Carbon black is made by burning or thermally decomposing hydrocarbons (oil, natural gas, or other carbon-rich fuels) in low-oxygen conditions, then collecting the resulting soot. The exact method ranges from massive industrial furnaces operating above 1,300°C to something as simple as holding a metal surface over a candle flame. Which approach matters depends on whether you need tons of reinforcing filler for tires or a small amount of fine black pigment for ink or paint.
The Furnace Process: How Most Carbon Black Is Made
Over 95% of commercial carbon black comes from the oil furnace process. An aromatic liquid hydrocarbon feedstock, typically a heavy petroleum fraction or coal tar oil, is heated and injected into a natural gas-fired furnace. Inside, the feedstock decomposes at temperatures between 1,320°C and 1,540°C with a deliberately limited supply of air. The restricted oxygen prevents the carbon from fully burning into carbon dioxide. Instead, the hydrocarbon molecules crack apart, and carbon atoms reassemble into tiny spherical particles that clump together into chain-like clusters called aggregates.
Once the carbon particles form, the reaction has to be stopped quickly or the particles will keep growing and lose the desired properties. Primary quench water is sprayed into the stream to cool the gases down to about 500°C, halting the cracking. Further cooling to around 230°C happens through heat exchangers and additional water sprays. The carbon black particles, still suspended in exhaust gas, are then separated using bag filters and compressed into pellets for shipping.
By adjusting temperature, feedstock injection rate, and quench timing, manufacturers control particle size and the degree of branching in those aggregate chains. This flexibility is why the furnace process dominates the industry. The global carbon black market was valued at nearly $29 billion in 2025, and about 61% of production goes into tires, where carbon black makes up roughly 30% of a tire’s weight.
Thermal Black: Batch Cracking of Natural Gas
Thermal black uses a completely different approach. Instead of partial combustion, it relies on pure heat to split methane molecules apart. Two refractory-lined furnaces work in tandem, alternating roles every five minutes. In the “heat cycle,” one furnace is fired with natural gas to bring its refractory lining up to about 1,300°C. Then the burners shut off and the process switches to the “make cycle,” where fresh natural gas flows into the hot chamber and thermally decomposes into carbon and hydrogen with no flame involved.
While one furnace is producing carbon black, the other is reheating. This back-and-forth cycle runs continuously. The resulting particles are larger and less structured than furnace black, which makes thermal black useful in rubber products that need low reinforcement but high loading, like inner tubes and seals.
Acetylene Black: High Purity Through Exothermic Decomposition
Acetylene black is a specialty grade made by decomposing acetylene gas at temperatures above 800°C. What makes this process unusual is that acetylene’s decomposition is exothermic: once ignited, the reaction sustains itself without additional heat. The carbon yield exceeds 97% of the theoretical maximum under optimal conditions, and the byproduct gas is essentially pure hydrogen (99%).
The decomposition proceeds through a chain reaction propagated by hydrogen atoms and terminated when they collide with the reactor walls. The resulting carbon black has an exceptionally high structure, meaning the particles form extensive branching networks. This gives acetylene black outstanding electrical conductivity, making it the preferred grade for batteries, conductive plastics, and electronic applications.
Channel (Impingement) Black: Small Flames, Fine Particles
The channel process is one of the oldest industrial methods. Small natural gas flames are directed upward to impinge on cool metal surfaces, and the carbon deposits are scraped off. The name comes from the steel channel irons originally used as collection surfaces. Modern versions use water-cooled rollers enclosed in steel boxes, with bag filters capturing additional particles from the off-gases.
This method produces very fine particles, some as small as 10 to 15 nanometers, which makes channel black ideal for pigment applications where deep, rich color matters. The tradeoff is low yield: rubber-grade channel black recovers about 60% of the carbon in the feedstock, and high-quality pigment grades recover only 10 to 30%. That inefficiency, combined with environmental concerns about emissions, means channel black has largely been replaced by furnace black for most applications.
Making Lampblack at Small Scale
If you’re looking to make carbon black yourself, the simplest method is lampblack, which is essentially controlled soot collection. All you need is a fuel source, a flame, and a cool surface for the soot to accumulate on.
The best results come from burning resinous materials: pine pitch, tree resins, tar, or resinous wood like pine. Hold a metal plate, ceramic tile, or the bottom of a metal basin over the flame at a distance where soot deposits thickly without the surface getting hot enough to burn it off. As the surface blackens, scrape the soot off with a feather or soft brush into a container. A 1612 English treatise describes exactly this technique: holding a torch under a brass basin, then sweeping the accumulated black into a shell with a feather.
You can also collect lampblack from a soy wax candle or an oil lamp, though the yield will be smaller and the particles somewhat coarser than what resinous fuels produce. For larger quantities, an 18th-century method involved burning pitch in a closed shed with sheepskins hung from the rafters. Soot collected in the fleece and was shaken out afterward.
To turn lampblack into usable ink or paint, mix the collected soot with water and a binding agent like gum arabic so it adheres to paper or other surfaces. For oil-based paints, the soot can be ground into linseed oil. The pigment is lightfast, permanent, and has been used continuously for thousands of years.
Surface Treatment for Specialty Uses
Raw carbon black is hydrophobic, meaning it repels water and resists mixing evenly into water-based inks, coatings, or polymer systems. To fix this, manufacturers oxidize the particle surfaces using strong chemical treatments. This adds oxygen-containing groups (similar to those found on the surface of oxidized graphite) that make the particles compatible with water and polar solvents.
Industrial oxidation typically uses mixtures of hydrogen peroxide and sulfuric acid, or a process involving potassium permanganate and sulfuric acid known as the Hummers method. These treatments don’t change the core carbon structure but graft reactive chemical groups onto the surface. The result is carbon black that disperses readily in aqueous systems, which is essential for inkjet inks, water-based coatings, and certain polymer composites.
Safety Considerations
Carbon black itself is relatively inert, but it often carries trace amounts of polycyclic aromatic hydrocarbons (PAHs), which are byproducts of incomplete combustion. NIOSH sets workplace exposure limits at 3.5 mg/m³ for carbon black dust and 0.1 mg/m³ for PAHs, and considers carbon black in the presence of PAHs a potential occupational carcinogen. Furnace-grade carbon black generally has lower PAH levels than channel or lampblack because the high-temperature process burns off more of these compounds.
If you’re making lampblack at home, work outdoors or in a very well-ventilated space. The fine particles are easily inhaled and can irritate your lungs. Wear a dust mask rated for fine particulates when handling dry soot, and avoid creating airborne clouds of the powder. Carbon black dust is also mildly combustible in concentrated airborne form, so keep it away from open flames once collected.