Presentation on theme: "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. 1000°C."— Presentation transcript:
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. 1000°C 1500°C 2000°C Blasts of hot air Molten slag (impurities) Outlet for molten iron Outlet for the slag Load if iron ore, coke and limestone Gas outlet Molten iron The blast furnace 2. Blasts of hot air (which give the furnace its name) are blown in near the bottom of the furnace. 3. Oxygen in the blasts of air reacts with coke (carbon) to form carbon monoxide. 2C + O 2 2CO This reaction is very exothermic and the temperature in the furnace reached 2000°C. 4. As the carbon monoxide rises up the furnace, it reacts with the iron ore (iron(III) oxide to form iron. Fe 2 O 3 + 3CO 2Fe + 3CO 2 5. 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.
Steel – properties and uses brittle Iron from the blast furnace is very brittle because it contains up to 4.5% carbon. Mild steel contains approximately 0.5% 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. Hard steel contains up to 1.5% carbon. Car bodiesTinplate It is possible to treat steel. Heat treatment Creating alloys with other metals Stainless steel (chromium and nickel) Very hard steel (tungsten) Tough steel (manganese) machinesDomestic appliances Additional Science Chapter 8
Recycling steel Steel is recycled on a large scale. Saves up to 50% of energy costs Helps to conserve iron ore Cuts down the emission of greenhouse gases Additional Science Chapter 8
Fluctuations in the cost of metals can affect the economy. The consequences of metal extraction When the ore runs out, the mine workings may be abandoned causing a deterioration of the landscape. Important for the economy (Economic boom in the UK during Industrial Revolution). Extraction and processing of minerals creates employment. Importing metals is very expensive for the country. Processing 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). Sometimes less useful and toxic metals are found with the ones that are needed. Advantages Disadvantages Additional Science Chapter 8