Mechanisms of the heat transfer by means of iron and slag drops in sme
lting reduction are discussed. The quantity of slag on the molten iron
exists in two forms depending on the different processes: either a th
in slag layer or a voluminous slag layer. In the case of a small amoun
t of slag, iron and slag drops are spattered in the free space above t
he bath furnace. By smelting reduction with a high post-combustion deg
ree, the spattered iron drops are quickly oxidized in the free space.
The spattered slag drops transfer heat from the free space to the molt
en iron. A definition for the heat transfer efficiency in the iron bat
h of a two-stage smelting reduction process is presented. Experiments
on heat transfer were made in an experimental EOF-furnace with 1 00 kg
iron. The post-combustion degree and the heat transfer efficiency wer
e on a high level, because inleaked air was used.