Characteristics of silicate glasses derived from vitrification of manganese crust tailings

Potential marine manganese crust mining operations will produce millions of tons of tailings requiring waste volume reduction and segregation from their surroundings. To address this situation, the tailings have been vitrified at 1160 °C for 30 min employing various additions of silica sand with borax flux. Resulting silicate glasses displayed microhardness (image) of 5.36 GPa, indentation fracture toughness (Kc) of 0.71 GPa, elastic modulus (E) of 98, thermal expansion coefficient (TEC) of 2.75 × 10−6 and excellent resistance to leaching. Study results indicate that vitrification technology is effective for stabilizing, volume reduction and recycling of tailings wastes, while also producing potentially marketable commercial glasses.