Graham G., Capil R. and Davies R.
Odour emissions from alumina refineries are an increasingly sensitive environmental issue. One source of odour is the organic matter in bauxite, which reacts with caustic liquor under elevated temperature and pressure at the digestion step.
Odour surveys at QAL have identified digestion heater vent gases as a major source of emissions. Means to combat these emissions were reviewed. The relatively low volume and easy capture of vent gases makes thermal oxidation a suitable technology for this stream.
This paper will describe the odour analysis and technology selection process, and present the results obtained from a pilot thermal oxidation unit at QAL.