Rio Tinto collaborates with Queensland University to develop new green method of bauxite processing

North Queensland is home to some of the world's largest bauxite deposits, but their potential remains largely hidden under the earth as no mining company has yet come forward to exploit it in a sustainable manner. Recently, a University of Queensland scholar has collaborated with the global mining giant Rio Tinto to find out a new way to process bauxite, the principal ore of aluminium, that will not only add value to it but will also help reduce the mine’s environmental impact significantly.

Dr Hong Peng, faculty at the UQ School of Chemical Engineering said the new method Rio Tinto is looking at, turned bauxite waste products, especially red mud, into economically viable resources.

“Bauxite ore is necessary to produce aluminium, which is in many of the products we use every day,” Dr Pend said. “Queensland is ideally placed to benefit from this technological improvement as bauxite is abundant in north Queensland and there are already processing facilities and experts established here. Now instead of wasting the bauxite ore by-products, we can recover most of the minerals, which also reduces the environmental impact of the mining activity.”

The new process would make bauxite usable to some mines where it was not so originally.



Bauxite ore is a rocky composite of minerals containing 30 to 54 per cent of aluminium oxide or alumina along with other minerals such as titanium dioxide, aluminosilicate or desilication product (DSP) and various oxides of iron. Alumina is refined from bauxite using a technique called Bayer process and thereafter used as an electrolyte in Hall Heroult Method of aluminium smelting.

In the conventional Bayer process, the DSP crystallises to a fine powder intermingled through the residue, which makes separation of the components impossible. Dr Peng has been working on a process aimed at controlling this crystallisation, while yielding a coarser material that can be separated and removed easily.

“The current process wastes a lot of these other minerals and creates bauxite residue,” he said. “The new method we’re developing has environmental benefits and financial benefits, as the by-products can be sold.”

Thought it depends on how the project progresses, Dr Peng is hopeful that the newly developed technology could be rolled out in Queensland within five or ten years from now.

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