Rice Concrete Cuts Greenhouse Emissions

A new way of processing rice husks for use in concrete could lead to a boom in green construction.

Rice husks form small cases around edible kernels of rice and are rich in silicon dioxide (SiO2), an essential ingredient in concrete. Scientists have recognized the potential value of rice husks as a building material for decades, but past attempts to burn it produced an ash too contaminated with carbon to be useful as a cement substitute.
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Now, Rajan Vempati of ChK Group, Inc. in Plano, Texas, and a team of researchers have figured out a way to make nearly carbon-free rice husk ash. Heating husks to 800 degrees centigrade (1,472 degrees Fahrenheit) in an oxygen-free furnace drives off carbon, leaving fine particles of nearly pure silica behind.

“The process emits some CO2, but it’s carbon neutral. Any that we emit goes back annually into the rice paddies,” Vempati said.

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