Smelting reduction of prereduced iron ore

Abstract

Investigations have been made to study the reduction kinetics of iron oxide in molten slag by dissolved carbon in liquid iron melt, and the behaviour of phosphorus transport at the slag/metal interface during smelting of prereduced iron ore (PRI). The experimental work included laboratory and large scale smelting of the PRI, While the laboratory studies were carried out in a Tamman furnace using a carbon saturated iron bath, the latter were carried out in a 500 kVA submerged are furnace. The data generated under controlled conditions have been subjected to kinetic analysis. A study of simultaneous effects of the major process variables during smelting reduction of the PRI on the phosphorus distribution between slag and metal is presented, The variables studied were: reduction period, temperature of the molten slag, and the major constituents (%FeO, %CaO, and %SiO2) in the molten slag. A series of statistically planned isothermal experiments has been carried out to quantitatively assess the effects of these variables on the phosphorus transport across the slag/metal interface. The paper describes the phosphorus distribution as a function of the governing process parameters obtained from two level factorial experiments and mathematical statistical models. The predicted distribution ratio, expressed as (P)/[P], is successfully compared with the controlled experimental results for the smelting of PRI. Within the range of the variables studied, the (P)/[P] distribution ratio has been correlated with the process variables and their interactions, and the model predictions are compared with the laboratory and large scale experimental data. Attempts have also been made to compare and correlate the smelting reduction phenomena of the PRI on a laboratory scale with the large scale conditions. (C) 1997 The Institute of Materials.