This article presents preliminary results of the study of neptunium(IV) oxide dissolution in aqueous solutions of Na₂CO₃ in the presence of ammonium persulfate and hydrogen peroxide. In these carbonate systems, the value of NpO₂ dissolution yield did not exceed 1.5–1.6%. Ultrasonication makes it possible to significantly increase the dissolution rate of neptunium(IV) oxide in Na₂CO ₃ solutions in the presence of hydrogen peroxide. Under such conditions, about 25% of neptunium(IV) oxide powder can be dissolved in one dissolution step (210–270 min). A possible factor affecting the increase of NpO₂ dissolution yield is the increase of oxidative and reaction activity in the carbonate systems under ultrasonic impact.

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N.M. Chervyakov, A.V. Boyarintsev, S.A. Perevalov, S.I. Stepanov, S.E. Vinokurov, "Oxidative dissolution of neptunium(iv) oxide in carbonate solutions", RAD Conf. Proc, vol. 5, 2021, pp. 94–99, http://doi.org/10.21175/RadProc.2021.18