Effect of Basicity on the Properties of Polyaluminum Chloride

When viewing the details of polyaluminum chloride products, it is often noted that the Basicity, so what is the basicity?

Definition of Basicity

Basicity (abbreviated B) is a measure of the ratio of hydroxyl (OH⁻) ions to aluminium (Al³ +) ions in polyaluminium chloride (PAC). It is usually defined as one third of the equivalent percentage of OH⁻ versus Al³ + in the PAC molecule and is therefore also called the alkalization degree or hydroxy-aluminum ratio. Basicity is one of the most important performance indexes of polyaluminum chloride, which has a direct influence on its flocculation effect.

Effect of basicity on polyaluminum chloride

Flocculation Property

1. High basicity: contains more hydroxide ions, has higher relative molecular weight and strong flocculation ability. It can rapidly condense suspended matter in water, and is suitable for treating water sources with turbidity or high suspended matter.

2. Medium basicity: It usually has good solubility and medium flocculation performance, and is widely applicable and suitable for most water sources.

3. Low basicity: containing less hydroxide ions, the generated flocculation particles are small and the surface area is large, suitable for clear water, especially low turbidity water or scenes requiring fine flocculation particles.

Solubility

1. The solubility of high basicity PAC is low, which may affect the dissolution speed and effect.

2. Low base PAC has high solubility and is more suitable for scenarios that require rapid dissolution.

Economic Benefit

Higher basicity means less use, which can significantly reduce production and use costs. For example, if the salinity is increased from 40% to 90%, the cost of raw materials can be reduced by 20% and the cost of use can be reduced by 40%. Although the unit price of high basicity PAC is higher, the overall cost of use is lower.

PH Effect

Basicity is proportional to pH. The pH of high basicity PAC in water is higher, which contributes to the formation and precipitation of aluminum hydroxide and enhances the flocculation effect. However, too high pH value may bring the risk of alkalization of the water body, and the appropriate base degree should be selected according to the water quality.

Other Factors

In addition to basicity, the flocculation effect of PAC is also affected by many factors such as water quality hardness, temperature and stirring time. Therefore, it is necessary to consider multiple factors when selecting PAC to obtain the ideal treatment effect.

Application of Basicity in other fields

In addition to its application in polyaluminum chloride, basicity is also widely used in soil science. For example, the base saturation of a soil represents the total amount of exchangeable base in the soil as a percentage of the cation exchange capacity and is used to assess the acid-alkalinity and improvement potential of the soil.

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