Product Page: Low Cationic Polyacrylamide
Technical Document Verified By
Henan Saifu R&D and Application Engineering Department
Target Application
Municipal Sludge Dewatering & Industrial Effluent Treatment
Product Overview
PAM-LC700 series is a linear, high-molecular-weight copolymer of acrylamide and cationic monomers with a low cationic charge density (10%–15%). Engineered for systems combining balanced organic and inorganic solids, it prevents over-charge bridging common in mineral-heavy or aged secondary sludges.
Supplied as free-flowing white granules (bulk density 0.65–0.75 g/cm³), it dissolves rapidly in industrial makeup systems, forming active polymer chains that destabilize suspended solids via charge neutralization and bridging.
Low Cationic Charge Characteristics
|
Charge Density |
10%–15% cationic molar substitution. |
|
Functional Group |
Quaternary ammonium groups copolymerized with non-ionic acrylamide backbones. |
|
Electrochemical Behavior |
Suppresses charge reversal in mineral-rich suspensions. |
|
Target Zeta Potential |
Optimized for moderate negative charges (-15 mV to -30 mV). |
Flocculation Mechanism & Particle Interaction
Adsorption: Ultra-long molecular chains (>15 × 10^6 Daltons) uncoil in aqueous solution, exposing active sites that attach to negatively charged suspended particles.
Bridging: Low electrostatic repulsion allows polymer segments to link multiple particles simultaneously, creating shear-resistant macro-flocs.
Synergistic Action: Deployed in dual-polymer setups following inorganic coagulants (PAC/alum) to aggregate micro-flocs.
Technical Specifications
|
Parameter |
Specification Range |
Test Method / Standard |
|
Appearance |
White free-flowing granules |
Visual Inspection |
|
Solid Content |
≥ 88% |
ISO 3251 (105°C, 2h) |
|
Molecular Weight |
12 – 18 × 10^6 Daltons |
Ubbelohde Viscometer |
|
Cationic Degree |
10% – 15% |
Colloid Titration |
|
Dissolution Time |
≤ 60 minutes (20°C in clean water) |
Stirring at 400 rpm |
|
Residual Monomer |
< 0.05% |
HPLC (GB/T 12005.3) |
|
PH (0.5% Solution) |
5.0 – 8.0 |
Glass Electrode |
Suitable Sludge & Wastewater Conditions
Municipal Sludge
Anaerobically/aerobically digested mixed sludge with inorganic ash >30%.
Industrial Effluents
Paper mill deinking/recycled fiber wastewater, textile dyeing effluent, and mineral processing wash water.
Equipment Compatibility
Gravity thickeners, belt thickeners, decanter centrifuges, and screw press units.
Low Cationic PAM Selection Guide
PAM-LC710 (Standard Molecular Weight): Recommended when inorganic ash exceeds 40% and pH is maintained between 6 and 8 for general municipal sludge dewatering on belt presses and centrifuges.
PAM-LC715 (Ultra-High Molecular Weight): Recommended for high-shear dewatering units such as screw presses requiring enhanced mechanical floc retention.
PAM-LC705 (Fast Dissolution Variant): Recommended for low-temperature winter water conditions (<10°C) with an optimized particle size distribution to ensure rapid hydration.
Dissolution, Preparation & Dosing
Stock Concentration: 0.1% – 0.3% (w/v). Allow 45–60 minutes aging for full chain uncoiling.
Makeup Water Quality: Hardness < 100 mg/L (as CaCO₃), total suspended solids < 10 mg/L. Iron and copper ions cause chain cleavage and viscosity loss.
Dosing Point: Inject upstream via an in-line static mixer. Avoid high-shear centrifugal pumps post-dosing to protect formed flocs.
Dewatering Performance & Process Evaluation
Capillary Suction Time (CST)
Reduces raw sludge CST from 60–90 seconds to 8–15 seconds.
Cake Solids Content
Yields 20% – 28% dry solids (DS) on municipal cake via decanter centrifuge.
Filtrate Clarity
Supernatant turbidity < 15 NTU, minimizing suspended solids return to biological basins.
Manufacturing & Quality Control
Polymerization: Temperature-controlled aqueous solution reactors with redox initiation for narrow molecular weight distribution.
Drying & Milling: Continuous fluidized-bed drying, mechanical air-swept pulverization, and multi-stage screening (20–60 mesh).
Batch Testing: Every lot verified for intrinsic viscosity, bulk density, residual monomer via HPLC, and jar-test flocculation performance.
Packaging, Storage & Supply
Packaging: 25 kg paper-plastic composite bags with inner PE liner; 750 kg PP woven jumbo bags with bottom discharge spout.
Storage: Palletize in a cool, dry, ventilated area (≤ 30°C). Shelf life is 24 months unopened.
Logistics: Standardized container loading (18 metric tons per 20-foot container on pallets).
Frequently Asked Questions
Q: Why do "fish-eyes" (undissolved gel lumps) form during preparation?
A: Fish-eyes occur when powder clumps upon water contact, forming a hydrated gel barrier that blocks water penetration to dry cores. This stems from dumping powder too quickly or using under-powered agitation.
Q: How to determine if Low Cationic PAM is correct instead of Medium/High Cationic grades?
A: Run a colloidal charge titration or jar test. If a medium/high cationic polymer causes immediate over-flocculation, dispersion breakdown, or charge reversal, switch to a low cationic grade (10%–15%).Low cationic polymers rely on molecular bridging rather than charge neutralization for mineral-rich or balanced organic sludges.
Q: What is the active lifespan of a prepared liquid stock solution?
A: Aqueous polyacrylamide solutions degrade under mechanical shear and biological activity. Active chains break down within 24 to 48 hours.Prepare fresh stock daily and clean storage tanks weekly.
Q: How do hard water and high salinity impact Low Cationic PAM performance?
A: Divalent cations (Ca²⁺, Mg²⁺) and high total dissolved solids (TDS) compress electrical double layers and restrict polymer chain expansionIf makeup water hardness exceeds 150 mg/L, extend aging time slightly or apply chelating pre-treatment.
Q: How does Low Cationic PAM handle high mechanical shear (e.g., progressive cavity pumps)?
A: High-molecular-weight synthetic polymers are sensitive to high shear stress. While Low Cationic PAM outperforms non-ionic grades via ionic anchoring, excessive shear rates from high-speed centrifugal pumps will physically rupture extended chains.Use low-shear progressive cavity or rotary lobe pumps after polymer addition.
Q: What compliance documents accompany international shipments?
A: Each shipment includes a batch-specific Certificate of Analysis (CoA), GHS-compliant Safety Data Sheet (MSDS), Technical Data Sheet (TDS), and non-dangerous goods declarations for sea and land transport.
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