As a commonly used water purification flocculant,
polyaluminium chloride is widely recognised. It finds extensive application across diverse industrial sectors. However, despite its familiarity, its efficacy varies considerably during use. Why is this? What factors readily influence its performance? Let us explore.
For polyaluminium chloride products, performance is significantly affected by aluminium oxide content, insoluble matter content, and basicity. Alumina content, in layman's terms, refers to purity. Higher content indicates greater purity, naturally yielding superior efficacy. While alkalinity may be unfamiliar to many, it constitutes a fundamental component determining product form. Typically ranging between 40% and 95%, alkalinity is not static. It serves as a crucial metric for assessing product quality. Products with high basicity incur higher production costs and command higher prices. Nevertheless, compared to low-basicity products, those with high basicity offer distinct advantages. In homogeneous wastewater treatment applications, high-basicity products typically require lower dosages to achieve the same results. This means that achieving the desired effect with a smaller quantity eliminates the need for larger volumes of low-basicity products. This approach reduces both labour intensity and overall costs, making it a cost-effective solution.
Additionally, insoluble matter significantly impacts the efficacy of polyaluminium chloride. Typically, insoluble matter comprises residues such as sand, clay, and calcium or magnesium carbonates. Given the product's complex composition, finer grinding can increase insoluble matter, leading to precipitation difficulties. How can insoluble matter be effectively addressed? Centrifugal separation and gravitational settling offer solutions. Centrifuges achieve high rotational speeds where centrifugal force overcomes gravity, enabling efficient precipitation and separation of suspended solids. Gravitational settling relies on separating dust particles from air streams, though its efficacy is most pronounced with larger particles and lower gas velocities. Another approach involves employing plate-and-frame filter presses to address insoluble matter. Utilising plate-and-frame filter presses enables continuous purification of solutions, yielding dry waste residue. This extends solution lifespan and reduces solution wastage. The use of polyaluminium chloride products proves particularly effective in industrial wastewater treatment processes.
