Powerscreen help turn a cost into a profit

Edinburgh-based CRM have taken delivery of an inert recycling plant from Powerscreen Sales Scotland that will allow them to recycle material that previously went to landfill at a cost of £2 per tonne.

The plant, which combines a Warrior 1400, a Powerscrub 120R and a MkII rinser, produces 75 tonnes/h of reusable material that CRM then use to produce drainage and concrete products. The clean, reusable material would cost around £6–8 per tonne if resold, and only 10% of the inert waste is now sent to landfill.

The incoming feed, which is normally demolition material, is processed through the Warrior 1400 dry-screening plant to produce a clean oversize (+40mm) material, which is then crushed, and a fine soil product (–5mm). The middle-grade material (–40mm +5mm) is sent to the Powerscrub 120R to remove any fines, clay, plastics or wood from the product.

The material proceeds to an in-line rinser where any remaining clay and dirt is removed to leave a clean, washed aggregate. A screen then separates the material into three products — pea gravel, 20mm and 40mm.

The dirty water created by the washing process is collected and fed to a cyclone plant, which dewaters the sand using a high-frequency dewatering screen, to remove any saleable sand in the solution. The dewatered product is then discharged into a holding bay ready for dispatch. The overflow from the cyclone, which contains only water and silt, proceeds to a water-management system. This is the final stage of the process where clean water is recovered by removing the silt. The clean water is recirculated to wash the product once again, the silt being collected and pressed to create a dry cake.