Experimental Study on the Optimization of Coal-Based Solid Waste Filling Slurry Ratio Based on the Response Surface...

Area of Science:

• Materials Science
• Geotechnical Engineering
• Environmental Science

Background:

• Coal power solid waste presents a significant environmental challenge due to low utilization rates.
• Effective utilization of coal gangue, fly ash, and gasification slag is crucial for regional resource management and ecological balance.

Purpose of the Study:

• To investigate the mechanical property evolution of coal-based solid waste filling materials.
• To determine the optimal composition for filling materials balancing pipeline transport and mechanical strength.

Main Methods:

• Characterization of physical and chemical properties of mixed solid waste.
• Application of Box-Behnken experimental design and response surface methodology.
• Development of a multivariate nonlinear regression model for predicting filling body strength over time.

Main Results:

• Identified key factors influencing filling material strength: slurry mass fraction, coal gangue, fly ash, and gasification slag content.
• Revealed significant interactions between components affecting strength at different curing stages (early, middle, final).
• Observed the formation of a stable 3D support system through hydration products like calcium alumina and C-S-H gel with extended curing.

Conclusions:

• The mechanical strength of coal-based solid waste filling materials is significantly influenced by component ratios and curing time.
• Optimized material composition and curing lead to enhanced strength and stability, crucial for mine backfilling applications.
• The study provides a data-driven approach to maximize the utilization of coal power solid waste in construction materials.