Refractory Material

Refractory materials in cupola furnaces

Specific requirements:

• Good processing characteristics for relining and repair work
• suitable for drying and heating processes in the shortest time mwith hot gases,
• thermal fatigue resistance especially with pre-blowing and melting down due to pronounced flame formation up to the ring chamber,
• chemical resistance especially to carbon monoxide; at the start of the melting process, carbon monoxide and carbon dioxide are produced continuously according to the Boudouard balance, having intensive contact with the refractory material and being chemically reactive.
• Sufficient mechanical load capacity due to the input material while moving through the various furnace zones,
• chemical resistance to the slag that forms, especially with high slag quantities,
• good breakout behaviour for relief of personnel,
• no use of masses containing pitch or chrome.

Cold blast cupola furnace

Structure of the refractory material in the shaft with
two lining layers:

Base lining:
Sprayed concrete high in alumina with low cement content.

Wear lining:
Mix of quartz and clay (classic clay sands)

Life of the wear lining: Usually only one day.

Example for the consumption of refractory material:
For the shaft of a cold blast cupola furnace with a daily melting output of 80 to 120 t of liquid iron, approx. 2.5 t spraying mix is needed for daily repairs; i.e. approx. 20–30 kg of refractory material per ton of liquid metal.

Labour per day: approx. 16 person hours

Material and labour costs for the refractory lining:
15–25 EUR/t liquid metal.

For comparison:
Consumption of refractory material with hot blast cupola furnace (cast lining):
0.4–1.2 kg of refractory material per ton of liquid metal.

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