Chemical Plant Supplying Carbon Dioxide for Residue Neutralisation at Alumina Refinery

Summary

Alcoa’s Kwinana alumina refinery is about to start using process carbon dioxide (CO2) to reduce the alkalinity (and hence leachability) of its bauxite residue, thus reducing environmental risks and significant ongoing management related to bauxite residue storage areas while also leaving options open for additional processing of the residue into other useful products at a future stage. The residue carbonation process was identified after many years of research into reuse potential and modification of the bauxite residue by mixing it with other industrial by-products or residues. The Kwinana refinery will tap into a consistent and concentrated source of process-CO2 from a nearby ammonia plant, resulting in greenhouse gas benefit equal to 70,000 tons CO2-eq per year and generation of a more benign waste that provides alternative reuse opportunities (Alcoa 2005).

Industry

Industry Sector	Specific Industry
chemical sector	producer of industrial chemicals and fertilisers
mining and minerals sector	alumina refinery

Region

Kwinana Industrial Area, Kwinana, Western Australia

Applied Technologies

• bauxite residue carbonation process

Triple Bottom Line Aspects (direct at operational level)

Economic	capital and operational costs to run bauxite residue carbonation process
Environmental	greenhouse gas benefit equal to 70,000 tons CO2-eq per year reduced environmental risks and management issues related to bauxite residue storage reduced alkalinity (and hence leachability) of bauxite residue generation of a more benign bauxite residue that provides alternative reuse opportunities
Social	increased employee satisfaction due to improved environmental performance of the chemical plant

Additional Comments

None.

References

• Alcoa Inc (2005) "Using One Process Waste to Neutralise Another", Retrieved: May 2005, from http://www.alcoa.com/global/en/environment/initiatives/kwinana_alumina_refinery.asp?initCountry=1000
• van Beers, D, Bossilkov, A and van Berkel, R (2005) “Capturing Regional Synergies in the Kwinana Industrial Area – 2005 Status Report”, CSRP Report (for Project 3B1), August 2005

Last Update

31 October 2005