Material Recycling the voice of India Recycling Industry Oct-Nov-2020
Electrical and electronic equipment (EEE) is made up of many different materials. When recycling this equipment, it is sought above all, and as far as it is possible, to fully recover the metallic fraction (ferrous, non-ferrous and precious metals). the metal fractions are the “object of desire” and various techniques are available for almost complete metal recovery. But electronic waste also contains other recyclables such as aBs, Ps and other materials. there could still be certain amounts of residual substances (like dust, glass, etc) which, in some cases have only low or no value at all. they nevertheless have to be separated from the recyclable materials.
Beside the “metals” resource, the “plastics” resource should also have to play a large role in recycling. this is however mostly not the case in practice, as recovery of clean plastic fractions from EEE waste is much more laborious than recycling of the metals. this is because the presently available sorting possibilities can only exploit the entire plastics raw material potential to a limited extent. a large proportion of this material is therefore lost and is used, for example, to recover thermal energy.
The granulate material purity achievable with electrostatic separation are very high and sometimes stretch beyond 99.50%. the recyclate is so clean that it can easily be used again to produce high-grade compounds and, in turn, can be processed into new technical products. in this way, valuable technical raw materials can be recovered from materials that cannot be processed further. Depending on the application, expensive virgin material can be entirely or at least partially replaced by more favourably priced recyclate. many products can then be produced entirely from recycled plastics. this is an important economic aspect, especially against a background of rising oil and raw material prices. In addition, it also makes an important contribution towards environmental protection through avoidance of waste.
Plastics from Electronic waste
By definition, “electrical and electronics scrap” arises from a number of different types of equipment. as no material pre-separation into clear-cut pre-separation according to types of materials is made in recycling companies while processing, this mixture of materials ends up in shredding plants. this leads to mixed plastics waste after the metal fraction has been separated out. the residual material, consisting not only different plastics, but will be dust, wood, glass, residual metals, elastomers and many other such undesired contaminants.
The task of plastics recyclers then consists of production from this complex mixture of re-usable plastics fractions. as experience shows, particularly high demands are placed on purity of the recyclate, as they often compete with virgin materials. on the other hand, there is also a task here of recovering the highest possible proportion of clean plastics, so that as little as possible good material is lost. Plastics recycling is only economical if the highest possible proportion of material fractions is recovered.
However, it has been observed in recycling that not all plastics can be brought back into circulation, on account of legal requirements. among these, plastics like that containing brominated flame retardants may not be reused, and have to be separated into separate fraction. there are furthermore also many other plastics present, such as Pc or Pmma, which are only present in low amounts of 1 – 2 % in the entire plastics fraction. on account of the low amounts of these plastics, recycling only pays off to a limited extent, as the effort required to recover these plastics is sometimes higher than the possible return from them. the largest proportion of plastics in mixed electronics waste consists of Ps and aBs, as well as PP. Experience shows that these materials make up around 55% of the input material and that 40 to 50% of the input material consists of uneconomically recoverable plastic, flame retarded materials, impurities, etc. Work is however ongoing to minimise this fraction with new processes and thereby to raise the return.