Technical Expertise
Four short guides our engineers use with every customer. No sales fluff — just the decision rules, procedures and fixes that keep a flocculant program on spec.
PAM selection
Two variables do most of the work: ionic character (which counteracts your particles' charge) and molecular weight (which builds floc size and strength). Match them to the table, then confirm with a jar test.
| Condition / goal | Recommended type |
|---|---|
| Neutral–alkaline water, sedimentation of mineral fines | APAM, high MW, medium anionicity |
| Biological / organic sludge dewatering | CPAM, charge matched to sludge (10–60%) |
| Acidic or high-salinity water | NPAM |
| Oil displacement, drilling, fracturing | PHPA, ultra-high MW |
| Fast make-down, no dissolution skid | Emulsion (cationic or anionic) |
| Potable / municipal water, low dosage | High-purity powder grade |
Jar test procedure
The jar test is the industry standard for finding grade and dosage. Six beakers, one afternoon, and you know exactly what to dose.
- Prepare a 0.1% (1 g/L) PAM stock solution: sprinkle powder into the vortex of swirling water and mix 60 minutes. Use within 24 hours.
- Fill six 1,000 mL beakers with your process water or sludge, at real temperature and pH.
- If you use a coagulant (PAC, alum), add it to all beakers first at its optimum dose and mix 1 minute.
- Dose a geometric series of PAM into the beakers — e.g. 1, 2, 4, 8, 16 and 32 mg/L (for sludge: 1–8 kg/t DS equivalent).
- Rapid mix 1 minute at ~150 rpm to disperse, then slow mix 10 minutes at 30–50 rpm to build flocs.
- Stop mixing and watch: record floc size, settling time to half volume, and supernatant turbidity at 15 and 30 minutes. The winner is the lowest dose that gives large flocs and clear supernatant.
Field tips
- Never add PAM powder directly to a beaker — always dose prepared stock.
- Compare grades, not just doses: the right grade often wins at one-quarter of the dose.
- For sludge, run a capillary suction time (CST) or filterability check on the two best beakers.
Dosage
Underdosing leaves water cloudy; overdosing restabilizes particles and wastes polymer — sometimes with a viscous, stringy mess. Start in these ranges, then trim to the minimum effective dose.
| Application | Starting dosage |
|---|---|
| Tailings / mineral sedimentation | 5–50 g/t dry solids |
| Industrial & municipal wastewater | 1–20 mg/L (after coagulant) |
| Sludge dewatering — belt press | 2–6 kg/t DS |
| Sludge dewatering — centrifuge | 3–8 kg/t DS |
| Alumina red mud settling | 100–600 g/t dry mud |
| Polymer flooding (EOR) | 500–2,000 mg/L in brine |
Prepare PAM as 0.1–0.2% stock and dose diluted. Polymer concentration above ~0.3% at dosing hurts mixing and floc formation.
Troubleshooting
Six symptoms our support team hears most — with the usual cause and the fix.
| Symptom | Likely cause | Fix |
|---|---|---|
| Fish-eyes in solution | Powder dumped too fast or into still water | Sprinkle slowly into the vortex; mix 200–300 rpm until fully wetted |
| Low viscosity after make-down | Short dissolution time or cold, very hard water | Extend mixing to 60–90 min; warm to ≤ 50 °C helps in winter |
| Cloudy supernatant | Underdose or wrong ionic type | Step dose up; check zeta/charge; verify coagulant dose |
| Water turns stringy / viscous | Overdose | Cut polymer by half and re-test; never chase clarity with more polymer |
| Flocs break in centrifuge | Charge or MW too low for the shear | Move to higher-charge CPAM; dose at lowest-shear point |
| Solution gels in tank overnight | Old stock or contamination | Use stock within 24 h; clean and flush make-down tank |