Sensor-Based Sorting Revolutionizes Plastics Recycling

by | Jul 23, 2015

plastic bottled for recyclingAdvances in recycling technology have made it easier to recycle previously difficult to treat plastics so they can be used to produce recycled products or fuel waste-to-energy facilities. With the right legislation and equipment in place, automated sorting technology has made it possible to achieve purity levels as high as 99.9 percent, according to an article on the Waste Management World website.

Recycling companies have traditionally struggled when it comes to meeting the high purity levels demanded by customers for food grade recycled PET flakes. To address this challenge, Tomra Sorting has developed an Autosort flake sorter that combines a visible range spectrometer camera to detect color and non-transparent contaminants, a near infrared spectrometer to detect different polymer types and a metal sensor to detect ferrous and non-ferrous particles. The Autosort flake sorter is capable of identifying and sorting flakes as small as 2 mm.

The Autosort unit is capable of detecting and separating out white opaque PET bottles and PET trays. The Autosort unit can also be used to achieve 100 percent recycled content clear foils. After the Autosort separates out the case PE foils from the other in-feed material, the contamination is then targeted to remove all fines and improve the purity of the end fraction.

Tomra has developed another unit to separate food and non-food PE. The unit uses an extended wavelength scanner to detect the difference between and separate the homo (food) and co-polymer (non-food) material. It effectively separates two polymers within one polymer group. Purity rates on both end fractions of close to 100 percent are achievable.

Recovering plastics from waste electrical and electronic equipment (WEEE) is perhaps one of the most challenging plastics recycling applications. WEEE typically contains ferrous metals, non-ferrous metals including PCBs, plastics, glass, wood and other materials. Traditional sorting methods cannot hand pick the metal elements off a plastic backed circuit board or determine whether a piece of plastic contains flame-retardant; however, sensor-based sorting is capable of identifying and separating different types of plastics, which can then be transformed into reusable granules.

Axion Consulting is partnering with Tomra, Dow Chemical, Nestlé, Unilever and other global companies to improve the recyclability of flexible packaging.

Photo: plastic bottles to be recycled via Shutterstock. 

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