Basic Research of Dry-Type Reconverted Resources Technology for Fluorocarbon

Abstract

To develop the newly dry-processing technology for reconverted resources fluorine as fluorite contained in waste chlorofluorocarbon (R22), the reaction characteristics of steam decomposition gases of chlorofluorocarbon with air and calcium carbonate were investigated. The gas–solid reaction of the chlorofluorocarbon decomposition gases, in which the HF concentration of about 30% and HCl concentration of about 15%, and calcium carbonate, of which grain size is 1–2 mm, was conducted at the temperature of 200°C and SV of 1860 h⁻¹. It was found that HF concentration contained in the off-gas from fixed-bed reaction furnace before HF break-through time was very as low as less than 1000 ppm, on the other hand HCl concentration becomes high with the range of 10–15%. This result shows that fluorine is alternatively absorbed by calcium carbonate in a fixed-bed reaction furnace. Moreover, the fluorite purity of the sample by which the reaction progressed comparatively into the fixed-bed reaction furnace became about 94%. Also, we demonstrated that the calcium chloride generated by reacting chlorine and calcium carbonate in the lower part of the fixed-bed furnace replaces calcium fluoride gradually with advance of a reaction time. From these results, the implement ability of the dry-type reconverted resources technology of waste chlorofluorocarbon can be verified.