German recycler adds equipment to process shredded refrigerators

CPE selects Ettlinger melt filter and adds automatic sorting line.

August 6, 2014

The German recycling and waste management firm CPE has chosen a system from Ettlinger that will allow the recycler to increase the amount and type of plastics it is able to process.

Robert Hartling, CPE’s managing director, says the company has been producing around 25,000 tons of recycled plastics a year since 1996.

“We operate several systems for processing foil waste, mostly PE (polyethylene) and PP (polypropylene), as well as used PET bottles and other manufacturing waste, which is generally sorted.”

Hartling adds, “Our latest project — recovering polystyrene from coarsely shredded refrigerator waste with a high proportion of contaminants — represents a new, higher-than-ever level of performance in plastics recycling.”

To recover the plastics, the company installed an ERF melt filter from the German equipment company Ettlinger Kunststoffmaschinen GmbH.

CPE integrated Ettlinger’s melt filter with its extrusion line to maximize the recycling of polystyrene. Additionally, CPE installed a continuous high speed filter equipped with a rotating drum.

“When the project first kicked off, we set ourselves the goal of converting the PS wastes that are inevitable when a fridge reaches the end of its service life — and that includes around 25 percent contaminants of all kinds — into high-quality recycled material. The result is currently used to make foils for thermoformed products such as plant trays,” Hartling notes.

For the final processing step, the extrusion of the PS waste after it has been pretreated in several stages, CPE equipped a single-screw extruder at its existing plant with an Ettlinger ERF 250 melt filter. The filter is installed directly between the extruder and the granulator.

"Two big advantages of the ERF are that the filter drum can be replaced simply and that the scraper, which removes the contaminants continuously from the rotating filter drum, is easy to take out of the unit and regrind," Hartling says.

The shredder material from the refrigerator's inner workings also contains such foreign materials as ferrous and nonferrous metals, PVC, paper, wood, paint, foam and rubber particles.

To make sure all materials are recycled, CPE also invested in a fully automatic sorting line for regrind and granules at its Liebenau, Germany, recycling facility. The infeed material is first regrinded to obtain a homogeneous particle size, then screened, sifted, separated and sorted. A color sorter and NIR (near infrared) sorter are integrated in the sorting line along with the magnetic separator.

According to Hartling, CPE can use this line to separate the nonferrous metals into copper, brass and zinc fractions for recycling. He says recovery or recycling of the refrigerator shredder material, which contains about 75 percent PS, is increased to more than 95 percent in the course of the pretreatment step.

"At the same time, we can presort the PS regrind according to colors right up to white quality if we need to obtain granules that are superior to the standard 'recycled gray.' The final treatment step on the road to high-quality recycled material is when the regrind is extruded with the integrated ERF melt filter,” Harting continues.