Polyacrylamide for Steelworks

Polyacrylamide is a water-soluble polymer. It is produced by the polymerisation of acrylamide monomers. Its molecular structure exhibits strong hydrophilic properties, enabling it to form hydrogen bonds with water molecules and create a stable aqueous solution. These characteristics allow polyacrylamide to perform exceptionally well in water treatment.
Polyacrylamide is generally classified into cationic, anionic and non-ionic types. Depending on their charge properties, they can be used in different water treatment applications. In the treatment of steel industry wastewater, cationic polyacrylamide is particularly favoured; its charge characteristics enable it to effectively bind with suspended solids, colloidal substances and heavy metal ions, thereby forming larger precipitates that facilitate subsequent separation and treatment.
 

In the steel production process, wastewater is primarily generated during cooling, washing and flushing operations. This wastewater typically contains large quantities of solid particles, oily substances and heavy metal ions, which severely affect water quality. The use of polyacrylamide can effectively resolve these issues. Its primary mechanisms include the following:

1. Removal of suspended solids. Through the processes of polymerisation and flocculation, polyacrylamide rapidly binds with suspended solids in the wastewater to form larger flocs. Due to their larger particle size, these flocs settle more readily, facilitating their rapid removal via sedimentation or filtration. This achieves the purification of the wastewater.
2. Oil-water separation. Many types of steel industry wastewater contain oily contaminants. Traditional treatment methods often perform poorly. Polyacrylamide binds with oil molecules and promotes their aggregation, thereby enhancing the efficiency of oil-water separation. This ensures that the treated water meets discharge standards, providing a safeguard for the sustainable development of the steel industry.
3. Removal of heavy metals. Common heavy metal ions in steel wastewater, such as lead, chromium and cadmium, pose a serious threat to the environment and human health. Polyacrylamide is capable of encapsulating these heavy metal ions within its molecular structure through complexation reactions, causing them to precipitate and thereby achieving their removal. Research indicates that when polyacrylamide is used to treat heavy metal contamination, it not only achieves high removal rates but also demonstrates long-lasting efficacy, effectively reducing the toxicity of the water.

In the treatment of steel industry wastewater, polyacrylamide offers significant advantages. These are manifested in the following aspects:
      1. High efficiency
treatment efficiency is significantly enhanced. Under identical conditions, its removal rate for suspended solids can reach over 90%, which is significantly higher than that of traditional treatment methods. Furthermore, its advantages in oil-water separation and heavy metal removal make it an indispensable material in the treatment of steel industry wastewater.
      2. Ease of Operation
      The use of polyacrylamide is relatively straightforward; it typically only requires dosing according to the recommended dosage, without the need for complex pre-treatment or post-treatment. Furthermore, it dissolves readily in water, enabling rapid achievement of the required treatment performance. This saves a considerable amount of labour and material costs.
      3. Environmental Friendliness
      During wastewater treatment, polyacrylamide effectively removes harmful substances and forms solid waste after sedimentation and filtration. The treated water quality generally complies with the ‘Sewage Discharge Standards’. More importantly, as a synthetic polymer, polyacrylamide has minimal negative impact on the ecological environment, making it a green and environmentally friendly treatment agent.
      4. Wide Range of Applications
      Polyacrylamide is not only suitable for steel industry wastewater treatment but is also widely used in various sectors such as papermaking, mining and chemical processing. Its superior performance enables it to demonstrate significant treatment capabilities across a variety of environments, meeting the diverse needs of different industries.

1. When using polyacrylamide specifically designed for steel mills, prepare a 0.01% aqueous solution. It is advisable to use neutral water free from salt impurities.
2. When dissolving polyacrylamide for steel mills, evenly sprinkle the anionic polyacrylamide product into stirring water. Maintain a stirring speed of 100–300 rpm. Gentle heating (<60°C) may accelerate dissolution.
3. Adjust the pH of the liquid to be treated to allow the anionic polyacrylamide to function effectively (determine the optimal pH and dosage of anionic polyacrylamide through testing).
4. When adding the product solution, accelerate mixing with the liquid to be treated. Once flocs appear, reduce the stirring speed to facilitate floc growth and accelerate settling.

 

Points to note:

1. Dissolution temperature. A certain temperature is required for dissolution to accelerate the process. However, excessively high temperatures may cause the polymer molecular chains to break, thereby reducing the product’s effectiveness. The most suitable dissolution temperature is 50–60°C.
2. Stirring conditions. Avoid stirring with excessive shear forces during dissolution, as this can cause molecular chains to break, thereby reducing performance. Low-speed impellers, such as anchor, frame or multi-blade types, are recommended. The stirring speed should be approximately 60 rpm. When transferring the solution, avoid using high-speed centrifugal pumps; piston or diaphragm pumps are more suitable.
3. Uniform Dispersion During Dosing. A critical aspect of polyacrylamide dissolution is the uniform dispersion of the material. Once the mixer is running, it is best to use a mechanical vibrating screen (10 mesh) for dosing. This helps to avoid the formation of ‘large clumps’ or ‘fish-eye-like’ insoluble particles, ensuring that the polyacrylamide dissolves fully and performs effectively.
4. Avoid contact with iron. In the dissolution, mixing, and dosing systems, it is best to use materials such as plastic, enamel, aluminium or stainless steel.

 

Packaging and Storage:

25 kg per bag (inner plastic liner with an outer plastic-coated kraft paper bag).

This product is non-toxic. Keep away from moisture and rain, and avoid exposure to direct sunlight.