This study involved the heterogenization of a binder pitch (BP) using a small amount of nanocarbon to improve physical properties of the resulting graphite electrode (GE). Heterogenization was carried out by adding 0.5–2.0 wt.% platelet carbon nanofiber (PCNF) or carbon black (CB) to a commercial BP. To evaluate the physical properties of the BPs, we designed a new model graphite electrode (MGE) using needle coke as a filler. The heterogenized binder pitch (HBP) with PCNF or CB clearly increased the coking value by 5–13 wt.% compared to that of the as-received BP. Especially, the model graphite electrodes prepared with HBPs containing 1.0 wt.% PCNF or CB showed significantly improved physical properties compared to the control MGE from the as-received BP. Although the model graphite electrodes prepared with HBPs showed similar properties, they had smaller pore sizes than the control. This indicates that heterogenization of the BP can effectively decrease the pore size in the MGE matrix. Correlating the average pore sizes with the physical properties of the model graphite electrodes showed that, for the same porosity, matrices formed by the HBP with a smaller average pore size can effectively improve the apparent density, tensile strength, and oxidation resistance of the model graphite electrodes.

Improvement of tensile strength and anti-oxidation property of graphite electrode for electric arc furnace through heterogenization of binder pitch
    Abstract
    1 Introduction
    2 Experimental
        2.1 Raw materials
        2.2 Preparation of heterogenized binder pitch (HBP)
        2.3 Preparation of model graphite electrode (MGE)
        2.4 Analysis of HBPs
        2.5 Sequential evaluation of morphological changes during heat treatment of model graphite electrode artifacts within the carbonization-temperature range
        2.6 Evaluation of tensile strength of model graphite electrodes
        2.7 Analysis of total pore area and average pore diameter for model graphite electrodes
        2.8 Analysis of specific electric resistance of graphitized model graphite electrodes [36]
    3 Results
        3.1 Results of HBP analysis
        3.2 Effect of heterogenization of BP on physical properties of model graphite electrodes
        3.3 Sequential evaluation of morphological changes of model graphite electrode artifact within the carbonation-temperature range
        3.4 Evaluations of the tensile strength and oxidation property of model graphite electrodes
            3.4.1 Tensile strength of model graphite electrodes prepared with HBPs
            3.4.2 Evaluation of anti-oxidation property of graphitized model graphite electrodes
            3.4.3 Evaluation of specific electrical resistivities of the graphitized model graphite electrodes
    4 Discussion
    5 Conclusion
    Acknowledgements 
    References

• Kohei Ono(Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Kasuga, Fukuoka 816‑8580, Japan)
• Minki Sung(Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Kasuga, Fukuoka 816‑8580, Japan)
• Yuanshuo Peng(Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Kasuga, Fukuoka 816‑8580, Japan)
• Seung‑Jae Ha(Hydrogen & C1 Gas Research Center, Korea Research Institute of Chemical Technology, Gajeong‑ro Yuseong‑gu, Daejeon 34114, Republic of Korea, University of Science and Technology, Gajeong‑ro Yuseong‑gu, Daejeon 34114, Republic of Korea)
• Young‑Pyo Jeon(Hydrogen & C1 Gas Research Center, Korea Research Institute of Chemical Technology, Gajeong‑ro Yuseong‑gu, Daejeon 34114, Republic of Korea, University of Science and Technology, Gajeong‑ro Yuseong‑gu, Daejeon 34114, Republic of Korea) Corresponding author
• Takahashi Ikuya(Hofu Laboratory, Tokai Carbon Co. Ltd., 569, Hamakata, Hofu, Yamaguchi 747‑0833, Japan)
• Hamaguchi Shusaku(Hofu Laboratory, Tokai Carbon Co. Ltd., 569, Hamakata, Hofu, Yamaguchi 747‑0833, Japan)
• Feiyu Kang(Institute of Materials Research, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China)
• Hyeonseok Yi(Research Institute of Industrial Science and Technology, Pohang 39673, Republic of Korea)
• Joo‑Il Park(Department of Chemical & Biological Engineering, Hanbat National University, Daejeon 34158, Republic of Korea)
• Koji Nakabayashi(Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Kasuga, Fukuoka 816‑8580, Japan, Institute for Materials Chemistry and Engineering, Kyushu University, Kasuga, Fukuoka 816‑8580, Japan)
• Jin Miyawaki(Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Kasuga, Fukuoka 816‑8580, Japan, Institute for Materials Chemistry and Engineering, Kyushu University, Kasuga, Fukuoka 816‑8580, Japan)
• Seong‑Ho Yoon(Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Kasuga, Fukuoka 816‑8580, Japan, Institute for Materials Chemistry and Engineering, Kyushu University, Kasuga, Fukuoka 816‑8580, Japan)