Fractionated Anionic PAM Dosing Under High Salinity: Controlling Floc Growth and Stability

Area of Science:

• Mineral Processing
• Colloid and Surface Chemistry
• Water Treatment

Background:

• Seawater use in mineral processing complicates solid-liquid separation due to polymer issues.
• Challenges include polymer chain contraction, coagulation, and brittle aggregates.

Purpose of the Study:

• To evaluate fractional dosing of anionic polyacrylamide (PAM) for floc formation and sedimentation in seawater.
• To compare single-pulse versus multi-pulse dosing strategies for quartz-kaolinite suspensions.

Main Methods:

• Fractional dosing of PAM (1-4 pulses) in quartz-kaolinite seawater suspensions.
• Analysis using sedimentation assays, FBRM, size distributions, fractal dimensions, and zeta potential.

Main Results:

• All fractional dosing schemes outperformed single-pulse dosing.
• A three-pulse strategy (0-30-60 s) yielded the highest settling rates and fines reduction.
• Multi-pulse dosing resulted in more compact, robust flocs with stepped growth and stable maturation.

Conclusions:

• Fractional PAM dosing mitigates issues associated with seawater processing.
• Progressive polymer availability enhances bridging efficiency and reduces brittle aggregate formation.
• The three-pulse method offers superior performance for solid-liquid separation in high-salinity conditions.