A sustainability framework for the beneficial reuse of alumina refinery residue

A sustainability framework for the beneficial reuse of alumina refinery residue

When bauxite is processed to manufacture alumina, a solid waste by-product is created. For every one tonne of bauxite digested by the refining process about 400 kg of alumina and 600 kg of waste residue are produced. As a consequence, each year up to 120 million tonnes of solid waste residue are generated by about 100 alumina refineries in Australia, China, Brazil, India and elsewhere, and in excess of three billion tonnes of waste residue are reportedly stockpiled in impoundments throughout the world, making alumina refinery residue the world’s single largest industrial waste product by volume.

The physical and chemical properties of alumina refinery residue have long been the subject of scientific investigation because the residue contains iron, aluminium, silica, titanium, sodium and other elements and compounds of potential value. In the last ten years, this investigation has centred on not only the recovery of valuable components of the waste but also on the various beneficial reuse possibilities associated with this type of residue, both as a way of reducing the amount of waste being stockpiled as well harnessing the inherent valuable components in it. The alumina industry has therefore developed a series of “technology roadmaps” to address the growing inventories of alumina refinery waste, including how to better dewater and store it safely. However, while commendable, these roadmaps have mostly focused on process improvement and productivity dividends and failed to address certain fundamental truths related to sustainable and beneficial reuse, including lifecycle analyses, how the residue can be incorporated into wider regional plans for sustainable development, and the inescapable fact that alumina refinery residue is a classified hazardous waste in most jurisdictions with potentially detrimental human and environmental health effects when applied incorrectly or inappropriately.

By considering not only the obvious industrial, commercial and chemical imperatives which drive residue reuse and inform current technology roadmaps, but also by including the regulatory, environmental, investment, research and social licensing dimensions (among other factors) of a complete and holistic future, this paper presents a new framework for the beneficial reuse of alumina refinery residue. The paper argues that only through a comprehensive understanding and consideration of all aspects of alumina refinery residue beneficial reuse and a meaningful engagement with the broadest possible range of stakeholders can a truly sustainable future for this type of waste be realized by society and industry.

c. Journal of Multidisciplinary Engineering Science and Technology