What is Calumite?

Calumite – an essential raw material for the glass industry

Calumite is a glassy calcium-alumino-silicate, produced from granulated blast furnace slag. Its unique melting and refining properties enable glassmakers to reduce energy consumption and reduce CO2 and NOx emissions while improving glass quality.

Calumite is a granular material that is 99% glassy in nature. It has traditionally been viewed as an alumina source but it is a valuable source of all the major glass making oxides. The particle size distribution ensures it is compatible with other glass making raw materials.

Table 1 typical Calumite chemical composition

Oxide %
CaO 38 – 44
SiO2 36 – 40
Al2O3 6 – 14
MgO 7 – 10
S2 – 0.7 – 0.9
Fe2O3 0.15 – 0.3