Production and Upgrading of Recovered Carbon Black from the Pyrolysis of End-of-Life Tires

Abstract

Increasing awareness regarding fossil fuel dependence, waste valorization, and greenhouse gas emissions have prompted the emergence of new solutions for numerous markets over the last decades. The tire industry is no exception to this, with a global production of more than 1.5 billion tires per year raising environmental concerns about their end-of-life recycling or disposal. Pyrolysis enables the recovery of both energy and material from end-of-life tires, yielding valuable gas, liquid, and solid fractions. The latter, known as recovered carbon black (rCB), has been extensively researched in the last few years to ensure its quality for market applications. These studies have shown that rCB quality depends on the feedstock composition and pyrolysis conditions such as type of reactor, temperature range, heating rate, and residence time. Recent developments of activation and demineralization techniques target the production of rCB with specific chemical, physical, and morphological properties for singular applications. The automotive industry, which is the highest consumer of carbon black, has set specific targets to incorporate recycled materials (such as rCB) following the principles of sustainability and a circular economy. This review summarizes the pyrolysis of end-of-life tires for the production of syngas, oil, and rCB, focusing on the process conditions and product yield and composition. A further analysis of the characteristics of the solid material is performed, including their influence on the rCB application as a substitute of commercial CB in the tire industry. Purification and modification post-treatment processes for rCB upgrading are also inspected.

Upcycling green carbon black as a reinforcing agent for styrene–butadiene rubber materials

“…As expected, the composite materials containing GCB had a large amount of residue (i.e., ash) because recovered GCB from waste tires oen contains additional impurities (e.g., Al, Cl, Zn, and Si) from the manufacturing process. 43,[49][50][51] The composition of typical VCB is reported by the manufacturers to be more than 95% carbon, with minimal quantities of O, H, N, and S.…”

“…, Al, Cl, Zn, and Si) from the manufacturing process. 43,49–51 The composition of typical VCB is reported by the manufacturers to be more than 95% carbon, with minimal quantities of O, H, N, and S.…”

Towards full recyclability of end-of-life tires: Challenges and opportunities

“…In contrast, different chemicals are used in the chemical method, e.g., KOH (Hu et al, 2022), NaOH (Frikha et al, 2022), H 2 SO 4 (Matandabuzo and Dovorogwa, 2022), each of which, depending on the porosity, has special applications. In general, activated carbons produced using acids and bases have a higher surface area and narrower distribution of pore sizes with a much wider range of applications compared to physical activation (Costa et al, 2022;Matandabuzo and Dovorogwa, 2022). Betancur et al (2009) pyrolyzed GTR using different CO 2 flows (50-150 ml min − 1 ) and high temperatures (800-900 • C) under a heating rate of 15 • C⋅min − 1 in a fixed bed reactor.…”

Application of plasma modified pyrolytic carbon black in improving mechanical properties of natural rubber composite

“…In order to achieve the goal of (partial or total) replacement of commercial CB by CBp, research and development work has focused on the purification and modification of CBp 13–15 . One of the most common methods to modify the CBp is pickling.…”

“…12 In order to achieve the goal of (partial or total) replacement of commercial CB by CBp, research and development work has focused on the purification and modification of CBp. [13][14][15] One of the most common methods to modify the CBp is pickling. The cheap and common solvents (HCl and NaOH) were used by Zhou et al to treat the CBp to remove most of the ashes from the surface of CBp.…”