What is high-purity poly-aluminum chloride (PACL)?

Poly-aluminum chloride (PACl) is one of the common coagulants for water and wastewater treatment. A new Chinese national standard of PACl has been implemented, where the concentration of insoluble substances, iron and heavy metals is to be controlled strictly, then researches on the preparation of high–purity PACl are needed.

Why is polyaluminum chloride a good coagulant for water treatment?

Polyaluminum chloride (PAC) is highly effective coagulant for water treatment over conventional coagulants because of low dosage requirement, shorter flocculation time, smaller amount of sludge, high efficiency and low aluminum residual in treated water .

What is the basicity of high-purity PACL?

The basicity of high-purity PACl can be maintained at about 92% after the adjustment by calcium aluminate (Table 3), it has exceeded the national and international standards of PACl.

What is the difference between high-purity PACL and conventional PACL?

The preparation process of high-purity PACl and conventional PACl is different as stated previously, where raw materials used and the operating conditions are different. As shown in Table 5, Al (OH) 3 is relatively expensive than bauxite but sulfydryl/PAM polymer is cheaper.

Does high-purity PACL reduce operating cost?

On the other hand, when the dose was greater than 4 mg L −1 as Al, the high-purity PACl showed great UV 254 -absorbance removal capacity; which was even much greater at high does (e.g., 10 mg L −1). Relative low dose requirement of high-purity PACl indicates the potential of the reduction of operating cost.

What are the properties of high-purity PACL based on bauxite & calcium aluminate?

Properties of the high-purity PACl (samples A–C) prepared with bauxite and calcium aluminate in comparison with a conventional PACl. The basicity of high-purity PACl can be maintained at about 92% after the adjustment by calcium aluminate (Table 3), it has exceeded the national and international standards of PACl.