Raw material potential for the steel industry - Geology experts analyze the quality of Swedish ores

Aerial view of Kiruna with the city and former open-pit mines
Research work on the Per Geijer iron ore deposits of Luossavaara-Kiirunavaara Aktiebolag (LKAB) near Kiruna is ongoing at TU Freiberg until August 2021. The results already show a very promising raw material potential for the associated supply of the iron and steel industry.

Core logging on the 1065 meter level of the Kiirunavaara mine from exploration drillings of the northern part of the deposit.Iron ore is the basis for the production of iron and steel - the world's most important materials for the construction of buildings, machines, tools, cars, ships and airplanes. To be able to meet future demand, existing iron ore deposits must be further developed. One of the largest European mining areas is located in northern Sweden. Researchers from the Division of Economic Geology and Petrology at TU Bergakademie Freiberg have been active in an exploration project for the Per Geijer deposits in the Kiruna mining district since 2018 and support the characterization of the so-called Kiruna deposit type to analyze its raw material potential for iron ore mining.


Deposit research shows great raw material potential

Photomicrograph of magnetite and different generations of hematite from the Per Geijer ores.The Per Geijer deposits consist of a total of five ore bodies which, in addition to iron ore minerals such as magnetite (Fe3O4, up to 72 % Fe content) and hematite (Fe2O3, up to 70 % Fe content), also contain significant amounts of phosphate due to apatite (Ca5 [F | (PO4)3], up to 42 % P2O5 content). "Above all, the Per Geijer iron oxide-apatite deposits are of great importance due to the characterization of the in-situ ore and its processability in the future," explains Patrick Krolop, research scientist at the Division of Economic Geology and Petrology at TU Bergakademie Freiberg. The mineral-chemical and process-mineralogical data currently compiled in Freiberg indicate positively that the product guidelines can also be complied with in the future and that a high-quality end product will be available. In particular, the low content of penaltyMeasurement profile through typical magnetite using electron beam microprobe to analyze chemical composition of iron oxide: elevated V & Ni contents. elements such as nickel, cobalt and chromium as well as the high degree of liberation of magnetite of over 90 percent after comminution are decisive for this. "With our applied deposit research at TU Bergakademie Freiberg, we are making a significant contribution to the future supply of Europe's steel industry with high-quality iron ores," adds Prof. Dr. Thomas Seifert, acting head of the Division of Economic Geology and Petrology. 


Practical research for more efficient iron ore processing

The project is being financed by the Swedish company LKAB with a grant of around 430,000 Euros. As Europe's largest iron ore producer, LKAB has been mining up to 47,5 million tons of extremely high-quality crude iron ore annually in underground and open-pit mining at three locations in northern Sweden (Malmberget, Svappavaara, Kiruna) for 125 years. Kiirunavaara displays LKAB's most important Massive magnetite-rich ore, -762 m level, Kiirunavara Fe mine, LKAB.mine and constitutes the largest underground iron ore mine worldwide. In total, the area around Kiruna comprises four deposits, including the Per Geijer ore bodies. The final products, the so-called iron ore pellets, are in high demand from steel producers in Europe and around the world. LKAB pellets have a very high iron content of 67 percent and are converted from magnetite to hematite during pelletization. The energy released is retrieved back into the process. This enables a more environmentally friendly manufacturing process. According to LKAB, this should even be completely CO2-free by 2045 and thus complement the exemplary environmental management with innovative iron ore extraction options such as electric and fully automated mining and transport machines.

Publication

Krolop, P., Jantschke A., Gilbricht, S., Niiranen K. and Seifert, T., 2019. Minerallogical Imaging for Characterisation of the Per Geijer Apatite Iron Ores in the Kiruna district, Northern Sweden: A comparative Study of Mineral Liberation Analysis and Raman Imaging. Minerals 9 (9), 544; DOI 10.3390/min9090544.

Krolop, P., Niiranen, K., Gilbricht, S., Seifert, T., 2019. Ore type characterisation of the Per Geijer iron ore deposits in Kiruna, Northern Sweden. Proceedings Iron Ore Conference, Australasian Institute of Mining and Metallurgy, Perth, 343-353.

Krolop, P., Niiranen K., Gilbricht, S., Schulz, B., Oelze, M. and Seifert, T., 2021 (under review). Trace element geochemistry of iron oxides from the Per Geijer apatite iron ores in the Kiruna district, northern Sweden: Implications for ore genesis and potential economic products. Ore Geology Reviews.

Fragen zu diesem Thema beantwortet: 
Prof. Dr. Thomas Seifert, Phone: +49 3731-39-3527/2662 and Patrick Krolop, Phone: +49 3731-39-3516