甲烷作用下硅镁型红土镍矿低温还原焙烧—磁选镍铁精矿

LOW-TEMPERATURE REDUCTION OF GARNIERITE USING METHANE FOLLOWED BY ROASTING-MAGNETIC SEPARATION FOR ENRICHMENT OF FERRONICKEL CONCENTRATE

选自云南元江的硅镁型红土镍矿在不同条件下进行甲烷低温还原,并通过磁选得到镍铁精矿。结果表明,还原温度在600~900℃,对镍和铁的品位和回收率影响很小,镍和铁的回收率随温度的变化趋势是一致的;镍和铁的品位及回收率随着还原时间的延长逐渐增加;甲烷浓度的增加使得镍和铁的品位降低,回收率则增加;在还原温度为800℃、还原时间为90 min条件下,当硫酸钠的添加量从5%增加到20%时铁的品位和回收率逐渐减小,而镍的品位和回收率则逐渐增加。用X射线衍射(XRD)和扫描电镜及能谱(SEM-EDS)分析还原过程中硅镁型红土镍矿矿相和微观结构的变化,结果表明精矿主要是镍以及铁的氧化物,并且精矿中铁的品位远远高于镍的品位。

In this study,the garnierite from Yuanjiang,Yunnan province was reduced by methane under different conditions followed by magnetic separation to obtain the ferronickel concentrate.The experimental results show that the reduction temperature in the range of 600°C to 900°C had no noticeable effect on the contents and recoveries of nickel and iron.The contents and recoveries of nickel and iron in the concentrates increased slightly with prolonging of the reduction time.In addition,the contents of nickel and iron decreased with increasing methane concentration,whereas the recoveries of nickel and iron increased.Decreases in the iron content and recovery were observed when the dosage of sodium sulfate varied from 5%to 20%under a reducing temperature of 800°C and a reducing time of 90 minutes,whereas the nickel content and recovery were gradually increased.The phase and microstructure transformation of garnierite in the reduction process were investigated using X-ray Diffraction(XRD),Scanning Electron Microscope(SEM),and Energy Dispersive Spectrometer(EDS).The results show that the nickel and iron oxides were the main phase in concentrate,and the content of iron was much higher than that of nickel.