Direct answer
What temperature should pyrolysis run at?
For oil, 450–550 °C with a cold quench. For char, 400–600 °C and stay there. For battery binder, 500–700 °C after a 100–300 °C dry. For PFAS leaving solids, ≥400–500 °C is the start; for PFAS mineralisation in gas, plan ≥850–950 °C with hydrogen donors. For asbestos fibres, plan 900–1100 °C hold, not a 600 °C kiln tour.
| °C | What happens | Use | Do not expect |
|---|---|---|---|
| 60–120 | Free moisture, some electrolyte solvents | Drying, vacuum solvent recovery | Pyrolysis |
| 150–250 | Hydrothermal TFA decarboxylation (with alkali for F−) | TFA in water | Dry pyrolysis of sludge |
| 180–300 | LIB carbonate electrolytes crack; LiPF6 → HF if wet | Vacuum dry preferred | Safe open-air heating of cells |
| 200–300 | Torrefaction | Solid fuel, grindability | Oil, PFAS kill |
| 350–450 | Onset of polymer and biomass depolymerisation | Vacuum tire oil | Complete conversion of all polymers |
| 400 | PFAS leave sludge solids in lab (≥99.6% of 24 PFAS in sand matrix) | Minimum for “PFAS off char” | Mineralisation; gas still loaded |
| 420–540 | PVDF binder decomposes (HF, fluorocarbons) | Black-mass pretreatment | Zero fluorine emissions |
| 450–550 | Sweet spot for plastic and biomass liquids; tire oil max | Most oil plants | PFAS mineralisation |
| 500–630 | Carbothermal reduction of NMC/NCA; Li → Li2CO3/Li2O | Selective Li leach | Smelting recoveries of Ni/Co |
| 600 | Municipal sludge pyrolysis + NCA Li optimum in one study; chrysotile dehydroxylation starts | PYREG-class, battery kiln | Asbestos fibre gone |
| 650–800 | More gas, less oil; chrysotile XRD fades; fibres may remain | Char polishing, some ACM research | Oil maximisation |
| 700–800 | Parent PFAS gas-phase headgroup loss; PIDs remain | First destruction, not last | CF4-free stack |
| 850–950 | Thermal treatment ~99.99% parent PFAS in some combustors; 1H-perfluoroalkane bottleneck ~950 °C, 2 s | Pyrolysis-gas oxidiser | Zero PIDs if starved of H |
| ≥950–1100 | More complete C–F mineralisation; asbestos → forsterite/enstatite | Incineration, ACM inerting | A pyrolysis-oil business case |
| 1500 | Battery pyrometallurgy / EnAM slag work | Alloy + slag, not pyrolysis | Li in metal; Li reports to slag |
Hold time
Battery PVDF: 15 min at 650 °C can work with casing intact; 1–3 h is common at 450–550 °C. Sludge PFAS-off-char: minutes at 600 °C in PYREG-class units, but the oxidiser is the destruction step. Asbestos: 30 min at 800 °C completed mass-loss in one cement-asbestos kinetic study; fibre morphology studies still ask for ≥900 °C / 2 h. Do not mix those papers.