1.What is the significance of recycling color-coated steel plates?
Efficient Resource Utilization: Steel is an infinitely recyclable metal. Recycling one ton of scrap steel saves 1.5 tons of iron ore, 0.6 tons of coke, and reduces carbon dioxide emissions by three tons.
Reduced Solid Waste Pollution: If directly discarded, the organic components in the coating may occupy land for a long time or release harmful substances. Recycling reduces the environmental burden.
Cost Reduction and Efficiency Improvement: For businesses, recycled materials can serve as a raw material supplement, reducing dependence on virgin steel, which offers economic advantages, especially during periods of fluctuating steel raw material prices.
2.What is the process of recycling color-coated plates?
Scrapped color-coated steel sheets (such as old factory wall panels, discarded home appliance casings, etc.) → Sorted and disassembled (removing non-steel components such as plastic and hardware) → Crushed/sheared (processing large sheets into small pieces for easy transportation) → Coated → Sent to the steel mill for smelting as scrap steel.
3.How to deal with the harmless treatment of coatings?
High-temperature incineration: In a specialized preheating furnace, the color-coated sheets are heated to 300-500℃ (below the melting point of steel), decomposing the organic coating into gases (primarily CO₂ and H₂O). These gases are purified through exhaust gas treatment equipment (such as activated carbon adsorption or catalytic combustion) and then discharged. The remaining uncoated substrate is then fed into the steelmaking furnace. This method is mature and suitable for large-scale recycling, but requires temperature control (to prevent excessive oxidation of the substrate) and exhaust gas treatment efficiency.
Chemical stripping: The color-coated sheets are soaked in an organic solvent (such as ketones or esters) or alkaline solution to separate the coating from the substrate (dissolving or peeling the coating). The stripped substrate is then cleaned and dried for recycling. The waste liquid can be distilled to recover the solvent and reuse it. This method is suitable for small-scale, high-precision recycling (e.g., where a surface-free substrate is required), but it is costly and requires chemical wastewater treatment to avoid secondary contamination.
Mechanical stripping: The coating is directly removed through physical methods such as grinding (sandpaper, wire wheels) or sandblasting (high-pressure quartz sand, steel shot). It is suitable for sheets with thick coatings or localized damage. The advantage is environmental protection (no waste gas or waste liquid), but the efficiency is low and it is easy to cause slight damage to the surface of the substrate (which may affect the surface quality of the steel in subsequent smelting), so it is mostly used as an auxiliary means.
4.What is the refurbishment process for color scrolls?
Old color-coated steel sheets → Surface pretreatment (remove old coating and rust: use sandblasting/high-pressure water cleaning to remove loose coating and rust, and sandpaper to smooth the surface) → Defect repair (fill local depressions and holes in the substrate with putty) → Recoating (spray primer and topcoat as needed, such as polyester paint or acrylic paint, using roller coating or spraying) → Curing (baking or natural drying) → Cutting/processing (making into wall panels, enclosures, pallets, etc. according to the new use).
5.What are the applicable scenarios for refurbished color-coated coils?
Lower weather resistance requirements: such as indoor shelves, trash can casings, and non-load-bearing partitions;
Public welfare facilities: such as community bulletin boards and rural road guardrails.