Tertiary and Quaternary Recycling

Explain the recycling hierarchy indicated by the terms primary, secondary, tertiary and quaternary recycling. 

What challenges face manufacturers who recycle their scrap How do they address these challenges  

What polymers are most commonly recycled from post-consumer sources Why  

Plastic lumber can be manufactured from mixed-polymer post-consumer recycled materials. One example incorporates polyethylene and polypropylene into a final material. How do processors achieve this incorporation in light of the immiscibility of the t vo polymers  

Why do polyethylene terephthalate bottle manufacturers not use any polyvinyl chloride for closures or labels on the bottle  

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Data relating to the nature and quantities of plastics wastes arising from industrial processes and municipal refuse have been reviewed [1,2], together with a consideration of the economics and appropriateness of primary, secondary, tertiary and quaternary recycling respectively. 

Processes that do not rely on the melting of plastic recyclate relate to large scale predominantly tertiary and quaternary recycling. Thermoset matrix composites recycling also falls within this description, and the principal recycling routes for thermoset matrix composites are outlined below. 

This chapter focuses on primary and secondary recycling where the plastic is reused rather than converted into chemicals or fuel to meet energy needs. Although tertiary and quaternary recycling routes are... 

Tertiary or quaternary recycling, (recovery of chemicals or energy), should only be considered when other types of recycling are not economically or technologically feasible. In tertiary recycling, waste plastics are converted to either monomers or fuels or petrochemical feedstocks. Conversion to monomers by solvolytic methods is feasible for condensation polymers but often requires pure polymer streams. Sorting and cleaning of the waste stream increases the cost of the process. 

Recycling processes for plastics can be classified in a variety of ways. One categorization differentiates between primary, secondary, tertiary, and sometimes quaternary recycling. 

Secondary or mechanical recycling processes differ from tertiary or feedstock recycling and quaternary or energy recovery processes principally in the potential to retain some of the energy used from plastics production, and in general terms provide for financially advantageous options. 

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