HEAT-INSULATING MIXTURE Russian patent published in 1995 - IPC

FIELD: ferrous metallurgy. SUBSTANCE: heat- insulating mixture for pouring liquid iron contains, by weight of: graphitizing furnace burden return with carbon and silicon carbide in the ratio of (2:1)-(3:1) 60.0-75.0; carbon-bearing material bloating in the process of heating (oxidized graphitizing furnace burden return) 2.0-12.0; inorganic refractory material selected in the silicate group containing blast-furnace slag, diatomite the balance. The mixture is fed to iron ladle bottom by spilling till liquid iron discharge is initiated. In the process of iron discharge, graphite carbon expansion suddenly occurs under the action of thermal shock. As a result the mixture volume is increased and density is reduced. Heat-insulating layer produced by the method prevents heat loss through metal surface and facilitates maintaining of it in liquid state for 2-4 hours. EFFECT: increased heat- insulating properties of mixture by reduced coefficient of heat passage at working temperatures and easy availability of mixture based on electrode production wastes (graphitizing furnace burden returns). 2 tbl