Technologies for improvement in Sintering Process Aug06

Technologies for improvement in Sintering Process...

Technologies for improvement in Sintering Process Sintering of iron ore is a metallurgical process carried out on a sintering machine. It is basically a pre-treatment process step during iron making to produce charge material called sinter for the blast furnace. It is an agglomeration process achieved through combustion. In this process air is sucked at the sinter strand through a bed of raw mixture (also called sinter mix) of iron ore fines, limestone, dolomite, sand and quartzite fines (flux), solid fuel (coke breeze or anthracite) and metallurgical wastes (collected dusts, sludge and mill scale etc). The fuel particles on the top surface layer are first ignited in a furnace and as the strand move forward, the ignited or combustion front proceeds gradually downwards through the bed until the end is reached. . In last few decades several technologies have been developed which have not only resulted into vast improvements in the process of sintering but also have improved the quality of sinter. Majors of these technologies are given below. Use of burnt lime as a replacement of limestone Burnt lime (CaO) is an active binder since it gets hydrated {Ca(OH)2} as a result of hydrate reaction with water’ As a binder it promotes the quasi particle property in the sinter mix. It helps in increasing the micro fines input through iron ore fines. Due to better granulation of sinter mix it improves sinter productivity. In addition to the binding property, burnt lime also reduces the coke breeze rate due to reduced calcination of limestone during the sintering process. The use of burnt lime also reduces the crushing and screening load of harder raw limestone and hence saves in energy. Intensive mixing and granulation system The raw materials for sintering which contain iron ore fines,...