Treatment of gases evolved from electrolytic cell - producing aluminum

摘要

Hydrogen fluoride and finely divided solids are removed from the gases evolved from electrolytic cells, by passing a continuous stream of the gases which contain less than 35 milligram of fluoride/cu.ft., through a bed of finely divided alumina particles. The gas is passed 2-12" deep and contains 50-150 lb. of alumina/lb. of HF in the gases. The individual gas molecules pass through the bed in 0.25 - 1.5 sec. The alumina particles containing HF are removed from the bed. The alumina particles pref. having a residence time of 2-14 hr. in the bed. This process provides an efficient and economical method of removing HF and solids.