球团氧化焙烧过程磁铁矿与红土镍矿界面反应行为分析  

Analysis of interfacial reaction behavior between magnetite and laterite nickel ore in pellet oxidation roasting process

作　　者：韩振 张峰 江祥红 岑玉龙 赵朝显 HAN Zhen;ZHANG Feng;JIANG Xianghong;CEN Yulong;ZHAO Chaoxian(School of Materials and Metallurgy,Guizhou University,Guiyang 550025,Guizhou,China)

机构地区：[1]贵州大学材料与冶金学院,贵州贵阳550025

出　　处：《中国冶金》2024年第6期55-63,82,共10页China Metallurgy

基　　金：国家自然科学基金青年科学基金资助项目(52004075);贵州省基础研究计划项目(黔科合基础-ZK[2021]一般262);贵州大学引进人才科研项目(贵大人基合字(2020)15号)。

摘　　要：为了揭示球团氧化焙烧过程中磁铁矿和红土镍矿之间的固结机制,采用扩散偶法研究该过程磁铁矿与红土镍矿界面反应。结果表明,在1300℃下氧化焙烧120 min后,未与红土镍矿接触的磁铁矿中Fe_(3)O_(4)绝大部分氧化为赤铁矿(Fe_(2)O_(3)),一些硅酸盐相填充孔隙辅助固结,这层主要以Fe_(2)O_(3)再结晶为主,固结强度高;磁铁矿与红土镍矿交界处形成了一层扩散层,该扩散层中的主要物相为镁铁尖晶石((Mg,Fe)O·Fe_(2)O_(3)),少量硅酸盐液相填充其中辅助固结;大量镁由红土镍矿向磁铁矿扩散,扩散之后形成了镁铁尖晶石,镁铁尖晶石的形成阻碍了磁铁矿的氧化再结晶,不利于球团抗压强度的提高;未与磁铁矿接触的红土镍矿主要由镁橄榄石、玻璃质及赤铁矿组成,其中镁橄榄石含量最多,玻璃质填充于镁橄榄石之间的缝隙中,而赤铁矿则存在于玻璃质中,红土镍矿中Fe_(2)O_(3)含量较少,分散的Fe_(2)O_(3)在高温焙烧过程中由于大量镁橄榄石的阻隔彼此之间接触较少,Fe_(2)O_(3)晶体难以有效联结长大,大量Fe_(2)O_(3)呈细小的晶体状态零散分布在整个红土镍矿中,因此该部分固结强度差。研究结果为制备高强度的含铬镍铁矿氧化球团提供了理论依据。In order to reveal the consolidation mechanism between magnetite and laterite nickel ore in the process of pellet oxidation roasting,the interfacial reaction between magnetite and laterite nickel ore in this process was studied by diffusion couple method.The results show that after oxidation roasting at 1300℃for 120 min,most of the Fe_(3)O_(4) in the magnetite that does not contact with the laterite nickel ore is oxidized to hematite(Fe_(2)O_(3)),and some silicate phases fill voids to assist consolidation.This layer is mainly composed of Fe_(2)O_(3) recrystallization,and the consolidation strength is high.A diffusion layer is formed at the junction of magnetite and laterite nickel ore.The main phase in the diffusion layer is magnesia-iron spinel((Mg,Fe)O·Fe_(2)O_(3)),and a small amount of silicate liquid phase is filled to assist consolidation.A large amount of Mg diffuses from laterite nickel ore to magnetite,and forms magnesia-iron spinel after diffusion.The formation of magnesia-iron spinel hinders the oxidative recrystallization of magnetite,which is not conducive to the improvement of compressive strength of pellets.The laterite nickel ore not in contact with magnetite is mainly composed of forsterite,glassy and hematite.Among them,the content of forsterite is the highest,and the glassy is filled in the gap between forsterite,while hematite exists in glassy.Because of the low content of Fe_(2)O_(3) in laterite nickel ore,the dispersed Fe_(2)O_(3) has less contact due to the barrier of a large amount of forsterite during high temperature roasting.It is difficult for Fe_(2)O_(3) crystals to effectively connect and grow,and a large amount of Fe_(2)O_(3) is scattered in the whole laterite nickel ore in a fine crystal state.Therefore,the consolidation strength of this part is poor.The results provide a theoretical basis for the preparation of high strength oxidized pellets containing chromium nickel iron ore.

关 键 词：红土镍矿 磁铁矿 氧化焙烧 元素迁移 固结机理 

分 类 号：TF046[冶金工程—冶金物理化学]