磁铁矿型烧结矿成矿过程对其RDI影响机理研究

Research on mechanism of influence of magnetite sinter mineralization process on RDI

基于工艺矿物学的研究方法,对磁铁矿型烧结矿的成矿过程进行系统的研究,旨在从矿相结构入手,探究影响其低温还原粉化指数(RDI)的机制。研究制取了9组不同温度梯度的烧结矿,通过对矿相结构的研究发现:随着温度的变化,烧结矿的矿相结构变化依次为:粉末状结构→熔融状结构→熔融状结构→斑状结构→粒状结构→熔蚀结构(初期)→熔蚀结构(中期)→熔蚀结构(末期)→粒状结构。其中,高温形成的斑状-粒状结构结晶出的雏晶/骸晶状磁铁矿会恶化其RDI,在熔蚀结构末期发育大量板柱状铁酸钙有利于提高烧结矿的质量。建议在烧结生产时,适当减少高温段的持续时间,以避免雏晶/骸晶状金属相的过多出现,适当延长低温段的烧结时间,以增加熔蚀结构的占比,从而改善烧结矿的RDI。

Based on the research method of process mineralogy,the mineralization process of magnetite sinter is systematically studied,aiming to explore the mechanism affecting its reduction degradation index(RDI)from the perspective of mineral phase structure. Nine groups of sinter with different temperature gradients are studied and prepared. Through the study on the structure of mineral phases,it is found that the structure of sinter,with the change of temperature,is as the following:powder structure→melt-down structure→melt-down structure→porphyritic texture→granular structure→melting erosion structure(initial stage)→erosion structure(middle stage)→erosion structure(later stage)→granular structure. Among them,the crystal formation of porphyritic-granular structure formed at high temperature leads to the deterioration of RDI of crystallite/skeleton crystal magnetite,and the development of large amount of plate-columnar calcium ferrite at the later stage of the corrosion structure is conducive to the improvement of sinter quality. it is suggested that during the sintering production,the duration of the high temperature zone should be reduced to avoid excessive occurrence of the crystallite/skeleton crystal metal phase,and the sintering time of low-temperature zone should be prolonged to increase the proportion of the melting erosion structure and thus improve RDI of sinter.