Research

Jump to: Review

14 pages, 5392 KiB

Open AccessArticle

Study on Corrosion Resistance of S-Carbon Bricks for Blast Furnace Hearth in Molten Iron

by Huangyu Shi, Cui Wang, Yanbing Zong, Yanxiang Liu, Zhongyi Wang and Jianliang Zhang

Metals 2023, 13(7), 1240; https://doi.org/10.3390/met13071240 - 06 Jul 2023

Viewed by 1042

This study simulated the corrosion reaction of S-carbon bricks in a hearth at different carbon contents, flow velocities and temperatures, and their macroscopic and microscopic morphologies were observed by scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). The results showed that the dissolution [...] Read more.

This study simulated the corrosion reaction of S-carbon bricks in a hearth at different carbon contents, flow velocities and temperatures, and their macroscopic and microscopic morphologies were observed by scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). The results showed that the dissolution of elemental carbon from carbon bricks into molten iron was a rate-controlled reaction. Increasing the temperature to around 1500 °C and decreasing the carbon content to around 4.5% reduced the saturated solubility of carbon in molten iron, and the erosion degree and dissolution rate of the carbon bricks increased correspondingly. For the flow velocity, its increase promoted mechanical flushing and led to an increase in the convective heat transfer coefficient of molten iron, which would increase the hot-side temperature of the hearth sidewall, promoting carbon unsaturation in hot metal and the dissolution reaction. Full article

(This article belongs to the Special Issue Low-Carbon Metallurgy Technology towards Carbon Neutrality)

► Show Figures

Figure 1

12 pages, 4592 KiB

Open AccessArticle

Effect of Main Composition on the Viscosity and Thermal Stability of BaO-Containing Slag

by Xiaoyue Fan and Jianliang Zhang

Metals 2023, 13(7), 1170; https://doi.org/10.3390/met13071170 - 23 Jun 2023

Viewed by 963

Abstract

The authors of this study systematically investigate the influence of the main components of BaO-containing slag on its viscosity and thermal stability. The results indicate that the viscosity of slag significantly increases with the mass fraction of the crystalline phase. Increasing the slag [...] Read more.

The authors of this study systematically investigate the influence of the main components of BaO-containing slag on its viscosity and thermal stability. The results indicate that the viscosity of slag significantly increases with the mass fraction of the crystalline phase. Increasing the slag basicity from 1.00 to 1.10 and the MgO content from 5.0% to 9.5% is an effective way to weaken the influence of crystallization on slag viscosity and improve the stability of BaO-containing slag. Al₂O₃ content over 11% is necessary to maintain a higher slag temperature, which enhances the ability of BaO-containing slag to resist the influence of crystallization on relative viscosity. When the heat of BaO slag is greatly reduced, increasing the slag basicity from 1.05 to 1.15 and MgO content to over 6.5% can help maintain the thermal stability of slag. The effect of Al₂O₃ content on the viscosity of slag under conditions of fixed heat is greater than that under constant temperature conditions. As the heat decreases, the Al₂O₃ content increase from 9% to 13% has a more significant effect on the viscosity and temperature of slag. A lower Al₂O₃ content in slag is advantageous for reducing the influence of heat fluctuation on slag viscosity. Full article

(This article belongs to the Special Issue Low-Carbon Metallurgy Technology towards Carbon Neutrality)

► Show Figures

Figure 1

14 pages, 2362 KiB

Open AccessFeature PaperArticle

Ranking of Injection Biochar for Slag Foaming Applications in Steelmaking

by Christopher DiGiovanni, Delin Li, Ka Wing Ng and Xianai Huang

Metals 2023, 13(6), 1003; https://doi.org/10.3390/met13061003 - 23 May 2023

Cited by 8 | Viewed by 2383

Abstract

The electric arc furnace (EAF) has the potential to significantly contribute to the decarbonization of the iron and steel industry. However, during EAF steelmaking, carbon still needs to be injected into the molten slag to initiate slag foaming, which is beneficial to the [...] Read more.

The electric arc furnace (EAF) has the potential to significantly contribute to the decarbonization of the iron and steel industry. However, during EAF steelmaking, carbon still needs to be injected into the molten slag to initiate slag foaming, which is beneficial to the energy efficiency and protection of the furnace. To move away from fossil carbon, biocarbon has gained attention as an injection carbon agent. In this study, two biochar candidates were added to the molten slag layer of an induction furnace for steel melting, to simulate EAF steelmaking conditions. The resultant slag foaming height was measured, and a ranking in comparison to two fossil carbon candidates was developed. The results indicate that the injection biochar sample, in the form of a bio-briquette, has a considerable degree of slag foaming capacity. More work is ongoing to develop a standardized testing methodology of ranking various injection biochar candidates for their suitability and qualification for use on a larger scale. Full article

(This article belongs to the Special Issue Low-Carbon Metallurgy Technology towards Carbon Neutrality)

► Show Figures

Figure 1

16 pages, 6965 KiB

Open AccessArticle

Preparation of Micro-Electrolytic Iron-Carbon Filler for Sewage by Recycling Metallurgical Dust

by Runsheng Xu, Yuchen Zhang, Xiaoming Huang, Minghui Cao, Jiyong Yu, Jianliang Zhang, Heng Zheng and Johannes Schenk

Metals 2023, 13(4), 673; https://doi.org/10.3390/met13040673 - 29 Mar 2023

Viewed by 1232

Abstract

In this paper, a new iron-carbon micro-electrolytic filler for wastewater treatment was prepared using the blast furnace dust. The effects of preparation conditions on the performance of the filler during the wastewater treatment were investigated. The optimal preparation conditions of the filler were [...] Read more.

In this paper, a new iron-carbon micro-electrolytic filler for wastewater treatment was prepared using the blast furnace dust. The effects of preparation conditions on the performance of the filler during the wastewater treatment were investigated. The optimal preparation conditions of the filler were obtained, which provided an experimental theoretical basis for the use of metallurgical dust sludge in the preparation of micro-electrolytic fillers. From the results of treating methyl orange-simulated wastewater with fillers of different preparation conditions, it could be obtained that the improvement of the filler processing performance requires a suitable iron to carbon ratio, sintering time, and sintering temperature. The optimum preparation conditions were a 1:2 iron-carbon ratio, 30 min sintering time, and 1100 °C sintering temperature. The effect of treatment conditions on the performance of the iron-carbon micro-electrolytic filler was also investigated. The results showed that increasing the filler addition, increasing the treatment temperature, and decreasing the initial pH could effectively improve the treatment efficiency of the filler for methyl orange-simulated wastewater. More than 99% of the methyl orange could be removed in the wastewater under the conditions of 5 g of filler, 40 °C, and pH = 3. Full article

(This article belongs to the Special Issue Low-Carbon Metallurgy Technology towards Carbon Neutrality)

► Show Figures

Figure 1

10 pages, 2385 KiB

Open AccessArticle

Parameter Optimization for Hydrogen-Induced Fluidized Bed Reduction of Magnetite Iron Ore Fines

by Heng Zheng, Johannes Schenk, Oday Daghagheleh and Bernd Taferner

Metals 2023, 13(2), 339; https://doi.org/10.3390/met13020339 - 08 Feb 2023

Cited by 2 | Viewed by 1297

Abstract

Hydrogen-based direct reduced iron (HyDRI) produced by fluidized bed has great potential for achieving the target of net-zero carbon in steelmaking. However, when magnetite ores were used as feedstock, several process parameters showed influences on its fluidization and reduction behaviors. To confirm the [...] Read more.

Hydrogen-based direct reduced iron (HyDRI) produced by fluidized bed has great potential for achieving the target of net-zero carbon in steelmaking. However, when magnetite ores were used as feedstock, several process parameters showed influences on its fluidization and reduction behaviors. To confirm the dominant influencing factors and its optimum process condition, the orthogonal experimental method was conducted in the present study. The result shows that the primary and secondary influencing factors are oxidation temperature, oxidation content, MgO addition amount, and gas velocity. The optimum condition is that the magnetite iron ore is deeply oxidized at 800 °C, mixed with 1.5 wt.% of MgO powder, and reduced in the fluidized bed at a gas velocity of 0.45 m/s. Full article

(This article belongs to the Special Issue Low-Carbon Metallurgy Technology towards Carbon Neutrality)

► Show Figures

Figure 1

Review

Jump to: Research

12 pages, 1956 KiB

Open AccessReview

Review on the Application and Development of Biochar in Ironmaking Production

by Shijie Wang, Yifan Chai, Yici Wang, Guoping Luo and Shengli An

Metals 2023, 13(11), 1844; https://doi.org/10.3390/met13111844 - 03 Nov 2023

Cited by 1 | Viewed by 1260

Abstract

In recent years, the concept of green, low-carbon and clean energy consumption has been deeply rooted in the hearts of the people, and countries have actively advocated the use of new energy. In the face of problems such as resource shortage and environmental [...] Read more.

In recent years, the concept of green, low-carbon and clean energy consumption has been deeply rooted in the hearts of the people, and countries have actively advocated the use of new energy. In the face of problems such as resource shortage and environmental pollution, we began to explore the use of new fuels instead of coal for production. Biomass resources have the characteristics of being renewable and carbon neutral and having large output. As an energy utilization, it is helpful to promote the transformation of the energy structure in various countries. Applying it to ironmaking production is not only conducive to energy conservation and emission reduction in the ironmaking process but also can achieve efficient utilization of crop waste. By introducing the source and main preparation methods of biochar, this paper expounds the main links and advantages of biochar in the ironmaking process and puts forward the direction of biochar in ironmaking in the future. Full article

(This article belongs to the Special Issue Low-Carbon Metallurgy Technology towards Carbon Neutrality)

► Show Figures

Graphical abstract

20 pages, 4881 KiB

Open AccessReview

Study on the Bath Smelting Reduction Reaction and Mechanism of Iron Ore: A Review

by Guilin Wang, Jianliang Zhang, Yaozu Wang, Yubo Tan, Zhen Li, Bo Zhang and Zhengjian Liu

Metals 2023, 13(4), 672; https://doi.org/10.3390/met13040672 - 29 Mar 2023

Cited by 1 | Viewed by 2323

Abstract

Against the background of low global carbonization, blast furnace ironmaking technology with coking puts huge amounts of pressure on the global steel industry to save energy and reduce emissions due to its high pollution levels and high energy consumption. Bath smelting reduction technology [...] Read more.

Against the background of low global carbonization, blast furnace ironmaking technology with coking puts huge amounts of pressure on the global steel industry to save energy and reduce emissions due to its high pollution levels and high energy consumption. Bath smelting reduction technology is globally favored and studied by metallurgists as a non-blast furnace ironmaking technology that directly reduces iron ore into liquid metal without using coke as the raw material. The smelting reduction reaction of iron ore, which is the core reaction of the process, is greatly significant to its productivity and energy saving. Therefore, this paper focuses on the behavior and mechanism of iron ore’s smelting reduction. This work focuses on three key aspects of smelting reduction, namely, the thermal decomposition characteristics of iron ore during the smelting reduction, the smelting reduction mechanism of iron-ore particles, and the smelting reduction mechanism of FeO-bearing slag. The experimental study methods, reaction mechanisms, influencing factors, and kinetic behavior of the three are highlighted. In this work, the reaction mechanism of thermal iron-ore decomposition, iron-ore particle smelting reduction, and FeO-bearing slag smelting reduction on the three reactions were observed, providing a theoretical basis for how to select and optimize raw materials for the bath smelting reduction process. Moreover, the kinetic study clarifies the limiting steps of the reactions and provides guidance for an improvement in the reaction rate. However, certain blank points in previous studies need to be further explored, such as the differences in the research results of same factor, the large variation in reaction activation energy, and the coupling mechanism and inter-relatedness of the three key aspects’ reactions with each other. Full article

(This article belongs to the Special Issue Low-Carbon Metallurgy Technology towards Carbon Neutrality)

► Show Figures

Figure 1

38 pages, 3935 KiB

Open AccessReview

A Comprehensive Review of Secondary Carbon Bio-Carriers for Application in Metallurgical Processes: Utilization of Torrefied Biomass in Steel Production

by Lina Kieush, Johannes Rieger, Johannes Schenk, Carlo Brondi, Davide Rovelli, Thomas Echterhof, Filippo Cirilli, Christoph Thaler, Nils Jaeger, Delphine Snaet, Klaus Peters and Valentina Colla

Metals 2022, 12(12), 2005; https://doi.org/10.3390/met12122005 - 23 Nov 2022

Cited by 14 | Viewed by 3100

Abstract

This review aims to show the significance of the use of secondary carbon bio-carriers for iron and steel production. The term ‘secondary carbon bio-carriers’ in this review paper refers to biomass, torrefied biomass, biochar, charcoal, or biocoke. The main focus is on torrefied [...] Read more.

This review aims to show the significance of the use of secondary carbon bio-carriers for iron and steel production. The term ‘secondary carbon bio-carriers’ in this review paper refers to biomass, torrefied biomass, biochar, charcoal, or biocoke. The main focus is on torrefied biomass, which can act as a carbon source for partial or complete replacement of fossil fuel in various metallurgical processes. The material requirements for the use of secondary carbon bio-carriers in different metallurgical processes are systematized, and pathways for the use of secondary carbon bio-carriers in four main routes of steel production are described; namely, blast furnace/basic oxygen furnace (BF/BOF), melting of scrap in electric arc furnace (scrap/EAF), direct reduced iron/electric arc furnace (DRI/EAF), and smelting reduction/basic oxygen furnace (SR/BOF). In addition, there is also a focus on the use of secondary carbon bio-carriers in a submerged arc furnace (SAF) for ferroalloy production. The issue of using secondary carbon bio-carriers is specific and individual, depending on the chosen process. However, the most promising ways to use secondary carbon bio-carriers are determined in scrap/EAF, DRI/EAF, SR/BOF, and SAF. Finally, the main priority of future research is the establishment of optimal parameters, material quantities, and qualities for using secondary carbon bio-carriers in metallurgical processes. Full article

(This article belongs to the Special Issue Low-Carbon Metallurgy Technology towards Carbon Neutrality)

► Show Figures