Direct reduction and smelting reduction – an overview

Abstract

A survey is given on the current state of direct reduction and smelting reduction processes. Several developments, such as coal injection, top‐gas recycling etc., contribute to decrease the coke consumption in the blast furnace. Coal‐based as well as gas‐based direct reduction processes have not succeeded in Western Europe. These processes have only attracted economical interest in locations where there is a cheap source of energy. Other developments to reduce iron ore are concerned with the direct production of liquid iron in a smelting reduction process with a substantial part of the reduction taking place in the liquid oxide phase. The ideal concept of a smelting reduction process with direct use of fine ore and coal as well as only liquid state reduction to a liquid product similar to steel has not yet been realized.

Developments in iron and steel making

“…On a world-wide basis, 91% of all operating direct reduction plants in 1988 were natural-gas-based (with 87% using the Midrex and HyL processes, mostly based on vertical shaft furnace reactors, as discussed later). The remaining 9% are one-step coal-based processes (with 7% using the SL/RN process and rotary kiln furnaces) (Steffen, 1989).…”

“…The Midrex process is still the dominant commercial process as its share is increasing dramatically, from 38.5% in 1979 to 48% in 1986 to 54% in 1988, to 60% in 1990 and to 67% in 1993. Over the same period, coal-based plant has fallen from 11.1% in 1979 to 9% in 1988, and the SL/RN process has fallen from 7% in 1988 to 3% in 1993 (Chatterjee, 1994;Scott, 1994;Steffen et al, 1988;Steffen, 1989;Steinmetz, 1986).…”

Direct smelting and alternative processes for the production of iron and steel

“…The important role played by the propeties of the raw materials in the direct smelting process is obvious and it is important to examine how this is affected by factors such as factory siting, the type of process and the raw materials used (Steffen, 1989). The iron and steel industries normally pay a price that includes transport (the CIF price) (Hoddinott, 1992(Hoddinott, , 1993(Hoddinott, , 1994.…”