by magnetic separation to produce ferronickel concentrate,which was developed by our research team in the previous study.The semi-pilot tests were conducted in a rotary kiln of 0.45 m inner diameter and 7.5 m length,and the pilot ones were conducted in another rotary kiln of 3.2 m inner diameter and 72 m length.The process mainly consists of four steps:feed preparation,solid-state metalized reduction,quenching and ballmilling,and magnetic separation.During 50 days of continuous semi-pilot tests,approximate 20 tons nickel oxide ores were consumed.the overall recoveries of nickel and iron reached 91.3%and 73.8%,while the nickel and iron grades of the ferronickel concentrate were 7.4%and 69.6%.And meanwhile,the nickel loss to residue was only 0.16%.In the 15 days of continuous pilot tests,approximate 8000 tons ores were consumed,whose results were similar to those of the above semi-pilot tests.The results further verified the stability and feasibility of industrial application.Preliminary calculation suggested that the electricity consumption was only approximate 300 kW·h when one ton ferronickel concentrate was produced,i.e.52.5 kW·h/t-ore.In all,magnesium-rich nickel oxide ore can be fully metalized reduced at a non-molten temperature using the proposed technology in order to beneficiate nickel and iron.