Extraction of Metals


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Extraction of Metals

  1. 1. Homework: Write an account of how iron is extracted from it’s ore haematite (iron oxide). Describe the process. Give word and symbol equations. Explain how the ‘reaction works’ in terms of oxidation and reduction. Due in Wednesday 15 th September
  2. 3. Lesson content: I can write equations for displacement reactions. (grade C) I can explain what the terms oxidation and reduction mean. (grade B) I understand which method of metal extraction is required to extract metals of different reactivities from their ores. (grade A)
  3. 4. Displacement Reactions (Modelling) 1. Iron + Copper Sulfate  Iron Sulfate + Copper 2. Copper + Silver Nitrate  Copper Nitrate + Silver 3. Sodium + Zinc Carbonate  Sodium Carbonate + Zinc 4. Potassium + Iron Oxide  5. Gold + Copper Carbonate  Gold + Copper Carbonate No reaction! Can you figure out why? Potassium Oxide + Iron
  4. 5. What are Ores? (Modelling) Most metals are too …………… to exist on their own in the ground. Instead they exist combined with other elements (typically o……….. or sulphur) as ……………….. called …………. A few metals are so ……………….. that they exist uncombined, as ……….metals e.g. gold, ……………….. Words: ores silver reactive oxygen compounds unreactive pure Metal Name of ore Compound in ore Aluminium Bauxite Aluminium oxide (Al 2 O 3 )
  5. 6. Watch this video clip: http://jchemed.chem.wisc.edu/JCESoft/CCA/samples/cca7thermite.html In practice I would demonstrate this reaction. <ul><li>It is called the thermite reaction. </li></ul><ul><li>The symbol equation is: Fe 2 O 3 + 2 Al  Al 2 O 3 + 2Fe </li></ul><ul><li>Which metal is oxidised? </li></ul><ul><li>Which metal is reduced? </li></ul><ul><li>Why does this reaction happen? </li></ul><ul><li>Do you think that it’s a commercially viable way of extracting iron from its ore? Explain your answer. </li></ul>How do we extract metals from ores? (Modelling)
  6. 7. Potassium Sodium Magnesium Aluminium Zinc Iron Copper Silver Gold Carbon (not a metal) So how is it done? The reactivity series of metals… Carbon can be used to extract some metals from their ores e.g. Copper oxide + Carbon  Copper + Carbon dioxide The copper oxide has lost oxygen. This is called a reduction reaction.
  7. 8. http://www.youtube.com/watch?v=6nEt6cW_GSw&feature=related Copper oxide + carbon ------  Demonstrate: Class Practical (Modelling)
  8. 9. Group/Pair Work: Carry out the class practical for copper oxide + carbon. Independent Learning: On the mini-whiteboards record answers to the following whilst carrying out the copper oxide+carbon practical. What did you observe happen? Complete a word equation for the reaction. Write a symbol equation for the reaction. Explain which element is reduced. Explain which element is oxidised.
  9. 10. Review and Reflection Ask a student to write up the correct symbol equation on the board: 2CuO + C ---------  2Cu + CO 2 Typical line of teacher questioning…. Which element is oxidised? Which element is reduced? What is meant by oxidation? What is meant by reduction? Why does the carbon displace the copper? Could you use this method to extract aluminium from Aluminium oxide? (HINT: look at reactivity series) Aluminium wasn’t discovered until 1886. Why? What does electrolysis mean? Metals like copper are getting more and more expensive. Why? How could we live more sustainably with metals? Which method electrolysis or reduction would you use to extract iron from iron oxide? (link to homework)
  10. 11. Potassium Sodium Aluminium Carbon Zinc Iron Copper Silver Gold Extracted from their ores by electrolysis (using electricity) Extracted from their ores by reduction by carbon No extraction necessary – found pure in the ground.
  11. 12. Progress <ul><li>I can write equations for displacement reactions (grade C) </li></ul><ul><li>I can explain what the terms oxidation and reduction mean. (grade B) </li></ul><ul><li>I understand which method of metal extraction is needed to extract metals of different reactivities from their ores (grade A) </li></ul>