Polyacrylamide (PAM) 9003-05-8

Polyacrylamide (PAM) is a water-soluble synthetic polymer with the formula (C₃H₅NO)ₙ. It is produced by polymerization of acrylamide monomers and is one of the most widely used flocculants globally. It is available in anionic, cationic, and nonionic forms with varying molecular weights and charge densities to suit different applications.

Anionic polyacrylamide (APAM) carries a negative charge and is used for treating positively charged suspensions, such as mineral tailings and alkaline wastewater. Cationic polyacrylamide (CPAM) carries a positive charge and is most effective for organic sludge dewatering and negatively charged colloids. Nonionic polyacrylamide (NPAM) has no ionic charge and works well in acidic conditions or where ionic interference is a concern. The choice depends on the specific water chemistry and solids characteristics.

In water treatment, polyacrylamide is used as a flocculant to aggregate suspended particles into larger flocs that can be removed by sedimentation, flotation, or filtration. It is typically dosed after coagulation with aluminum or iron salts. PAM significantly improves the settling rate and effluent clarity while reducing coagulant dosage requirements.

In mining, polyacrylamide is essential for tailings dewatering and mineral processing. It flocculates fine mineral particles in tailings slurry, allowing water to be recovered and recycled while producing dense, stackable solids for disposal. It is also used in coal washing, bauxite processing, and other mineral beneficiation processes. Anionic PAM is the most commonly used type in mining applications.

Polyacrylamide should be stored in a cool, dry place away from moisture, heat, and direct sunlight. It is hygroscopic and will absorb moisture, causing lumping and reduced solubility. When preparing solutions, PAM powder should be added slowly to agitated water at room temperature. Typical solution concentrations are 0.05-0.5%. Solutions have a limited shelf life due to potential biodegradation and viscosity loss. Always prepare fresh solutions for best results. Under proper dry storage conditions, powder shelf life is 24 months.