Trash to treasure: A general strategy to prepare high performance graphite block via constructing interfacial transition layers with highly chemically active on recyclable graphite powder

Abstract

Recently, the cycling of graphite residuum generated in the machining process of isostatic graphite has aroused great interest in both academia and industry as it offers an important solution to reduce the waste of resources and environmental disruption. However, conventional method of simple backfilling of residuum suffers drawbacks of low added-value and environmental pollution owing to the high graphitization degree and low chemical activity of these graphite powders. Herein, we report a general strategy to prepare high-performance graphite block (GBB) while using recyclable graphite powder (RGP) as starting compound via constructing highly chemical active interfacial transition layers (ITLs) on the surface of RGP by impregnated pitch (IP). The ITLs decorated recycled graphite powder (RGP@SC), as reflected in FT-IR, ESR, TG-DTG and EA, contains abundant surface functional groups, free radicals, and heteroatoms which ensures the high chemical activity, thus obviously improving the self-sintering and self-adhesion properties of GBB. As a result, GBB with RGP@SC as the main aggregate display a high homogeneity and mechanical properties. The average open porosity, flexural and compressive strength are determined to 9.90%, 56.60 MPa and 123.50 MPa, respectively, which even outperforms most reported graphite blocks. Impressively, due to the absence of impregnating and multiple calcinating, the process has a short production cycle, which not only saves energy, but also is environmentally friendly. The current work displays benchmark example of the employment of RGP for synthesis of high-performance graphite block.