Engineering Materials : Pig Iron
DefinitionManufacturing
Composition
Definition
➨ It is a Crude iron or impure iron and It is used as a row material for manufacturing of All ferrous material like Steel, Wrought iron, Cast Iron
➨ It is Known as " Grand Father Of All Ferrous Matals"
➨ It Contains high Amount of Carbon
Manufacturing Of Pig Iron By Blast Furnace
Fig
Construction
➨ Pig Iron Is manufacture by Blast Furnace
➨ Blast Furnace Consist 800 to 1200 Tones Capacity in single stroke charging
➨ Blast Furnace is Mixing Of Two fulcrum From Upper and Bottom bot are joint back to back , Because we need larger diameter at centre [30 feet]
➨ It having tall steel Structure And Refractory lining , Refractory lining can bear very high temperature
➨ At the Top Of Blast Furnace , There is Bell And Cone Arrangement for Feeding Charging Pattern, such arrangement where the charge which can not be returned and charge is mixing of iron core, coke and Flux.
➨ There is Chimney Provided For Removing Hot Gases from Blast Furnace.
➨ Blast Furnace Is Divided into 4 Zones
- Throat
- Stack
- Bosh
- Hearth
➨ There is one Ring provided for stiffening of two fulcrum
➨ There is Number of Tuyers are Provided or supplying Hot Air to furnace
➨ Higher Tap Is For Removing Slag and Lower tap is For Removing Pig Iron From Blast Furnace
➨ Furnace Is Line Of Refractory Fire Brick which 25 to 35 mm Thick
Manufacturing Steps
1. Concentration Of Ores
- Collection of iron ores
- Uniform Size
- Washing Of Ore
2. Clacination / Roasting of Ores
- Removing Hot Gases
3. Smelting
- Melting Process Iron Ore to Iron
Iron Ores
1. Red Hematite [Fe3O4]
2. Magnetite [Fe2O3]
3. Limonite [Fe2O3-H2O]
4. Iron Pyrites [FeS2]
5. Siderite [FeCO3]
Composition Of Pig Iron
| Element | % |
| Carbon(C) | 2 to 5 |
| Silicon(Si) | 3 |
| Phosphorus(P) | 0.1 |
| Sulpher(S) | 0.3 |
| Manganese(Mn) | 1 |
| Remaining | Pig Iron |
Charging Pattern
Pig Iron = Flux(1/6) + Fuel(1/3) + Iron Ore(1/2)
Fuel
Hard Coke is Commonly used as Fuel in Blast Furnace which has to deliver following two function
1. Provide Required amount of heat for melting of charge
2. Combine with iron ore and oxygen and Reduce the same
Characteristics Of Fuel [Hard Coke]
1. It should be sufficient hard enough to withstand load of charge.
2. It should posses high calorific value
3. It should have low ash contain
4. It should posses high densigy and good porosity
5. It should be free from sulpher and Phosporous and Should be Uniform in size
Flux
➨ Flux is added to the charge so that it may melt and drive the impurities it in the form of slag
➨ Mostly limestone is used as a flux sometime dolomite is also used as a flux
➨ 500-750 lg of limestoneis to be added in the charge for Producing each tone of pig iron