Reduce / Reuse / Recycle

June 19, 2003

 

Colored Glass Now Recyclable

Keywords: Reduce / Reuse / Recycle University / Research institute 

The Kansai Center of Japan's National Institute of Advanced Industrial Science and Technology (AIST) has developed a method to recycle colored glass, which mostly winds up in landfills because of difficulties involved in its recycling.

It has been difficult to recycle colored glass because small amounts of metal ions are added as coloring agents. The AIST Kanasai research, involving treatment with boric acid, proved successful in removing coloring metals and alkalis from discarded colored glass to get transparent silica (silicon dioxide, SiO2), which can be reworked into colorless glass after firing.

In addition, silica gained in this research process can be used to create transparent and stable oxide fluoroglass, which is highly valuable and recyclable. Expectations are high that the possibilities for recycling colored glass into a high-value material will contribute to the solution of recycling issues that are usually set aside because of high costs.

Stable oxide fluoroglass is very resistant to heat and chemicals. Possible applications include use under water, or in traffic signs that would utilize its transparency to natural light during the daytime, and its florescent quality to alert drivers to danger at night. It can be easily recycled back into the same fluoroglass material.

One of the challenges for practical application is developing a closed-loop recovery and recycling system for the boric acid in the wastewater from the acid treatment process. AIST Kansai is optimistic about solving this problem.



Posted: 2003/06/19 08:25:29 AM
Japanese version

 

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