Classification of the Iron-making Processes for Excavated Slag by the Evaluation of Chemical Composition

Abstract

The results of chemical compositions for excavated slag were drawn as figures of the relation between T.Fe and TiO₂, and the relation between T.Fe and SC (slag component defined as SC=SiO₂+Al₂O₃+CaO+MgO). The excavated slag can be classified to 6 regions of ironmaking process and forging process as follows; 1. Smelting slag of iron-sand process, 2. Refining slag of iron-sand process, 3. Forging slag, 4. Slag adhered to refractory clay, 5. Smelting slag of iron-ore process, and 6. Semi-reduced iron-sand.
The extrapolated and specified points of analyzed data as described in Fig. 2 were referred to the phase diagram for FeO-SiO₂-TiO₂ system. Resultant classification of excavated slag for the iron-making processes assisted by phase diagram was obtained as shown in Table 4.
Accordingly, it may be concluded that at most high content of TiO₂ or at lower content of TiO₂ in the raw material of iron-sand, the smelting process of generated liquid-slag would be happened under nearly same conditions as smelting temperature (about 1250°C) and slag component (about SC=30% constant).