The purpose of a blast furnace is to chemically reduce and physically convert iron oxides into liquid iron called "hot metal". The blast furnace is a huge, steel stack lined with refractory brick, where iron ore, coke and limestone are dumped into the top, and preheated air is blown into the bottom. The raw materials require 6 to 8 hours to descend to the bottom of the furnace where they become the final product of liquid slag and liquid iron. These liquid products are drained from the furnace at regular intervals. The hot air that was blown into the bottom of the furnace ascends to the top in 6 to 8 seconds after going through numerous chemical reactions. Once a blast furnace is started it will continuously run for four to ten years with only short stops to perform planned maintenance.

CONCLUSION

The blast furnace is the first step in producing steel from iron oxides. The first blast furnaces appeared in the 14th Century and produced one ton per day. Blast furnace equipment is in continuous evolution and modern, giant furnaces produce 13, 000 tons per day. Even though equipment is improved and higher production rates can be achieved, the processes inside the blast furnace remain the same. Blast furnaces will survive into the 2000 millennium because the larger, efficient furnaces can produce hot metal at costs competitive with other iron making technologies.