Peculiarities of molten KBr-2 SrBr₂ mixture deoxidization under the action of reactive gas medium

The process of the oxygen-containing admixtures removal from molten mixture KBr-2 SrBr2 (deoxidization) was studied by emf method in the cell with transference at 973 K. The deoxidization was performed by passing bromine vapor through the melt containing carbon suspension (graphite or active coal powder). The membrane oxygen electrode Pt(O-2) \ YSZ (YSZ - 0.9ZrO(2) + 0.1Y(2)O(3)) was used for the determination of equilibrium and current concentrations of oxide ions, O2-, at the running of the studied processes. The chemical stage of the deoxidization process in the molten KBr-2 SrBr2 was found to undergo the kinetics of the 2(nd) order with the respect to O2- ions. The rate constant value for the case of graphite powder use was estimated as 1.34 center dot 10(5) kg center dot mol(-1)center dot min(-1). The use of the active coal resulted in the increase of the rate of KBr-2 SrBr2 deoxidization process by approximately 25 per cent, although, it did not affect the melt purification limit. The latter fact is an essential argument confirming the achieving of the chemical equilibrium in the studied system. The minimal equilibrium concentration of O2- after the finishing of the deoxidization process was 3.6 center dot 10(-7) mol center dot kg(-1). The obtained results are in good agreement with those obtained for the chloride melt of the same cation composition (KCl-2 SrCl2), that is a common trend for the deoxidization of chloride and bromide melts in the reactive gas medium.