Study On The Reduction And Enrichment Of Nickel By Nickel And Nickel-bearing Laterite Ore Based On Accelerator And Iron Content

Global exploration of nickel resources involves mainly two types of nickel sulphide ore and laterite nickel ore.As nickel sulphide ore resources have been mined and its reserves have fallen sharply,plentiful laterite ores have attracted interest,and increasingly more processing has led to greater efforts to improve recovery of nickel from laterite ore.In this paper,two kinds of low-grade laterite nickel ore in Yunnan are used as raw materials,The coal based reduction followed by magnetic separation process was studied for the limonite nickel ore,and through changing the proportion of two kinds of ore samples and adding iron oxide to garnierite ore to studied the effect of iron bearing minerals on reduction and aggregation of nickel.The results provide theoretical support for the efficient utilization of low grade laterite nickel ore in China.Physical and chemical properties of two kinds of ore sample study found that two kinds of ore samples belong to different types of oxidized ore.The main phase is lizardite and nickel is associated with oxides(10.98%)and silicates(84.15%),accounted for 95.13%in the garnierite.The main phase is goethite and nickel is associated with oxides(27.40%)and silicates(69.35%),accounted for 96.75%in the limonite.The thermodynamic analysis and reduction roasting-magnetic separation experiments were carried out on the reduction process of limonite laterite under the action of sodium sulfate.Thus determining the main parameters(reduction temperature,reduction time,amount of sodium sulfate and amount of anthracite)that affect the experimental results.The experimental results indicate that for a ferronickel content of 13.26%Ni and 67.34%Fe,nickel recovery of 88.40%,iron recovery of 14.71%could be obtained under the best condition of reduction temperature 1100?,reduction time 60 min,the mass fraction of additive 20%and reductant 8%by the application of a 200 mT magnetic field.The addition of sodium sulfate destroys the silicate mineral structure,and the majority of nickel and iron is liberated from silicates,at the meantime,FeS is generated,The formation of FeS inhibits the reduction if iron,decreases the system melting point,intensifies the process of metal irons mass transfer and enhances ferronickel particles growth during the reduction of laterite.Study the effect of iron-bearing minerals on reduction roasting process of laterite ore,The phase transformation process of the garnierite and limonite two kinds of low-grade lateritic nickel ores roasted at different temperature were studied and found that the hematite and maghemite play the same role during the roasting process of the two kinds of ores.Maghemite is gradually converted into hematite and then hematite is transform to spinel containing iron.Through changing the proportion of two kinds of ore samples and adding iron oxide to garnierite ore to studied the effect of Iron bearing minerals on reduction and aggregation of nickel.It is indicated that the Fe2O3 reacts with amorphous silicate minerals that produced by serpentine dehydroxylation to avoid the generation of olivine and makes nickel is embedded in enstatite,nickel embedded in enstatite is easier to reduce than in forsterite,at the same time,the newly generated magnesioferrite reacts with nickel silicate to produce a more easily reduced trevorite.The formation of trevorite is strengthens the aggregation of nickel and iron.