Prof Discovers a Way to Recyle Red Mud
October 22, 2010 - News Release
A University of Guelph chemist has discovered that red mud - an alkaline waste by-product of the aluminum industry - can potentially be used to turn agricultural and forestry biomass into usable oil.
Red mud has captured headlines because of a recent collapse of a reservoir in Hungary, where a catastrophic spill of rust-coloured sludge flooded villages and killed several people.
About 70 million tonnes of red mud are produced each year worldwide. This toxic by-product is stored in massive reservoirs several square kilometres in size.
Prof. Marcel Schlaf has found a way to combine red mud with oil from agricultural and forestry by-products to create higher-grade heating fuel.
“There are gigatonnes of red mud lying around and it’s a big problem because no one knows what to do with it,” said the chemistry professor. “We think we have found a way in which we can use this aluminum mining by-product to process by-products from agriculture and forestry to create fuel. The ultimate goal is that this process of making fuel would be carried out all over the world, including rural and developing areas as well as subtropical regions where there is often a lot of biomass available.”
Schlaf made his discovery while investigating ways to lower the high acid levels found in “bio oil.” Bio oil is produced by pyrolysis - subjecting biomass to high temperatures for short periods of time while excluding air.
“The goal has always been to use bio oil as a replacement for crude oil, but it’s difficult to find a way to lower the acid levels formed in the oil to be able to use it,” he said. “We needed to find a chemical process to transform the acid components into something non-acidic. This upgraded state would then make the oil compatible with existing technology.”
High acid makes the oil unstable, corrosive and impossible to store. It’s also difficult to use the metal-based catalysts typically used to upgrade other oil substances because acidity can corrode the catalysts, leaving toxic heavy metals in the oil, said Schlaf.
“I had to figure out which metals I could use as a catalyst that are non-toxic, cheap and can end up in the fuel but not be a big problem. The list of these metals is very short and it just so happens that red mud is composed of those metals.”
Red mud consists mainly of iron, titanium, silicon and aluminum oxides.
Once Schlaf realized red mud could be the solution to his problem, he obtained red mud from Rio Tinto ALCAN’s operations in Jonquière, Quebec and bio oil from Cedric Briens and Franco Berruti, professors at the Institute for Chemicals and Fuels from Alternative Resources at the University of Western Ontario.
Tests by Schlaf and post-doc Elham Karimi found that red mud contains the perfect combination of metals, which catalyze a chemical reaction in the oil to lower the acid level of the organic liquid and produce higher-grade oil. The same process changes red mud itself into a neutral magnetic material that is no longer caustic and toxic but could be used as a building material or iron ore.
In collaboration with Murray Thomson, an engineer at the University of Toronto, the researchers will evaluate upgraded bio oil as a fuel.
Along with Guelph physicists Stefan Kycia and Ariel Gomez, Schlaf published a paper about recent findings earlier this year in the journal Energy and Fuels and has spoken about the potential use of red mud at universities in Canada and the United States.
“These findings potentially provide an economical and ecological solution to taking bio-based material and transforming it into fuel, while at the same time turning a toxic mining waste into something less harmful or even useful.”
This research was funded by Agriculture and Agri-Food Canada through the Agricultural Biorefinery Innovation Network for Green Energy, Fuels and Chemicals.
For media questions, contact Communications and Public Affairs: Lori Bona Hunt, 519-824-4120, Ext. 53338, or lhunt@uoguelph.ca, or Deirdre Healey, Ext. 56982 or d.healey@exec.uoguelph.ca.
