Synthetic magnesite sinters, low in iron and boron, are used as raw materials for magnesite brick production. Their categorization is based on the CaO/SiO₂ ratio. Their excellent resistance against numerous basic slags and alkali oxides is typical for these products. Magnesite bricks are used in the regenerator chambers of glass melters and in furnaces in the non-ferrous metal industry. The MgO content of these bricks lies well above 90 %.