PRAESTOL 2640 is a high–molecular weight anionic polyacrylamide (APAM) widely used as a flocculant in solid–liquid separation processes across many industrial sectors. As part of the well-known PRAESTOL® product range, it is engineered to provide strong particle bridging, fast settling, and stable performance under varying water chemistries. Because of its anionic charge and long polymer chains, PRAESTOL 2640 is especially effective for treating suspensions rich in fine inorganic particles, mineral solids, and metal hydroxides. Its main applications include mining and mineral processing, alumina refining, wastewater treatment, sludge thickening and dewatering, paper and pulp operations, and industrial water clarification.

1. Mining and Mineral Processing

One of the most important applications of PRAESTOL 2640 is in mining and mineral processing operations. During crushing, grinding, flotation, and classification, large volumes of process water become contaminated with fine mineral particles that settle very slowly. PRAESTOL 2640 is used in thickeners, clarifiers, and tailings treatment systems to aggregate these fine particles into larger, heavier flocs.

Through polymer bridging, PRAESTOL 2640 significantly improves settling rates, resulting in clearer thickener overflow and higher underflow solids concentration. It is commonly applied in iron ore, copper, gold, coal, phosphate, and bauxite operations. Improved water recovery allows plants to recycle process water more efficiently, reduce freshwater consumption, and improve tailings management and dam stability.

2. Alumina Refining and Red Mud Treatment

PRAESTOL 2640 is widely used in alumina refineries operating the Bayer process. During bauxite digestion, red mud is generated as a highly alkaline residue consisting of extremely fine particles. Efficient separation of red mud from pregnant liquor is essential to minimize caustic soda losses and maintain high alumina production efficiency.

In primary settlers, mud washers, and secondary clarification units, PRAESTOL 2640 enhances red mud flocculation and accelerates settling. Its chemical stability under high pH and elevated temperature conditions makes it suitable for harsh Bayer process environments. The use of PRAESTOL 2640 results in improved liquor clarity, better washing efficiency, reduced soda losses, and increased refinery throughput.

3. Industrial Wastewater Treatment

Another major application area of PRAESTOL 2640 is industrial wastewater treatment. Many industries generate wastewater containing suspended solids, inorganic fines, pigments, and colloidal particles that are difficult to remove by physical means alone. PRAESTOL 2640 is used in primary and secondary clarification systems to promote aggregation and rapid settling of these contaminants.

Industries such as metallurgy, power generation, chemicals, ceramics, construction materials, and textiles benefit from its strong flocculation performance. When used alone or in combination with inorganic coagulants such as ferric chloride or aluminum sulfate, PRAESTOL 2640 forms large, dense flocs that settle quickly. This leads to lower turbidity, improved effluent quality, and reduced sludge production.

4. Municipal Wastewater and Sludge Treatment

In municipal wastewater treatment plants, PRAESTOL 2640 is mainly applied for sludge thickening and dewatering rather than direct clarification. It is used to condition primary sludge, waste activated sludge, or mixed sludge prior to mechanical dewatering.

PRAESTOL 2640 improves floc strength and water release, making it compatible with belt filter presses, centrifuges, screw presses, and filter presses. Higher cake solids content can be achieved, reducing sludge volume, transportation costs, and disposal expenses. Its efficient performance also helps plants reduce polymer consumption and overall operating costs.

5. Paper and Pulp Industry

In the paper and pulp industry, PRAESTOL 2640 is applied for white water clarification, fiber and filler recovery, and sludge dewatering. During papermaking, significant quantities of fine fibers, calcium carbonate, kaolin, and pigments can be lost in process water. PRAESTOL 2640 flocculates these fines, allowing them to be recovered and reused in the production process.

Additionally, it is used in pulp and paper mill wastewater treatment systems to clarify effluents and improve dewatering of primary and biological sludges. Improved solids removal helps mills comply with environmental discharge regulations and optimize internal water recycling.

6. Industrial Water Clarification and Recycling

PRAESTOL 2640 plays an important role in industrial water clarification and reuse systems. Applications include cooling water blowdown treatment, mine water clarification, surface water treatment, and process water recycling. By promoting rapid settling of suspended solids, PRAESTOL 2640 produces clear water suitable for reuse within the plant, supporting sustainable water management and reducing environmental impact.

7. Key Advantages and Performance Characteristics

The broad application of PRAESTOL 2640 is driven by several technical advantages. It offers high flocculation efficiency at relatively low dosages, good solubility when properly prepared, and reliable performance across a wide pH range. Its anionic nature makes it particularly effective for mineral-rich and metal-containing suspensions and compatible with commonly used inorganic coagulants.