Development of the Molten Slag Reduction Process -1 Characteristics of Closed Type DC arc Furnace for Molten Slag Reduction

Abstract

To develop a slag reduction process (IBX process: Iron Bath for X), three kinds of slag reduction tests were carried out using different pilot scale and commercial scale DC arc furnaces. The goals are to recover the valuable elements such as Fe or P from the steelmaking slag and to modify the slag composition. The main target is to use molten slag directly in the reduction process and to establish a stable operation for improving the energy consumption, productivity, and processing cost. In the present paper, we describe the results obtained in a pilot scale closed-type 2 MW DC arc furnace (Test 1), commercial scale open-type 30-MW DC arc furnace (Test 2), and newly designed closed-type 4-MW DC arc furnace (Test 3). Reduction efficiency and the metallurgical properties in DC arc furnaces, the mechanism of slag foaming, and the influence of the atmosphere in the furnace were discussed based on the experimental results. Finally, model calculations of the flow patterns in the furnace were carried out for further comprehension of the metallurgical phenomena. From these results, it was confirmed that the closed-type DC arc furnace can achieve efficient and stable reduction of steelmaking slag with hot charging.