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

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 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.