The high cost of magnesium is one of the key problems for the practical application of struvite chemical precipitation. Ammonium in wastewater was recycled by changing the initial conditions of struvite precipitation with cheap magnesia. The results showed that when the initial pH was 2

the removal rate of ammonium was above 90% by struvite precipitation technology with cheap magnesia as magnesium

which was above 82% at the conditions of the mole ratio of Mg2+:NH4+:PO43-

1:1:1 and calcination temperature of magnesia of 200-400℃. The XRD and FTIR results also showed that the crystal structure of magnesia was distorted with changed bond length of Mg O at different calcination temperature

leading to redshift and blueshift. A direct correlation was found between Mg O bond length and ammonium removal ratio.