04-06-2012, 01:13 PM
Mini Blast Furnace (MBF)
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INTRODUCTION
Iron Ore is smelted in the Blast Furnace in order to remove unwanted impurities such as rocks, clay and sand, and also to seperate the Iron from the Oxygen. Theresult is Iron which is about 95% pure. The remaining impurities are other elements whichcan be removed later if necessary. A Blast Furnace is about 100ft. high and produces about1000 tons of molten Iron a day. It is made from steel. On the diagram below of the BlastFurnace ,just click on the labels for a more detailed description. If you scroll past the diagram you can read about the Blast Furnace process.
The Mini Blast Furnace (MBF) is a very flexible and competitive equipment, suitable for both basic and foundry grade hot metal production, in the range of 80.000 to 300.000 tpy.
Its flexibility allows the burdening from 100% lump ore to any blend of lump ore and agglomerates (sinter or pellets) in the burden composition.
HISTORY
The early iron-making process
The raw materials for iron-making, iron ore, limestone and coke, were usually found close to the foundry. Iron ore deposits in the Welsh mountains, which were visible and collectable above ground, were known as patches.
Smelting the iron ore required a large amount of heat, and a furnace was needed to contain the materials and withstand the high temperature. The first furnaces were made of stone and lined with fire bricks. The raw molten iron gathered in the bottom of the furnace and was tapped off into receptacles called pigs. The expression pig iron is still used in modern steel-making.
The principles of iron and steel manufacture have changed very little, except that very much bigger modern blast furnaces incorporate much more automatic control in order to increase the furnace output and efficiency.
During the 1950s and the early 1960s, UK blast furnaces compared favorably with those in other countries. Hearth diameters in this period varied between 8 and 9.5 meters, with capacities of 1,800 to 2,000 tones per day and working volumes of around 1,500 m .
PRINICIPLE OF BLAST FURNACE
Blast furnace
The blast furnace area provides the raw material for steel-making. Iron produced in the blast furnace contains a high proportion of carbon, typically 4%, and lacks any of the additives needed to give the steel its various special properties.
Blast furnace is essentially an apparatus for hearting the ore in the presence of an excess of carbon, principally in the form of carbon monoxide, which is the reducing agent. That is, it combines with oxygen present in the ore and thus reduces the ore to iron:
Conveyor System
The Conveyor System takes the Charge from the area where it is maxed together to the top of the Blast Furnace. The Charge is carried in Skip Cars which run on a rail track. All the required raw materials for the Mini Blast Furnace are discharged in a receiving ground hopper, from where are conveyed by belt conveyors to the day bins for storage and posterior handling in the burden preparation. The burden preparation is made per batching; the system comprises screens and vibrating chutes as well as weighing bins. The burden preparation system can be dimensioned to operate with charcoal or coke. The use of sinter in the MBF burden improves considerable the operational conditions reducing the consumption of reducer (charcoal or coke) and increasing the productivity.After the raw materials weighing, the same ones are carried to the MBF top though belt conveyors. The entire weighting process and loading of raw materials on MBF top is made automatically by the supervisory system through the furnace control cabin. The system that involves the handling and storage of raw materials is equipped with devices to capture dust collected in bag filters – this is the first part of the secondary dedusting.