Fortis IBA has recently invested in a Liwell flip-flow technology screen for its incinerator bottom ash (IBA) processing facility in Hampshire. The A303 facility currently processes 120,000 tonnes a year of ash from energy-from-waste facilities, transforming it into recycled aggregate products.
It was critical to ensure that the equipment would increase metallic extraction rates significantly and improve processing efficiencies, while enhancing the engineering properties of the final aggregate.
Tema (Machinery) was selected to carry out detailed trials at the A303 facility using its mobile version of the Liwell screener. The trials proved highly successful, and a 2 x 6m double-deck screener was installed at the Barton Stacey site.
Simon Parry-Jones, sales engineer for Tema, said: “Initially, the remit was to clean the infeed material – specifically the feed to the <5mm eddy current separators which required frequent cleaning, having an impact on process continuity and costs.
“But it became apparent to Fortis that cleaning the feed on its own would not be justification for the investment, so it sought an improvement on metals recovery.
“The test facility was again hired to look at making separations smaller than thought possible with this material, and the Liwell screen proved they could make those reductions and recover more metals.”
The Liwell principle ensures the mat is subject to at least 50g acceleration, yet the screen itself is under very little stress, in fact just over 2g when operating. Liwell machines are known for their operational longevity.