A novel treatment processes of struvite with pretreated magnesite as a source of low-cost magnesium

作者:Yu, Rongtai; Ren, Hongqiang*; Wu, Jichun*; Zhang, Xuxiang
来源:Environmental Science and Pollution Research, 2017, 24(28): 22204-22213.
DOI:10.1007/s11356-017-9708-8

摘要

By crystallization process, phosphorus can be recycled from wastewater. However, the reagent cost limits the application of struvite precipitation. Magnesite, as a low-cost magnesium source, can result in a cost savings, while the poor dissolution offset of low-cost reagent. In this study, most of the pyrolysate of magnesite was dissolved by changing the process of reagent addition; the solubility of the pyrolysate was increased at acid wastewater. The removal rate of phosphate by the pyrolysate was higher than that of magnesite, the phosphate removal rate was from 70.2 to 88.2% at 600 degrees C, 0.5 h to 1200 degrees C, 3 h. Phosphate removal rate was achieved optimal when calcination temperature was 700 degrees C at 2 h. By adding the pyrolysate to acid wastewater (pH <= 2) before NH4Cl, phosphate removal rate was closed to that of MgCl2 as magnesium source, while magnesite was priced at similar levels to lime.