A Quebec firm has solved a critical challenge for the aluminium industry, earning the 2014 Canadian Green Chemistry and Engineering Award (CSA Group Award for Organizations) from the Chemical Institute of Canada.
Orbite Aluminae’s high purity alumina production facility in Cap-Chat, Que. has been recognized with a green chemistry award. Photo credit: Orbite Aluminae Inc.
Orbite Aluminae Inc., based in Montreal, has come up with an alternative to the standard method of extracting aluminum from bauxite ore, which dates back to 1887. Known as the Bayer process, the ore is washed with heated sodium hydroxide, then subsequently cooled and treated with carbon dioxide, which yields alumina (Al2O3), the penultimate step of making aluminum metal. Unfortunately, for every tonne of alumina that is produced this way, as much as two tonnes of very high alkaline tailings are generated. Billions of tonnes of this “red mud” sit in holding ponds around the world, an amount that will continue to increase as long as the Bayer process is used.
However, Orbite’s innovation could stop or even reverse this flow of red mud. The company has developed an entirely new approach to alumina extraction, a technique that starts with acid dissolution of a variety of ores — including aluminous clay, kaolin, argilite and nepheline — followed by selective precipitation, hydrolysis and then acid recovery. In 2011, a Norwegian lab demonstrated that Orbite’s metallurgical-grade alumina can be used to produce aluminium ingots to the industry’s highest quality.
Above all, this output produces no red mud. In fact, the same process can be applied to that mud or to fly ash, extracting valuable metals and rare earths contained in existing stockpiles of this dangerous waste, while leaving behind a dry, inert powder that has only 10 percent of the original volume. “That’s what I call a truly disruptive technology,” says Robert Boily, the technology consultant who nominated Orbite for the award. “It’s totally different from how aluminium is currently made. Not only is it a green technology, it’s cost effective,” Boily says.
Boily had previously catalogued some of the most notorious cases of red mud disposal, such as the 2010 collapse of a red mud retaining wall that flooded rural areas of Hungary with about a million cubic metres of this material, killing nine people, injuring dozens of others and contaminating some 40 square kilometres of land as well as the lower Danube River. Boily’s extensive knowledge of the serious threat posed by production of this fundamental commodity made him all the more impressed by what Orbite had achieved. “Instead of using the traditional manufacturing process and wondering about what to do with the bauxite residue, they decided to get rid of that residue right from the start,” he says. “Nobody had questioned that process until Orbite came with this new technology. For me, it’s fantastic.”