Production of SG Grade Pig Iron in Mini Blast Furnace

Abstract

The entire life of a Blast furnace operator is spent to achieve the following aims: • To increase the productivity of Blast Furnace as high as possible. • To decrease the coke rate as low as possible to produce unit ton of hot metal. • To produce the hot metal of superior SG quality with particular reference to Sulphur & Silicon. • To keep the production cost as low as possible. The process indices of Mini Blast Furnace are similar to that of a conventional blast furnace. But, conventional blast furnace is capital intensive, solely dependent on good quality metallurgical coke, the gestation period is longer, and requires elaborate burden preparation. There is huge gap between demand and supply of steel in India. Also, India is dreaming to become developed nation by 2020. In such situations, the role of Mini Blast Furnace becomes very important. The slag chemistry is an important parameter to improve the process indices of MBF. The slag chemistry includes its chemical composition, liquidus temperature, fluidity, Sulphide capacity etc, which has an important bearing on the smooth & efficient operation of the MBF. The main important constituent of SG grade pig iron, particularly, Sulphur & silicon content should be 0.040% maximum and 1.20% to 2.20% maximum respectively. The chemical compositions of SG Grade Pig Iron is C- 3.80-4.20%, Mn – 0.35- 0.80%, Si – 1.20- 2.20%, S - 0.040% maximum and P – 0.15% maximum. The role of slag to produce such a low sulphur & low silicon in Mini Blast Furnace is very important. Therefore, to control Sulphur and silicon in SG Grade Pig Iron in Mini Blast Furnace, the optimisation of Slag Chemistry is an essential step.