A study of the efficacy and structural performance of modified coal tar and dimethylpolysiloxane as binders for coal-carbon composites

Abstract

Amidst global resource depletion and population growth, repurposing carbon-containing waste as raw materials into products offers promise for a more resource-efficient, circular economy. This research examines the efficacy of using coal tar modified through air-blowing as a binder for producing coal composite, alongside exploring dimethylpolysiloxane as an alternative binder. The effects of the binder type, mixing ratios, and coal fine composition on the properties of the composites were systematically studied. Microscopic analysis revealed anisotropic spherules in pitch formed at 400 °C/9 h and 450 °C/6 h possess favorable chemical properties like low H/C ratios (0.24–0.25) and high carbon content (96–97 %). Pyrolyzed coal fines and modified pitch-based composites exhibited moderate weight loss (11–17 %), notable compressive strength (106.58–344.71 MPa), and flexural strength (49–160 MPa). However, composites produced from coal tar pitch (400 °C/9 h) blended with 50 % GG1 and further pyrolyzed at 600 °C for 5 h exhibited a high water absorption (19 %). Also, composites with inferior flexural strength were produced using dimethylpolysiloxane as a binder, rendering them unsuitable for structural applications. This straightforward approach offers a viable means to repurpose significant quantities of coal fines and coal tar destined for landfills. This research is intended as a reference for researchers seeking to tranform coal waste into structural composites, thereby promoting circularity, and mitigating associated environmental risks.