Predictive Formula for the Competitive Adsorption of HF and SO2 on Smelter Grade Alumina Used in Dry Scrubbing Applications

Smelter grade alumina (SGA) is the preferred agent for recovering HF from pot exhaust gases since the alumina also serves as feed to the electrolysis process, thereby allowing return of the recovered fluoride to the process. This alumina-based recovery loop includes sulfur that evolves from cells as SO2 and that is co-adsorbed on SGA that is not completely saturated by HF. Previously, Dando and Lindsay (Light Met Miner Met Mater Soc 527531, 2016, [1]) reported on the competitive adsorption of HF and SO2 on smelter grade alumina by investigating the temporal breakthrough behavior of both HF gas and SO2 gas to quantify the mechanisms behind adsorption of both gases on the same particle of alumina. In this paper follow-on work is presented where this research data is translated into an empirical formula that can be used by engineers and technologists. Examples are given of applications that may be practical in making predictions on the removal of SO2 by alumina in a dry scrubber.