Recent progress in the research and development of natural graphite for use in thermal management, battery electrodes and the nuclear industry

Duan, Shengzhi; Wu, Xiaowen; Wang, Yifan; Feng, Jian; Hou, Shiyu; Huang, Zheng‐Hong; Shen, Ke; Chen, Yuxi; Liu, Hongbo; Kang, Feiyu

doi:10.1016/s1872-5805(23)60717-6

Cited by 23 publications

(1 citation statement)

References 88 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Graphite products play a key role in the development of photovoltaic technologies [21,22], including the manufacture of polysilicon raw materials, the drawing of monocrystalline silicon rods, and the casting of polysilicon ingots. Because graphite materials have excellent density, hardness, compressive strength, high-temperature resistance, high-pressure resistance, corrosion resistance, good electrical conductivity, and stable performance, they can be made into silica-graphite crucibles used during the purification of polysilicon and silicon rods [23][24][25][26][27]. Therefore, it is necessary to regenerate and purify waste graphite generated in the photovoltaic industry.…”

Section: Introductionmentioning

confidence: 99%

Purification of Waste Graphite from Crucibles Used in Photovoltaic Crystallization by an Alkali-Acid Method

Zhang

Chen

Xie

et al. 2023

Metals

View full text Add to dashboard Cite

The photovoltaic industry generates large amounts of waste graphite (WG) that contains useful metals that can be recycled into high-value products. This study elucidated the impurity elements and their existence states in WG, analyzed and verified the source of the main impurity phase SiC, and determined the SiC content to be 4.66%. WG was purified using an alkaline-acid method, whose optimal process parameters were a solid alkali ratio of 3, calcination temperature of 600 °C, calcination time of 120 min, HCl concentration of 1 M, and acid leaching time of 40 min. Under these conditions, a graphite product with a fixed carbon content of 98.45% was obtained. Impurities were determined to migrate via three pathways: (1) Most main elements (Al, K, and Si) in silicates were removed by alkaline roasting, while the remaining elements were dissolved in acid. (2) Impurities containing metal elements such as Fe, Mg, Ca, and Zn were decomposed in NaOH to form hydroxides or oxides that were dissolved in HCl. (3) Silicon carbide impurities were removed by the alkaline-acid method without decomposition and often existed with graphite in the acid-leaching slag.

show abstract