What is the difference between Polyaluminium Chloride and Aluminium Chlorohydrate

In the water treatment industry, Polyaluminium Chloride (PAC) and Aluminium Chlorohydrate (ACH) are two commonly used high-efficiency coagulants that are often compared. While they share similarities in appearance and application scope, they differ significantly in chemical structure, flocculation mechanisms, treatment efficiency, and cost-effectiveness.

For procurement managers of large-scale water treatment projects, understanding the differences between PAC and ACH is essential, as it directly affects treatment performance, cost control, and regulatory compliance. This article provides a comprehensive comparison of these two coagulants—covering chemical properties, treatment performance, application scenarios, and procurement considerations—to help buyers make informed and rational decisions.

Let’s dive into a detailed comparison and uncover the strengths and limitations of PAC and ACH in modern water treatment.

Polyaluminium Chloride (PAC) is an inorganic polymer coagulant produced by hydrolysis and polymerization of aluminum salts under controlled conditions. It is a highly efficient coagulant that works by forming positively charged polymeric aluminum ions through hydrolysis, which neutralize charges, destabilize suspended solids, and promote the formation of flocs.

Aluminium Chlorohydrate (ACH) is a high-concentration, pre-hydrolyzed aluminum coagulant typically found in colorless to light yellow liquid or powder form. It consists mainly of highly polymerized hydroxy-aluminum ions and is known for its very high basicity and excellent charge neutralization.

• High basicity—requires minimal pH adjustment, reducing pH correction costs.
• Strong adaptability—performs better in low-temperature, low-turbidity conditions, ideal for winter or challenging scenarios.
• Lower residual aluminum—produces water with less aluminum residue, essential for drinking water safety.
• Stable liquid formula—has a longer shelf life than PAC solutions.
• High purity—suitable for sensitive industries like pharmaceuticals, cosmetics, food, and beverage.

Polyaluminium Chloride (PAC) and Aluminium Chlorohydrate (ACH) are two vital aluminum-based coagulants, each with distinct advantages in the water treatment industry. Choosing between them depends on specific treatment goals. PAC remains the top choice for large-scale, cost-sensitive projects due to its affordability and wide applicability. ACH offers superior efficiency, lower residuals, and higher stability—making it the ideal solution for drinking water and specialized high-end industries.

For buyers, the decision should consider water quality, performance targets, cost control, compliance requirements, and supply chain reliability. A well-informed selection between PAC and ACH ensures effective treatment, economic feasibility, and sustainable operations.

OYI provides customized PAC and related water treatment chemicals (PAM, SDIC, TCCA) to global industrial clients. Backed by a 3,000 m² factory, ample inventory, and fast delivery, we help you achieve safe, compliant, and cost-effective water treatment solutions.

Contact: oyi@oyipolymer.com

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