High alumina ceramic for temperatures up to 1700 deg C and cast zirconia for temperatures from 1800 to 2000 deg C are optimal corrosion resistant materials.
In addition, the use of a “spill trap” rather than a flat hearth plate to catch spills from broken crucibles or “boil-overs” is highly recommended.
Some glasses, such as those containing significant amounts of sodium, fluorine, or chlorine, will also attack molydisilicide heating elements. In these cases an element protection liner should be used to separate the elements from the furnace hot zone.
Glass Fining. If you will be fining the glass with a stirring apparatus or gases bubbled into the melt, the furnace you select should have a top opening to permit the use of a stirring apparatus or gas supply tube. The opening must be designed to resist heat and any corrosive fumes escaping from the furnace chimney. You may also want the manufacturer to supply the stirring mechanism or make modifications for your equipment.
High Temperature Pouring. If you will be pouring the glass at temperature, then the furnace you select should be designed for optimal ease of loading and removing the melts and for maximum operator safety.
Experience. Choose a supplier whose glass melt furnaces have been performance proven in the field. Ask your colleagues for recommendations and ask manufacturers for references. Don’t settle for an all-purpose off-the-shelf fiber lined furnace which will require frequent relining. Get a furnace designed to withstand glass attack that is also custom designed and sized to fit your particular application requirements. Visit our website for examples of custom and standard bench top and production models. Call us to discuss how our 45 years of experience in customer driven glass furnace design can serve your application requirements.