Optimization of process parameters and kinetics of fluoride extraction from spent potlining using response surface...

Area of Science:

• Environmental Chemistry
• Chemical Engineering
• Materials Science

Background:

• Spent potlining (SPL) treatment historically focuses on hazardous compound extraction, particularly fluorides and cyanides.
• Optimization and kinetic studies for fluoride extraction from SPL are insufficiently addressed in existing literature.
• Efficient, cost-effective, and sustainable SPL treatment requires detailed understanding of fluoride extraction factors.

Purpose of the Study:

• To statistically model and optimize fluoride extraction from SPL in acidic environments.
• To investigate the kinetics of fluoride extraction using the shrinkage core model (SCM).
• To identify key factors influencing fluoride extraction efficiency and establish optimal treatment parameters.

Main Methods:

• Response surface methodology (RSM) combined with central composite design (CCD) for statistical modeling.
• Shrinkage core model (SCM) for investigating fluoride extraction kinetics.
• Arrhenius plot analysis to determine activation energy and reaction control mechanisms.

Main Results:

• A second-order quadratic model with high accuracy (R²=0.986, Adj R²=0.973) was developed.
• Optimal fluoride extraction of 87.49% was achieved at 48.43 °C, 0.752 mm particle size, 1.2 M acid concentration, and 10 min.
• Liquid film diffusion mechanism governs fluoride extraction kinetics, with an activation energy of 36.26 kJ/mol.

Conclusions:

• The study provides an optimized, statistically validated method for fluoride extraction from SPL.
• Optimized parameters ensure efficient, sustainable, and cost-effective industrial treatment of SPL.
• Integration of kinetic frameworks offers a novel approach to SPL treatment analysis and optimization.