Preparation of high-purity molten FLiNaK salt by the hydrofluorination process

The preparation conditions and purification reaction mechanism for H-2-HF treatment of molten FLiNaK salt were investigated. The optimal process conditions for preparation of high-purity molten FLiNaK salt were obtained. They are purification temperature of 650 degrees C, liquid height of 0.9 m, purification time of 48 h, flow ratio of H-2/HF = 10, flow volume magnitude of 800 mL/min, and reaction pressure of 0 MPa. The oxygen content of the prepared molten salt was around 80 ppm, corrosion impurity elements (Cr, Fe, and Ni) were less than 20 ppm, and the S and P contents were below 5 ppm. The quality of FLiNaK molten salt prepared by this hydrofluorination process is better than that obtained by adding NH4HF2 as a fluorinating reagent. (C) 2017 Elsevier B.V. All rights reserved.