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1774217 
Book/Book Chapter 
Alumina dry-scrubbing technology: Development of a cascade feeding system for improved capture efficiencies 
Vendette, H; Dando, NR; Moras, A; Marion, E; Xu, W 
2007 
LIGHT METALS 
187-191 
WOS:000247423900029 
Aluminum smelters use alumina-based dry scrubbers for capturing fluoride evolved from the smelting process. In injection-based dry scrubbers, alumina is typically fed through vertical reactors arranged in parallel flow paths. A direct relationship exists between the capture efficiency of an aluminabased dry injection-type scrubber, the alumina feed (or recycle) rate and the fluorination level of the recirculated alumina used to scrub the off-gases generated from an aluminum electrolysis potline. To take advantage of this relationship, an alternative (serial, as opposed to parallel) fresh alumina distribution scheme was developed. This serial feeding system directs a maximum quantity of alumina to the first scrubber module of a series and sequentially redirects the overflow of the non-saturated alumina to the next module in the series until the material exits the last reactor of the series. Solios and Alcoa Primary Metals have collaborated to evaluate the long-term performance of this process at an operating aluminum smelter. The test results indicate a 26-44% reduction in fluoride emissions relative to parallel feed operation. The purpose of this paper is to document the results observed from a long-term (four-month) test of this process at an operation aluminum smelter. 
alumina; dry-scrubber; dry-scrubbing; air pollution control