1.How to disassemble the pretreatment stage?
Manual disassembly: Use a magnetic separator to separate color-coated plates from non-metallic components (screws, sealing strips, etc.); retain intact large plates (size > 1m²) to avoid excessive crushing that increases the risk of zinc volatilization.
Coating toxicity detection: Use an XRF spectrometer to quickly screen the content of heavy metals such as lead, chromium, and cadmium.
Plates that exceed the standard (such as lead > 100ppm) → enter the hazardous waste treatment line separately.
Plates that meet the standard → enter the regular recycling process.
2.How does mechanical exfoliation work?
Process: High-pressure water jet (350MPa) cuts the plate edge → Hydraulic stripping machine separates the coating
Recovery rate: 98% for steel plate, 60% for zinc layer
Cost: ￥80-120/ton
3.How does electrolytic stripping work?
Process: steel plate as anode → alkaline electrolyte (NaOH 15%) → coating stripping
Products: ◦ Bare steel plate (directly returned to the furnace for smelting) ◦ Zinc-containing sludge (extract zinc ingots, purity 99.5%)
Applicable scenarios: high-end PVDF coated plate processing
4.What are the key technologies for pollution prevention and control?
Dust control
Crushing process: closed negative pressure + bag dust removal (emission <10mg/m³)
Heavy metal control
Pyrolysis ash: glass solidification treatment (heavy metal leaching concentration <0.1mg/L)
Dioxin inhibition
Pyrolysis furnace: rapid cooling device
Adding urea: decomposition of chlorine source
5.What are the practical suggestions for actual application?
Pre-building demolition planning: color-coated board roof/wall → whole piece demolition → laser coding traceability → direct delivery to pyrolysis plant.
Urban recycling network: community recycling point → regional sorting center → pyrolysis base (radiation radius ≤ 200km).
Extended producer responsibility: color-coated board manufacturers are required to promise: for every ton of board sold, 0.8 tons of waste board will be recycled