Cooperative removal of Mn2+, NH4+−N, PO43−−P and F− from electrolytic manganese residue leachate and phosphogypsum leachate

Electrolytic manganese residue leachate (EMRL) contains plenty of Mn2+ and NH4+−N, and phosphogypsum leachate (PGL) contains large amounts of PO43−−P and F−. Traditional methods of EMRL and PGL discharge could seriously damage the ecological environment. In this study, an innovative method for cooperative removal Mn2+, NH4+−N, PO43−−P, F− from PG and POFT was studied. The result showed that Mn2+, PO43−−P and F− were mainly removed in forms of Mg3Si4O10(OH)2, Mn3O4, Mn3(PO4)2, Mg3(PO4)2, CaSO4·2H2O, MnF2, MnOOH and Ca2P2O7·2H2O, when LG−MgO was used to adjust the pH value of the system to 9.5, and the volume ratio of EMRL and PGL was 1:4, as well as reaction for 1 h at 25 °c. NH4+−N was mainly removed by struvite precipitate, when the molar ratio of N:Mg:P was 1:3:2.4. The concentrations of Mn2+, NH4+−N and F− were lower than the integrated wastewater discharge standard. The concentration of PO43−−P decreased from 254.20 mg/L to 3.21 mg/L. This study provided a new method for EMRL and PGL cooperative harmless treatment.