Difference Between Polyaluminum Ferric Chloride And Polyaluminum Chloride

Polyaluminum ferric chloride (PAFC) and Polyaluminum Chloride (PAC) are two commonly used inorganic polymer coagulants, and their main differences are as follows:

1. Composition and appearance

• Polyaluminum chloride (PAC): The main component is aluminum salt, yellow, beige or white (food grade). White PAC is the highest purity and used for drinking Water Treatment.
• Aluminum ferric polychloride (PAFC): a compound of aluminum and iron salts, usually containing about 4% iron, and appearing as reddish brown or brown powder.

2. Scope of application

• PAC: can treat drinking water, industrial water and sewage; especially good at purifying river water, the effluent quality is soft, not easy to cause fabric hardening.
• PAFC: only used for industrial wastewater treatment (such as steel mills, paper mills, printing and dyeing wastewater, etc.), not suitable for drinking water; it has a significant effect on high turbidity and low temperature and low turbidity wastewater, and the flocculation sedimentation speed is fast.

3. Performance features

• PAC: strong turbidity and decoloration performance, wide range of applicable pH (6-9); low corrosion, but the effect may decrease in low temperature environment.
• PAFC: it has the adsorption and bridging ability of aluminum salt and the precipitation speed of iron salt, and the floc is dense; it has stronger low temperature adaptability and higher removal rate of heavy metals (such as Cr⁶⁺).

4. Raw materials and processes

• PAC: Aluminum hydroxide powder is used for drinking water grade, calcium aluminate powder can be used for industrial grade.
• PAFC: Using aluminum calcium powder and iron compound as raw materials, the production process introduced iron ion to enhance the coagulation effect.

5. Cost and purpose

• The price of PAC is higher, especially the high purity white PAC;
• PAFC has low cost and is suitable for large-scale industrial wastewater treatment.

Summary Suggestions:

• Select PAC: drinking water, low turbidity water source or softening water scenarios (e.g., textile wastewater);
• Choose PAFC: highly polluted industrial wastewater (such as heavy metal, high COD wastewater) or low temperature environment.

The specific dosage should be determined through small tests (generally PAC dosage 1-15g/ton of water, PAFC dosage 3-40g/ton of water). If it is necessary to combine and enhance the efficiency, PAC and polyacrylamide (PAM) can be used together.