In the Induction Furnace melting it is normally difficult to get the Slag deoxidized and get” White Slag” as in the Electric Arc Furnaces. The formation of ‘White Slag’ ensure in a way that the steel is in a better state of deoxidation and the slag is having very low Iron Oxide (FeO) content which also denotes that steel quality should be better.
With the use of Sponge Iron, the condition of slag worsen further as the slag contain a much higher percentage of Iron Oxide (FeO). Moreover, carbon reduction of the steel promotes the formation of iron oxide so the iron oxide content of slag is much higher than where Sponge Iron had not been used.
These Aluminium Dross is in powder form and dissipates on the slag very fast. It is having very potent deoxidizers for the steel and reacts quickly with the Iron oxide in the slag and deoxidizes the available slag first and then steel.
For the Electric Arc furnace of specification Aluminium (7-9%) and alumina (70-75%) is used for fluidizing the slag. For the same basicity, the higher the alumina more fluid is the slag. So even slag with a basicity of 4.5 – 5.0 can be made fluid by controlling alumina. It is suggested to add before the start of the LF process, preferably at a temperature beyond 1590 degrees centigrade.
