The chlorination kinetics of zirconium dioxide in the presence of carbon

Abstract

The kinetics of the chlorination of compacted spherical pellets of zirconium dioxide and carbon were studied over a particle temperature range of 1400 to 1950 K. A plasma of pure chlorine generated by an induction torch provided both the high-enthalpy field and the reacting gas. The influence on the rate of conversion of temperature, chlorine concentration and carbon content were determined experimentally. Based on both experimental and theoretical studies, rate equations were developed.The rate of chlorination was influenced by the separation distance between Z r o , and carbon particles in the pellets, hence a shrinking-core model was not obeyed. Instead, a new reaction model was proposed. The experimental results provided adequate information for the selection of optimum conditions with respect to reactor type, temperature and carbon content for an industrial process.he high-temperature chlorination of purified, de-T halfniated ZrO, is an important step in the conventional process for the production of nuclear-grade zirconium metal. The ZrCL vapors produced by this reaction are then reduced by magnesium to yield a pure zirconium sponge

Kinetics of chlorination of tantalum pentoxide in mixture with sucrose carbon by chlorine gas

“…[1][2][3][4][5][6][7][8] A higher carbon percentage implies a greater availability of active sites, both for the formation of active chlorinating species and for the reaction of carbon oxidation with the oxygen released in the oxide chlorination stage. [1][2][3][4][5][6][7][8] A higher carbon percentage implies a greater availability of active sites, both for the formation of active chlorinating species and for the reaction of carbon oxidation with the oxygen released in the oxide chlorination stage.…”

“…[1][2][3][4][5][6][7][8] Few studies have dealt with the study of the mechanism and kinetics of Ta 2 O 5 carbochlorination in the presence of carbon and using Cl 2 as chlorinating agent. Carbochlorination of a metal oxide using carbon as the reducing element and Cl 2 as the chlorinating element is a complex process that involves two solids and Cl 2 gas.…”

Untitled

“…ZrCl 4 is used as the starting material in other proposed methods for the production of zirconium as an alternative to conventional route 11 . According to the following reaction, Zirconium tetrachloride is produced using chlorination of zirconia in the presence of carbon which is really an approximation (CO 2 formation occurs simultaneously with CO) 12 :…”

A model for the role of carbon on carbochlorination of TiO2

“…[1] The Gauvin [5] examined the chlorination of ZrO 2 -C pellet and carbochlorination stoichiometry at high temperatures (800 proposed a model where the reaction rate is proportional to ЊC to 1000 ЊC) is well represented by the following the initial carbon concentration. Recently, in a kinetic study equation: [2][3][4][5][6] on TiO 2 chlorination, using alternatively carbon and CO as MeO 2 (s) ϩ 2Cl 2 (g) ϩ 2C(s) ϭ MeCl 4 (g) ϩ 2CO(g) [1] reductants, [13] the effect of carbon content on reaction rate was included as a factor in a pseudo rate constant, but the where Me is Zr or Ti. The chlorination of ZrO 2 and TiO 2 analysis was only qualitative.…”

“…In addition, an accelerating Cl 2 (g) reaction atmosphere, has been thermogravimetrically effect of carbon on reaction has been reported (kinetic investigated as a function of both temperature (460 ЊC to effect). [2,5,[7][8][9][10] Although the carbochlorination mechanisms 950 ЊC) and carbon content in solid mixture. [10] The TiO 2 are incompletely understood, most reports [2,6,8,11] have carbochlorination, as the ZrO 2 carbochlorination, [14,15] agreed that physical contact between carbon and oxide partiexhibited two well-differentiated and successive reaction cles is not necessary.…”