화학공학소재연구정보센터
Thermochimica Acta, Vol.383, No.1-2, 145-152, 2002
Thermoanalytical investigation of iron phosphate obtained by spontaneous precipitation from aqueous solutions
Iron(Ill) phosphate has been precipitated under supersaturation conditions from equimolecular aqueous solutions of 0.025 M Fe(NO3)(3).9H(2)O and K2HPO4, at pH = 2.00 and at ambient temperature. The precipitate has been characterised by TG/DTG/DTA and DSC techniques, chemical analysis, IR-spectroscopy and X-ray powder diffraction. A yellowish-white amorphous solid of formula Fe-2(HPO4)(3).xH(2)O has been obtained. Alternatively, a pinkish-white amorphous precipitate of formula FePO4.2H(2)O is obtained under the same conditions from Fe(NH4)(2)(SO4)(2).6H(2)O using hydrogen peroxide as the oxidising agent. Although the IR spectra and the thermal behaviour of both compounds are quite different, they crystallise as FePO4 when annealed at 650 degreesC in air.