http://www.rusal.ru/en/press-center/news_details.aspx?id=870Red Mud - a resource for the future
07.05.2013
MetalBulletin
As part of Metal Bulletin's Next 100 series of articles looking at the future of the metals and mining industries, United Co Rusal's head of R&D Viktor Mann explains how the waste of alumina production will become a resource.
Annual world aluminium production is expected to break the 50,000,000-tonne barrier this year.
Making one tonne of aluminium requires about two tonnes of alumina. The production of two tonnes of alumina creates two to four tonnes of red mud or bauxite residue, which is presently regarded as waste from the Bayer process - but it is potentially a valuable resource.
The production of 200,000,000 tonnes of red mud every year has a serious effect on the environment. For now, technology enables us to store the residue harmlessly, but this does not remove the problem.
Will this issue be resolved over the next century?
Currently, only alumina and gallium are extracted from bauxite ores, whereas bauxite contains almost all the elements of the periodic table.
While alumina is the main component (about 30-60%), the other major oxides found in industrial bauxites are Fe2O3 (5-25%), SiO2 (1-9%), and TiO2 (1-7 %).
Like most ores and soils, bauxite can also contain trace quantities of metals including manganese, chromium, lead, mercury, beryllium, nickel and others.
There is little doubt that in 100 years there will be no alumina producer who can afford to maintain giant storage pits. There are extremely strict conditions on the development of new areas for the disposal of waste in Europe, even now.
Even if the LME aluminium price is higher in 2113, no producer will miss out on the opportunity to commercialise the dozens of metals and minerals contained in bauxite ore.
At present, the amount of bauxite residue being processed is limited. The maximum recycling rate is about 30% for an individual plant.
Worldwide bauxite residue processing does not exceed 5 million tpy. That means that less than 2.5% of the amount produced is currently recycled.
Targets
Industry targets regarding the red mud problem are ambitious. The International Aluminium Institute predicts that at least 25% of all red mud will be recycled by 2025.
One major problem is that bauxite composition differs greatly depending on the deposit, meaning there is no established bauxite residue processing technology that can be applied at all the alumina refineries in the world.
Nevertheless, in a challenging environment of low LME prices, companies are looking for more opportunities to extract profit from waste produced during production.
For Rusal, which is the world's third-largest alumina producer, zero-waste alumina production is one of two major technological challenges for the future, along with a carbon-emissionless electrolysis process (ie inert anode).
Rusal is building a 40,000-tpy pilot recycling plant in the Urals, Russia, and will look to expand it to 200,000 tpy.
Rusal's analysts see the demand for red mud and its by-products from Russian enterprises at 3 million tpy, which would easily pay back the planned $20 million of investment. The main consumers in Russia will be the iron and steel industry and the construction sector.
Shared goals
Red mud recycling technologies are being cultivated by the Russian and Chinese national governments already.
Rusal's recycling project was supported by the Russian Ministry of Science as a next-generation technology. Rusal's involvement in the red mud recycling project is one of the company's main environmental stewardship programmes.
Rusal's Engineering and Technology Centre is the project's engine and there is also a think-tank, involving major Russian technology and engineering partners.
The Chinese government has set a target of recycling 10% of all of its red mud by 2015, while our Chinese colleagues from Chalco have already introduced several solutions taken from the iron and rare earth metals extraction industries, so the residues can be used for steel and concrete.
A recent memorandum between UC Rusal and Chalco foresees joint R&D projects, and we hope that together we can find ways to solve the red mud problem.
UC Rusal is also working together with our Canadian partner Orbite Aluminae on new refining technologies that can bring completely new sources of alumina into the industry, such as aluminous clay.
I believe that over the next 100 years, the most ambitious goal will be not only to reach a 100% utilisation rate for the bauxite, but to also recycle all
3 billion tonnes of the planet's red mud stocks.
Waste can turn into wealth in a very unexpected way: at the dawn of the 20th century, the replacement of kerosene as a light source by electricity brought oil producers to the edge of bankruptcy.
The oil producers only survived thanks to a cheap solvent produced as a by-product of kerosene distillation, which until then had often just been burned off - gasoline.
Viktor Mann is the head of R&D and technical director at United Co Rusal, the world's largest aluminium producer
As part of its centenary celebrations, Metal Bulletin has asked leading participants from different parts of the metal and mining industry to take part in MB's Next 100, a series of pieces on how the future might unfold.