Effect of olivine as MgO-bearing flux on low- and high-alumina iron ore pellets
Abstract
In the present study, the effect of MgO in the form of olivine flux on low- and high-alumina iron ore pellet mineralogy and pellet quality was studied. Green pellets were prepared by varying the MgO content from 0 to 1.5% with a basicity (CaO/SiO2) of 0.30. The pellets were tested for green pellet properties, cold crushing strength (CCS), and reduction degradation index (RDI) and fired at temperatures between 1300 and 1320 oC. An optical microscope with an image analyzer, SEM-EDS, was used to assess the mineralogical phases present in the pellets and the chemical analysis of the mineralogical phases, respectively. The laboratory tests showed that with increasing MgO addition in both low and high alumina pellets, magnesio-ferrite & silicate melt phases increased and the porosity and hematite phases decreased. The decrease in porosity was due to increase in silicate melt formation from the silica in the olivine. With increasing MgO addition, the CCS value of the pellets increased up to an MgO content of 0.9 to 1.1%. Thereafter, the CCS value of the pellets decreased with increasing MgO addition for both low and high alumina pellets. At an MgO content of 0.9 to 1.1%, the CCS value was higher due to the formation of a low melting point magnesio-ferrite phase, which imparted strength to the pellets. For pellets with an MgO level of >1.1, the RDI was within the control limit for both low- and high-alumina pellets. This may be due to a reduction in the porosity of the pellet and a better distribution of the silicate melt phase. Low-alumina pellets showed better physical and metallurgical properties compared to high-alumina iron ore pellets.
References
1. Iljana, M., Kemppainen, A., Paananen, T., Mattila, O., Heikkinen, E.P., Fabritius, T., 2016, “Evaluating the reduction-softening behaviour of blast furnace burden with an advanced Test”. ISIJ Int. Vol.56, No.10 , pp 1705–1714.
2. Kemppainen, A., Mattila, O., Heikkinen, E., Paananen, T., Fabritius, T., 2012, “ Effect of H2-H2O on the reduction of olivine pellets in CO-CO2 Gas”. ISIJ Int. Vol. 52, No.11 , pp 1973–1978.
3. Matsumura, M., Hoshi, M., Kawaguchi, T., 2005, “ Improve of sinter softening property and reducibility by controlling chemical compositions”, ISIJ Int. Vol. 45, No.4, pp 598–607.
4. Meraj, Md., Susanta, Pramanik., and Jagannath. Pal., 2015, “ Role pf MgO and its different minerals on properties of iron ore pellets”, Transactions of the Indian Institute of Metals, DOI: 10.1007/s12666-015-0676-8.
5. Hesham, M., Ahmed,Charlotte Andersson., and Bjorkman, B., 2015, “ Efect of olivine fineness and thermal profile on oxidation- sintering of magnetite concentrate pellets”, AISTech— The Iron & Steel Technology Conference and Exposition, At Convention Center, Cleveland, USA.
6. Prestes, E., Chinelatto, A.S.A., Resende, W.S., 2009. “Post mortem analysis of burned magnesia-chromite brick used in short rotary furnace of secondary lead smelting”. Ceramica Vol.55, No.33, pp 61–66.
7. Jian-liang. Zhang., Zhen-yang, Wang., Xiang-dong, Xing., and Zheng-jian. Liu., 2014, “Effect of alumina oxide on the compressive strength of pellets”, International Journal of Minerals, Metallurgy, and Materials vol. 21, NO.4, PP. 339–344.
8. Srinivas, Dwarapudi., and Madhu. Ranjan., 2010, “Influence of oxide and melt phases on the RDI of iron ore pellets suitable for shaft furnace of direct reduction, ISIJ International, Vol. 50, No. 11, pp.1581-1589.
Authors retain copyright of the published papers and grant to the publisher the non-exclusive right to publish the article, to be cited as its original publisher in case of reuse, and to distribute it in all forms and media.
The Author(s) warrant that their manuscript is their original work that has not been published before; that it is not under consideration for publication elsewhere; and that its publication has been approved by all co-authors, if any, as well as tacitly or explicitly by the responsible authorities at the institution where the work was carried out. The Author(s) affirm that the article contains no unfounded or unlawful statements and does not violate the rights of others. The author(s) also affirm that they hold no conflict of interest that may affect the integrity of the Manuscript and the validity of the findings presented in it. The Corresponding author, as the signing author, warrants that he/she has full power to make this grant on behalf of the Author(s). Any software contained in the Supplemental Materials is free from viruses, contaminants or worms.The published articles will be distributed under the Creative Commons Attribution ShareAlike 4.0 International license (CC BY-SA).
Authors are permitted to deposit publisher's version (PDF) of their work in an institutional repository, subject-based repository, author's personal website (including social networking sites, such as ResearchGate, Academia.edu, etc.), and/or departmental website at any time after publication.
Upon receiving the proofs, the Author(s) agree to promptly check the proofs carefully, correct any typographical errors, and authorize the publication of the corrected proofs.
The Corresponding author agrees to inform his/her co-authors, of any of the above terms.