Extraction of Metals Flashcards
Ore of zinc?
Zinc Blende (ZnS)
Ore of aluminium
Bauxite (Al2O3)
Ore of iron
Hematite (Fe2O3
Raw materials of a blast furnace:
- haematite
- coke
- limestone (CaCO3)
Why is coke used in a blast furnace?
To produce CO to reduce the iron ore
Describe the process in a blast furnace
- Coke burns in the hot air to produce CO2
- CO2 is reduced to CO
- CO reduces haematite to iron
- Limestone undergoes thermal decomposition, producing CaO and CO2
- CaO combined with SiO2 (sand) to form CaSiO3 (calcium silicate)
Describe the extraction process of zinc
- Zinc blende is heated strongly in the presence of oxygen to convert zinc sulphide to zinc oxide
- Zinc oxide is reduced with carbon
Common forms of metal found naturally?
Metal carbonates/sulphides/oxides
What does the anode typically produce?
Nonmetals, or oxygen
What does the cathode typically produce?
Metals, or hydrogen
What happens during electrolysis?
- A direct current passes through the electrolyte
2. Electrical energy is changed to chemical energy
[cathode] ease of discharge chart
Fluorine Sulphate Nitrate Chlorine Bromine Iodine Hydroxide
Common inert electrodes:
- carbon
- platinum
Common active electrodes:
Copper, silver
How are results different with concentrated electrolytes?
Concentrated ions tend to crowd out other ions, and so obtain preference for discharge.
Anions that will never be discharged in electrolysis
Fluorine, sulphate, nitrate, carbonate
Cations that will never be discharged in electrolysis
Potassium, sodium, calcium, magnesium, aluminium
Why use electroplating:
- improves appearance of a metal
- prevents corrosion of metal
What is an electrochemical cell?
A device that converts chemical energy to electrical energy. It consists of electrodes (2 different metals) and an electrolyte solution.
How is the anode/cathode determined when electrodes are made of 2 different metals?
The more reactive metal becomes the anode by losing electrons.
Define electrolysis:
Breaking down substances using electricity
