Figure 139.
A novel hybrid process for sustainable iron making with hydrogen as a reductant. It consists in a combination of partial hydrogen-based direct reduction (in the solid state of the oxide) and a subsequent hydrogen-plasma-based smelting reduction (i.e., in the liquid state) of such a semireduced metal/metal oxide compound material.123 The reasoning behind such a sequential combination of two different reduction processes (solid state direct reduction and liquid state plasma reduction) is that hydrogen from sustainable production will not be available in sufficient quantities to meet the demands of the entire metallurgical market in the coming decades. For this reason, the highest possible stoichiometric efficiency must be ensured in all processes that use hydrogen as a reducing agent, and this can be achieved through this very combination. The figure is reproduced with permission from ref (123). Copyright 2022, Elsevier.