Investigation of neutral yttrium phosphate formation conditions

Crystallization process of neutral yttrium phosphate, formed in the process of interaction between aqueous solutions of yttrium chloride and phosphoric acid, depending on reagent concentration (0.1-10 mol/l, mole ratio 1:1), synthesis temperature (20-100 deg C), mixing intensity and solution pH, has been investigated. It is shown, that the type of kinetic crystallization curves at 20 deg C, as well as the shape and dimensions of YPO4x2H2O crystals formed, to a considerable degree are determined by the initial concentration of solution. The increase in the synthesis temperature to 100 deg C, depending on concentration, results in the formation of products, differing both in composition and structure. Neutralization of initial mixture solution by ammonium to pH 2.0-2.5 leads to the increase in yttrium phosphate yield from 35-40 to 92-94% without the change in the product composition. Crystallization mechanism of yttrium phosphate is considered, taking into account structural changes in solution