磷酸镁水泥固化电解锰渣特性及机理研究.

The severe environmental problems caused by electrolytic manganese residue（EMR） have aroused extensive concern of scholars at home and abroad, and it is urgent to treat EMR harmlessly. Magnesium phosphate cement（MPC） was used as curing agent to stabilize EMR. The variation of compressive strength of MPC-EMR solidified body with different MPC content and different ages was studied; the curing efficiency of MPC for heavy metals and ammonia nitrogen in EMR was investigated; XRD,SEM and EDS were used to compare and analyze the phase composition and micro morphology of the cured body; at the same time, the internal mechanism of pollutants in MPC stabilized EMR was discussed. The results show that the compressive strength of the solidified body with 5%～15% MPC content is positively related to the MPC content, while the change rule of the compressive strength of the solidified body with 15%～60% MPC content is not obvious; at 15% MPC dosage, the compressive strength of the solidified body at 3,7,28 d and 56 d is 0.51,0.9,8.5,10.92 MPa respectively. The leaching concentrations of Mn2+ and NH+4-N in the raw slag are 1 220 mg/L and 140 mg/L respectively, which are 610 times and 9.3 times of the Class I discharge standard in the Integrated Wastewater Discharge Standard（GB 8978--1996）. The curing efficiency of Mn2+ and NH+4-N in the 28 d curing body can be as high as 99.98% and 98.68% with the addition of 5% MPC.After MPC curing, the soluble Mn2+ in EMR is finally stabilized and solidified with insoluble compounds such as Mn（OH）2,Mn3（PO4）2·3H2O,and then further consolidated by adsorption of struvite gel or encapsulation of crystal structure network; NH+4-N is mainly solidified by struvite crystal（NH4MgPO4·6H2O）.Under alkaline environment, part of NH+4-N will be converted into NH3 and escape. [ABSTRACT FROM AUTHOR]