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High quality carbon black from ELT tires (End of Life Tires)
The unique patented CFC*-pyrolysis technology, upon which Enviro’s full scale plant is built, gives a high quality recycled Carbon Black product, EnviroCB™, from end-of-life tires. The high quality is to a large extent correlated to what degree the oil is driven away from the tire chips during pyrolysis, which is a type of dry distillation in a nitrogen atmosphere.
First key evidence that the pyrolysis has been successful is the result from the toluene extract test showing that all oil residues have been driven out, leaving a completely odour free product. The high and consistent surface area and OAN number will indicate that the original carbon black is ready to again to interact with the polymer to enhance the properties of the rubber material. The final evidence of the high quality is the evidence that the recycled carbon black can be re-used in rubber compounds. As the EnviroCB™ is since one year replacing 100% virgin N550 in a commercial rubber application for Volvo Cars this is a true proof of concept. is carbon black. All the major producers are global players. The price of carbon black is correlated with the world market price of crude oil, which has increased by severalfold over the past 20 years.
Uses of carbon black
Carbon black, is the first commercial nano-material, and comes in a variety of grades depending on the end-application. 90% of all carbon black produced is used in rubber applications where as a reinforcing filler. Apart from that carbon black is also used as a common black pigment in everything from plastics to mascara. A third property of carbon black is that it is electrically conductive and can therefore be used to handle static electricity. An extra feature is that addition of carbon black gives UV-protection to a material. In the early days of industrial food production small particles of carbon black were even used to give synthetic vanilla sauce an impression of containing natural vanilla seeds from the plant! Enviro’s focus has been to recycle carbon black first of all for re-use in rubber materials.
Carbon black grades in the recycled product
Virgin carbon black is produced with various sophisticated methods, the most common nowadays being the furnace process. The most common raw material feedstock is oil but also other sources eg natural gas can be used. Depending on the exact wanted properties in the rubber material there are a variety of different carbon black grades to choose from. The pyrolysis technique does not create any new carbon black, but recovers the original range of carbon black grades that were in the tire rubber, from N110 up to N772. Any carbon black product from ELT –pyrolysis would therefore have the innate property of being a mixture of the inherent grades (unless a specific part from a specific brand is sorted out and pyrolysed!). Several different grades together tend to interact and so enhance the performance.
Properties of re-cycled carbon black
The carbon black obtained typically comprises around 30 percent of a batch. After pyrolysis there are several post-processing steps where the steel and textile are separated from the carbon black. The carbon black is then milled into micro-sized particles to expose of the active surface of the carbon black nano-particles. Virgin carbon black also form micro sized particles coming from agglomerates of the small nano-sized primary particles.
Carbon black grades differ mainly by the surface-size and the structure. The structure of the recycled carbon black have most likely been slightly altered during the mixing of rubber, it is however not unlikely that some structure is re-created in the hot environment in the pyrolysis reactor. The surface is again exposed after pyrolysis and milling. All in all, the carbon black from a controlled mixture of end-end-of life passenger car and truck tires pyrolysed by Enviro is today replacing virgin carbon black (N550) up to 100% in commercial applications which is a true proof of concept. Enviro continues to develop and widen its range of quality carbon black products, primarily via choice of raw material source.
Approximately 1.5 to 2 kg of crude oil is needed in order to produce 1 kg of virgin carbon black of quality so using recycled carbon black reduces the carbon foot print.
Recycling carbon black also mean re-using a precious raw material, thus moving higher up the recycling hierarchy.
In addition the process of producing the recovered material has significantly lower CO2 footprint compared to traditional furnace process.
The carbon black market
The global market for carbon black accounts for an annual turnover of approximately 25 billion USD, and is expected to grow by around 4 percent per annum until 2020. Asia is currently the largest producer and consumer of carbon black, accounting for about 55 percent of global production and consumption according to 2010 figures. China accounts for nearly half of Asian consumption. The majority of the increase in carbon black production capacity expected to come about in the next five years will come out of Asia, with China leading the way. The growth in carbon black production is closely linked to the automotive industry and to tyre production. The fact that more and more global automotive production is moving to China, India and Eastern Europe is prompting the tyre industry, and therefore also carbon black producers, to follow.
There is a steady trend toward concentration and consolidation among carbon black producers. Petroleum companies have scaled back their production of carbon black, and the sector is now dominated by chemical companies whose main product is carbon black. All the major producers are global players. The price of carbon black is correlated with the world market price of crude oil and vary over time.
The recovered carbon black from our process is less impacted by the crude oil price volatility and able to keep a more stable value over time.