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CHAPTER 5: METALS AND ALLOY INDUSTRY - Coggle Diagram
CHAPTER 5: METALS AND ALLOY INDUSTRY
INTRODUCTION
The substances (element or compounds) that make up rocks are called minerals.
Minerals
Metallic
Metals
Non-metallic (industrial)
Building materials
Fertilisers
Fuels
Chemical industy
Extraction of Minerals
Underground mining
Placer mining
Suface (open pit) mining
In-Situ mining
Factors to decide the method of extraction of mineral
Location of the deposit
Strength of the rock
Ore grade
Mining Costs
Shape of the deposit
Current market price of the commodity
Classification of industrial minerals
Widely available
Abundant
Rare
EXTRACTION OF LEAST REACTIVE MATERIAL
Metals are located at the bottom of the reactivity series
Found as free metals in the minerals
Usually collected and crushed to free metals (physical method)
Eg: gold, silver
EXTRACTION OF LESS REACTIVE METALS
Metals in the middle of the series less
Less strongly bonded in their compounds
Their oxides can be reduced by carbon to give the metal (carbon reduction)
Eg: zinc, iron, tin, lead, copper, mercury
eg: zinc extraction
Zinc metal is extracted from zinc oxide by removing oxygen atom
By reduction method by "roasting" metal oxide with coke
Metal is left and carbon dioxide is produced
2ZnO (s) + C (s) > 2Zn (s) + CO2 (l)
eg: zinc sulfide
Be heated in the air to produce metal oxide
Oxide will be heated with carbon through carbon reduction
2ZnS (s) + 3O2 (g) > 2ZnO (s) + 2SO2 (g)
2ZnO (s) + C (s) > 2Zn (s) + CO2 (g)
eg: Titanium extraction
TiO2 (s) + 2Cl2 (g) + 2C (s) > TiCl4 (s) + 2CO (g)
Ti is being replaced by a more reactive metal, eg: Mg or Na
TiCl4 (s) + 4Na > Ti (s) + 4NaCl (l)
Conditions
temp: 550 degree celcius
argon atmosphere
batch process
eg: Extraction of iron
Common ore
haemetite, Fe2O3
magnatite, Fe3O4
The Blast Furnace
C (s) + O2 (g) > CO2 (g)
C (s) + CO2 (g) > 2CO (g)
Fe2O3 (s) + 3CO > 2Fe (s) + 3CO2 (g)
Fe2O3 (s) + 3C (s) > 2Fe (s) + 3CO (g)
The function of limestone
To convert iron ore into slag
Extraction of Copper
2CuFeS2 (s) + 2SO2 (g) +4O2 (g) > Cu2S (s) + 2FeSiO3 (s) + 3SO2 (g)
Cu2S (s) + O2 (g) > 2Cu (s) + SO2 (g)
Electronic refining
from copper(I) sulfide
produces sulfur dioxide
be used in the Contact Process
to make sulfuric acid, H2SO4
alternative: by displacement reaction with scrap iron
Extraction of tungsten
from an ore, wolframite: (FeWO4) + (MnWO4)
convert to tungsten oxide, WO3
WO3 (s) + 3H2 (g) > W (s) + 3H2O (l)
tungsten(vI) oxide is heated, 550;850 degree celcius
in a stream of hydrogen
EXTRACTION OF VERY REACTIVE METALS
Difficult to extract
eg: Al and metals above it in electrochemical series (Mg, Ca, Na, K)
Most are extracted by decomposing their compounds with electricity via electrolysis process
Bayer Process
Reaction with NaOH solution
Precipitation of aluminium hydroxide
Formation of pure aluminium oxide
Conversion of Al2O3 into aluminium by electrolysis
Alloys
Metallic compounds made up of one metal and one or more non-metal elements
eg: Steel, iron + carbon
eg: Brass, copper + zinc
eg: Bronze, copper + tin
Properties
good electrical conductivity
high strength
hardness
heat
corrosion resistance
Alloys (Iron)
cast iron
wrought iron
mild steel
high carbon steel
Special Steel
Titanium steel
Manganese steel
Stainless steel
Alloys (Copper)
Boilers and heat exchangers
Making brass
Domestic plumbing
Coinage
Electrical wiring
Alloys (Aluminium)
alloyed with other elements such as
copper
magnesium
silicon