Transcript No Slide Title

Metals
Metallurgy
• the extraction of metals from ores
by reduction (less reactive metals)
by electrolysis of melt (reactive metals)
• the preparation of metals for use
• the study of the relationship between
structures and properties of metals
Metal extraction
• Pre-treatment of Ore
• Concentration
• Roasting
Pre-treatment of ore
• crude ore is crushed
Concentration
• floatation
Roasting
• converting sulphide ore to oxide
2ZnS(s) + 3O2(g) -----> 2ZnO(s) + 2SO2(g)
2CuS(s) + 3O2(g) -----> 2CuO(s) + 2SO2(g)
3FeS2(s) + 8O2(g) -----> Fe3O4(s) + 6SO2(g)
Manufacture of Iron and Steel
• Chemistry of blast furnace
• Chemistry of basic oxygen furnace
Chemistry of blast furnace
iron reduction
raw materials
Several Blast Furnaces
Liquid Iron Pour
Iron(l) & Slag(l) Pours
Chemistry of blast furnace
raw materials:
iron ore – several kinds
limestone – calcium carbonate
coke – heated coal
air – to provide the blast
Chemistry of blast furnace – raw
materials
iron ore => source of iron
Could be any of the following:
Fe2O3, Fe3O4, FeO,
Ore names: haematite, magnetite, ferrite
Sand impurity - SiO2
Chemistry of blast furnace – raw
materials
Limestone (calcium carbonate) is used to remove
impurities – it reacts with the sand which is
usually found mixed with the iron ore. In the heat
of the furnace it decomposes to calcium oxide
(lime) and this then reacts with the silicon dioxide
to produce calcium silicate (slag)
CaCO3  CaO + CO2
CaO + SiO2  CaSiO3
Chemistry of blast furnace
coke => reducing agent
C
Chemistry of blast furnace
C(s) + O2(g) -----> CO2(g)
coke air
Chemistry of blast furnace
CO2 + C ---> 2 CO
coke
Chemistry of blast furnace
3 Fe2O3(s) + CO(g) -----> 2Fe3O4(s) + CO2(g)
iron ore
Chemistry of blast furnace
Fe3O4(s) + CO(g) -----> 3FeO(s) + CO2(g)
iron ore
Chemistry of blast furnace
FeO(s) + CO(g) -----> Fe(l) + CO2(g)
iron ore
pig iron
Chemistry of blast furnace
CaCO3(s) + heat -----> CaO(s) + CO2(g)
limestone
lime
Chemistry of blast furnace
CaO(s) + SiO2(s) -----> CaSiO3(l)
lime
sand
slag
Purification of Metals
• Electrolysis
• Chemical Reactions
Production of Copper
Cu2S(l) + O2(g) -----> 2 Cu(l) + SO2(g)
Cu(s)
impure
----->
Cu(s)
electrolysis pure
Chemistry of Basic Oxygen Furnace
iron purification
steel making
raw materials
Chemistry of Basic Oxygen Furnace
raw materials
pig iron from blast furnace
fluxing agent to remove impurities
alloying agents
Chemistry of Basic Oxygen Furnace
Removal of excess of carbon
C(s) + O2(g) -----> CO2(g)
impurity air
in pig iron
Magnetism
• 2 main types
– diamagnetism => all electrons are paired
– paramagnetism => one or more unpaired
electron, parallel spins on electrons