On Vaporization of Some Slag Components: Studies of hanging of a blast furnace-IV

In the reports “Studies of hanging of a blast furnace- I, II”, we presented the results of investigation on the hanging in the shaft of blast furnace. In this report, we studied the hanging in the lower part of the blast furnace where the temperature was high. In the test of the experimental blast furnace, a hanging occurred frequently when the temperature of combustion zone rose above 1750°C In order to explore this phenomenon, we carried out experiments on the vaporization of components of some blast furnace slag. The results obtained are as follows: (1) Vaporized materials were mainly composed of MgO, followed by SiO2 and MnO, CaO and Al2O3 being negligible. (2) The quantity of each of the vaporizing components was related to its content in the slag. (3) Vaporization of MgO, SiO2 was intensified with a rise of slag temperature. (4) Oxidized components of slag were reduced. The reduction was accompanied with boiling action, producing a carbide. (5) Vaporized materials seem to include lower oxides and reduced metals, in addition to the vaporizing oxidized components of slag.