The recovery and reuse of magnesium (Mg) phosphates such as struvite (MgNH₄PO₄•6H₂O) has the potential to protect surface water quality, extend phosphorus (P) reserves for use in industry and agriculture, and provide facility operators with a potentially valuable byproduct. Recovery technology can be used in wastewater treatment plants (WWTPs), intensive livestock operations, and industrial facilities with high-P waste effluent, and the product of treatment can be applied as a P fertilizer.

Four recovered magnesium phosphates were examined: crystalline struvite produced from livestock waste effluent, amorphous Mg phosphate made using the same method as the crystalline struvite, Mg phosphate made using a modified method, and crystalline dittmarite (MgNH₄PO₄•H₂O) recovered from a food processing plant during cleaning. The crystalline samples were clearly identifiable from X-ray diffraction (XRD) spectra, while no crystalline Mg phosphates were identified from XRD spectra of the amorphous samples. Mg phosphate particles of various sizes were identified in all samples using scanning electron microscopy and energy dispersive spectroscopy (SEM-EDS).

Many of the particles examined using EDS showed a 1:1 ratio of Mg and P. However, particle morphology ranged from crystalline and regular to semi-crystalline to completely amorphous and irregular. This wide variation in recovered Mg phosphate morphology highlights the need for further investigation into the practical effects of structure on the beneficial reuse of recovered phosphate materials.