Estimation of iron ore pellet softening in a blast furnace with computational thermodynamics
|Author:||Iljana, Mikko1; Heikkinen, Eetu-Pekka1; Fabritius, Timo1|
1Process Metallurgy Research Unit, University of Oulu, P.O. Box 4300, FI-90014 Oulu, Finland
|Online Access:||PDF Full Text (PDF, 3 MB)|
|Persistent link:|| http://urn.fi/urn:nbn:fi-fe2021111855829
Multidisciplinary Digital Publishing Institute,
|Publish Date:|| 2021-11-18
In blast furnaces it is desirable for the burden to hold a lumpy packed structure at as high a temperature as possible. The computational thermodynamic software FactSage (version 7.2, Thermfact/CRCT, Montreal, Canada and GTT-Technologies, Aachen, Germany) was used here to study the softening behavior of blast furnace pellets. The effects of the main slag-forming components (SiO₂, MgO, CaO and Al₂O₃) on liquid formation were estimated by altering the chemical composition of a commercial acid pellet. The phase equilibria for five-component FeO-SiO₂-CaO-MgO-Al₂O₃ systems with constant contents for three slag-forming components were computed case by case and the results were used to estimate the formation of liquid phases. The main findings of this work suggested several practical means for the postponement of liquid formation at higher temperatures: (1) reducing the SiO₂ content; (2) increasing the MgO content; (3) reducing the Al₂O₃ content; and (4) choosing suitable CaO contents for the pellets. Additionally, the olivine phase (mainly the fayalitic type) and its dissolution into the slag determined the amount of the first-formed slag, which formed quickly after the onset of softening. This had an important effect on the acid pellets, in which the amount of the first-formed slag varied between 10 and 40 wt.%, depending on the pellets’ SiO₂ content.
|Type of Publication:||
A1 Journal article – refereed
|Field of Science:||
216 Materials engineering
This research was funded by Business Finland as a part of the Towards Fossil-free Steel (FFS) research programme, grant number 45774/31/2020.
© 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).