Tuesday, July 21, 2009

Good silica, bad silica

All this green stuff can get a tad confusing. Over here we have researchers trying to replace silica used to make vehicle tires, and over here their counterparts are making rice into silica to use when making cement.

The Oregon State University “wood science” researchers have found cellulose in wood can replace silica as a reinforcing material in tires, decreasing the energy used to make the tire, reducing costs, increasing fuel efficiency and better resisting heat buildup.

The cellulose replaces silica, which is energy intensive to produce, or carbon black, increasingly expensive because it comes from oil.

The full story is here.

Then there’s the concrete. Heat rice hulls up to 1,475 degrees to drive off the carbon and it becomes a fairly pure type of silica, perfect to increase the strength and reduce corrosion of concrete made from cement with rice silica. Making a ton of cement with silica results in one ton of carbon dioxide emission, according to the Discovery Channel Web site.

There are several biproducts that are used to make cement, but the rice hulls make sense these days because India and China, big consumers of rice, are also big consumers of cement.

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