High-Value and Environmentally Friendly Recycling Method for Coal-Based Solid Waste Based on Polyurethane Composite...

Area of Science:

• Materials Science
• Environmental Science
• Chemical Engineering

Background:

• Coal-based solid waste, such as fly ash and coal gangue, presents disposal challenges.
• Developing high-value applications for this waste is crucial for environmental sustainability.
• Polyurethane composites offer versatile material properties for waste incorporation.

Purpose of the Study:

• To create novel composite materials using modified fly ash (MFA) and modified coal gangue powder (MCG) with polyurethane (PU).
• To evaluate the mechanical properties, flame retardancy, and environmental safety of these MFA/PU and MCG/PU composites.
• To establish a high-value and environmentally friendly application for coal-based solid waste.

Main Methods:

• Preparation of MFA/PU and MCG/PU composites with varying filler content (10-40%).
• Mechanical testing (compressive strength) and flame retardancy analysis (limiting oxygen index, cone calorimetry).
• Microstructural analysis using scanning electron microscopy (SEM) and water quality tests for heavy metal leaching.

Main Results:

• Composites with 30% filler content exhibited optimal properties: MFA/PU (84.1 MPa compressive strength, 29% LOI) and MCG/PU (46.3 MPa compressive strength, 23.5% LOI).
• SEM analysis indicated improved interface compatibility with increased filler content.
• Both composites demonstrated condensed-phase flame retardancy, with MCG/PU forming a more stable barrier layer; no heavy metal leaching was detected.

Conclusions:

• Modified fly ash and coal gangue powder can be effectively utilized in polyurethane composites.
• MFA/PU composites offer superior mechanical and flame-retardant properties compared to MCG/PU.
• This research presents a viable strategy for the safe and high-value recycling of coal-based solid waste into functional materials.