Round and round: Newcastle University and Wastefront team up to improve tyre recycling

NEWCASTLE University and rubber recycling firm Wastefront, will use a new UK tyre recycling plant to improve the recovery of carbon black to help produce new tyres from old ones.

Almost every plastic or black rubber product such as hoses, pipes and seals, contain a finely divided pellet or powder known as carbon black. But, by far the largest use of carbon black is in tyres – as much as 70% of the world’s production of carbon black is used to produce more new ones.  

Not to be confused with black carbon, which is the sooty black material emitted from gas and diesel engines and coal-fired power plants, carbon black can be recovered from end-of-life-tyres, but the process is difficult. Depending on the study, research indicates that between 1-1.8bn tyres end up as waste each year, and of those, only 10% are recycled, while a staggering 75% end up in landfill. 

Wastefront wants to cut down the number of tyres going to landfill and create a local, circular solution to a global problem. Earlier this year, the firm received permission to go ahead with plans to construct what it says will be the ‘UK’s greenest tyre recycling plant’ in Sunderland at a cost of around £100m. Construction is expected to begin sometime in 2022 and once operational, around 100 jobs could be created.  

Currently, Wastefront uses pyrolysis to thermally depolymerise a tyre’s materials at high temperatures. In addition to the recovered carbon black, combustible gas, liquid hydrocarbon, and heat is also produced. The recovered carbon black is then washed and milled to upgrade its chemical properties, before being reused in tyres, other rubber goods or as a filler for plastics. 

By integrating the recovered carbon black into new tyres, the emissions for each tyre subsequently produced will be reduced by 80% said the firm. 

Wastefront has already secured a 10-year supply deal with Vitol, which will see the energy trader purchase all of the plant’s available liquid hydrocarbons and certain non-liquid products made during the recycling process. 

To identify more ways some of the estimated 29 m t of vehicle tyres which reach the end of their lifespan each year can be better used, Wastefront has now teamed up with Newcastle University for an 18-month study into how the production of recovered carbon black can be improved. 

This will include developing methods to reduce inorganic components in recovered carbon black, understanding how different solvents which have varying degrees of dispersion interact, and by developing methods to better understand the nature of the surface within the recovered carbon black material. 

“End-of-life-tyres, together with thermosetting plastic are one of the most challenging waste products for the waste supply chain to integrate into circular economy”, said engineering researcher  Katarina Novakovic at Newcastle University. “Circular use of resources in place of virgin material is the way forward in achieving sustainable living. To make this happen we need to secure comparable quality between virgin and recycled material and do so at industrial scale. In this project we focus on recovered carbon black and scalable enhancements of its properties to support its reuse.”