Effect of Anti‐Encrustation Additives on Zirconium Molybdate Hydrate

Abstract

Anti-encrustation additives were mainly investigated in nitric acid solution with zirconium (Zr), molybdenum (Mo), and tellurium (Te) to prevent the encrustation of zirconium molybdate hydrate (ZMH). The ZMH generated by reaction crystallization of Mo and Zr as main fission products has a high adhesion property in spent nuclear fuel reprocessing. In addition, it is reported that Te, which is also one of the fission products, precipitates together with ZMH. Encrustation of precipitates containing Te was effectively prevented by adding molybdenum trioxide (MoO 3 ) crystals as an anti-encrustation reagent. The encrustation amount was found to be larger than that under the condition of only Zr and Mo without Te. Consequently, it was suggested that the high adhesion property of Te affected the encrustation amount of ZMH.

A Novel Simulated Moving Plug Flow Crystallizer (SM-PFC) for Addressing the Encrustation Problem: Simulation-Based Studies on Cooling Crystallization

“…Lower supersaturation also affects the crystallization process adversely as the driving force for both the crystallization and encrustation is the same . Chemical additives have also been used to suppress the encrustation . The other usage of additives includes control of morphology or polymorphs during crystallization. , However, in some studies, additives are found to suppress nucleation and crystal growth leading to a low yield of crystallization .…”

“…3 Chemical additives have also been used to suppress the encrustation. 14 The other usage of additives includes control of morphology or polymorphs during crystallization. 15,16 However, in some studies, additives are found to suppress nucleation and crystal growth leading to a low yield of crystallization.…”