Eggersmann delivers new processing plant near Dublin
Eggersmann Anlagenbau GmbH has commissioned a new plant for the processing of incineration bottom ash (IBA) for Knockharley Landfill Ltd. north of Dublin (Ireland) with the assistance of its dealer for the United Kingdom and Ireland Kaizen Recycling Limited.
Over 120,000 tonnes of bottom ash per year
The new plant is designed for a throughput of 59 tonnes per hour. With the planned eight-hour single-shift operation on 255 days per year, a total of over 120,000 tonnes of IBA will be processed. The plant aims to recover valuable metals from the bottom ash. In this case not only ferrous metals are retrieved, but also non-ferrous metals. The non-ferrous metals are separated into sizes of 0 to 4, 4 to 30 and 30 to 150 mm. The FE fraction, on the other hand, is separated into a fraction smaller than 150 mm and one larger than 150 mm.
Comprehensive process engineering
Eggersmann Anlagenbau supervised the project as general contractor and was responsible for every phase of the project, from planning to installation and commissioning. This also included the production of the 527 metres of conveyor technology. The biggest challenge for the process technology in the recovery process is the sintered bottom ash. This mineralised material, which is produced by heating and then cooling the ash, is crushed in an impact mill so that the trapped metals are released. Using strong magnets, sieving machines and other separation solutions, further metals can now be extracted in a targeted manner.
Processing the fine fraction of the dried IBA
„After thermal treatment, the bottom ash and slag are cooled in a water bath first,“ explains Jens Thomas, the Project Manager. „Then either the very moist and still highly abrasive fresh slag can be treated directly, or it is first stored and dried.“ Storage also improves the pH value. Both processes have a number of advantages and disadvantages. „There is no right or wrong – both methods lead to the same goal. We therefore also offer solutions for both processes.“ In the case of the Knockharley Landfill plant, the bottom ash is dried for around two to three weeks until it only has a residual moisture content of 16 to 19 %. „The fine fraction of the ash from zero to four millimetres is also processed here in order to really extract all valuable materials. This follows a general trend in the market, which is associated with special challenges. But with the right concept, that’s not a problem either.“
From mobile-modular concept to recycling plant
Knockharley Landfill has been processing IBA for subsequent landfill on the site since 2014. Until now, the company has relied on a mobile-modular solution. „The customer approached us because the previous mixture of mobile machines and stationary process technology as a small plant was no longer sufficient for this demanding material and these high throughputs,“ explains Thomas. „The time was right for a full turn-key recycling solution. A plant that not only offers a higher degree of automation, but can also cope with highly abrasive materials. This significantly minimises maintenance and down time.“
Source: Eggersmann Group
