AN INVESTIGATION OF BEHAVIOUR OF CERIUM IN MOLTEN IRON AND ITS REACTION ON REFRACTORIES BY MEANS OF TRACER

The behaviour of rare earth elements, taking cerium as representative, in moltencommercial pure iron and their reactions on refractories have been inveshgated bymeans of autoradiography and radioassay. Results show that under steelmaking tem-peratures the evaporation of cerium from molten iron or cerium oxide from slag isvery slight, and cerium in molten iron reacts in different degrees on crucibles made offireclay, high-alumina, magnesia, alumina-magnesia, silica, as well as alundum, electro-fused-magnesia and zirconia. These erosive reactions are affected not only by the chem-ical constituents but also by the physical properties of refractories. It was observed byautoradiography that the erosive reaction products may spall away then to form rareearth inclusions in iron consequently. A considerable part of these reaction productsand the rare earth inclusions do not float to the surface of liquid metal, and may adhereto the crucible wall. The blockage on laddle nozzle and runner during teeming has beenalso discussed.