scholarly journals Estimation of Iron Ore Pellet Softening in a Blast Furnace with Computational Thermodynamics

Metals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1515
Author(s):  
Mikko Iljana ◽  
Eetu-Pekka Heikkinen ◽  
Timo Fabritius
Keyword(s):  
Blast Furnace ◽  
Sio2 Content ◽  
Al2o3 Content ◽  
Softening Behavior ◽  
Liquid Phases ◽  
Iron Ore Pellet ◽  
Packed Structure ◽  
Acid Pellet ◽  
The Postponement ◽  
Liquid Formation

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.

scholarly journals Liquid Flow in Blast Furnace Hearth Concentrated on Inner Packed Structure

2001 ◽  
Vol 87 (5) ◽  
pp. 388-395 ◽  
Author(s):  
Akihiko SHINOTAKE ◽  
Morimasa ICHIDA ◽  
Hajime OOTSUKA ◽  
Yoichi SUGIZAKI
Keyword(s):  
Blast Furnace ◽  
Liquid Flow ◽  
Furnace Hearth ◽  
Blast Furnace Hearth ◽  
Packed Structure

Equilibrium of reduction of titanium oxides from blast-furnace-type slags of the CaO-MgO-SiO2-Al2O3-TiO2 system in liquid phases

1989 ◽  
Vol 152 (2) ◽  
pp. 447-461 ◽  
Author(s):  
Ryszard Benesch ◽  
Andrzej łȩdzki ◽  
Roman Kopeć ◽  
Ryszard Stachura
Keyword(s):  
Blast Furnace ◽  
Titanium Oxides ◽  
Liquid Phases

scholarly journals Effect of Basicity and Al2O3 on Viscosity of Blast Furnace Slag and Thermodynamic Analysis

2021 ◽  
Author(s):  
Jian Zhang ◽  
Zhengjian Liu ◽  
Jianliang Zhang ◽  
Cui Wang ◽  
Hengbao Ma ◽  
...  
Keyword(s):  
Activation Energy ◽  
Thermal Stability ◽  
Blast Furnace ◽  
Constant Temperature ◽  
Slag Basicity ◽  
Al2o3 Content ◽  
Wave Number ◽  
Slag Viscosity ◽  
Slag Structure ◽  
Slag Temperature

With the increased use of laterite nickel ore, the impact of high Al2O3 slag on blast furnace smelting has gradually increased. In this paper, the effects of slag basicity and Al2O3 content on slag viscosity and enthalpy change under constant temperature conditions was investigated. The changes in slag structure were analyzed by activation energy and Fourier Transform Infrared (FT-IR) spectroscopy. The relationship between slag components and slag temperature and viscosity when slag heat is reduced was investigated. The results showed that the viscosity first slightly decreased and then significantly increased with increasing basicity at constant temperature. With the addition of Al2O3 content, the viscosity of the slag increases. The activation energy increases with increasing slag basicity and Al2O3. With increasing basicity, the [SiO4]4- tetrahedral unit trough depth becomes shallow, the [AlO4]5- asymmetric stretching band migrates to lower wave numbers, and the slag structure depolymerizes. With the increase of Al2O3 content, the trough of [SiO4]4- tetrahedra deepens and the center of the symmetric stretching band moves to a higher wave number. The [AlO4]5- asymmetric stretching band becomes obvious, indicating the complexity of the slag structure. When the heat decreases, the slag temperature increases as the basicity increases, and the slag thermal stability is better at the basicity of 0.95-1.05. As the Al2O3 content increases, the thermal stability of the slag becomes worse.

Optimizing MgO distribution between sinter and pellet based on melting behavior and interaction

2021 ◽  
Vol 118 (3) ◽  
pp. 318
Author(s):  
Kaikai Bai ◽  
Yuzhu Pan ◽  
Jingsong Wang ◽  
Haibin Zuo ◽  
Qingguo Xue
Keyword(s):  
Blast Furnace ◽  
Melting Point ◽  
Cohesive Zone ◽  
Melting Behavior ◽  
Excessive Amount ◽  
Trade Off ◽  
Liquid Phases ◽  
Blast Furnace Ironmaking ◽  
Distribution Index ◽  
Higher Temperature

During blast furnace ironmaking, MgO flux is added to the sinter or pellets to reduce the viscosity and improve the desulfurization capacity of the slag. The distribution of total MgO addition between the sinter and pellets affects the interaction between the ferrous burdens. Inappropriate interaction between different burdens promotes the formation of an excessive amount of low-melting-point liquid phases, which reduces the permeability of the cohesive zone. In this study, the effect of MgO on the interaction between the sinter and pellets was visualized during heating and further investigated using thermodynamic calculations. A new concept named the distribution index of MgO was proposed for optimizing the MgO distribution between the sinter and pellets. A trade-off between the permeability and interaction between burdens in the cohesive zone was observed, which can be addressed by postponing the interaction between burdens to a higher temperature (i.e., a lower part of the cohesive zone).

scholarly journals Influence of Al2O3 Content on the Melting and Fluidity of Blast Furnace Type Slag with Low TiO2 Content

2018 ◽  
Vol 2018 ◽  
pp. 1-6
Author(s):  
Hao Liu ◽  
Yuelin Qin ◽  
Yanhua Yang ◽  
Qianying Zhang ◽  
Nengyun Deng
Keyword(s):  
Blast Furnace ◽  
Viscous Flow ◽  
Slag System ◽  
Al2o3 Content ◽  
Slag Viscosity ◽  
Flow Activation Energy ◽  
Flow Units ◽  
Precipitated Phase ◽  
Flow Activation ◽  
Furnace Slag

The increasing usage of iron ores with high Al2O3 content significantly increases the amount of Al2O3 in blast furnace slag and consequently affects its performance. This work uses slag sampled on site to study the effects of changes in Al2O3 content on the fluidity of the CaO–SiO2–Al2O3–MgO–TiO2 slag system that is characterized by high Al2O3 and low TiO2 contents, as well as on the phase transition law during the cooling process. Slag viscosity exhibits a rising trend with an increase in Al2O3 content, and Al2O3 in the tested slag is alkaline. The viscous flow activation energy of molten slag rises from 157 kJ/mol to 172 kJ/mol with an increase in Al2O3 content, and the viscous flow units in the slag become large and complicated. When slag is cooled, the main precipitated phase is melilitite. Spinel, perovskite, and olivine are also observed. The crystallization amount of the melilitite phase decreases constantly with an increase in Al2O3 content.

scholarly journals Effects of Packed Structure and Liquid Properties on Liquid Flow Behavior in Lower Part of Blast Furnace

2005 ◽  
Vol 45 (10) ◽  
pp. 1461-1465 ◽  
Author(s):  
Yoshiyuki BANDO ◽  
Satoru HAYASHI ◽  
Atsushi MATSUBARA ◽  
Masaaki NAKAMURA
Keyword(s):  
Blast Furnace ◽  
Liquid Flow ◽  
Flow Behavior ◽  
Packed Structure

scholarly journals Roles of MgO and Al2O3 on the Viscous and Structural Behavior of Blast Furnace Primary Slag, Part 1: C/S = 1.3 Containing TiO2

Metals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 866 ◽  
Author(s):  
Tingle Li ◽  
Changyu Sun ◽  
Sunny Song ◽  
Qi Wang
Keyword(s):  
Blast Furnace ◽  
Network Structure ◽  
Equilibrium Phase ◽  
Phase Region ◽  
Structure Characterization ◽  
Al2o3 Content ◽  
Slag Viscosity ◽  
Stable Operation ◽  
The Difference ◽  
Cylinder Method

This research provides fundamental insight into the roles of MgO and Al2O3 on the viscous and structural behaviors of CaO−SiO2−MgO−Al2O3−10 mass% TiO2−5 mass% FeO (CaO/SiO2 = 1.3) system primary blast furnace slag. The slag viscosity is measured by the rotating cylinder method, which is essential to the efficient and stable operation of a blast furnace. The network structure characterization of the quenched vitreous samples was conducted using Fourier Transformation Infrared (FTIR) and Raman spectroscopy. Unusual viscous behaviors (that the slag viscosity and the activation energy decrease or increase with increasing MgO or Al2O3 content) were observed, corresponding to changes in the network structure certified by FTIR and Raman analyses. It seems that the addition of MgO and Al2O3 prefers to modify the Si−O and Ti−O network in the present slag. When the slag composition reaches 10% MgO and 12% Al2O3, unexpected viscous behaviors (that MgO increases viscosity and Al2O3 decreases viscosity) are discovered. The roles of MgO and Al2O3 could be interpreted by changes in the arrangement structure of ions in liquid, corresponding to changes in the primary equilibrium phase region determined in phase diagrams and variation in the difference between the experimental and liquidus temperature, respectively.

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