Mineralogical Imaging for Characterization of the Per Geijer Apatite Iron Ores in the Kiruna District, Northern Sweden: A Comparative Study of Mineral Liberation Analysis and Raman Imaging (original) (raw)

Iron Ore Quantitative Characterisation Through Reflected Light- Scanning Electron Co-Site Microscopy

Ninth International Congress for Applied Mineralogy (ICAM-2008), 2008

The traditional trading of iron ores is based on chemical specifications and particle size distribution. However, recent characterisation studies, that bring additional information like mineralogical composition and microstructural (textural) aspects, have become important. They contribute to determination of the iron ores downstream beneficiation operations and subsequent steelmaking processing, allowing improvements on both new and existing processes. Despite progress in commercial scanning electron microscope/energy dispersive spectrometer (SEM/EDS) automatic instruments in the last decade, these systems are not capable of performing the identification and discrimination of major iron ore minerals (haematite and magnetite) and the consequent description of its microstructure. On the other hand, reflected light microscopy (RLM) can easily distinguish the iron oxides by their reflectancies, but it cannot discriminate quartz and epoxy resin, which present similar colour on images. The present work proposes an innovative method to perform a quantitative mineralogy characterisation of iron ore based on RLM-SEM co-site microscopy. This technique combines images obtained by RLM and SEM through an automatic registration procedure that accurately aligns the two kinds of images of each field. In fact, it creates multi-dimensional images, which are then analysed using image processing and pattern recognition techniques. The case study is an itabiritic iron ore from Quadrilátero Ferrífero (Brazil) which contains mainly quartz, goethite, magnetite and haematite. The discrimination of phases that are not distinguishable with either RLM (epoxy resin and quartz) or SEM (haematite and magnetite) can be performed through this multimodal approach, allowing the subsequent mineralogical quantification. The mineralogical quantification computed by image analysis was consistent with independently obtained results based on the Rietveld technique.

Rare earth mineralogy in tailings from Kiirunavaara iron ore, northern Sweden: Implications for mineral processing

Minerals & Metallurgical Processing, 2017

Four main and three minor rare-earth-element (REE)-bearing minerals were identified and quantified in the Kiirunavaara apatite iron ore tailings using optical microscopy, an electron probe microanalyzer (EPMA) and a mineral liberation analyzer, and their chemical compositions were analyzed by the EPMA and laser ablation inductively coupled plasma-mass spectrometry. REEs are shown to be contained in the minerals apatite, monazite, allanite, titanite, zircon, thorite and synchysite. In zircon, thorite and synchysite, they occurred in only trace amounts and contributed limited amounts to the total REE budget, and these are consequently of minor importance. Monazite occurred as inclusions in apatite and as free particles, 90 percent liberated. Allanite occurred to some degree in mixed grains with magnetite but also as free particles. Monazite mainly reported to the apatite concentrate, while allanite and titanite largely went to the tailings, the latter preferably to those fractions sma...

The Malmberget iron mine , Sweden A world class mineral locality

2016

The Malmberget iron mine near Gallivare, Lappland, Sweden has produced a series of well crystallised, interesting mineral species since the end of the Hi century. Since the 1980's the author has documented and participated in some discoveries of exceptional crystals such as hematite, calcite, fluorite, sti/bite, stellerite, pyrite, fluorapatite, quartz, feldspars, ferrohornblende, chalcopyrite, titanite etc. It should be noted that during most of the last two decades, primarily a couple of miners have had the license from the mining company to recover mineral specimens. These miners, together with the miners giving them tips of encountered pockets, and the positive attitude of the LKAB mining company to restricted mineral specimen recovery, are the true heroes of saving world class specimens and thus have been vital in making Malmberget a world renowned locality among connoiseurs. Geology Northern Sweden has several of the worlds largest and richest magnetite deposits of magmati...