No.5（2002）5.Development of Miyake-Glass

Kazuhiro OOKUBO, Shigeru SUZUKI, Minoru TANAKA, Hidemi KOYAMA and Fumiko KUGAI

Miyakejima Island was covered with a large quantity of volcanic ash, due to the volcanic eruption of Mt. Oyama in 2000. We used Miyakejima Island's volcanic ashes as raw material of glass, and succeeded in developing a high- quality product that possesses melting quality and viscosity that can be achieved in a normal manufacturing process, as well as thermal shock resistance and chemical resistance. We named this product Miyake-Glass. Miyake-Glass contains iron. When iron is in the form of bivalent iron ion (Fe²⁺) in glass, it assumes a blue color. In the case of producing Miyake-Glass no refining agent is necessary, because calcium sulfate (CaSO₄) in the volcanic ashes of Miyakejima Island works as a refining agent. The thermal expansion coefficient of Miyake-Glass is 100x10^-7/℃, the quantity of alkali leaching test (JIS R 3502) is 1.36mg and effect of heat-absorbing is high. Due to the effect of volcanic ashes which also work as a refining agent, clear, blue and beautiful Miyake-Glass can be produced.

Keywords
Miyake-Glass, Miyakejima, Glass, Volcanic ash, Iron, Calcium sulfate, Refining agent

Back to Contents