Cleaning gases from polishing crystal glass components

Crystal glass components are polished at the Skopa Glass Plant after mechanical treatment by immersion in a H2SO4/HF mixture followed by washing in dilute H2SO4. Air extraction carries off vapour, fine spray and mist containing fluorides as well as minute glass particles. Marked reductions in residual fluoride concentration are provided by two-stage or multi-stage treatment with different absorbers. Tests were carried out on a ion-exchange method of treating gases containing less than 100 mg/m3 of hydrogen fluoride. The system consisted of a packed scrubber and an ion-exchange filter. The scrubber traps most of the fluorides, including solid and gel components, while the filter provides the final cleaning. The process is described. Test showed that the system provides the high degree of purification needed for environmental protection. 3 refs.