Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Can Hungary's red sludge be made less toxic with carbon?

14.10.2010
The red, metal-laden sludge that escaped a containment pond in Hungary last week could be made less toxic with the help of carbon sequestration, says an Indiana University Bloomington geologist who has a patent pending on the technique.

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 brickerd@indiana.edu.

David Bricker | EurekAlert!
Further information:
http://www.indiana.edu

More articles from Life Sciences:

nachricht Two Group A Streptococcus genes linked to 'flesh-eating' bacterial infections
25.09.2017 | University of Maryland

nachricht Rainbow colors reveal cell history: Uncovering β-cell heterogeneity
22.09.2017 | DFG-Forschungszentrum für Regenerative Therapien TU Dresden

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: LaserTAB: More efficient and precise contacts thanks to human-robot collaboration

At the productronica trade fair in Munich this November, the Fraunhofer Institute for Laser Technology ILT will be presenting Laser-Based Tape-Automated Bonding, LaserTAB for short. The experts from Aachen will be demonstrating how new battery cells and power electronics can be micro-welded more efficiently and precisely than ever before thanks to new optics and robot support.

Fraunhofer ILT from Aachen relies on a clever combination of robotics and a laser scanner with new optics as well as process monitoring, which it has developed...

Im Focus: The pyrenoid is a carbon-fixing liquid droplet

Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.

A warming planet

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Fraunhofer ISE Pushes World Record for Multicrystalline Silicon Solar Cells to 22.3 Percent

25.09.2017 | Power and Electrical Engineering

Usher syndrome: Gene therapy restores hearing and balance

25.09.2017 | Health and Medicine

An international team of physicists a coherent amplification effect in laser excited dielectrics

25.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>