Sondages dans l'homme mort du haut fourneau à travers une tuyère

Helleisen, M.; Nicolle, R.; Metz, B.; Bouget, J.; Jusseau, N.

doi:10.1051/metal/198784110747

Cited by 3 publications

(3 citation statements)

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“…Alkalis are known to influence the solution loss reaction by initiating gasification reaction at considerably lower temperatures (750-850°C) compared to classical gasification temperatures of 950°C, and also increase the reaction rates as a function of potassium content. 8,9) The catalytic effect of alkalis and iron phases on coke gasification was also reported in other studies. 10) Potassium content of coke varies at different locations in a blast furnace e.g.…”

Section: Introductionmentioning

confidence: 92%

“…alkalis are completely vaporised at raceway and their concentration becomes low in hearth coke while alkali concentration is significantly high in the deadman coke such that potassium content reaches up to 30 % of total coke ash. 8,11,12) Potassium is generally believed to weaken the coke strength at high temperatures. 8) Concentration gradient of alkali in coke lump was reported to be responsible for stress abrasion of alkali-rich layer of coke.…”

Section: Introductionmentioning

confidence: 99%

“…8,11,12) Potassium is generally believed to weaken the coke strength at high temperatures. 8) Concentration gradient of alkali in coke lump was reported to be responsible for stress abrasion of alkali-rich layer of coke. 14) In other study, up to 5 % variation of alkalis in coke did not indicate any adverse impact on the coke strength (CSR).…”

Section: Introductionmentioning

confidence: 99%

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Degradation Behaviour of a High CSR Coke in an Experimental Blast Furnace: Effect of Carbon Structure and Alkali Reactions

et al. 2005

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A high CSR coke was tested in the LKAB's Experimental Blast Furnace (EBF) at Luleå. The evolution of physical and chemical properties of the centre-line coke samples were analysed by Light Optical Microscopy (LOM), BET N 2 absorption and SEM/XRF/XRD. Alkali distribution in the EBF cokes was examined by XRF/SEM and EDS. Thermo Gravimetric Analysis (TGA) was used to measure isothermal and nonisothermal CO 2 reactivity of the cokes. The crystalline order of carbon and the concentration of alkalis were found to increase as the coke descended through thermal reserve zone to the cohesive zone of the EBF. The crystallite height (L c ) of EBF coke carbon displayed a linear correlation with the measured EBF temperatures demonstrating the strong effect of temperature on carbon structure of coke in the EBF. Alkali concentration of the coke was increased as it descended into the EBF, and was uniformly distributed throughout the coke matrix. The CO 2 reactivity of lower zone cokes was found to increase when compared to the reactivity of the upper zones cokes, and was related to the catalytic effect of increased alkalis concentration. The deterioration of coke quality particularly coke strength and abrasion propensity were related to coke graphitisation, alkalization and reactivity. Coke graphitisation is shown to have a strong influence on the coke degradation behaviour in the EBF.KEY WORDS: coke; CSR; abrasion; graphitisation, XRD; gasification; TGA reactivity; alkali.experimental blast furnace. Even though the EBF tests are time consuming, tedious and highly expensive, the information generated is of great value in terms of their reliability suitability due to simulation of more realistic conditions of a blast furnace process.Coke degradation in a blast furnace occurs due to chemical, mechanical and thermal effects. At higher flame temperature, cracking of coke is mainly attributed to thermal stress while at lower temperatures, the degradation behaviour is influenced by coke reactivity which is dependent on other coke properties. The coke reactivity can be influenced by its three major properties namely porosity, carbon structure and constituent minerals. Coke pore structure is modified by growth and/or coalescence of pores, which is often related to fluidity and swelling characteristics of parent coals, 5) and modifies the available carbon surface area for gas reactions. Coke displays graphitisation behaviour particularly at temperatures exceeding 1 200°C, which is influenced by the catalytic effect of minerals such as iron, and is believed to weaken the abrasion resistance.6) Iron in coke is also believed to catalyze gasification reactions 7) which could have different implications on coke behavior in the EBF. The influence of other minerals particularly those containing alkali on the coke degradation is less certain. The main aim of this study is to investigate the effect of alkalis on coke behaviour in the experimental blast furnace. Therefore, it is imperative to discuss further various aspects of alkalis influence on...

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Section: Introductionmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Degradation Behaviour of a High CSR Coke in an Experimental Blast Furnace: Effect of Carbon Structure and Alkali Reactions

et al. 2005

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Method of Determining the Degree of Combustion of Pulverized-Coal Fuel in Blast Furnaces

et al. 2013

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Effects of alkali metal on solution loss and coke degradation

Guo

Liang

et al. 2019

Metall. Res. Technol.

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To research the effect of alkali metals on the solution-loss rate and coke strength after reaction, potassium and sodium vapors were prepared by a high-temperature thermal-reduction method, and the thermal properties of four industrial cokes that absorbed potassium and sodium vapor were studied. The thermal properties include the traditional thermal-property indices, coke reactive index and coke strength after reaction, and the coke strength after a 25% mass loss, which is obtained by a continuous thermogravimetric test. Results show that because of the different adsorption mode, the catalytic effect of potassium and sodium is different. During the early stages of the solution-loss reaction, the reaction rate of the potassium-rich coke is higher than that of the sodium-rich coke, but the reaction rate decreases rapidly. The reaction rate of the sodium-rich coke in the later stage of the reaction is higher than that of the potassium-rich coke. The coke strength after reaction of the alkali-rich coke is low, mainly because of the high carbon-solution loss. The coke strength after the 25% mass loss of potassium-rich coke was higher than that of the original coke because the solution reaction was closer to the surface reaction.

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Sondages dans l'homme mort du haut fourneau à travers une tuyère

Cited by 3 publications

References 0 publications

Degradation Behaviour of a High CSR Coke in an Experimental Blast Furnace: Effect of Carbon Structure and Alkali Reactions

Degradation Behaviour of a High CSR Coke in an Experimental Blast Furnace: Effect of Carbon Structure and Alkali Reactions

Method of Determining the Degree of Combustion of Pulverized-Coal Fuel in Blast Furnaces

Effects of alkali metal on solution loss and coke degradation

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