Technology

Questions & Answers on EPS Recycling Technology

1. How is EPS made?

2. How a recycling scheme works?

3. How to manage the EPS foam waste?

4. In which way can we recycle EPS?

5. How to explain “4R” waste reduction options for EPS?

6. Can all kind of waste EPS be recycled?

7. How is the trend of EPS recycling?

Q: How is EPS made?

A: Expanded Polystyrene (EPS) is PS foam that use pentane gas as the blowing agent. During the material production process call “Polymerization” the polystyrene resin granules impregnated with the blowing agent. EPS production process begins in the pre-expansion process where the EPS bead will expand by the heat of steam usually 50 times in volume. Next step is molding process where expanded foam bead will be heated again with steam then they expand further until they fuse together, forming as foam products.

EPS bead

Q: How a recycling scheme works?

A: Many major electronic and car manufacturers and electrical retailers have successful, economically viable EPS recycling schemes. Here is a guideline of how most recycling schemes work:
1. Compaction – in order to recycle used EPS, it must be separated from other materials. EPS is easily recognised and can be collected at retail outlets, distribution centres, factories or warehouses. Then the collected material is compacted up to one-fortieth of its original size for easy, cost-effective transportation.

2. Collection – the recycler will send a lorry to collect the material once there is a full lorry load ready. This is taken back to the recycler’s factory.

3. Granulation – the recycler feeds the EPS into a granulator that chops the material into smaller pieces.

4. Blending – the material is passed into a blender for thorough mixing with similar granules.

5. Extrusion – the material is fed into the extruder, where it is melted. Colour can be added and the extruded material is then moulded into a new value added product

EPS recycling process

EPS recycling scheme

Q: How to manage the EPS foam waste?

A: Waste EPS is generally from construction, packaging and container. It is expensive and difficult to transport due to its large volume.
The main methods to manage waste EPS are as follows.

methods to manage EPS foam waste

treatment of EPS foam waste

  • Landfill: unable to biodegrade;
  • Burning: generating heat;
  • Compacting and pelletizing: using EPS recycling and pelletizing machines turning waste EPS into PS pellets and manufacturing various products such as coat hanger, flowerpot, video cassettes, etc.
  • Melting and pelletizing:
  • Reground and mix with concrete to produce new building products such as prefabricated concrete blocks to reduce the weight and increase insulation properties;
  • Crush into small particle and mix with soil to improve ventilation in the soil.

Q: In which way can we recycle EPS?

A: EPS is recycled in four ways:

  1. Remoulding into foam – post consumer packaging can be processed, as a partial or direct substitute for virgin polymer, into raw material for the production of loose-fill packing or even for new EPS mouldings.
  2. Re-use in non-foam applications – examples include plastic stationery products, video and CD cases, coat hangers, plant pots, etc
  3. Re-use in extruded applications – one example, hardwood replacement, can be used to make products such as garden furniture, window and picture frames
  4. Re-use in lightweight concrete and building products – grounded EPS is mixed with cement to make a lightweight concrete material for insulating swimming pools, flat roofs, floors, etc.

Q: How to explain “4R” waste reduction options for EPS?

A: 1. Reduce– refers to the reduction of natural resources used. By optimising pack design, moulders can reduce EPS usage, thus reducing environmental burden and cost.

2. Re-Use – EPS packaging can be re-used as multi-trip packaging, e.g. for the internal transport of partially assembled goods. Another simple re-use of the packaging is to grind it and use it as soil conditioner to improve drainage and aeration. EPS seed and pot-holding trays are often re-used in this way at garden centres.

3. Recycle – is the reprocessing of used EPS packaging to make a new material such as hardwood replacement for making garden furniture, slate replacement for roofing tiles and new plastics items such as coat hangers, CD and video cases

4. Recover – EPS has a very high calorific value, higher than that of coal, and can be safely burnt within energy recovery units, or incinerators, without giving off toxic or environmentally damaging fumes

Q: Can all kind of waste EPS be recycled?
A: Not all materials are well suited for recycling. Post-consumer EPS packaging must be clean and free of tape, film and cardboard. Expanded polystyrene made with a fire retardant additive, typically used in the manufacture of EPS building insulation, requires special reprocessing conditions.

Q: How is the trend of EPS recycling?

A:

Post-Consumer & Post-Commercial EPS Recycling Rate History: 1990-2008

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