Preparation of Nd(III) carbonate by precipitation stripping of Nd(III)-loaded VA10

The preparation of fine particles of Nd(III) carbonate from kerosene soluti on, from which Nd(III) was extracted with versatic acid 10 (VA10) by a prec ipitation stripping technique using an aqueous NH3-(NH4)(2)CO3 solution as stripping medium, was studied. In preliminary experiments, we were unable to recover Simple Nd(III) carbon ate from Nd(III)-loaded VA10 by CO2 gas bubbling, when water, (NH4)(2)CO3, NH4HCO3, NaHCO3, or Na2CO3 solution saturated with COP was used as the stri pping solution. To obtain simple Nd(III) carbonate, it is necessary to use more than the st oichiometric amount of NH3 compared to VA10 and about 10 times as much (NH4 )(2)CO3 as Nd(III). The solution mixture of NH3-(NH4)(2)CO3 acts as a pH bu ffer, an adductor for VA10, and a CO32- ion source. Although it was conclud ed that the precipitates are Nd-2(CO3)(3). xH(2)O (x is approximately equal to 4), their X-ray pattern does not coincide with that quoted by JCPDS. By heating these precipitates, cubic Nd2O3 was obtained at 823 K, while, at 9 73 K, hexagonal Nd2O3 was formed. Since the stripping solution consisting o f NH3-(NH4)(2)CO3 was highly alkaline, VA10 was also stripped in the aqueou s phase. To use a closed-circuit system for the precipitation stripping of Nd(III) carbonate from Nd(III)-loaded VA10, it is important to regenerate V A10 in the organic phase. For this purpose, evaporation of NH, by air bubbl ing was studied. By bubbling air into a stripping solution warmed at 333 K, almost all the VA10 can be transferred to the organic phase.