recovered carbon black (rCB)

Recovered carbon black (rCB) is the upgraded form of the solid carbon residue that pyrolysis produces. When end-of-life tyres or certain plastics are heated in the absence of oxygen, roughly 30-40% of the tyre mass by weight remains as a black carbonaceous char. In its raw state this char is a dusty, contaminated low-value material. Processing it — removing steel and fibre, milling to a controlled particle size, and pelletising — converts it into rCB, a manufactured carbon product that can be sold rather than dumped.

The value lies in substitution. Virgin carbon black is made by partial combustion of fossil feedstock and is the reinforcing filler in tyres, conveyor belts, hoses and many rubber and plastic goods. It sells in India broadly in the range of Rs 80-130 per kg depending on grade (N330, N550, N660). rCB sells at a discount to virgin — commonly 40-70% of the virgin price depending on quality — but its production cost is largely already absorbed by the pyrolysis process, so the margin on a tonne of well-finished rCB can be substantial. This is why, in tyre and plastic pyrolysis economics, rCB is frequently the difference between a marginal and a profitable plant: the oil pays the operating costs, the rCB carries the profit.

Quality determines which market a producer can reach. Key parameters are ash content (the inorganic residue, ideally below 10-12%; high ash signals poor feedstock or incomplete steel/fibre removal), residual hydrocarbons, particle size distribution and BET surface area. Low-ash, well-milled rCB can enter semi-reinforcing rubber compounds and replace N660-grade virgin black; high-ash unmilled char is limited to low-grade fillers, pigments for paints and inks, or is sold as carbon fuel at a fraction of the price. Many Indian tyre-pyrolysis units sell unprocessed char cheaply because they have not invested in the milling and pelletising line — leaving most of the available value on the table.

For an Indian recycler the operational guidance is to treat rCB as a product line, not a waste stream. That means a magnetic separator and screen to remove steel and fibre, a micronising mill to hit a target particle size, and a pelletiser to make a dust-free, transportable product. Get the rCB tested at a NABL lab for ash, sulphur and surface area so you can offer a documented specification, and pursue an offtake with a rubber compounder or master-batch maker rather than selling loose char into the spot fuel market. The capital for the finishing line is modest relative to the price uplift it unlocks.