The bauxite residue now covers 40 square kilometers south of the Danube River, and has caused the deaths of eight Hungarians and injured at least 150. The residue also has caused the extinction of life in a local river and as yet unknown environmental damage elsewhere.
While human deaths in the wake of the disaster may have been strictly a result of the containment failure, injuries have mostly been attributed to the chemical properties of the sludge, whose high pH (between 11 and 13) can quickly damage and kill living cells. Bauxite residue is between 10,000 and 1,000,000 times more basic than pure water, which has a pH around 7.
"We propose one way to reduce the pH of bauxite residue is to mix it with another kind of industrial waste -- oil-field brine, which is a by-product of oil and gas production -- and then carbon dioxide," said IU Bloomington geologist Chen Zhu, who submitted a U.S. Department of Energy patent application in 2007 describing the technique.
The water-based brine provides the medium for carbon dioxide to dissolve. Once dissolved, the carbon dioxide can chemically react with water to form carbonic acid. The carbonic acid counteracts some of the red mud's alkalinity, and what's left -- the negatively charged carbonate -- can serve as a partner for positively charged metal ions, such as iron, calcium and magnesium. Some of these salts spontaneously precipitate out of solution, which is a good thing, since the metals in these salts will longer will be free to interact with, say, living matter.
Bauxite residue, sometimes called "red sludge" or the more euphemistic "red mud," is the waste created by industries that produce aluminum. At present, the residues simply accrue in containment ponds. Worldwide, there are in excess of 200 million tons in these ponds.
"Companies don't voluntarily spend money to neutralize waste unless someone tells them to do it, sadly," Zhu said. "Our technique could be quite expensive. When you have a disaster like the one we're seeing in Hungary, though, I think perhaps companies and governments may think twice about what 'too expensive' means."
The combination of bauxite residue and oil-field brine is a novel approach to waste disposal, but this isn't an instance where the combination of two negatives equals a positive. It's more of a less-negative, Zhu says.
"By reducing the pH and causing the precipitation of problematic salts, what we're left with is not something that's non-toxic, but less toxic than what we started with," he says. "Every year millions of tons of bauxite residues are being generated by industry around the world. Disposal ponds are where most of it goes. There is a great need for research on how to improve disposal."
Zhu is working with the American aluminum producer Alcoa and the Department of Energy to perfect the technology.
To speak with Zhu, please contact David Bricker, University Communications, at 812-856-9035 or email@example.com.
David Bricker | EurekAlert!
Multi-institutional collaboration uncovers how molecular machines assemble
02.12.2016 | Salk Institute
Fertilized egg cells trigger and monitor loss of sperm’s epigenetic memory
02.12.2016 | IMBA - Institut für Molekulare Biotechnologie der Österreichischen Akademie der Wissenschaften GmbH
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water
In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...
The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.
Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
02.12.2016 | Medical Engineering
02.12.2016 | Agricultural and Forestry Science
02.12.2016 | Physics and Astronomy