A method of heating molten aluminum flowing in a heated trough member comprising
the steps of providing a source of molten aluminum and providing a rough member
comprised of a first side and a second side, the first and the second sides having
outside surfaces, the sides formed from a ceramic material resistant to attack
by molten aluminum. The first side and second side have heating element receptacles
provided therein with protection tubes provided in the receptacles. The protection
tubes are comprised of a refractory selected from the group consisting of mullite,
boron nitride, silicon nitride, silicon carbide, graphite, silicon aluminum oxynitride
or a metal selected from Kovar and titanium. Electric heating elements are
positioned in the tubes. Molten aluminum is flowed along the trough member from
the source and electric power is passed to the heating elements to heat the molten
aluminum as it flows along the trough member.