VERFAHREN ZUR AUFARBEITUNG VON ZUR ABSCHEIDUNG VON FLUORVERBINDUNGEN AUS ABGASEN ALS ADSORBENTIEN EINGESETZTEM ALUMINIUMOXID, NATRIUMALUMINAT UND/ODER ALKALISIERTEM ALUMINIUMOXID

1479924 Fluorine adsorbents; removing HF VEREINIGTE ALUMINIUM WERKE AG and METALLGESELLSCHAFT AG 15 Aug 1974 [15 Sept 1973] 36035/74 Heading ClA Solid adsorbents comprising alumina, sodium aluminate and/or alkalized alumina (as defined) which have been used to remove fluorine compounds from exhaust gases, and contain as impurities, e.g. P, V, Fe, Ti, S and Si compounds, emanating from the electrolytic production of aluminium are subjected to particle sizing to produce a plus and minus 20 micron fraction and the fraction of smaller particle size, which contains the major of the impurities, is subjected to pyrohydrolysis at above 500‹ C. to effect removal of the fluorine content of the absorbent as hydrogen fluoride.