Minerals Processing Plant of the Year: Alcoa’s Kwinana Refinery

Alcoa's Kwinana Refinery located in Western Australia is a finalist in the 5th Annual Australian Mining Prospect Awards.

Alcoa’s Kwinana Refinery located in Western Australia is a finalist in the 5th Annual Australian Mining Prospect Awards.

The refinery was the first Alumina Refinery in the world to achieve ISO14001 accreditation in 1998 and the fundamentals of ISO1400 are the foundation of all Kwinana’s environmental management practices and systems.

ISO14001 requires each location to identify activities with the potential to significantly affect the environment, define the controls in place to manage those risks and develop action plans for improvement.

Recently, a global research team, based at the refinery, set a benchmark for the alumina industry with the development of an innovative residue treatment process that delivered a range of sustainability benefits.

Known as residue carbonation, the process adds carbon dioxide to bauxite residue which is a mixture of minerals that are left behind when alumina is removed from bauxite. Although it is thoroughly washed, the residue retains some alkaline liquor and requires long-term storage.

Mixing CO2 into residue reduces its pH level to the levels found naturally in many alkaline soils, where it can potentially be re-used in road base, building materials or soil amendments.

Since January 2007, the Kwinana carbonation plant has been operating at full capacity, treating all of the residue produced by the refinery.

Prior to this, the plant had been treating around 25% of the refinery’s residue for the past two years, while awaiting the construction of a pipeline to deliver CO2 direct from the CSBP ammonia plant.

Alcoa’s Technology Delivery Group is conducting further research to support the deployment of carbonation in refineries that do not have a nearby CO2 supply like the Kwinana refinery.

Moreover, Alcoa plans to deploy the technology across all three Western Australian refineries, leading to CO2 savings of 300,000 tonnes each year – equivalent to taking 70,000 cars off the road.

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