Ultrafine Graphite Scrap and Carbon Blocks Prepared by High-Solid-Loading Bead Milling and Conventional Ball Milling: A Comparative Assessment.

Abstract

A comparison between the physical characteristics of graphite ultrafine particles and the properties of graphite blocks prepared from graphite scrap using bead and conventional ball milling techniques is presented. Industrial-scale bead milling was used to prepare graphite scrap with an initial particle size d50 of 24 μm in the ultrafine range of <10 μm. Bead milling can significantly reduce the production time of ultrafine graphite from graphite scrap from 72 h by ball milling to 10 min. Ultrafine graphite scrap prepared from both ball milling and bead milling yields particles with a similar morphology, with a minor difference in crystalline size La and stacking height Lc observed. Carbon blocks were fabricated from both techniques, yielding carbon blocks with an almost identical microstructure and block density. Blocks from bead milling have slightly higher flexural strength as well as comparable hardness and resistivity. The block's flexural strength, hardness, and resistivity were 68.37 MPa, 99, and 36.9 μΩ·m, respectively, in a bead-milled carbon block and 61.86 MPa, 95.5, and 38.6 μΩ·m, respectively, for a ball-milled carbon block. Bead milling can be applied for the preparation of ultrafine graphite particles and graphite blocks with production that is 9 times faster for the same ultrafine graphite particle output and final product quality.