Bauxite Residue Management

Bauxite residue is a by-product of alumina refining and consists primarily of iron and silica minerals.

The coarse sand comprises about 40 per cent of residue and 60 per cent of fine silt fraction. Much of the sand is reused to construct residue drying areas, which are eventually capped and revegetated.

The effective management of bauxite residue is a critical focus for our operations. Each of our three refineries have a Long-Term Residue Management Strategy, which can be viewed through the links below.

Globally, Alcoa is exploring a multi-faceted strategy towards zero bauxite residue. This includes reducing the amount of residue that is produced during the refining process, along with exploring reuse opportunities.

In Western Australia, we are looking at how to economically modify our mining process to screen out ore that does not contain aluminium oxide before it goes through the refining process. Referred to as beneficiation, this has the potential to increase the volume of viable ore that we mine and reduce the amount of bauxite residue during refining.

We are also implementing a process called bauxite residue filtration. This technology reduces the moisture content of the bauxite residue, allowing the resulting filter cake to be more easily handled and more efficiently stored. The water captured during the process of filtration is captured and returned to the process.

To read more about these efforts, view about Alcoa’s global focus on designing the Refinery of the FutureTM.

Globally, Alcoa aims to reduce bauxite residue land requirements per metric tonne of alumina produced by 15 per cent by 2030, from a 2015 baseline. A key driver in achieving the goal is to explore opportunities to repurpose bauxite residue by converting it into commercially marketable products for use in applications such as road construction, cement production or soil amelioration.

Our global refining research and development team has identified a number of possible sustainable uses including Red Sand™, a product that has been successfully trialled as a fill for industrial land development, turf top dressing and in road base construction. More about this can be viewed through this global news story.

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