Clay Culture: Greener Silica

1 Rendered image of the current method to produce silica: combining silicon metal (left) and carbon (right) and treating them in an electric arc furnace at 3000°F.

Even after thousands of years of working with ceramic materials there are still new methods being developed that improve how those materials are processed.

Silica is a hot commodity—hundreds of thousands of tons of silica are produced every year, and it’s used in everything from paint and electronics to toothpaste and tires (not to mention clay and glazes).

But how silica is produced isn’t the most energy efficient or cost effective.

Earlier this year, American Ceramic Society (ACerS) member Richard Laine, a professor of materials science and engineering at the University of Michigan, published research that pioneers a new approach to silica mass production—one that uses much less energy and can be generated from otherwise wasted agricultural materials. “I’ll be honest, the answer has been staring us in the face for 15 years and we missed it. I’m really excited that it finally occurred to us and not somebody else,” Laine said in a recent video produced by University of Michigan’s engineering department.

2 The new method uses antifreeze with ethanol to distill the silica down to 99.99999% purity.

3 Jars full of agricultural waste (rice ash), silica depleted rice ash, and pure silica. 1–3 Photos: Still images from Greener Silica From Rice, produced by Michigan Engineering (University of Michigan).

The current method to mass produce silica is built on the process of silicon metal, Laine explains in the video, which is done by taking mined silicon metal and carbon (anthracite coal) and treating them in an electric arc furnace at 3000°F—a very expensive process that also produces a lot of CO2. The technique is not cost-efficient, and not green.

The new technique developed by Laine and his team involves dissolving silica in antifreeze with a bit of recyclable base and then replacing the antifreeze with ethanol to distill the silica down to 99.99999% purity.

And with this method, silica can be purified from agricultural waste—like silica-rich rice ash—which would otherwise just be dumped in landfills, says Laine.

Laine and his team believe the new process could eliminate millions of tons of CO2 emissions every year, and it’s 90% less expensive than the current method.

This article originally appeared in Ceramic Tech Today, http://ceramics.org/ctt, which is maintained by our colleagues here at the American Ceramic Society.

 


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Credit: Michigan Engineering; YouTube. For more information, visit http://www.mse.engin.umich.edu/about/videos/laine-group-greener-silica-from-rice

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