The cement industry is expected to come under increased pressure to obtain valuable material for alternative fuels due to legislation in the European Union driving a shift away from waste incineration in favour of recycling. “We can expect that, as a consequence, chemical recycling will be increasingly used in the future, reducing the amount of good quality input material for the RDF channel,” says Wolfgang Köser, Stadler sales director for Germany, Austria and Switzerland. 

“The most important requirement for the cement industry is a homogeneous material with a specific granulometry, without impurities such as PVC or metal, and a specific humidity,” explains Natalya Duarte, Stadler sales manager for Mexico and central America. “High-quality RDF or SRF delivers constant calorific power and has limited chlorine content, which is important for the good operation of the kiln and means that less maintenance is required.”

The challenge is to achieve the high quality demanded by cement kilns from the very heterogeneous materials left in the MSW stream after the removal of recyclables. This requires a complex treatment process. 

The sorting process has evolved over the years: “In the past, the quality of the RDF was controlled by combining different materials at the feed, followed by screening and the removal of metals. Now NIR technology plays an important role,” says Mr Köser.