Transforming rotting garbage into glass
How much do you know about glass, other than that it’s a pain to clean up when it breaks? Glass is made from a combination of sand, flint, or other silica, thrown together with some fixed alkalies, and in some cases a metallic oxide. Glass is a marvelous substance. It’s the only material that can be recycled indefinitely without losing quality (unlike plastic).
Unfortunately, to make the massive amount of glass used (and not recycled) by our society, we’ve taken to mining the earth for the silica and other minerals needed. Engineers at Colorado School of Mines recently discovered there’s a way to harvestglass-making minerals without destroying the environment, however. They’re mining mountains of garbage instead.
“The process uses organic waste (such as eggshells, rice and wheat husks, peanut shells and banana peels) that is rich in the primary minerals that make up the most common oxides used in the manufacture of windows, containers and specialty glass,” according to a School of Mines press release.
First, the waste is ground up in blenders and then allowed to dry. The garbage is “then pounded into fine white powder containing pure minerals, such as silica and oxides, that typically are mined using heavy diggers and toxic,” reports the Denver Post. After that, the harvested minerals are heated to 3,000 degrees, which melts the silica powder into a molten red substance that can be poured into molds, where it hardens into glass.
Not only could this creative process save glass manufacturers lots of money, thus encouraging the use of recyclable glass packaging over plastic, but it’s also an environmentally-conscious way to recast our vast food waste as a valuable resource.
“Organic waste can potentially provide at least some of the metal oxides required to produce glass and glass-ceramics products. Thus, glass manufacturing processes provide a uniquely suited potential route to recycle and reuse these organic wastes, producing useful glass products and reducing the influx of waste into landfills,” said Mines researcher Ivan Cornejo in a statement.
The U.S. government has already registered a provisional patent for the “garbage glass” on behalf of the researchers.