Presentation on theme: "Extracting iron from its ore Chemical reduction with carbon"— Presentation transcript:
1 Extracting iron from its ore Chemical reduction with carbon 1. Raw materials (iron ore, coke and limestone) are added at the top of the furnace.2. Blasts of hot air (which give the furnace its name) are blown in near the bottom of the furnace.Load if iron ore, coke and limestone3. Oxygen in the blasts of air reacts with coke (carbon) to form carbon monoxide.2C + O2 2COThis reaction is very exothermic and the temperature in the furnace reached 2000°C.Gas outletThe blast furnace1000°C4. As the carbon monoxide rises up the furnace, it reacts with the iron ore (iron(III) oxide to form iron.Fe2O3 + 3CO 2Fe + 3CO21500°C5. Molten iron runs to the bottom of the furnace. It is tapped off from time to time.6. The molten iron is used to make steel or poured into moulds to solidify. The large chunks of iron formed are called ‘pigs’ so this metal is called ‘pig iron’.2000°CBlasts of hot airBlasts of hot airMolten slag(impurities)Outlet for the slagMolten ironOutlet for molten iron
2 Steel – properties and uses Iron from the blast furnace is very brittle because it contains up to 4.5% carbon.Most of this iron is converted to steel, which is far more useful, by removing most of the carbon. Mild steel contains approximately 0.5% carbon.Car bodiesTinplateHard steel contains up to 1.5% carbon.machinesDomestic appliancesAdditional ScienceIt is possible to treat steel .Chapter 8Heat treatmentCreating alloys with other metalsStainless steel (chromium and nickel)Very hard steel (tungsten)Tough steel (manganese)
3 Recycling steel Steel is recycled on a large scale. Additional Science Saves up to 50% of energy costsHelps to conserve iron oreCuts down the emission of greenhouse gasesAdditional ScienceChapter 8
4 The consequences of metal extraction DisadvantagesAdvantagesWhen the ore runs out, the mine workings may be abandoned causing a deterioration of the landscape.Extraction and processing of minerals creates employment.Importing metals is very expensive for the country.Sometimes less useful and toxic metals are found with the ones that are needed.Important for the economy (Economic boom in the UK during Industrial Revolution).Additional ScienceFluctuations in the cost of metals can affect the economy.Chapter 8Processing minerals have a detrimental effect on the environment.A lot of electricity is needed to produce aluminium.Many minerals are sulphides – produce sulphur dioxide (the gas that causes acid rain).
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