rCB can be sourced from any rubber waste, but end-of-life tyres are widely available and offer a consistent waste stream; representing the bulk of rubber recycling in the UK. Carbon black is an integral component of tyre production, as it is in other rubber goods, plastics and coatings. Due to the presence of other materials in tyres, rCB contains around 80% carbon black, with the remainder made up of other materials, such as silica and zinc. These other materials can enhance the overall properties of Recovered Carbon Black providing masterbatch producers or rubber compounders, with both environmental and technical benefits of using a sustainable carbonaceous alternative when compared to virgin carbon black.
Carbon black has a near ubiquitous presence and can be found in a vast range of products that are used today. A vital component in making products stronger, deeper in colour and longer lasting, carbon black in its pure form is a fine black powder, composed of elemental carbon. It is produced by partial burning of low-value oil residues at high temperatures, under controlled process conditions.
Carbon black is mainly used to provide physical and mechanical characteristics in rubber products, usually tyres, but can also act as a pigment, UV stabiliser, and conductive or insulating agent in a variety of rubber, plastic, ink and coating applications. Apart from tyres, other everyday uses of carbon black include hoses, conveyor belts, plastics, printing inks and automotive coatings.
There are broadly three types of carbon black – reinforcing (tread blacks), semi reinforcing (carcass blacks) and speciality blacks:
Reinforcing grades are valued for their abrasion resistance and elasticity. They are used in applications calling for good durability, such as tyre treads, sidewalls, engine mounts, conveyor belts, marine bumpers, as well as numerous other products.
Semi-reinforcing grades are used in items requiring flexibility and elasticity, such as tyre sidewalls, hoses, belts, seals, and inner liners/inner tubes.
Specialty blacks are used as black pigments and performance fillers in products such as plastic film and pipe, printing inks, inkjet toners, paints and coatings.
Recovered Carbon Black is produced from pyrolysed tyre char. As a recycled product it is a sustainable carbonaceous alternative to virgin carbon black.
Pyrolysed tyre char is produced through a tyre recycling process known as tyre pyrolysis. The tyre char produced by this process contains carbon black and a mixture of inorganic compounds, such as silica, zinc and sulphur; present due to their usage in the production of rubber compounds.
The tyre pyrolysis process heats tyre rubber in the absence of oxygen effecting thermal decomposition, which causes the rubber to break down into oil, gas and char. The oil produced can be sold, providing tyre pyrolysis operations with a healthy revenue stream. The challenge until now for pyrolysis operators is what to do with the tyre char that has been produced. While the process for turning tyre char into Recovered Carbon Black is now understood, it is expensive and complex. Many tyre pyrolysis operations lack the skills and the capital to establish rCB production plants.
Fortunately, Waverly Carbon can help. Waverly Carbon sources high quality tyre char and converts it into rCB. This provides tyre pyrolysis operators with a revenue stream for their tyre char and produces a sustainable carbonaceous material, an alternative to virgin carbon black suitable for a wide range of applications.
If you would like to speak to us about our Recovered Carbon Black please contact us