Precipitation
Different amounts of oxalic acid were added to 10 mL of a
solution containing 3.5 M of NH4Cl and 26.7 g L1 neodymium.
The mixtures were stirred for 2 h at 800 rpm at room temperature.
Aerwards, they were centrifuged and the remaining
metal content in the aqueous phase was measured with TXRF.
The percentage precipitation (%P) of neodymium was calculated
by the following formula:
%P ¼
1 CNd;final
CNd;initial
100 (6)
where CNd,initial and CNd,nal the initial and nal neodymium
concentration before and aer the precipitation procedure
respectively.
C