The effect of nitric acid concentration in the 90% v/v CH3OH-10% v/v 0.1-9.0 M HNO3 system on the yield of purification of yttrium(III) macroquantities from neodymium(III) microquantities using the frontal analysis technique on Wofatit SBW x 4 was studied. Weight distribution coefficients were determined from the neodymium(III) break-through curves. It was stated that the yield of ion-exchange purification process of yttrium(III) from neodymium(III) increased from 0.1 to 7.0 M and then decreased slowly at the concentrations 8-9 M HNO3 in the 90% v/v CH3OH - 10% v/v HNO3 system. The best results were obtained for the 90% v/v CH3OH - 10% v/v 7 M HNO3 system. Then 1.222 kg Y2O3 could be purified with the decrease of neodymium content from 1% to the value below 0.001% on 1 dm(3) of Wofatit. SEW x 4 in NO3- form in the 90% v/v CH3OH - 10% v/v 7 M HNO3 system.