Extraction of Iron Flashcards
Define a ‘rock’
A mixture of minerals having no fixed chemical composition
Define a ‘mineral’
A solid element or compound which is found naturally in the Earth’s crust
Define an ‘ore’
A mineral which contains a high percentage of a metal and can be extracted profitably
Name the 3 most important ores
Oxides
Sulphides
Carbonates
List 5 properties of metals
Density Electrical Conductivity Thermal Conductivity Strength Malleability
List the 5 steps of metallurgy
- Mining to extract ore from the ground
- Ore concentration to remove impurities
- Reduction to crude metal
- Refining to obtain the pure metal
- Mixing with other metals to form an alloy
What is concentrating/enriching? Name 3 processes.
The removal of impurities from the ore is called concentration or enrichment of the ore.
- Hydraulic washing
- Froth floating
- Magnesium separation
Name and define the two processes for converting ores into oxides.
- Roasting: Heating of sulphide ore in the presence of air to form oxide and sulphur dioxide.
- Calcination: Heating of carbonate ore in the absence of air to form oxide and carbon dioxide.
Name four things which the method of extracting a metal depends on.
- Purity required
- Energy requirements
- Cost of the reducing agent
- Position of the metal in the reactivity series
When is carbon used for extraction? Explain
- To extract a metal lower down in the reactivity series
- Metal is displaced from its non-metal anion by the more reactive carbon
- Carbon is used as it is readily available (coke and charcoal also carbon)
When is electrolysis used for extraction? Breifly explain electrolysis.
Used for metals above carbon in the reactivity series.
Passing electricity through a molten ore will split up the compound and so extract the metal. Electrical energy decomposes the compounds and reduces the ore.
e.g. Aluminium oxide —-> Aluminium + Oxygen
List the 6 steps in the production of Iron.
- Ore is graded and crushed
- Iron ore is compacted
- Conveyors take iron, limestone and coke to top of furnace
- Inside the furnace, the whole mixture is heated to “white hot” temperature
- Smelted iron is tapped off
- Limestone + impurities —-> slag
List and define the 4 raw materials used in the extraction of Iron. (3 of which are added through the top of a blast furnace)
- Haematite (Fe2O3) - a source of iron
- Coke - the fuel/reducing agent (cheap and plentiful)
- Limestone - conversion of silica into slag (calcium silicate)
- Air - source of oxygen for combustion
List the three types of furnace used in the production of iron and steel.
- The Blast Furnace
- The Basic Oxygen Furnace
- The Electric Arc Furnace
What is the reducing agent in a blast furnace?
Carbon Monoxide
