Effects of redox condition on waste glass corrosion in the presence of magnetite

Static corrosion tests of a powdered simulated waste glass were performed in the presence of magnetite under oxic and anoxic conditions, respectively. The corrosion tests under oxic conditions were performed in air, and those under anoxic conditions were performed in a glove box purged with mixed gas(Ar+5%H2). The experimental results showed that the presence of magnetite can enhance glass corrosion under both oxic and anoxic conditions, and the enhancement under anoxic conditions was small compared to that under oxic conditions. A large portion of the Si and insoluble elements were sorbed onto the magnetite surface, and the sorption under anoxic conditions was small compared to that under oxic conditions. It was suggested that the enhancement of glass corrosion by magnetite results from the sorption or precipitation of silica on the magnetite surface, which can be greatly affected by redox condition. Under anoxic conditions, it was suggested that precipitation of amorphous silica on the magnetite surface may be the dominant process for enhancement of glass corrosion in addition to sorption.