Micro Pore Structure and Reaction Rate of Coke, Wood Charcoal and Graphite with CO2

Kawakami, Masahiro; Taga, Hiromitsu; Takenaka, Tohru; Yokoyama, Seiji

doi:10.2355/isijinternational.44.2018

Cited by 18 publications

(15 citation statements)

References 10 publications

(13 reference statements)

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“…The gasification rate of biomass charcoal is generally much higher than that of coke and graphite. 9) We also confirmed that the gasification rate of semi-charcoal was higher than that of coke and char. Therefore, all semicharcoal composite pellets was reduced higher than the coke composite pellets.…”

supporting

confidence: 75%

Effect of Residual Volatile Matter on Reduction of Iron Oxide in Semi-charcoal Composite Pellets

2010

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supporting

confidence: 75%

Effect of Residual Volatile Matter on Reduction of Iron Oxide in Semi-charcoal Composite Pellets

2010

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“…The gas ratio of the ore-coke composite starts to increase at approximately 750 K and it reaches the coexistence line of Fe 3 O 4 and FeO at approximately 1200 K. The gas ratio of the H1-graphite composite starts to increase at approximately 1 150 K. This is the maximum temperature employed in this study, because graphite contains little volatile matter and its gasification rate is lower than that of coke and coal. 16) On the other hand, the gas ratio of the ore-coal composites starts to increase at approximately 700 K. This behavior is caused by both the gasification of H 2 gas from coal, as shown in Fig. 5(a)), and the generation of H 2 gas by the cracking reaction of CH 4 gas, which generates from the coal present in the composites.…”

Section: Effect Of Ore Type On the Reduction Behavior In The Compositementioning

confidence: 95%

Lowering Reduction Temperature of Iron Ore and Carbon Composite by Using Ores with High Combined Water Content

2009

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The steel industry is facing two difficult and urgent tasks to reduce CO 2 emissions and to use low-grade iron resources effectively. The utilization of an iron ore-carbon composite is one of the promising methods to solve the former. The latter is concerning to goethite ores such as Australian Marra Mamba and pisolite ores, which contain high concentration of combined water. In this study, the effect of combined water on the reduction behavior of the iron ore-coal composites at elevating temperature was examined under inert gas flow.Below 1 200 K, the reduction of iron oxide in Marra Mamba ore-coal and pisolite ore-coal composites proceeded faster than that in hematite ore-coal composite. It can be attributed to the larger specific surface area of the ores after decomposition of the combined water. Metallic iron also formed at lower temperature in the composites containing Marra Mamba and pisolite ores. The generation rate of CO gas from these composites showed the maximum value at approximately 1 170 K; however, that from the hematite-coal composite gave no peak, because formed metallic iron could act as a catalyst for the gasification of carbon. These results indicate that the reduction of ores with high combined water concentration can proceed at lower temperature. Above 1 373 K, however, the reduction rate of these ores in the composite significantly decreased due to a drastic decrease in the specific surface area of the ores and the formation of slag.KEY WORDS: ironmaking; iron ore-coal composite; reduction degree; combined water. centration of combined water and gangue minerals in different iron ores on the reduction and gasification behaviors of various composites were systematically evaluated at a constant heating rate. Experimental ProcedureFive types of iron ores: one hematite (H1), two Marra Mamba (M1 and M2) and two pisolite (P1 and P2) ores with particle sizes from 105 to 250 mm were used to prepare the composites. The chemical composition and loss on ignition (LOI) of these ores are shown in Table 1. The weight change in these ores was measured by TG-DTA (20 K/min, Ar: 1.66ϫ10Ϫ6 Nm 3 /s) to understand the dehydration behavior. The ores were heat-treated for 1.8 ks under Ar atmosphere at 673 K and for 3.6 ks in air at 1 073 K. And, the specific surface area of these ores was measured. Noncoking coal (VM: 36 %, fixed carbon: 56 %, ash: 8 %) having size of Ͻ44 mm and graphite reagent (average particle size: 20 mm) were used as a carbonaceous reductant.The ratio, C/O, which was defined as the molar ratio of fixed carbon in coal to oxygen in iron oxide, was 0.8. Powders of ore and coal were well mixed without reducing the particle size. Then, the mixed powder was press-shaped under a pressure of 9.8ϫ10 7 Pa. A composite sample with 10 mm in diameter and 10 mm in height was obtained. Figure 1 shows a schematic diagram of the a) sample holder and b) experimental system used for the reduction of the composite. The holder consisted of an alumina tube coated by platinum paste. Fifty alumina balls with 2 mm ...

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“…2. Yoshida et al 21,24) reported that CaO and CaS hardly dissolved in 2%TEA solution containing 0.20 w/v% BaO within 3 h. In contrast, Kawakami et al 32) reported CaO dissolution in 2%TEA-0.8 w/v% Ba. In the present study, 2%TEA solution containing 0.04 or 0.10 w/v% BaO which was dried at 1 473 K for 1 h was also used in the MgO dissolution test.…”

Section: Stability Of Mgo Particles In Solutionmentioning

confidence: 98%

Extraction of Nonmetallic Inclusion Particles Containing MgO from Steel

et al. 2011

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Extraction of inclusion particles from a metal matrix allows for accurate three-dimensional estimation of their morphology, size, and composition. In this study, the stability of MgO and MgAl2O4 particles was examined using acid, halogen-methanol, and nonaqueous electrolytes. These particles hardly dissolved in a 2% TEA-Ba (2 v/v% triethanolamine-1 w/v% tetramethylammoniumchloride-methanol containing 0.05-0.20 w/v% Ba) electrolyte. The potentiostatic extraction method using nonaqueous electrolytes with various Ba and H2O contents was examined for the extraction of MgO inclusion particles from metals. The O content of the extracted MgO and MgAl2O4 inclusion particles agreed approximately with the analyzed total O content of the metal. The Mg contents of the extracted inclusion particles were in agreement with those calculated using the results of two-dimensional measurements. Finally, it was concluded that 2% TEA-Ba was the most suitable for the electrolytic extraction of MgO and MgAl2O4 inclusion particles from steel.

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Micro Pore Structure and Reaction Rate of Coke, Wood Charcoal and Graphite with CO2

Cited by 18 publications

References 10 publications

Effect of Residual Volatile Matter on Reduction of Iron Oxide in Semi-charcoal Composite Pellets

Effect of Residual Volatile Matter on Reduction of Iron Oxide in Semi-charcoal Composite Pellets

Lowering Reduction Temperature of Iron Ore and Carbon Composite by Using Ores with High Combined Water Content

Extraction of Nonmetallic Inclusion Particles Containing MgO from Steel

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