Study on the thermal field material of FZ-Si crystal waste graphite purified by ultrasonic enhanced acid leaching

Yonghang Zhang; Zhengjie Chen; Keqiang Xie; Xiuhua Chen; Xiaowei Chen; Yiyou Hu; Wenhui Ma

Arabian Journal of Chemistry (Dec 2024)

Study on the thermal field material of FZ-Si crystal waste graphite purified by ultrasonic enhanced acid leaching

Yonghang Zhang,
Zhengjie Chen,
Keqiang Xie,
Xiuhua Chen,
Xiaowei Chen,
Yiyou Hu,
Wenhui Ma

Affiliations

Yonghang Zhang: Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, China; State Key Laboratory of Complex Nonferrous Metal Resources Cleaning Utilization in Yunnan Province, Kunming University of Science and Technology, Kunming 650093, China
Zhengjie Chen: Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, China; State Key Laboratory of Complex Nonferrous Metal Resources Cleaning Utilization in Yunnan Province, Kunming University of Science and Technology, Kunming 650093, China; National Engineering Research Center of Vacuum Metallurgy, Kunming University of Science and Technology, Kunming 650093, China; Corresponding author at: Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, China.
Keqiang Xie: Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, China; State Key Laboratory of Complex Nonferrous Metal Resources Cleaning Utilization in Yunnan Province, Kunming University of Science and Technology, Kunming 650093, China; National Engineering Research Center of Vacuum Metallurgy, Kunming University of Science and Technology, Kunming 650093, China
Xiuhua Chen: School of Materials and Energy, Yunnan University, Kunming 650091, China
Xiaowei Chen: Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, China; State Key Laboratory of Complex Nonferrous Metal Resources Cleaning Utilization in Yunnan Province, Kunming University of Science and Technology, Kunming 650093, China
Yiyou Hu: Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, China; State Key Laboratory of Complex Nonferrous Metal Resources Cleaning Utilization in Yunnan Province, Kunming University of Science and Technology, Kunming 650093, China
Wenhui Ma: Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, China; State Key Laboratory of Complex Nonferrous Metal Resources Cleaning Utilization in Yunnan Province, Kunming University of Science and Technology, Kunming 650093, China; National Engineering Research Center of Vacuum Metallurgy, Kunming University of Science and Technology, Kunming 650093, China

Journal volume & issue: Vol. 17, no. 12
p. 106051

Abstract

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This study examines the acid-leaching and purification process of waste graphite in the production of Czochralski monocrystalline silicon. The optimal leaching conditions are identified as a liquid-to-solid ratio of 6, a leaching temperature of 70 °C, an acid concentration of 8 mol, and a leaching time of 60 min. The use of hydrofluoric acid, sulfuric acid, and nitric acid in the acid-leaching process increases the fixed carbon content of waste graphite from ∼94 % to ∼98.5 %. To address the low fixed carbon content that cannot be achieved through conventional acid-leaching, a method combining ultrasonic intensification with hydrofluoric and hydrochloric acid leaching is proposed and successfully implemented. Under ultrasonic enhancement conditions, the leaching effect is optimal at a temperature of 60 °C, acidity of 4 mol, and leaching time of 60 min. These results demonstrate that the introduction of ultrasound significantly strengthens the acid-leaching process. The method proposed in this study not only purifies waste graphite through acid-leaching but also elucidates the reaction behavior of various impurity elements during the leaching process. Overall, these findings provide a foundational basis for the recovery of waste graphite in the thermal field.

Published in Arabian Journal of Chemistry

ISSN: 1878-5352 (Print)
Publisher: Elsevier
Country of publisher: Netherlands
LCC subjects: Science: Chemistry
Website: http://www.journals.elsevier.com/arabian-journal-of-chemistry/

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