Improvement of Ball Mill Performance in Recycled Ultrafine Graphite Waste Production for Carbon Block Applications

Abstract

A carbon block is a carbonaceous material used in various applications such as bearings, mechanical seals, and electrical brushes. This work aims to fabricate carbon blocks from industrial graphite waste, a residue from the cutting and tooling process of graphite block production. The ball milling process was used to fabricate ultrafine graphite waste to enhance the packing of carbon blocks. The milling performance was profoundly affected by dispersing agents in which sodium dodecyl sulfate (SDS), lignosulfonate (LS), and mixed dispersant (LS−SDS) were applied. The results showed that LS−SDS had the best milling performance, the greatest grinding index, and a flowable slurry, indicating the potentiality of this formulation for the environmentally friendly manufacture of ultrafine graphite waste. Carbon blocks were prepared from oven-dried ultrafine graphite waste, which was mixed with amorphous carbon and pitch. This carbon mixture was formed a block by compaction before carbonization and impregnation. The density of the fabricated carbon blocks increased from 1.76 to 1.83 g/cm 3 after impregnation along with the increase in hardness, flexural strength, and reduction in electrical resistivity from 83, 62 MPa, and 40 μΩ m to 88, 81 MPa, and 39 μΩ m, respectively. The physical properties of carbon blocks prepared from ultrafine graphite waste were comparable to the properties of typical pristine carbon products.

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

“…To avoid the viscosity build-up, chemical additives such as surfactants have been used for lowering the viscosity during milling. In this experiment, a sufficient amount of surfactants was used to control viscosity. ,, The slurry viscosity process from both the bead and ball milling processes, as shown in Figure , revealed an increase in the viscosity as the milling time increased. The results revealed an exponentially improving rate of viscosity in bead milling and a linear increase in the ball milling process.…”

“…A surfactant helps control viscosity build-up during the milling process due to an increase in the total surface area of the particle by preventing milled graphite particles from reagglomeration. Our previous publication 40 emphasized the effect of surfactants (SDS, LS, and LS-SDS) on the ball milling performance for the preparation of ultrafine graphite scrap production from graphite waste and found that mixed surfactants (LS-SDS) provided better milling efficiency as well as better control of slurry viscosity build-up during ultrafine graphite production. An anionic surfactant (SDS) provides electrostatic stabilization for the ground slurry.…”

“…The green block was then carbonized by heat treatment at 950 °C. After the heat treatment, carbon blocks were cut into small specimens of 1 × 1 × 10 cm 3 for further property characterization, including microstructure, density, flexural strength, hardness, and resistivity …”

A facile treatment of graphite as a reinforcement for Al‐based nanostructured composite

“…36,37 The Raman spectra of G and TG powders shown in whereas the 2D band became thinner and broader due to the graphite treatment and the deformation of the graphite structure. 37 According to the research conducted by Kanlayakan et al, 38 broken bonds result in a significant number of defects at the edges of graphite particles.…”

“…This, in turn, can amplify the imperfections caused by the edge effect of the graphene layers. 38 The stress induced on the TG particles also affects the number of crystal defects. The I D /I G ratio has increased, possibly due to the partial exfoliation and fragmentation of graphite particles into smaller particles with fewer graphene layers.…”