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Chromsteine

Chromium Oxide Bricks

Highly purified escolait materials (Cr₂O₃ > 92 %) give a very high service lifetime and guarantee low glass fault rates in glass melters. Notably outstanding properties of chromium oxide materials to be mentioned are firstly their low solubility of the content in silica melting processes, the high hardness and the high melting point of chromium oxide. Chromium oxide also displays a complete mixability with Al₂O₃ (chromium corundum formation) and does not react in chemical bonding with silicate glasses.

The possibility of isostatic shaping achieves utmost compression with an ideal texture (homogenity, size of pores and pore distribution). Isostatically pressed « dense » chromium oxide bricks with a chromium oxide content >92 % are used for E-glass melters  (endless fibre of textile glass) with glass contact. This brick type with an open porosity of
Isostatically pressed  „porous“ chromium oxide bricks (>92 % Cr₂O₃) with an improved thermal shock resistance have an open porosity of about 18 % and have a very good corrosion resistance as opposed to boric oxide glass melters and alkali oxide-alkaline earth oxide silicate glass melters. This quality is used for glass contact applications such as the manufacture of endless glass fibres (E-glass), and is used in areas exposed to high wear like doghouses, walls and throats of hollow glass melters (white glass and color glass), and as cover tile  in the glass level area of flat glass melters.

The uniaxially shaped chromium oxide brick (>92 % Cr₂O₃ ) is used for glass contact areas as shaped brick, as thin walled tile formats in the bottom area, or as cover tile in E-glass melters.