Polyaluminium Chloride

Polyaluminium Chloride

Polyaluminium chloride (PAC), also known as basic aluminum chloride, is an organic polymer flocculant. Its main component is a polyacrylamide molecular chain, which has high molecular weight and carries various charge types. It is widely used in water treatment, drinking water purification, sewage treatment, and other fields.

The positively charged aluminum ions generated by polyaluminium chloride after dissolution can neutralize the negatively charged suspended particles in the water so that the particles aggregate into larger flocs and promote sedimentation and separation. Due to its fast flocculation speed, wide applicability, and significant effect, PAC plays an important role in the field of industrial and municipal water treatment.

Flocculation Principle

The suspended matter is neutralized and aggregated mainly through electrical neutralization, so that the particles lose their charge repulsion, thus forming larger floccules. It is suitable for treating negatively charged suspended matter and colloidal particles.

The Difference between PAC and PAM

First, the color is different. PAC has rich colors including white, yellow, and khaki. Because PAC contains iron, the whiter the color, the less iron powder there is. However, the purity requirement in the water treatment industry is not high, so the khaki PAC is the most common. The iron powder is added to neutralize the charge on the surface of the suspended particles, making flocculation easier. In contrast, PAM is only white.

Secondly, the working principles are different. polyaluminium chloride mainly neutralizes the suspended particles and then aggregates them through electrical neutralization, while polyacrylamide mainly adsorbs fine particles through bridging action to make them condense.

Finally, the usage method is different. The dosage of PAC is generally larger and needs to be dissolved in a certain proportion before adding. It is suitable for automated polymer dosing systems, especially in continuous processing processes. The dosage of PAM is smaller and is usually dissolved at a low concentration of 0.1%-0.5%, but the dissolution needs to be added gradually to prevent coagulation, and the dissolution time is longer.

Precautions for Use

Dissolution ratio: It is usually recommended to dissolve solid PAC into liquid at a ratio of about 0.1%, and it should be fully stirred before use.

Dosing control: Reasonably adjust the amount of PAC added according to the water quality. Excessive addition may cause secondary pollution of the water body.

Storage conditions: Solid PAC should be stored in a dry and ventilated place to avoid moisture, and liquid PAC should be stored in a sealed place to prevent long-term exposure from causing a loss of efficiency.