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FILTRATION & SEPARATION SEPARATION IMPROVES RECYCLING RATES


Stephen Harding, managing director of Gough Engineering, emphasises the need for companies to invest in processing


equipment to recover and derive value from recycled products


reenpeace argues that mechanical recycling, the prevalent method employed in waste management, will fail for plastics due to their difficult sorting nature. The organisation’s ‘Circular Claims Fall Flat Again’ report highlights that plastic recycling rates have declined to about five percent in 2021, down from 8.7 percent in 2018. However, the European Commission (EC) has mandated that EU member states reduce packaging waste by five percent by 2030, encompassing packaging design and waste management. The lack of recycling infrastructure is identified as a significant impediment for companies dealing with plastic waste, contributing to the shortcomings of the existing mechanical recycling systems.


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Indeed, today's recycling processing centres are ill-equipped to handle the overwhelming influx of recycling materials, let alone meet the ambitious new targets. According to a report by the Ellen MacArthur Foundation, only 14 percent of the plastic packaging used globally is recycled, while the remaining 86 percent is either incinerated or ends up in landfills or the environment. This stark statistic emphasises the urgent need for better-equipped recycling facilities to effectively process and manage the overwhelming influx of materials to achieve recycling goals.


For certain recycling, the front-end process requires machinery to granulate product using a predefined set of blades to turn the raw material into smaller particle sizes. These centres face the challenge of transforming inconsistently shaped materials of different types into a uniformly shaped end product that may be separated. This is challenging for several reasons. Firstly, irregular shapes can make it difficult to establish consistent manufacturing processes, such as moulding or extrusion, that require standardised input materials. Secondly, the varying shapes affect the efficiency of sorting and separation methods used in recycling facilities, increasing the risk of contamination and reducing the quality of the end product. Lastly, achieving uniformity in particle size and


material type is crucial for ensuring the integrity and usability of recycled materials in subsequent manufacturing processes, making it essential to invest in specialised equipment and processing techniques to overcome these challenges. Therefore, once granulation is completed, the classification and sorting by particle size using Gough’s product range is fundamental in controlling quality during the next packaging or end- product forming processes.


But what kind of specialised equipment are we referring to? In short, the solution to these obstacles lies in investing in sieving, and sorting equipment.


Sorting products is a crucial aspect of recycling, and industrial sieves are invaluable across various sectors for classifying and sorting products. Vibratory sieves, for example, are commonly employed to sort raw materials, ensuring the end product achieves a uniform size by passing through different mesh aperture sizes.


Let’s look at the example of polyethylene terephthalate (PET) bottles. In recycling, sieves are extensively used to sort granulated PET bottles. They help separate the different particle sizes, allowing for efficient utilisation of the PET materials for different repurposed value products. Beyond PET bottles, industrial sieves and screens can separate a wide range of materials, including scarce metals in


electronics to certain rubber tyre recycling, granulated cable/copper and Waste Electrical and Electronic Equipment (WEEE) waste. Further investment in such equipment can address numerous recycling challenges while reducing or eliminating landfill charges for certain products.


Illustrating this, let's examine the case of a recycling company in Norfolk, UK, which required a screening operation to classify glass fibres according to quality. Gough Engineering recommended the Vibrecon GVC5 separator. This customisable system removes fine particles, separates oversize and agglomerates, and facilitates conveying between processes. The system, equipped with two stainless steel grade 304 decks, classified glass fibres at a rate of 750kg per hour. The top deck eliminates oversized particles, the bottom deck allows easy discharge of fine or undersized particles, and the middle deck ensures the ejection of good material. By implementing this method, the recycling centre ensures the effective separation of all particles. Due to the diverse configurations of sieves in recycling applications, consulting an expert like Gough Engineering is always recommended. The company’s Vibrecon vibratory screening systems, available in different sizes ranging from 610mm to 1,630mm in diameter, cater to an array of applications.


While Greenpeace's ‘Circular Claims Fall Flat


Again’ report rightly highlights the limitations of mechanical recycling in handling plastic waste, sieving and screening equipment offer a solution to these challenges. Recycling companies are well aware of the difficulties associated with separating materials, and should work with a trusted material handling equipment partner to tackle their material separation challenges. Investing in equipment to improve separation processes should be a first step towards meeting the EC’s targets.


Gough Engineering www.goughengineering.com


MARCH 2024 | PROCESS & CONTROL 15


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