Investigation of clorine trifluoride absorption by crystalline calcium carbonate

Abstract

The effect of temperature factor on the efficiency of absorption of fluorine- and chlorine gas by a chemical absorbent, marble chips of a grade CA-MC, was researched. The degree of absorption of fluoride compounds at room temperature was 91%. The degree of recovery of total chlorine was 47.3%, that is because the low reactivity of the absorbent and an increase in an amount of Cl2 in gases due to displacement of it by the fluorides from formed CaCl2. Calculation of thermodynamic characteristics of the processes showed that the equilibrium constant for the reaction of chlorine with CaCO3 increased with a temperature growth, which proved larger intensity of the chlorine absorption by the hot absorbent. According to the suggested method, the gases containing chlorine fluorides successively passed through three distinct temperature zone of calcium carbonate: 230–600°C, 25–35°C and 300–600°C. In this case, the degree of recovery of fluorine compounds was 99%, and 98% of elemental chlorine was absorbed.