Polyethene terephthalate

Transesterification is a crucial step in several industrial processes such as (i) production of higher acrylates from methylmethacrylate (for applications in resins and paints), (ii) polyethene terephthalate (PET) production from dimethyl terephthalate (DMT) and ethene glycol (in polyester manufacturing),... 

X-ray fluorescence (XRF) sorting is especially usefirl for sorting polyethene terephthalate (PET) from polyvinyl chloride (PVC). This is essential if the PET is to ultimately be used for food contact applications, and desirable in most other applications, since under the conditions used for PET recycling the PVC would partially degrade and be seen as black specks in the final product. When bombarded with X-rays, polymers containing heavy atoms such as chlorine emit a readily detectable X-ray signal. This signal can be used to control an air jet separation system similar to the one described above. 

---