Reduction of Costs of Iron Production by Changing Parameters of the Mixed Blast-furnace Wind

The blast-furnace process consists of a large number of processes that are physicochemical, thermal and mechanical interconnected processes. In addition to main processes consisting of iron oxides reduction, pig iron and slag melt creation, also realised are fuel combustion, gas flow, charge and melt flow, dissociation and other reactions in the solid and liquid phases. Inputs to the blast-furnace process are blast-furnace charge and combined wind. Blast-furnace charge consists of ore charge, coke and slag former. The functions of coke are putting heat and substances reduction to the blast-furnace, pig iron carbonisation, and creation of solid skeleton of the blast-furnace for the gas flow. The combined blown wind is the oxygen source for coke combustion and at the same time hydrogen source as reduction gas that is created by dissociation of steam. Outputs from the blast-furnace process are pig iron, slag and blast-furnace gas. Overall the blast-furnace process can be characterised as a non-stationary process with distributed parameters. Its basic characteristics are as follows 16 : – The blast-furnace is counter current reactor. – The blown wind and off take blast-furnace gas is continuous. – The input of charge, pig iron and slag tapping is almost continuous. – The reduction of iron from charge is nearly ideal, negligible loss of iron is to the slag. – Heat exchange in the blast-furnace is basically finished. It is related to high level of heat utilization. – Relatively low level of utilization of carbon chemical energy from coke comes not from process incompleteness, but from its essence.