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Corrosion

Corrosion. Today’s Lesson. What is corrosion and how can it be prevented. Corrosion Questions Start Write Up for Design Task Finish Ore Questions. Corrosion. When a metal is attacked by air, water, or other substances in its surroundings, the metal is said to corrode.

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Corrosion

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  1. Corrosion

  2. Today’s Lesson • What is corrosion and how can it be prevented. • Corrosion Questions • Start Write Up for Design Task • Finish Ore Questions

  3. Corrosion • When a metal is attacked by air, water, or other substances in its surroundings, the metal is said to corrode. • Some examples include: • Iron rusting in air forming Iron Oxide • Sodium metal reaction with water to form Sodium Hydroxide • Lead rusting in air forming Lead Oxide

  4. Prevention Corrosion • Below are some ways to minimize corrosion: • Painting – Painting prevents air and water coming into direct contact with the metal. • Grease – Tools and machine parts can be coated with grease or oil to stop them coming into contact with water or air. • Plastic – Steel and other metals can be covered with plastic (powder coated) and stops weathering of the metal.

  5. Preventing Corrosion • Galvanizing – Iron can be covered with Zinc which is less reactive than Iron. Zinc is more expensive than Iron – but a thin covering of it can protect the Iron from air and water. • Tin Plating – Steel cans are covered with Tin to stop the can from rusting from air or water. • Chromium Plating – Chromium is often used as a coating for car parts to make sure the iron is protected from the elements. It’s also very shiny so it is astatically pleasing

  6. Preventing Corrosion • Sacrificial Protection – Zinc and Magnesium are more reactive than Iron. As such, they will oxidize before Iron. As such, Iron will not corrode until there is no Zinc or Magnesium left in elemental form. • Examples of where this occurs is Zinc bolts on large ships. The Zinc bolts will oxidize but the ship will not corrode unless all of the Zinc has all oxidized.

  7. Doe’s Aluminium Corrode • Unlike Iron Oxide, Aluminium Oxide is quite strong and acts as a protective layer for the metal. • As such, the Aluminium Oxide is needed to protect the rest of the aluminium in elemental form. It also stops air and water getting into the Aluminium.

  8. Questions • Read page 88/89 and answer Q 1-6. • We will also start our next design task which is on corrosion. • The write-up needs to be finished by next lesson so I can get the equipment ready ASAP. • Your Ore Questions are also due next week.

  9. Removing Metals from Ores • First Choose an Ore from Below: • Bauxite Al2O3 • Chalcopyrite CuFeS2 • Chromite Fe or MgCr2O4 • Galena PbS • Hematite Fe2O3 • Magnetite Fe3O4 • SphaleriteZnS • UraniniteUO2

  10. Answer Following Questions • Using the internet for research – answer the following questions. Not all answers can be found easily: • What is the metal extracted from your ore • How is your metal extracted or removed from your ore? Explain. • What conditions are needed for the rock to form so there is enough of the metal in the ore? • Name some of the major mines that this ore can be found. • How much of the metal is needed for the ore to be economic? • What are some of the environmental impacts or issues associated with extracting the metal from your ore? • What are the major uses for your metal? • How does the mine dispose of the slurry or left over ore?

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