Dependence of flame front speed on iron ore sintering conditions

Zhao, Jia Pei; Loo, C. E.

doi:10.1080/03719553.2016.1166565

Cited by 11 publications

(8 citation statements)

References 9 publications

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“…Increasing the coke addition rate was observed to increase the peak bed temperature and time at temperature, consistent with past observations [10]. The increase in coke rate results in increases in the heat generated.…”

Section: Peak Bed Temperaturesupporting

confidence: 91%

“…The temperature and thermal history of sinter can be controlled with the addition of coke breeze and adjustment of the sinter draft pressure [1]. Previous modelling and sinter pot tests have demonstrated that with an increase in coke rate there is an increase in the sinter peak bed temperature and time at temperature [10], and with an increase in the draft pressure there is a decrease in the sinter peak bed temperature and time at temperature.…”

Section: Introductionmentioning

confidence: 99%

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Measurement of Process Conditions Present in Pilot Scale Iron Ore Sintering

Nicol

Chen

et al. 2019

Minerals

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An improved experimental technique has been developed to measure, concurrently, the oxygen partial pressures and temperatures within a pilot scale iron ore sinter pot as a function of time. The measurements and thermodynamic calculations have demonstrated that the oxygen partial pressure at peak bed temperature and during cooling can be oxidising or reducing relative to hematite. Examples of typical microstructures and phase assemblages observed in product sinters are presented. Potential mechanisms of hematite and magnetite formation at sub-liquidus and sub-solidus conditions are demonstrated. The relative impacts of changes to coke rate and draft pressure drop on the process conditions and proportions of the phases formed in the sinter have been measured. Increasing coke rate was shown to result in a faster sinter heating rates, higher peak bed temperatures and times at peak temperature. Higher draft pressures across the sinter bed resulted in faster sinter heating rates and shorter times at peak temperature.

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Section: Peak Bed Temperaturesupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Measurement of Process Conditions Present in Pilot Scale Iron Ore Sintering

Nicol

Chen

et al. 2019

Minerals

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“…On the other hand, it is found that the maximum exhaust-gas temperature is proliferated dramatically with external mechanical pressure increased from 0 Pa to 6242 Pa, while that rises slightly as the external mechanical pressure continues to reach 7803 Pa. Furthermore, the sintering time is prolonged constantly with external mechanical pressure and the relevant vertical sintering speed is continuously lowered, as shown in Figure 5b due to the densification of the loose sinter from the surface to the central layer under external mechanical pressure [41]. This is harmful to the productivity of the product sinter to some extent.…”

Section: Thermodynamic and Kinetic Conditions During Sinteringmentioning

confidence: 93%

“…Thus, the proper increase of external mechanical pressure (0-6242 Pa) is conducive to the significant improvement of sintering performance of limonitic laterite. However, as the external mechanical pressure exceeds the appropriate value, the permeability of the sinter bed is overly lowered because of the excessive densification of the sinter, resulting in rather low vertical sintering speed, and then the deterioration of the sintering performance [41]. Hence, the optimum external mechanical pressure is recommended at 6242 Pa.…”

Section: Effect Of External Mechanical Pressure On Sintering Performancementioning

confidence: 99%

Effective Utilization of Limonitic Nickel Laterite via Pressurized Densification Process and Its Relevant Mechanism

et al. 2020

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Limonitic laterite contains low iron and nickel grades and much high smelting minerals and loss on ignition (LOI), identified as refractory iron ore for sintering. Thus, sinter pot tests of limonitic laterite via pressurized densification sintering and its intensification mechanism were conducted, and the industrial application prospect was explored. The results indicate that the sintering performance of the limonitic laterite of the new process is significantly improved with the tumble index and productivity increased by 19.2% and 18.6%, respectively, and solid fuel rate lowered by 10.3%. The external pressure field promotes the synchronization of heat front velocity and combustion front velocity for better sintering heat and mass transfer conditions, which also greatly improves the mineral compositions and microstructure of the product sinter. The microstructure is converted from large thin-wall pores into small thin-wall or large thick-wall pores with the sinter porosity decreased by 42.4%. Much close interlocking texture between hercynite and silico-ferrite of calcium and alumina (SFCA) is formed with hercynite grains aggregation and growth, and SFCA amount substantially increased. The better sintering performance will bring about a remarkable economic benefit of 282.78 million RMB/a if the industrial application is implemented. The pressurized densification sintering process is considered as one of the effective technologies for improving limonitic laterite sintering.

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“…Results from carefully controlled tests on a pilot-scale sinter pot were used to validate the 2D sintering model. All of the experimental results have been discussed in earlier publications. ,,, The dimension of the cylindrical sinter pot is 600 mm in height and 330 mm in diameter, as shown in Figure . The inner pot wall was made of stainless steel.…”

Section: Methodsmentioning

confidence: 99%

A Fundamental Study of the Cocombustion of Coke and Charcoal during Iron Ore Sintering

Zhao

Loo²,

Yuan

et al. 2018

Energy Fuels

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In a global carbon cycle, the net greenhouse gas (e.g., CO2) emissions can be significantly reduced if fossil fuels could be substituted with renewable and cleaner biomass-derived fuels. In the traditional iron ore sintering process, the complete replacement of coke, a coal-derived fuel, with charcoal is not possible because the two fuels have very different properties and combustion behaviors, resulting in an unacceptable deterioration in sintering performance. Consequently, only low substitution ratios can be tolerated. However, research has indicated that this ratio can be increased through altering the combustion behavior of charcoal. Most fuel particles in a sintering bed have an encapsulated layer of fine ore and flux particles. Through intentionally altering the properties of this adhering layer, combustion behavior can be altered, leading to improved sintering performance. This work uses a newly developed combustion model and a 2D sintering model to appropriately describe the combustion behavior in sintering based on fuel properties and defines the optimum thickness and porosity of the adhering layer. In this study, the required properties of the adhering layer encapsulating charcoal particles, so as to match the combustion behavior of coke particles, are determined theoretically. This study also shows that the conditions required for different fuels to have similar sintering performance are (a) comparable ignition temperature and overall combustion rate, and (b) comparable rates of combustion at various temperatures. Matching the overall combustion rate alone does not necessarily result in comparable sintering performance. Meanwhile, the apparent density and water holding capacity of the substituting fuels should be close to the equivalent values for coke to ensure similar granulation performance and, subsequently, the properties of the bed prepared for sintering. Until these conditions are fully met, combustion efficiency, the properties of the formed flame front (e.g., width, temperature, and speed), and, consequently, sintering performance will deteriorate. In practice, fully matching all of these conditions is difficult. The present work has given guidelines on which are the critical variables of the adhering fines layer that have to be considered when charcoal is introduced into sintering and also how the variables interact to determine flame front properties.

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Dependence of flame front speed on iron ore sintering conditions

Cited by 11 publications

References 9 publications

Measurement of Process Conditions Present in Pilot Scale Iron Ore Sintering

Measurement of Process Conditions Present in Pilot Scale Iron Ore Sintering

Effective Utilization of Limonitic Nickel Laterite via Pressurized Densification Process and Its Relevant Mechanism

A Fundamental Study of the Cocombustion of Coke and Charcoal during Iron Ore Sintering

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