Calumite is produced from blast furnace slag that has been rapidly quenched to form a homogenous, glassy material. During the Calumite production process, this material is dried, crushed and screened to produce a granular material, of a size consistent with other glass making raw materials.

We understand that quality and chemical consistency are key for glassmakers. The slag is delivered to our site directly from the blast furnaces. We receive daily chemical analysis from the iron makers to allow us to pre-select suitable material and test all stock piles prior to use. This allows us to blend material if necessary to maintain chemical consistency of the Calumite product. All material is tested for chemical and physical compliance in fully equipped laboratories prior to despatch.