India Sand Washing Wastewater Case | Anionic PAM Flocculation Test by Hengfeng

Project Background

Recently, Jiangsu Hengfeng Fine Chemical conducted a laboratory flocculation test using a batch of sand washing wastewater samples brought back from India.

Sand washing operations generate wastewater containing a high concentration of suspended solids, fine sand, silt and clay particles. Due to the small particle size and complex composition of the slurry, these particles can remain suspended for a long time and are difficult to settle naturally.

For efficient wastewater treatment, an appropriate flocculant is required to promote particle aggregation, accelerate sedimentation and improve solid-liquid separation.

Based on the actual wastewater sample from the Indian customer, Hengfeng's technical team carried out a series of PAM selection and jar tests.

Wastewater Characteristics

The tested sample was generated from a sand washing process and showed typical characteristics of mineral washing wastewater:

• High concentration of suspended solids

• Large amount of fine particles

• Presence of silt and clay

• Slow natural sedimentation

• High turbidity of the untreated water

• Requirement for efficient solid-liquid separation

The characteristics of sand washing wastewater can vary significantly depending on the raw material, geological conditions, clay content and washing process. Therefore, selecting the appropriate PAM grade is important for achieving stable treatment performance.

PAM Selection and Laboratory Testing

For this project, Hengfeng focused on Anionic Polyacrylamide, which is widely used in sand washing, mining and mineral processing wastewater treatment.

Different PAM grades were tested against the actual wastewater sample. The testing process focused on several key indicators:

• Floc formation

• Floc size and strength

• Flocculation speed

• Settling performance

• Supernatant clarity

• Solid-liquid separation efficiency

During the tests, PAM was added to the wastewater under controlled mixing conditions. The technical team observed the formation and growth of flocs before allowing the treated slurry to settle.

Compared with untreated wastewater, the properly selected PAM promoted rapid aggregation of fine suspended particles and produced visible, larger flocs. The treated water also showed improved clarification after settling.

Why Anionic PAM Is Widely Used in Sand Washing

Anionic Polyacrylamide works primarily through adsorption and bridging between suspended particles.

For sand washing and mineral processing wastewater, fine particles often have difficulty settling independently because of their small size and surface properties. The addition of an appropriate anionic polymer can connect these particles into larger flocs, making them easier to separate from water.

However, PAM performance depends strongly on molecular weight, charge density and wastewater characteristics.

A product with excessive or insufficient charge density, unsuitable molecular weight, or inappropriate dosage may result in weak flocs, poor settling or increased chemical consumption.

For this reason, laboratory testing with actual customer samples is an important step before selecting the final PAM grade.

Hengfeng PAM Products for Sand Washing & Mineral Processing

Hengfeng supplies a range of Polyacrylamide products for wastewater treatment and mineral processing applications.

Anionic Polyacrylamide

Anionic PAM is one of the most commonly used flocculants for:

• Sand washing wastewater

• Mining wastewater

• Mineral processing

• Coal washing

• Tailings treatment

• Industrial wastewater

• Solid-liquid separation

Different molecular weights and charge densities are available to match different mineral and wastewater conditions.

Cationic Polyacrylamide

Cationic PAM is mainly used in sludge dewatering and wastewater treatment applications where positively charged polymers are required.

Typical applications include:

• Municipal sludge dewatering

• Industrial sludge treatment

• Paper mill sludge

• Sewage treatment

• Solid-liquid separation

Nonionic & Amphoteric Polyacrylamide

Hengfeng also provides nonionic and amphoteric PAM for applications requiring different charge characteristics and polymer structures.

The appropriate product can be selected according to the customer's wastewater properties, process conditions and treatment equipment.

PAM Emulsion

In addition to dry powder PAM, Hengfeng manufactures Polyacrylamide Emulsion.

PAM emulsion can provide convenient preparation and rapid dissolution and is suitable for customers with continuous dosing systems or specific on-site application requirements.

Customized PAM Selection Based on Actual Samples

One of the key factors in successful PAM application is product selection based on actual operating conditions rather than simply choosing a standard grade.

For overseas customers, Hengfeng can conduct laboratory testing based on:

• Wastewater samples

• Mineral or slurry samples

• Water quality information

• Existing treatment processes

• Equipment and dosing conditions

Based on the test results, our technical team can recommend a suitable PAM type and provide guidance on product application and dosage optimization.

From Laboratory Testing to Industrial Application

The India sand washing wastewater test demonstrates the importance of matching PAM characteristics with the actual wastewater.

For sand washing plants and mineral processing operations, the objective is not simply to add more flocculant, but to achieve effective particle aggregation with an appropriate PAM grade and controlled dosage.

A suitable PAM can help improve floc formation, accelerate settling, enhance water clarification and support more efficient solid-liquid separation.

Hengfeng provides both PAM dry powder and emulsion products, with customizable molecular weight, charge density and formulations for different industrial applications.

With a total PAM production capacity of approximately 100,000 tons per year, Hengfeng supplies customers in more than 60 countries and regions and provides technical support, product documentation and customized solutions for international customers.