1. INTRODUCTION
Over the past thirty years there has been considerable effort in research, development and design for
processes to replace the blast furnace for the production of iron (Strassburger, 1969). The interest in
these processes lies in a number of technical and economic factors, among the most important of which
are the availabilities and costs of fuel, iron ore and scrap.
For the blast furnace, expensive coking coal is needed to produce the low ash strong metallurgical
coke which is needed. Today, metallurgical coke can be substituted for, using different fuels as tuyere
injections, so reducing the quantity of coke needed per tonne of iron. To a certain extent, this has
extended the lifetime of the reserves of suitable coals, but these savings are now decreasing rapidly.
Additionally, a considerable effort has been put into producing coal blends which can produce a
satisfactory metallurgical coke, but this is of no help to the large number of countries which have no
reserves of coking coal, but plentiful supplies of other fuels such as lignites, natural gas, non-coking coal
or oil. Electricity is also a possibility where cheap electricity is available, usually from hydroelectric power
stations.
Process conditions are also determined by a combination of the character of the available iron ore and
the suitability of local coals for coke production. For example, due to its extreme reducing conditions, the
blast furnace cannot economically handle certain types of iron ore such as as titanoferrous ore. In the
blast furnace, iron ores such as titanoferrous sands, which are rich in titanium, create problems because
carbides and nitrides form as solid particles in the slag. These cause a buildup in the hearth and reduce
hearth capacity. For this reason, titanoferrous sand is normally processed using a rotary kiln reactor and
a direct reduction iron process (Open University, 1979).
Similarly, iron ores which are high in vanadium are best handled by processes which optimize