Handling of Hot Metal in Blast Furnace Iron Making Feb10

Handling of Hot Metal in Blast Furnace Iron Making...

Handling of Hot Metal in Blast Furnace Iron Making  Hot metal (HM) is produced by the reduction of descending ore burden by the ascending reducing gases in a blast furnace (BF). It is liquid in nature and gets collected in the hearth of the BF. From the hearth, the HM is tapped from the taphole of the BF after an interval of time. Normally in large BFs, HM tapping rates of 7 ton/min and liquid tapping velocities of 5 m/sec, in tap holes of 70 mm diameter and 3.5 m long, are typically encountered. The tapping rate of HM is strongly influenced by the taphole condition and taphole length. Generally the temperature of tapped HM varies in the range of 1420 deg C to 1480 deg C. The tapped HM is handled in the following three stages. Handling of the HM in the cast house i.e. from taphole to the hot metal ladles HM ladles and their transport Processing of HM either in the pig casting machine (PCM) for the production of pig iron (PI) or in the steel melting shop for making steel. Historical development of hot metal handling During the seventeenth century, the produced liquid iron (usually around 450 kg per cast) from the iron making furnace was drawn into a single trench or ladled into sand moulds to produce domestic products such as pots, pans, stove plates etc.  As the BF production increased due to many design improvements, removal of liquid products (iron and slag) became an issue. Production of charcoal BF had increased over the period from one ton to 25 tons per day. This higher tonnage could not be handled with two casts per day through a single trench in front of the tap hole. The cast house contained...