The article introducied results of reseaching of determination of hafnium (Hf) in mixture with zirconium (Zr) by a masking agent and use dye xylenol orange (XO). These were: use HClO4 0.038M and H2O2 3.8M which cant maske Zr, the efficiency is above 88 percent. The second, these established calibration curves for the determination of (Zr + Hf) and Hf at 550,5nm and 434,5nm, concentration was from 0.2 to 1 ppm. Special, reseaching an influence concentration of acid, extractant, some salt. these were: HClO4 0.13M with the separation (S) was 9.4
CTAS 0.004M in C6H6 with for extraction of Zr, Hf by CTAS in C6H6 was 2.6
the concentration is 0.015M, the. effect of KClO4 (S=4.1) to the separation of Zr and Hf was higher than that of KSr (S=2.3).