Chemical and low-expansion treatments for purifying natural graphite powder
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Korea Institute of Geoscience and Mineral Resources
Publication date: 2007-01-01
Corresponding author
Jeongyun Kim   

Mineral Processing Group, Minerals and Materials Processing Division, Korea Institute of Geoscience and Mineral Resources, Gajeong-dong 30, Yuseong-gu, Daejeon 305-350, Korea
Physicochem. Probl. Miner. Process. 2007;41(1):37–49
Fine natural graphite powder shows good properties in heat resistance, heat expansion and electric conductivity, and has been used as the materials for high-efficient secondary batteries, lubrication, etc. Graphite powder, as a high-tech material, is made through purifying and surface control processes. Developed countries produce high functional graphite powders by additional intercalation processes and sub-micronizing. This study is conducted to utilize low grade natural graphite powders as nano- material resources. Prior to production of the ultrafine graphite powder, studies on its pretreatments were performed. Typical acid/alkali treatments with expansion process were conducted. Expanding temperature for gasification process is set low compared to those of the traditional processes. This will make possible to give appropriate expansion ratio for effective chemical treatments and grinding processes. Expansion ratios were controlled as 20~30% of the original volume at 200~250°C, since excessive expansion of graphite powder by traditional approach at high temperature leads to a low grinding efficiency.