turning alcoa sand into a valuable product
Did you know that local sand supplies are in decline and Alcoa could soon be in a position to help solve that issue - thanks to the great work by Alcoa’s global refining research and development group?
Just as our actual product, aluminium, is endlessly recyclable, we’ve found ways that our by-products can be useful to the community. Through research spanning over 20 years, we have identified a number of possible sustainable uses for our bauxite residue, one of which is Red Sand™.
The Technology Delivery Group, which services Alcoa globally, has developed a carbonation and wash process which we use to process Red Sand™ - this neutralises any caustic and removes most of the remaining carbonate salts, making Red SandTM environmentally benign. Red Sand™ is essentially crushed rock that is red in colour.
Limestone, sand and gravel are fast diminishing, particularly in the South-West of WA, and organisations carrying out construction projects are looking for alternatives. Our Red SandTM could fill this need, and not only could Red SandTM be a cost effective alternative, but it could also be a high quality construction sand thanks to its excellent drainage and strength characteristics.
Use of Red SandTM is already happening within our operations and is a demonstration of residue being put to a sustainable use. It’s used in the construction of residue drying areas and in surface capping for residue rehabilitation. Without our own sand, we would need to purchase quarry sand for these tasks, and with sand supplies in decline, our reuse is a big benefit to the community.
The potential uses for the sand and mud components of our bauxite residue include:
- As a soil amendment for broad use acre farming and horticultural uses;
- As a sand for use in cement manufacture;
- In effluent treatment ponds and septic systems;
- For trace metal retention from road runoff, rubbish tips and acid mine drainage;
- In ceramic manufacturing;
- In plastics manufacturing; and
- For use as a road base.
Alcoa is now looking to commercialise Red Sand™ as a useful and valuable resource external to our operations. This would have a range of potential benefits including:
- as a viable substitute for increasingly scarce supplies of quarry sand;
- reducing the clearing of natural bushland for sand quarries; and
- reducing the requirement for residue containment facilities.
Read more about bauxite residue at www.alcoa.com.au/residue
breakthrough for R&D group
Alcoa’s global refining research and development group, based in Western Australia, has achieved a significant breakthrough in both health and safety and production technology.
The Technology Delivery Group (TDG) has created one of the most complex chemical processing robots in the world which is helping to optimise the performance of Alcoa’s alumina refineries worldwide - including our operations in Kwinana, Pinjarra and Wagerup.
The new robotic system has been custom built by our in-house scientists in collaboration with local industry. The system eliminates a number of potential occupational risks - including exposure to fumes and repetitive strain injuries.
“This has best practise safety systems and removes any human and machine interaction,” said Kim-Louise Burke, TDG Project Officer.
The robot carries out the complex chemical preparation required for the analysis of oxalate. Oxalate is an extremely important impurity in the alumina refining process. TDG has in-depth knowledge of the behaviour of oxalate in all of our refineries derived from the ability to carry out thousands of oxalate analyses per year. The oxalate analysis is used to optimise refinery performance.
“We simply could not afford to do the number of analyses we currently do if we didn’t have the new robot - it saves many millions of dollars,” said Dr Michael Nunes, TDG Program Manager.
“The robot can work overnight and therefore has the ability to prepare 500 samples in any 24 hour period which significantly helps us to meet project needs. This is important because it frees up our scientists to be working on other new discoveries,” Ms Burke said.
“It took us about two years to design and build the robotic system and it provides very fast, precise and safe oxalate analysis at very low operating cost,” Dr Nunes said.
The Technology Delivery Group, based at the Kwinana Refinery, has been developing innovative new equipment and processes for cleaner, more efficient production at Alcoa refineries since 1968. TDG consistently helps to solve environmental challenges through developing and implementing new technology solutions across its global refining system.
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