Determination of Iron Ore and Gangue Mineral Associations Using Optical and Backscattered Electron Images with Electron Probe Microanalysis

摘要

Iron ore oxide and oxyhydroxide minerals such as haematite (eg various types of martite andrnmicroplaty haematite), different forms of goethite, magnetite, hydrohaematite and kenomagnetiternwere analysed using optical microscopy, scanning electron microscopy (SEM) and electron probernmicroanalysis (EPMA) techniques, to determine the type and proportion of deleterious elementsrnpresent and the chemistry of associated gangue minerals. The aim was to characterise elementsrnpotentially deleterious for agglomeration and steelmaking, eg sulfur, phosphorus, aluminium andrnsilicon and correlate their distribution with mineral texture and association, to provide feedbackrnon downstream processing performance and product quality.rnExamples of characteristic mineral associations are shown from various genetic styles of ironrnores, including magnetite banded iron formation (BIF), BIF-derived martite-goethite and skarntypernmagnetite ores.rnA number of examples are presented demonstrating the benefi ts of the use of combined techniquesrnof refl ected optical microscopy, SEM and EPMA data to reliably identify ore and gangue mineralsrnand their associations in different types of iron ores.