Evaluation of recovered Carbon black as a sustainable alternative to commercial Carbon black in solid tyre cushion compounds

Pyrolysis is a sustainable solution for waste tyre (WT) management. Recovered carbon black (rCB), is a second highest by-product of tyre pyrolysis process, contains a high amount of carbon, ash and inorganic impurities. In the present study, rCB derived from WTs was upgraded through magnetic separation, ball milling, and purified treating twice with 2M HCl and once with 2M NaOH at 60⁰C for one hour using 2 g/mL rCB: leachate ratio to obtain demineralized rCB(drCB). Both raw rCB and drCB were characterized by particle size analysis, proximate and ultimate analyses, TGA, ICP-OES, FT-IR, XRD, and iodine adsorption. The drCB exhibited a substantial reduction in ash content from 22.20% to 3.42 % (by weight) and an increase in carbon content up to 94.41 % (% wt). The upgraded drCB was subsequently incorporated into solid tyre cushion compounds as a partial replacement for commercial carbon black (CCB, N550) to evaluate industrial feasibility. Physico-mechanical properties of the drCB compound demonstrated improved modulus, tear strength, hardness, and other properties such as tensile strength, rebound resilience within the industrial standard limits. These findings confirm the technical feasibility of rCB as a partial replacement of the filler in industrial solid tyre cushion compounds, supporting circular economy concept in the rubber and tyre industry.