Hydrolysis of Carbonyl Sulfide (COS) on Smelting Grade Alumina
Carbonyl sulfide (COS) is present in aluminum smelter off-gas at low ppm concentrations. The primary source of COS is the 2–3 wt% sulfur contained in carbon-based anodes. COS is directly evolved from anode oxidation during aluminum electrolysis. Upon evolution, COS is further oxidized to SO2, while a minor fraction of evolved sulfur is emitted in the form of COS. Very little, if any, of the evolved COS is captured by the dry scrubbing systems.
In this work, a series of laboratory experiments was conducted to characterize interactions of COS with smelting grade alumina (SGA) as a function of gas temperature and humidity. The effect of other smelter off-gas components (HF and SO2) was also evaluated. This work suggests that SGA is an efficient catalyst for COS hydrolysis, however, the presence of hydrogen fluoride, SO2 and humidity negatively affects its catalytic activity.
Keywordscarbonyl sulfide COS aluminum smelter emissions catalyst smelting grade alumina catalytic COS decomposition industrial scrubbing emission monitor
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