Polyelectrolyte Flocculants Supplier South Africa

What Are Polyelectrolytes?

Polyelectrolytes (polyacrylamide-based flocculants, PAM) are high-molecular-weight synthetic polymers carrying ionisable charge groups — anionic (negatively charged, from acrylic acid co-monomers), cationic (positively charged, from quaternary ammonium or amine monomers), or non-ionic (neutral, polyacrylamide without charged groups). They function as flocculants through a bridging mechanism: each high-MW polymer chain adsorbs to the surface of multiple particles simultaneously, physically bridging between them to form large, open, rapidly settling floc aggregates. Polyelectrolytes are used as the second stage of a two-stage coagulation-flocculation process — after an inorganic coagulant (alum, ferric, PAC) destabilises colloidal charge, the polyelectrolyte bridges the resulting microfloc into large, rapidly settling macro-floc.

Selection of Anionic, Cationic, and Non-ionic Grades

The choice of polyelectrolyte grade depends on the application: anionic polyacrylamides are used in mineral processing (tailings settlement), municipal water clarification (bridging pre-coagulated floc), and effluent polishing — anionic grades adsorb to positively charged sites on floc surfaces; cationic polyacrylamides are used for sludge dewatering (activated sludge, primary sludge) and in positively charged systems; non-ionic polyacrylamides are used where pH or ionic strength makes charge uncertain, and in mineral processing of certain clay and slime systems. In mining and mineral processing, anionic polyelectrolytes are used extensively in tailings thickeners, paste thickeners, clarifiers, and wash circuits to settle fine mineral particles and recover process water.

Application in Water Treatment and Mining

In municipal and industrial water treatment, polyelectrolytes are added in the slow-mix (flocculation) stage after coagulant addition, at doses of 0.1–2 mg/L active polymer. They dramatically improve floc size, strength, and settling rate, increasing clarifier throughput and reducing turbidity in the overflow. In sludge dewatering, cationic polyelectrolytes (higher charge, lower MW) condition activated sludge or thickened primary sludge before belt filter presses or centrifuges, improving cake dryness and filtrate quality. In mining, anionic polyelectrolytes are the primary flocculant for tailings thickener operations — flocculant dose and selection is optimised for each mineral slurry type. Terracore Chemicals supplies anionic, cationic, and non-ionic polyelectrolyte grades in powder bags and emulsion drums.