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blast furnace

used for melting metals

perumalsamy
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blast furnace

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  1. What is a BlastFurnace? • The purpose of a blast furnace is to reduce and convert iron oxides into liquid iron called "hotmetal". • The blast furnace is a huge, steel stack lined with refractorybrick. • Iron ore, coke and limestone are put into the top, and preheated air is blown into the bottom.

  2. WhydoesIronhavetobeextractedina BlastFurnace??? • Iron can be extracted by the blast furnace because it can be displaced bycarbon. • This is more efficient method than electrolysis because it is more costeffective

  3. Step 1 - the formation ofsinter

  4. Step 2 - the BlastFurnace The outer case is a water cooled steel casing that provides the main supportfor the 30 m high furnace.

  5. Step 2a - the BlastFurnace The sinter is added through a hopperat the top of the Blast Furnace. The design of the hopper stops gases escaping through the top as sinter isadded.

  6. Step 2b - the BlastFurnace The inner lining is made of insulating bricks, designed to reduce heat loss through the outer walls of thefurnace.

  7. Step 2c - the BlastFurnace A A The furnace is run continuously for upto 2years. Air is blasted in atthe bottom at pointA.

  8. Step 2d - the BlastFurnace When running continuously, iron is run out through atap hole, drilled into the furnace at the bottom, B. A B A

  9. Step 2e - the BlastFurnace Slag is less dense than iron andfloats on thesurface. Slag is run out through a secondtap hole labeledC. A B A C

  10. Step 2f - the BlastFurnace D D Wasted gasespass out through the topof the furnace, at point D. The hot gases are used to pre-heat the incoming gases atA. A B A C

  11. Step 2g - the BlastFurnace D D Iron that forms inthe furnace melts at the temperature of1700 °C. The iron dripsdown to thebottom. A B A C

  12. TheMethod Three substances are needed to enable to extraction of iron from its ore. The combined mixture is called the charge: Iron ore, haematite - often contains sand with iron oxide,Fe2O3. Limestone (calciumcarbonate). Coke - mainlycarbon The charge is placed a giant chimney called a blast furnace. The blast furnace is around 30 metres high and lined with fireproof bricks. Hot air is blasted through thebottom.

  13. Severalreactionstakeplacebeforetheironis finallyproduced... • Oxygen in the air reacts with coke togive carbondioxide: • C(s) + O 2(g) CO2(g) • The limestone breaks down to formcarbon dioxide: • CaCO3(s) CO2 (g) +CaO(s) • Carbon dioxide produced in 1 + 2 react with more coke to produce carbonmonoxide: • CO2(g) + C(s) 2CO(g)

  14. The carbon monoxide reduces the iron inthe ore to give molteniron: • 3CO(g) + Fe2O3(s) 2Fe(l) +3CO2(g) • The limestone from 2, reacts with the sandto form slag (calciumsilicate): • CaO(s) + SiO(s) CaSiO3(l)

  15. Both the slag and iron are drained from the bottom of thefurnace. • The slag is mainly used to buildroads. • The iron whilst molten is poured into moulds and left to solidify - this is called cast iron and is used to make railings and storagetanks. • The rest of the iron is used to makesteel.

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