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Recovered carbon black (rCB) brokerage

The solid co-product of tyre pyrolysis, and the one that decides whether a plant is viable. Grades, the tests buyers actually run, and why the same material is a premium rubber filler for one buyer and a low-value fuel for the next.

We broker recovered carbon black (rCB) from tyre pyrolysis, alongside the oil from the same plant. The thing to understand first is that rCB is not one product: the difference between material that a rubber compounder qualifies and material that ends up as a fuel is ash content, residual volatiles and consistency, not the process that made it. Ash comes from the inorganic fillers and the zinc oxide in the original tyre and it cannot be pyrolysed away, only separated. Send us the ash, the toluene transmittance, the particle size distribution and three consecutive batch reports, and we will tell you which market you are in.

From bale to polymer, or to fuel
  1. 1Waste plastic sorting
  2. 2Pyrolysis
  3. 3Upgrading and filtration
  4. 4Steam cracker or refinery
  5. 5New polymer or fuel

Which of the last two boxes you land in decides the rules that apply: mass balance and recycled content, or the recycled carbon fuel regime.

Why the plant economics run through rCB, not the oil

A tyre pyrolysis plant makes roughly three saleable outputs: oil, recovered carbon black and steel. By mass the solid fraction is the largest of the three, and it is usually the one that decides whether the plant works commercially. Operators who arrange the oil first and treat the char as a residue tend to find out late that the residue was the business.

That is also why we prefer to look at both together. An oil enquiry from a plant with no home for its solid output is a different conversation from one where both streams are placed, and pretending otherwise wastes everyone's time. See tyre pyrolysis oil for the liquid side.

Ash is the number that decides the market

A tyre is not just rubber and carbon black. It carries silica, zinc oxide from the vulcanisation activator, and other inorganic fillers. Pyrolysis removes the organic fraction and concentrates everything inorganic into the solid product. Ash content is therefore set by the feedstock, not by the reactor, and no amount of process tuning removes it.

That single fact explains most of the price spread in this market. Material with low, stable ash competes with virgin furnace black in rubber compounding. Material with high ash competes with fuel. The processing route in between, milling, classification and pelletising, is about particle size and handling, not about ash.

  • Ash content is the first screen for almost every buyer, and it is where feedstock selection shows up. Mixed or dirty tyre input carries straight through to the number.
  • Toluene transmittance indicates residual hydrocarbon left on the surface. Low values mean the char was not fully devolatilised and will smell, smoke or bleed into the compound.
  • Particle size and structure determine whether it disperses. Unmilled char with agglomerates behaves nothing like a milled and classified grade even at the same ash.
  • Sulphur and zinc come from the tyre and matter to compounders working to their own limits.
  • Consistency across batches is what actually closes a term contract. One good report is a sample; three matching reports is a supplier.

The standards exist now, and buyers use them

For years rCB was traded on ad hoc datasheets, which made comparison impossible. ASTM Committee D36 was formed in 2017 specifically for this material and there is now a usable set of standards. Quoting them is the cheapest credibility a seller can buy.

  • ASTM D8178 sets the terminology, including what may and may not be called recovered carbon black.
  • ASTM D8466 is the guide to which carbon black test methods apply to rCB, which matters because not all of them transfer unchanged.
  • ASTM D8474 determines composition by thermogravimetric analysis: organic residue, total carbon and ash in one run.
  • ASTM D8621 covers ash content specifically.
  • ASTM D8585 addresses shelf life, which is more relevant than it sounds for material that sits in a warehouse before qualification finishes.

There is also a classification convention: an R for recovered, followed by two numbers, the first for the class of toluene transmittance and the second for the class of inorganic content. Refined grades are compared against the semi-reinforcing virgin series, broadly the N500 to N700 range, rather than against the reinforcing grades used in tyre treads.

Who buys it, and what each one is actually screening for

  • Tyre manufacturers, the outlet with the most attention and the hardest qualification. Bridgestone and Michelin published joint guidelines for rCB in a 2023 white paper, aimed at making requirements comparable between manufacturers rather than each writing its own. Several producers hold multi-year offtake agreements with tyre makers.
  • Non-tyre rubber compounders, conveyor belt, hose, seals, mats and moulded goods. Often the realistic first market: the volumes are smaller but the qualification is achievable and the tolerance on ash is wider.
  • Plastics and masterbatch, where the material is used as a black pigment and filler and dispersion behaviour matters more than reinforcement.
  • Coatings, inks and construction products, where colour strength and consistency lead.
  • Carbon black producers themselves, some of whom have taken equity stakes or offtake positions in rCB rather than treating it purely as competition.
  • Fuel and cement, the floor of the market. It clears material but it does not pay for a milling line.

Two things moving the European market in 2026

First, the carbon accounting argument has become a purchasing argument. Virgin furnace black is made by burning oil, and its footprint is high. The published work from tyre manufacturers puts the reduction from using rCB instead at up to around 85 % on that specific input. For a buyer with a product carbon footprint target, that is a lever with few alternatives, and it is why qualification programmes exist at all.

Second, virgin carbon black is an oil product. It is made by burning heavy aromatic feedstock, so its cost tracks the oil market and its footprint is high by construction. That is a structural position, not a cycle. Note what this does NOT mean: carbon black is not on the CBAM list. CBAM covers cement, iron and steel, aluminium, fertilisers, electricity and hydrogen, and nothing in that list is carbon black, so anyone telling you the carbon border levy is about to reprice your filler is mistaken.

What both do is the same thing: they widen the gap between rCB that a compounder can qualify and rCB that can only be burned. The premium sits on consistency, and consistency is a plant decision made years earlier, at the point where the feedstock contract is signed.

What we ask for

A plant that can answer those six points is taken seriously immediately. A plant that cannot is not being judged on its material, it is being judged on whether the material can be relied on, and that is a fair question.

  • Ash content, with the method stated.
  • Toluene transmittance, or an honest statement that it has not been measured.
  • Particle size distribution, and whether the material is milled, classified, pelletised or raw char.
  • Three consecutive batch reports, not the best one.
  • Feedstock, whether the input is sorted passenger car tyres, truck tyres or mixed. This predicts the ash before any laboratory does.
  • Monthly tonnage and the form it ships in, big bags, bulk or pellets.

Frequently asked questions

What is recovered carbon black?

The solid carbonaceous product recovered from the pyrolysis of end-of-life tyres, after the organic fraction has been driven off as oil and gas. ASTM D8178 sets the terminology, including what may properly be called recovered carbon black rather than char. In practice the distinction is processing: raw reactor char is not the same product as milled, classified and pelletised rCB, even from the same reactor.

What ash content do buyers want?

Lower and, above all, stable. Ash comes from silica, zinc oxide and other inorganic fillers in the original tyre, so it is set by the feedstock and cannot be pyrolysed away. Rubber compounding applications screen on it first. Rather than quoting a single figure that varies by application, the useful answer is that ash decides which market you are in, and feedstock decides your ash.

Can recovered carbon black replace virgin carbon black completely?

Not one for one across all grades. rCB is generally compared against the semi-reinforcing virgin series rather than the reinforcing grades used in tyre treads, and most compounders use it as a partial replacement in a formulation rather than a straight substitution. That is still a large market, and it is the realistic target for a producer starting out.

Which ASTM standards apply to rCB?

D8178 for terminology, D8466 as the guide to which carbon black test methods transfer, D8474 for compositional analysis by thermogravimetry, D8621 for ash content and D8585 for shelf life. ASTM Committee D36 was formed in 2017 for this material. Quoting the method alongside the number on a datasheet is what separates a serious offer from a generic one.

What does toluene transmittance measure?

Residual hydrocarbon left on the surface of the material after pyrolysis. A low value means incomplete devolatilisation, which shows up later as odour, smoke during compounding or migration into the finished product. It is one of the two numbers in the R classification, alongside inorganic content.

Do you place rCB separately from the oil?

Yes, but we would rather look at both. A tyre pyrolysis plant's economics generally depend on placing oil, recovered carbon black and steel, and by mass the solid product is the largest of the three. Treating either stream in isolation gives a misleading picture of what the plant actually needs.

Is raw char the same thing as rCB?

No, and conflating them causes most of the disappointment in this market. Raw char straight from the reactor contains agglomerates and steel fragments and behaves nothing like a milled and classified grade in a compound, even at identical ash. The question a buyer is really asking is not what your reactor produces but what leaves your milling line.

Why does feedstock matter so much?

Because ash is inherited, not created. Sorted passenger car tyres, truck tyres and mixed end-of-life material each carry a different inorganic load, and that load arrives in your product unchanged. A plant that fixed its feedstock contract without thinking about ash has already decided which market it can sell into, usually without knowing it.

What volumes are worth discussing?

Regular monthly tonnage in a consistent form matters more than size. Buyers qualifying a new filler are committing formulation work, so what they are buying is reliability over time. A modest steady volume with three matching batch reports is a stronger position than a large one-off parcel.

Market news

Recent headlines from across the feedstock and renewable fuel sector. Nothing specific to this market has come through the wires lately, so this is the wider view. The links go to the publisher; we do not host or edit their reporting, and a headline here is not our endorsement of it. Scroll for more.

18 headlines, updated automatically. Last refreshed .

Sources and further reading

Primary sources for the rules and figures on this page, so you can check them yourself. Legislation is amended: always read the consolidated text on the date that matters to you.

Who to ask about Recovered carbon black (rCB)

Just ask. rCB to place, or looking for consistent filler? Send the ash, the toluene transmittance, the particle size and three consecutive batch reports. You get Bart van den Brug on the other end, same working day, in English or Dutch, and across the team also in French, Portuguese, Polish, Czech and Russian.

On how we work: on the feedstocks and fuels on this site we are a broker. We never take title, we do not trade our own book, and we are paid a commission on business that concludes. Additives are the one exception: those we also buy and sell for our own account, and we say in which capacity we are acting before you commit to anything. Either way you will hear it from us when the answer is no, or when your parcel is not ready for the conversation you want to have. A market read or a second opinion on a specification costs nothing and commits you to nothing.

Happy to look at whatever you have, even if it is half an analysis and a question.

+31 6 115 83 448
bart@sustainablecommodities.eu
Sustainable Commodities 3 B.V., Lemmer, the Netherlands

Ask about Recovered carbon black (rCB)

A direct line to the desk. We answer the same working day in almost all cases, and we will tell you plainly when a cargo is not something we can place.

Prefer email? bart@sustainablecommodities.eu · +31 6 115 83 448

Last reviewed 03 September 2026. Regulatory references are given for orientation and are not legal advice: verify against the current Official Journal text before contracting.