DESILICATION OF MACROPOROUS ANION-EXCHANGE RESINS USING HYDROFLUORIC ACID IN URANIUM HYDROMETALLURGY

https://doi.org/10.48498/minmag.2026.258.10.009

Macroporous anion exchange resins of the «Ambercept 920», «Purolite 500» and «APM» grades were used. The thermodynamic parameters of the ion exchange reaction were calculated using a modified Debye-Hückel model, considering the limita-tions of its applicability at high ionic strength. It has been established that ammonium bifluoride (NH4HF2) effectively desilicifies macroporous anion-exchange resins used in uranium hydrometallurgy. At a concentration of 30–50 g/dm³, a degree of desiliconisation of 96,3 ± 1.2% is achieved, with a reduction in strength of no more than 10–12%. The process follows pseudo-second-order kinetics (R² = 0,992). The formation of a stable SiF62- complex (ΔG = -7,3…-13,0 kJ/mol) has been demonstrated. The results obtained confirm the high efficiency and technological feasibility of using NH4HF2 for the regeneration of ion-exchange resins.

*Zh. S. Kenzhetaev, M. K. Kylyshkanov, T. B. Yelemessov, R. G. Temirkhanova