The Application of PolyDADMAC for Mining

1. Introduction to PolyDADMAC in Mining

PolyDADMAC (polydiallyldimethylammonium chloride) is a strong cationic, water-soluble polymer widely used in the mining industry as a coagulant and charge neutralization agent. Unlike high-molecular-weight flocculants such as polyacrylamide, PolyDADMAC has a relatively low molecular weight but very high cationic charge density, making it particularly effective for destabilizing fine, negatively charged mineral particles.

In modern mining operations, PolyDADMAC plays an important role in solid–liquid separation, water clarification, and process water recycling, especially where fine clays, silica, or colloidal particles are present. Its fast reaction speed and stable performance under varying pH and salinity conditions make PolyDADMAC a valuable chemical for mineral processing circuits.

2. Mechanism of PolyDADMAC in Mining Applications

The primary function of PolyDADMAC in mining is charge neutralization. Most mineral particles and suspended solids in mining slurries carry a negative surface charge, which causes them to remain dispersed and resist settling.

When PolyDADMAC is added:

• The strong positive charges neutralize the negative surface charges

• Electrostatic repulsion between particles is reduced

• Fine particles rapidly destabilize and agglomerate

This rapid coagulation process allows PolyDADMAC to work effectively alone or as a coagulant aid ahead of anionic or nonionic polyacrylamide flocculants. In many mining systems, PolyDADMAC is used as the first step to prepare particles for efficient flocculation.

3. Application of PolyDADMAC in Mining Water Clarification

3.1 Process Water Clarification

Mining operations require large volumes of water for grinding, flotation, and material transport. Over time, process water becomes contaminated with fine suspended solids that reduce process efficiency.

PolyDADMAC is widely used in process water clarification systems to remove:

• Clay fines

• Silica particles

• Metal hydroxides

• Colloidal solids

By rapidly coagulating these fines, PolyDADMAC improves overflow clarity in thickeners and clarifiers, allowing treated water to be recycled back into the plant. This reduces fresh water consumption and supports sustainable mining practices.

3.2 Recycling and Reuse of Mine Water

Water scarcity and environmental regulations have increased the importance of water reuse in mining. PolyDADMAC enables efficient clarification even under high turbidity, high salinity, and variable pH conditions.

Its benefits include:

• Faster clarification rates

• Stable performance in recycled water systems

• Reduced solids carryover into downstream processes

As a result, PolyDADMAC helps maintain consistent water quality for reuse in grinding and flotation circuits.

4. Application of PolyDADMAC in Tailings Treatment

4.1 Tailings Thickener Feed Conditioning

In tailings treatment, fine particles often remain suspended due to strong surface charges. PolyDADMAC is commonly used as a pre-coagulant before high-molecular-weight flocculants.

In tailings thickeners, PolyDADMAC:

• Neutralizes particle charges quickly

• Improves flocculant efficiency

• Reduces overall flocculant dosage

• Enhances settling velocity

This combination results in higher underflow density and clearer overflow water, improving thickener performance and stability.

4.2 Improvement of Overflow Water Quality

Clear thickener overflow is essential for water recovery and environmental compliance. PolyDADMAC effectively removes ultrafine particles that conventional flocculants alone may not capture.

The use of PolyDADMAC leads to:

• Lower turbidity in overflow water

• Reduced suspended solids discharge

• Improved efficiency of downstream water treatment systems

5. Application of PolyDADMAC in Specific Mining Segments

5.1 Coal Mining and Coal Washing

In coal preparation plants, PolyDADMAC is applied in coal slurry clarification and thickener systems. Coal fines and clay impurities are highly negatively charged and difficult to settle.

PolyDADMAC improves:

• Settling of coal fines

• Clarity of clarified water

• Performance of dewatering equipment

This enhances water reuse and reduces waste volume.

5.2 Metal and Mineral Mining

PolyDADMAC is used in the processing of:

• Iron ore

• Copper ore

• Gold ore

• Phosphate and bauxite

In these applications, PolyDADMAC supports clarification of process water and tailings, particularly where fine gangue minerals and clays are present.

6. Advantages of PolyDADMAC in Mining

PolyDADMAC offers several advantages compared with traditional inorganic coagulants:

• Very fast reaction and floc formation

• Effective at low dosages

• Stable across a wide pH range

• No metal salt addition to the system

• Compatible with polyacrylamide flocculants

• Reduced sludge volume compared with inorganic coagulants

These advantages make PolyDADMAC especially suitable for modern high-throughput mining operations.

7. Dosage and Application Guidelines

Typical PolyDADMAC dosages in mining applications range from 5 to 100 g per ton of dry solids, depending on slurry characteristics and process conditions. PolyDADMAC is usually added as a diluted aqueous solution and requires good initial mixing to ensure uniform distribution.

Jar testing and on-site trials are recommended to determine the optimal dosage and combination with flocculants.

8. Conclusion

PolyDADMAC is a highly effective coagulant for mining applications, particularly in process water clarification, tailings treatment, and water recycling systems. Through its strong charge neutralization mechanism, PolyDADMAC improves solid–liquid separation efficiency and enhances the performance of downstream flocculation processes.

As mining operations continue to focus on water conservation, operational stability, and environmental compliance, PolyDADMAC remains a key chemical solution for achieving efficient and sustainable mineral processing.