FLOPAM AN934 is an anionic polyacrylamide (APAM) flocculant from SNF's FLOPAM range. Its principal function is to improve coagulation, flocculation, clarification, sedimentation, thickening, filtration, and solid-liquid separation. Current NSF listings identify FLOPAM AN934 PWG and several AN934 variants as polyacrylamide products for coagulation and flocculation. Some specific AN934 grades are also listed as well-drilling aids.

The basic mechanism of FLOPAM AN934 anionic polyacrylamide is polymer adsorption and particle bridging. The polymer chains interact with suspended particles and help connect many small particles into larger flocs. These larger flocs can settle more rapidly, be captured by flotation, or be separated more efficiently by filtration.

1. Mining and Mineral Processing

One of the most important applications of FLOPAM AN934 is mining and mineral processing.

Mining slurries contain large quantities of fine mineral particles that can remain suspended for long periods. Anionic PAM can promote aggregation of these particles, improving settling and thickening.

Typical applications include:

• Mineral tailings thickening
• Ore-washing wastewater
• Concentrate thickening
• Tailings clarification
• Mineral slurry settling
• Process-water clarification
• Thickener underflow concentration

The main objective is to obtain clearer overflow and denser underflow. Improved water recovery can also allow process water to be recycled to the mining circuit.

SNF's product literature identifies FLOPAM products for mining applications, while published research specifically identifies FloPam AN934 BPM as an anionic polymer containing a sodium-acrylate component.

2. Mineral Tailings Treatment

FLOPAM AN934 anionic polyacrylamide is particularly relevant to tailings treatment.

Tailings contain fine particles of minerals, clay, silica and other solids. Without chemical flocculation, these particles can settle slowly and produce a large volume of dilute slurry.

AN934 can help produce larger aggregates, potentially improving:

• Settling velocity
• Overflow clarity
• Underflow density
• Water recovery
• Thickener capacity
• Tailings handling

This makes anionic PAM useful in both conventional thickeners and other solid-liquid separation systems.

For high-solids or high-rate applications, however, the exact AN934 grade is important. SNF lists AN934, AN934 VHM, AN934 K, AN934 K VHM, AN934 SHU, AN934 BPM and other variants, which should not automatically be considered identical products.

3. Sand Washing Wastewater

Another important application of FLOPAM AN934 is sand washing and aggregate processing.

Sand-washing wastewater commonly contains:

• Fine sand
• Silt
• Clay
• Mineral fines
• Suspended solids

The finest particles can remain suspended and create high turbidity. Anionic polyacrylamide can aggregate these particles into larger flocs that settle more rapidly.

Potential benefits include:

1. Faster settling.
2. Lower turbidity.
3. Clearer overflow.
4. Higher underflow solids concentration.
5. Improved water recycling.
6. Reduced freshwater consumption.

For sand-washing plants, the optimum dosage depends strongly on the clay type and concentration. Therefore, jar testing or settling-column testing is recommended.

4. Coal Washing and Coal Preparation

FLOPAM AN934 can also be considered for coal-washing wastewater and coal-slurry treatment.

Coal preparation produces wastewater containing fine coal, clay and mineral matter. These fine solids can be difficult to separate without flocculation.

Applications include:

• Coal-slurry clarification
• Thickener feed treatment
• Fine-coal recovery
• Tailings settling
• Coal-washing wastewater treatment
• Process-water recycling

By producing larger flocs, AN934 can improve settling and help generate cleaner recycled water.

5. Industrial Wastewater Treatment

Another broad application of FLOPAM AN934 anionic polyacrylamide is industrial wastewater treatment.

It can be evaluated for wastewater containing substantial suspended or colloidal solids from industries such as:

• Mining
• Steel processing
• Metal processing
• Paper manufacturing
• Chemical production
• Food processing
• Aggregate production
• General manufacturing

A typical treatment process is:

Raw wastewater → coagulant → FLOPAM AN934 → flocculation → clarification → filtration

An inorganic coagulant such as PAC, aluminum sulfate or ferric chloride may first destabilize the colloids. AN934 can then promote formation of larger flocs.

The exact chemical sequence should be established by jar testing because some wastewaters perform better with polymer-first treatment.

6. Sludge Thickening and Dewatering

Anionic polyacrylamide can also be used for sludge thickening and dewatering, particularly where the sludge contains significant mineral or inorganic solids.

Possible equipment includes:

• Belt filter presses
• Centrifuges
• Filter presses
• Screw presses
• Gravity thickeners

AN934 can help aggregate fine particles, potentially improving water release and solids capture.

However, this application requires careful polymer selection. Many biological municipal sludges respond better to cationic polyacrylamide, so FLOPAM AN934 should not be selected simply because it is a strong flocculant.

For mineral-rich industrial sludge, anionic PAM can be much more appropriate.

7. Water Clarification

FLOPAM AN934 is also suitable for appropriate water clarification applications.

Current NSF records list AN934 PWG and multiple variants as coagulation and flocculation products, with a listed maximum use of 1 mg/L for the applicable NSF/ANSI/CAN 60 certification.

This is particularly relevant to water containing fine suspended particles that are difficult to remove by natural sedimentation.

The treatment mechanism can be summarized as:

Fine particles → polymer adsorption → particle bridging → larger flocs → faster separation → clearer water

For potable-water treatment, only the specific certified grade should be used.

8. Well-Drilling Applications

Some FLOPAM AN934 grades have an additional application in well drilling.

Current NSF listings identify AN934 PWG, AN934 BPM PWG, AN934 MPM PWG, AN934 SHU QW4 PWG and other variants for certain well-drilling-aid applications.

This demonstrates that the AN934 product family includes grades designed for more than conventional wastewater flocculation.

Depending on the specific grade, anionic polyacrylamide can be used in drilling operations for applications associated with:

• Drilling-fluid treatment
• Solids control
• Cuttings management
• Drilling-water clarification
• Drilling-waste treatment

The exact grade should be checked before using AN934 in a drilling-fluid formulation.

9. Process-Water Recycling

One of the most valuable applications of FLOPAM AN934 is improving process-water recovery.

This is particularly important in mining, coal washing, sand washing and mineral processing.

The basic objective is:

Suspended solids → concentrated underflow

and

Clarified water → recycled process water

By improving the separation between solids and water, AN934 can reduce turbidity in the recovered water and increase the amount available for reuse.

This can reduce freshwater requirements and improve the overall economics of the treatment system.

10. Importance of the AN934 Grade

A critical point when purchasing or replacing FLOPAM AN934 is that the complete grade designation should be considered.

SNF's current listings include:

• FLOPAM AN934
• FLOPAM AN934 BPM
• FLOPAM AN934 K
• FLOPAM AN934 K VHM
• FLOPAM AN934 VHM
• FLOPAM AN934 SHU
• FLOPAM AN934 XD
• Other application-specific variants

These are not necessarily interchangeable.

For example, published SNF literature identifies AN934 BPM as a low-molecular-weight anionic polyacrylamide, while VHM denotes a different molecular-weight category.

Consequently, the best AN934 grade for a mineral thickener may not be the best grade for wastewater clarification.

11. Dosage and Preparation

There is no single universal dosage for FLOPAM AN934 anionic polyacrylamide.

The optimum dosage depends on:

• Suspended-solids concentration
• Particle size
• Mineralogy
• Clay content
• pH
• Ionic strength
• Water hardness
• Temperature
• Mixing conditions
• Required effluent clarity

The polymer should normally be prepared as a dilute solution before application. Good dispersion is important because undissolved polymer lumps can produce poor performance.

The optimum concentration should be determined through jar tests, settling tests or pilot-scale trials.

Overdosing can produce excessively large or weak flocs, while underdosing may result in poor settling and high residual turbidity.