Extracting Metals How do we extract metals from their ores? An ore is a compound of the metal (usually the oxides, sulphides, chlorides or carbonates) mixed with large amounts o of earth and rock. Earth and rock are removed before metal is extracted from the o ore. The metal is then extracted by heating with carbon or using e electricity.
W When do we use heating or electricity? The position of a metal in the reactivity series determines the method used for its extraction.
Gold is found naturally uncombined as a metal.
Extracting Iron from Haematite The main ore of iron is haematite. . Haematite contains iron(III) oxide mixed with impurities such as sand and clay. Iron is extracted from haematite in a blast furnace.
Chemical Reactions that Take Place i in a Blast Furnace 1. Carbon dioxide is produced. C Carbon in coke burns in hot air to produce carbon dioxide. C + O2------> CO2 Limestone decomposed by heat to form carbon dioxide and calcium oxide. CaCO3 -------> CaO + CO2
2. Carbon monoxide is produced. As carbon dioxide rises up in the blast furnace, it reacts with more coke to form carbon monoxide. C + CO2 ------> 2CO Chemical Reactions that Take Place in a Blast Furnace CaSiO3 is called calcium silicate or slag. It floats on top of molten iron. It is tapped off separately from the iron.
3 3. Haematite is reduced to iron. Carbon monoxide reduces iron(III) oxide in haematite to i iron. Fe2O3 + 3CO-----> 2Fe + 3CO2 A good reducing agent Molten iron is formed and it runs to the bottom of the blast furnace. Waste gases e.g. nitrogen, carbon dioxide escape from the top of the blast furnace.
4. 4 Impurities are removed. C CaO + SiO2 ------>CaSiO3
Summarised 1. The method used to extract metal from its ore depends on the positioj of the reactivity series. Metal higher up in the series can be extracted using electricity metals