par Ghodsi, Mehdi 
;Progneaux, Eric ;Reinhard-Derie, D.
Référence Pollution atmosphérique, 20, 77, page (23-25)
Publication Publié, 1978
;Progneaux, Eric ;Reinhard-Derie, D.Référence Pollution atmosphérique, 20, 77, page (23-25)
Publication Publié, 1978
Article révisé par les pairs
| Résumé : | The Boyer-Rickman plant manufactures basic materials for enamelling processes, composed of a borosilicate called 'fritte', and purifies the gas given off, by adding sodium carbonate. This chemical reacts with HF to form NaF. The purpose of the treatment is to reduce the HF content in the gases discharged to the German standard, i.e. 5 mg/Nm3. The sodium carbonate, in this technique, is gradually saturated with NaF and slowly loses its efficacity. The chemical is renewed when the NaF content reaches 20 to 25% by weight. Consumption of Na2CO3 is about 3 tons per day for the present production of 90 T/day of fritte. The object of this research is decontamination of industrial waste and the possibility of recycling by use of a simple method. The method consists of transforming sodium bicarbonate into an insoluble bicarbonate. The NaF remaining in the liquid phase is changed into insoluble CaF2 by addition of CaCl2. Sodium bicarbonate, when changed into carbonate, and calcium fluoride, are recycled in the production circuit. |
