OBJECTIVES

Environmental pressures are putting tighter constraints on residue disposal and emissions (mainly impurities) from Bayer alumina refineries.

Airborne emissions include volatile organic compounds and also volatilised heavy metals from the digestion, flash train and liquor burning stages. Increased knowledge of the deportment (location) of impurities through the Bayer process and into the atmosphere is needed to be able to develop strategies to reduce emissions and find containment alternatives.

Bauxite residue disposal creates an ongoing requirement for larger storage areas, and increased problems of caustic containment. Residue storage options and treatment options for producing a more benign material would benefit the industry. Development of methods for further processing existing and future residue to produce valuable by-products would not only have economic value but also environmental value through reducing the quantity of residue requiring storage.

The research in this project aims to:

• understand the deportment of species that ultimately give rise to airborne emissions, and develop mitigation strategies for these emissions
  
• determine the effectiveness of current residue treatments to prevent caustic leaching and improve handling
  
• develop novel processes to ameliorate residue or economically produce value-added products from it.

INDUSTRY BENEFITS

• technical solutions for decreasing the release of volatile organic compounds (cause odours) into the air during alumina processing
  
• strategies to remove minor elements (trace heavy metals) from the Bayer process and from residues
  
• decreased dust formation in bauxite residue storage areas
  
• economic options for bauxite residue re-use.

RESEARCH TEAM
Dr Craig Klauber (Project Leader)
Mr Neil Francis
Ms Nicole Harwood
Ms Renee Hockridge
Dr Greg Power
Dr Peter Smith
Dr Chris Vernon

RESEARCH COLLABORATION
CSIRO Minerals
CSIRO Land & Water

PROJECT DURATION
2005-2008