As a procurement manager in the chemical industry, understanding the science behind the products you source is crucial for making informed purchasing decisions. Polyaluminium Chloride (PAC), identified by CAS 1327-41-9, is a complex inorganic polymer with remarkable properties that make it indispensable in water treatment and other industrial processes. As a dedicated manufacturer and supplier of PAC in China, we aim to demystify its chemical intricacies and highlight why it's a superior choice for your procurement needs.

Chemical Structure and Properties: The Foundation of PAC's Efficacy

PAC is not a single compound but rather a family of inorganic polymers. Its general chemical formula is often represented as [Al2(OH)nCl6-n]m, where 'n' and 'm' indicate variable degrees of hydrolysis and polymerization. This structure is key to its function:

  • Hydrolysis and Polymerization: When aluminum chloride reacts with water, it undergoes hydrolysis, forming various poly-nuclear aluminum species. These species are positively charged and possess a high charge density.
  • High Charge Density: The positively charged aluminum complexes are highly effective at neutralizing the negative surface charges of suspended particles and colloidal matter in water. This destabilizes the colloids, initiating the coagulation process.
  • Polymeric Nature: The polymeric chains of PAC can adsorb onto multiple destabilized particles, acting as bridges to form larger, more stable flocs. This 'sweep flocculation' mechanism is highly efficient in trapping impurities.
  • Variable Basicity: The basicity of PAC (the ratio of hydroxyl groups to aluminum) can be adjusted during manufacturing. Different basicity levels influence the charge density, polymerization degree, and thus, the coagulant's performance in specific water conditions. For example, higher basicity often leads to more efficient charge neutralization.

Why PAC Outperforms Traditional Coagulants

Traditional inorganic coagulants like aluminum sulfate (alum) and ferric chloride work primarily through charge neutralization and precipitation. However, PAC offers several scientific advantages:

  • Greater Charge Neutralization: The highly polymerized and positively charged aluminum species in PAC provide a greater charge neutralization capacity per mole of aluminum compared to simple aluminum ions.
  • Improved Floc Formation: The polymeric structure facilitates stronger bridging and sweep flocculation, leading to larger, denser, and faster-settling flocs. This results in better clarification and reduced treatment times.
  • Wider pH Applicability: PAC is effective over a broader pH range (typically 5.0-9.0) than alum, which often requires significant pH adjustment. This simplifies the treatment process and reduces the need for additional alkaline chemicals.
  • Lower Dosage: Due to its higher efficiency, PAC often requires lower dosages to achieve the same level of purification, leading to reduced chemical consumption and lower overall treatment costs.

Sourcing PAC: A Procurement Manager's Checklist

When you are ready to buy PAC, consider these points when evaluating a supplier:

  • Purity and Specifications: Ensure the PAC meets the required Al2O3 content, basicity, water insolubles, and crucially, heavy metal limits for your intended application (especially for drinking water).
  • Manufacturing Process: Understanding whether it's spray-dried or roller-dried can indicate particle size and dissolution rate.
  • Consistency: A reliable manufacturer ensures batch-to-batch consistency, critical for maintaining stable treatment plant performance.
  • Technical Support: A good supplier can offer technical guidance on optimal dosage and application methods.

As a leading manufacturer in China, we pride ourselves on providing high-quality PAC with transparent specifications and expert technical support. We are committed to offering competitive prices for this vital chemical. We invite procurement managers to reach out to us to learn more and to secure a reliable supply of PAC for their operations.