Extraction of metals Flashcards
What do you use to extract reactive metals?
Electrolysis E.g Aluminium
What do you use to extract unreactive metals?
Reduction E.g Iron
What is phtyomining?
The use of plants to absorb metal compounds from soil as part of metal extraction.
What are the four steps of phtyomining?
- Plants are grown on ground that contains low-grade ores, so the metal is removed from the ore and enters the pant.
- The plants are harvested, dried out and then burned to produce an ash, which is rich in metal compounds.
- An acids such as H2SO4 is added to the ash and insoluble metal compounds react to produce a solution containing soluble copper compounds. This is called a leachate.
- The metal can be obtained by adding scrap iron iron to the leachate causing a displacement reaction to occur.
Advantages of phytoming?
- No dust, light or noise pollution
- No transport of rock
- No traffic
- Produces energy at the same time
Disadvantages of phtyomining?
- Supply is seasonal
- Long time to grow plants
Example word equation of the displacement reaction in phytomining with copper?
Fe(s) + Cu(aq) 2+ ——> Fe (aq) 2+ + Cu(s)
What is the main ore of iron known as?
and what is its chemical name and symbol?
Haematite
Iron (III) Oxide - Fe2O3
What is added at the top of the blast furnace when extracting iron?
Coke, Iron Ore and Limestone
What layers is the molten iron and slag tapped off at in the blast furnace?
Top Layer - Molten Slag
Bottom Layer - Molten Iron
What are the three stages of extracting iron ore in the Blast Furnace?
- Formation of the reducing agent
- Reduction of the iron oxide to iron
- Removal of the acidic impurities
Explain this stage of extracting iron ore in the Blast Furnace:
1. Formation of the reducing agent
The coke burns to give CO2, Then the further reaction with coke produces carbon monoxide which is the reducing agent.
Explain this stage of extracting iron ore in the Blast Furnace:
2. Reduction of the iron oxide to iron
The carbon monoxide reduces the iron oxide to iron. The iron formed is molten and sinks to the bottom where it is run off.
Explain this stage of extracting iron ore in the Blast Furnace:
3. Removal of the acidic impurities
At high temps the limestone undergoes thermal decomposition an d becomes calcium oxide and carbon dioxide.
The calcium reacts with the main impurity in the iron oxide silicon dioxide giving calcium silicate (Slag) and leaving pure iron.
Explain some uses of iron?
- Bridges and structures due to its strength
- The pig iron produced is soft and is mixed with carbon it produce the alloy steel, to increase its strength.
What can slag be used for?
Roads / Buildings
Diagram of the Blast furnace with labels
Look in Book
