Melting Behaviour of Iron Ore Pellet Bed under Nut Coke Mixed Charge Conditions

Gavel, Dharm Jeet; Adema, Allert T.; Stel, Jan van der; Kwakernaak, C.; Sietsma, Jilt; Boom, R.; Yang, Yongrong

doi:10.2355/isijinternational.isijint-2019-246

Cited by 10 publications

(18 citation statements)

References 16 publications

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“…Fossil-based nut coke was used as a reference material in the reactivity experiments, which was provided by SSAB, Raahe. Nut coke is a term used for metallurgical coke that is typically in the size range of 8-40 mm in diameter [15].…”

Section: Methodsmentioning

confidence: 99%

Effects of Briquetting and High Pyrolysis Temperature on Hydrolysis Lignin Char Properties and Reactivity in CO-CO2-N2 Conditions

et al. 2021

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Carbonaceous reductants for pyrometallurgical applications are usually obtained from fossil-based sources. The most important properties of the reductants greatly depend on the application and the feeding of the reductant into the process. However, the mechanical strength, calorific value, fixed carbon content, and reactivity of the reductant are the properties that usually define the applicability of the reductant for different processes. The reactivity of the biochars is usually high in comparison to metallurgical coke, which may restrict the applicability of the biochar in reduction processes. One cause of the higher reactivity is the higher surface area of the biochars, which can be suppressed with agglomeration treatment, e.g., briquetting. In this work, hydrolysis lignin was used for slow pyrolysis experiments to produce biochars. The biochars were pyrolyzed in briquetted form and in as-received form at various temperatures. The reactivity values of the biochars were tested in dynamic reactivity tests in a CO-CO2-N2 gas atmosphere at temperatures of up to 1350 °C. It was found that the yield of the hydrolysis lignin char only decreased by 3.36 wt% when the pyrolysis temperature was elevated from 600 to 1200 °C, while a decrease in yield of 4.88 wt% occurred when the pyrolysis temperature was elevated from 450 to 600 °C. The mass loss of hydrolysis lignin biochar in the reactivity experiment in CO-CO2-N2 atmosphere was significantly decreased from 79.41 wt% to 56.80 wt% when the hydrolysis lignin was briquetted before the slow pyrolysis process and the temperature of the pyrolysis process was elevated from 600 to 1200 °C. This means that the mass loss of the material was suppressed by 22.61 wt% due to the higher pyrolysis temperature and briquetting process.

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Section: Methodsmentioning

confidence: 99%

Effects of Briquetting and High Pyrolysis Temperature on Hydrolysis Lignin Char Properties and Reactivity in CO-CO2-N2 Conditions

et al. 2021

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“…Gavel et al reported that the carburization of solid iron with solid carbon is superior to that with CO gas. [3][4][5] There are several steps in the melting reaction of iron with solid carbon: a) melting reaction of iron, b) carbon diffusion in solid iron, c) mass transfer in liquid Fe-C alloy and d) dissolution of graphite into liquid Fe-C alloy. Some researchers have reported the In-situ observation behavior of carburization and melting of iron.…”

Section: Effect Of Silica In Ash Of Coke On Carburization and Melting Of Ironmentioning

confidence: 99%

Effect of Silica in Ash of Coke on Carburization and Melting of Iron

2021

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Reducing energy consumption in ironmaking process is essential for decreasing the amount of carbon dioxide emission from the blast furnace process. To effectively reduce carbon dioxide emission, a faster reduction of iron ore, as well as the acceleration of carburization and melting of the reduced iron is important. Understanding the ash behavior of coke in blast furnace is necessary for controlling carburization because ash prevents carburization. In this study, the following were investigated:1) Condensation behavior of the ash components on the surface of coke by gasification under the simulated blast furnace condition 2) Melting behavior of iron tablet by the direct contact with coke plate 3) In-situ observation of the melting behavior of coke-iron composite and effect of deashing treatment 4) In-situ observation of the melting behavior of Fe-Si alloy using graphite The results revealed that ash condenses on the coke surface via gasification, and the ash coverage ratio of the coke surface increases with increasing in the coke reactivity. In addition, the melting of iron by carburization with coke proceeds at lower temperature when the coke reactivity is high. However, the effect of ash coverage on this behavior is significantly higher than that of coke reactivity, and an increase in the ash coverage ratio suppresses the carburization and melting of iron. In addition, during holding at high temperature, SiO 2 in ash is reduced to Si, and it alloys with metallic iron. Furthermore, an increase in Si concentration in metallic iron increases the melting temperature of Fe-Si system. Consequently, carburization and melting iron are suppressed.

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“…The iron present as the pellet shell carburises first by its direct contact with the coke to melt later. This continues to cause the layer-wise melting and dripping of the pellet bed [19,25].…”

Section: Quenched Pellet Bedmentioning

confidence: 99%

A comparative study of pellets, sinter and mixed ferrous burden behaviour under simulated blast furnace conditions

Gavel

Adema

Stel

et al. 2020

Ironmaking & Steelmaking

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Physicochemical behaviour of the pellets, sinters and its mixture (60% pellets: 40% sinter) is investigated by a series of smelting and quenching experiments. For all ferrous raw-material beds, three distinct stages of bed shrinkage occur due to indirect reduction, softening and melting. However, the characteristic nature (displacement, temperature and permeability) differ with the ferrous raw-material type. In mixed ferrous bed, the first and third stages are found to be controlled by the pellets (individual particle shrinkage) and sinter (slow melting rate), respectively. Second stage behaviour is initially observed to be close to the pellet and later to that of sinter. In mixed bed (upto 1505°C), the interaction between the pellet and sinter is limited to the interface only. The sinter slag is observed to control the melting and dripping properties of the mixed bed.These results gives an understanding of individual and mixed burden behaviour under blast furnace conditions.

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Melting Behaviour of Iron Ore Pellet Bed under Nut Coke Mixed Charge Conditions

Cited by 10 publications

References 16 publications

Effects of Briquetting and High Pyrolysis Temperature on Hydrolysis Lignin Char Properties and Reactivity in CO-CO2-N2 Conditions

Effects of Briquetting and High Pyrolysis Temperature on Hydrolysis Lignin Char Properties and Reactivity in CO-CO2-N2 Conditions

Effect of Silica in Ash of Coke on Carburization and Melting of Iron

A comparative study of pellets, sinter and mixed ferrous burden behaviour under simulated blast furnace conditions

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