Preparation and characterization of some phosphate salts from crude phosphoric acid

ABSTRACT

Monosodium phosphate, MSP, di - sodium phosphate, DSP, and trisodium phosphate, TSP, samples were prepared both from partially purified and solvent extracted phosphoric acid fractions. Chemical analysis and preliminary tests showed that the degree of purity of the prepared samples from the solvent extracted acid were in good agreement with the standard samples. TGA confirmed the above findings. The x-ray diffraction patterns and IR- spectra showed that the prepared MSP [b,c], DSP [c] and TSP [c]possessed the same crystalline structures and specific IR absorption bands as the standard sample [S]. Preparations from partially purified phosphoric acid using step filtration and back-acidification, indicated that the orthophosphates obtained had satisfactory purity, but it was slightly less than those of samples produced from solvent extracted acid