How does NPAM work in mining wastewater treatment?
2026-04-14 10:58:31
In mining wastewater treatment,Nonionic Polyacrylamide(NPAM)acts as a highly efficient flocculant that achieves rapid solid–liquid separation through adsorption,bridging,and netting effects.Its working mechanism is especially suitable for mine wastewater with high suspended solids,high metal ion content,and often acidic or high‑salt conditions.
1.Adsorption of fine mineral particles
NPAM’s long molecular chains contain a large number of amide groups(-CONH₂),which form hydrogen bonds and van der Waals forces with the surface of suspended mineral particles(sludge,ore fines,clay,tailings).
Unlike charged polymers,NPAM adsorbs stably even when particles have weak or variable surface charges.
2.Bridging and floc formation
The long-chain macromolecules of NPAM adsorb multiple fine particles at the same time,connecting dispersed particles into large,compact flocs.
This bridging effect is critical in mining wastewater,where particles are often extremely fine and difficult to settle naturally.
3.Netting and trapping small colloids
As flocs grow,they entrap and sweep smaller colloids,metal hydroxides,and suspended impurities in the water body,further improving clarification.
4.Resistance to acidity and high salinity
Most mine wastewater is acidic and contains high concentrations of metal ions and salts.
NPAM is electrically neutral,so it is not easily shielded or degraded by ions,maintaining flocculation performance where anionic or cationic PAM may lose efficiency.
5.Accelerated sedimentation and clarified effluent
The formed large flocs settle rapidly,allowing clear recycled water to be reused in mineral processing.
This greatly reduces turbidity,improves solid recovery,and supports water recycling in mines.
6.Improved tailings dewatering
In tailings treatment,NPAM helps form dense,low‑moisture filter cakes,making dewatering by filter presses,centrifuges,or belt filters more efficient and reducing tailings pond management pressure.
References
GB/T 7714
Yu X,Li G,Zhang L.Flocculation Performance of Nonionic Polyacrylamide in Coal Mine and Metallic Ore Wastewater[J].Journal of Central South University,2021,28(4):1120–1130.
MLA
Yu,Xiang,Guosheng Li,and Lin Zhang.“Flocculation Performance of Nonionic Polyacrylamide in Coal Mine and Metallic Ore Wastewater.”Journal of Central South University,vol.28,no.4,2021,pp.1120–1130.
APA
Yu,X.,Li,G.,&Zhang,L.(2021).Flocculation performance of nonionic polyacrylamide in coal mine and metallic ore wastewater.Journal of Central South University,28(4),1120–1130.
