Red mud was pre-treated with process of reduction roasting followed by magnetic separation, and the obtained non-magnetic material was calcined and then dissolved in hydrochloric acid. After that, it was filtered after addition of saturated sodium meta-aluminate polymerizing agent, and then matured to prepare polymeric aluminum chloride (PAC) base liquid, which was used in a purification test. With PAC-base liquid and manganese-containing wastewater in a volume ratio of 1∶120, stirring speed of 140 r/min, pH of 8, reaction temperature of 30 ℃, and addition of polyacrylamide (PAM) at an amount of 20 mg/L, the manganese mass concentration in the wastewater reduced from 325.3 mg/L to 1.5 mg/L after 5 hours of settlement, showing manganese removal rate up to 99.5%. It is shown that the manganese mass concentration in the purified liquid can meet class Ⅰ limit in the national discharge standard.

wastewater treatment  /  manganese  /  flocculation and precipitation  /  manganese-containing acidic wastewater  /  red mud  /  non-magnetic material  /  polymeric aluminum chloride (PAC)  /  polyacrylamide (PAM)