Foaming during reduction of iron oxide in molten slag

Coal based direct liquid ironmaking processes, also known as smelting reduc tion (SR) processes, are now receiving serious consideration in the industr y. However, although several processes have reached pilot plant trials, onl y one, namely Corex, has been commercialised. In all SR processes, most of the iron oxide is reduced in the molten slag phase and foaming is an import ant phenomenon. Better understanding of the foaming behaviour will result i n design of a more efficient and economic reactor. Accordingly, some basic studies on the foaming behaviour of some typical SR process slags have been undertaken in this work. Experimental data on foaming in a 50 kW capacity plasma reactor are discussed in this paper. The data generated are analysed in terms of foaming index, which is equal to the residence time or travell ing time of the gas in the foam layer. The influence of FeO percentage in t he slag, slag basicity, crucible surface area, initial slag height, and CaF 2 addition in the slag on foaming has been studied.