Experimental study on high concentration entrainment of ultrafine powder

Zheng, Xinglong; Yin, Shenghua; Ding, Yulong; Wang, Li

doi:10.1016/j.powtec.2018.12.025

Cited by 7 publications

(2 citation statements)

References 28 publications

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“…However, the proposed method has several difficulties. The fluidization of ultrafine silicon particles with high concentration remains a challenge, although some improvements have been reported through external forces and coarse particles. − The reaction and crystallization kinetics of silicon particles is also challenging. Several studies have been conducted on accelerating the crystallization of amorphous silicon nitride by silicon. − However, the nitridation and crystallization of fine silicon particles have not been given in detail.…”

Section: Introductionmentioning

confidence: 99%

Kinetics of Silicon Nitridation and the Formation Mechanism of α/β-Si₃N₄ at Atmospheric Pressure and 1410 °C

Zheng

Sergeev

et al. 2022

Ind. Eng. Chem. Res.

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The formation of α/β-Si3N4 relates to the reaction process in the direct nitridation method, which can produce cheap ultrafine Si3N4 powder on a large scale in a fluidized bed. Complete nitridation of silicon powder was conducted in a 1 atm nitrogen atmosphere at 1410 °C, which is slightly lower than the silicon melting point of 1414 °C. Comprehensive analyses with thermogravimetric analysis, X-ray diffraction, and scanning electron microscopy show several-stage nitridation kinetics of silicon powder. Compared with previous research projects, more reaction details can be observed. The reaction undergoes evaporation and multiple melting–freezing processes, causing the deviation of the actual reaction curve from the theoretical logarithm curve in a solid–gas reaction. According to heat flow curves and their derivative to time curves, the reaction can be divided into 4 main stages. The repeated melting–freezing phenomenon and the produced α/β-Si3N4 phase were investigated. The increase of particle size increases the liquid–gas and liquid–solid–gas reaction time which causes β-Si3N4 to increase rapidly.

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Section: Introductionmentioning

confidence: 99%

Kinetics of Silicon Nitridation and the Formation Mechanism of α/β-Si₃N₄ at Atmospheric Pressure and 1410 °C

Zheng

Sergeev

et al. 2022

Ind. Eng. Chem. Res.

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“…Therefore, researchers have tried to prepare ultrafine Si 3 N 4 powder directly on large scales by using a fluidized bed with cheaper ultrafine silicon powder. − Through regulating the preservation temperature, the produced α-Si 3 N 4 could be comparable to that using the self-propagation method, which is up to 85%. , Temperature, which is the key factor of the fluidized bed, not only affects the nitridation rate but also affects the produced α/β-Si 3 N 4 ratio. At lower temperatures, the nitridation rate is too slow to be suitable for the fluidized bed. , A higher temperature can greatly increase productivity and is conducive to fluidized-bed production.…”

Section: Introductionmentioning

confidence: 99%

Mechanisms of Powder Diameter and Thermal Diffusion on the Produced α/β-Si₃N₄ Proportion

Zheng¹,

Wu²,

Wang

2019

Ind. Eng. Chem. Res.

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Producing high-proportion α-Si3N4 powder in a fluidized bed is an advanced method that is low cost and high in production. Traditional investigations on silicon powder nitridation isolated the phase transformation from the nitridation process, which brings difficulties in predicting and controlling the produced α/β phase ratio. In this paper, the silicon nitridation process was related to the final α/β phase ratio, and multiple related parameters were discussed. A thermal gravimetric analysis instrument was used to detect the detailed nitridation process. Silicon powders with different specific surface areas (i.e., diameters) were used at temperatures just below their melting point (1410 °C). The nonsharp interface model was implemented to simulate the nitridation and predict the ratio of α/β-Si3N4. Some key factors on diffusion and reaction were analyzed. The α/β ratios from simulations were highly consistent with those of X-ray diffraction tests. Mechanisms of powder diameter and thermal diffusion on the production of α/β-Si3N4 were summarized.

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Entrainment from Bubbling and Turbulent Beds

Fotovat

2020

Essentials of Fluidization Technology

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Experimental study on high concentration entrainment of ultrafine powder

Cited by 7 publications

References 28 publications

Kinetics of Silicon Nitridation and the Formation Mechanism of α/β-Si₃N₄ at Atmospheric Pressure and 1410 °C

Kinetics of Silicon Nitridation and the Formation Mechanism of α/β-Si₃N₄ at Atmospheric Pressure and 1410 °C

Mechanisms of Powder Diameter and Thermal Diffusion on the Produced α/β-Si₃N₄ Proportion

Entrainment from Bubbling and Turbulent Beds

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Experimental study on high concentration entrainment of ultrafine powder

Cited by 7 publications

References 28 publications

Kinetics of Silicon Nitridation and the Formation Mechanism of α/β-Si3N4 at Atmospheric Pressure and 1410 °C

Kinetics of Silicon Nitridation and the Formation Mechanism of α/β-Si3N4 at Atmospheric Pressure and 1410 °C

Mechanisms of Powder Diameter and Thermal Diffusion on the Produced α/β-Si3N4 Proportion

Entrainment from Bubbling and Turbulent Beds

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Product

Resources

About

Kinetics of Silicon Nitridation and the Formation Mechanism of α/β-Si₃N₄ at Atmospheric Pressure and 1410 °C

Kinetics of Silicon Nitridation and the Formation Mechanism of α/β-Si₃N₄ at Atmospheric Pressure and 1410 °C

Mechanisms of Powder Diameter and Thermal Diffusion on the Produced α/β-Si₃N₄ Proportion