Due to its special properties, PTFE has a large melt viscosity, and it hardly flows when it reaches the melting point. It will decompose when the temperature rises. Therefore, it cannot be recovered by melt polymerization and injection molding methods like ordinary thermoplastic resins. Driven by catalytic technology, chemical recycling has shown good economic prospects. The chemical recovery of PTFE by the high-temperature cracking method can not only directly convert it into monomer, but also upgrade it and regenerate it.

High-temperature pyrolysis recycling method

Pyrolysis is to decompose PTFE into small molecules at a high temperature of 425 °C to 700 °C, and then recover useful small molecules; sometimes in order to obtain certain small molecules, the pyrolysis temperature can be as high as 800 °C.

Among the available small molecule compounds are tetrafluoroethylene (TFE), hexafluoropropylene (HFP), octafluorocyclobutane (OFCB), octafluorobutene (OFB), etc. At the same time, a small amount of octafluoroisobutene is also produced (OFB), fluorophosgene (COF) and other highly toxic substances, which should be avoided and controlled during the operation.

Advantages and disadvantages of pyrolysis

• There are no specific requirements for fluoropolymer waste, and it is suitable for processing various polytetrafluoroethylenes, and can completely recover organic fluorides produced by pyrolysis and residual fillers after pyrolysis.
• The requirements for the pyrolysis device and the condensing device are high, the process is more complicated, and the production of toxic substances needs to be suppressed, and the exhaust gas can be discharged after treatment.

Fluidized bed high temperature cracking recovery technology

• Optimal temperature range

545°C to 600°C (1013°F to 1112°F)

The main decomposition products

Tetrafluoroethylene (TFE), hexafluoropropylene (HFP) and cycloperfluorobutane (c-C4F8).

Process advantages

1. The produced monomers can be purified before repolymerization, so that more valuable products can be produced, and the process allows continuous operation.
2. It can handle different PTFE compounds and a large number of composite materials, without the need to grind the waste into small particles.