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Extraction Of Metals
Principal of extraction of metals:Most metals do not exist in free state in earth crost, but they exist in a combine state in form of
ores
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By washing away earth material in stream of water
2
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g in the case of zinc ore): Here the ore is chained up with oil and water to
form froth
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3
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g copper ore) are passed through magnetic field / seperator
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If the ore is not an oxide, it can be concentrated by converting it to an oxide which is easier to
deal with in extraction
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in the principles of extraction, the method of extraction of any metal depends on the stability of
the ore which depends on the position of the metal in the electrochemical series 1 K & Na exist
mostly as chlorides and the method of extracting them is the electrolysis of the fused hydroxide
and chloride
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Ca, Mg, and Al exist mostly as chlorides and trioxocarbonateVI and the method of extraction
is the electrolysis of the fused chloride
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Al exist as oxide and is extracted through the electrolysis of the oxdies
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Zn and Fe exist as oxides, trioxocarbonate IV and sulphides
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5
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6
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From the above, the four (4) main methods of extracting metals are:1
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2
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3
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4
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g
Of these four the cheapest method is reduction of oxides while the costliest is electrolysis
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The compound are first converted to the oxides
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Extraction By Electroysis:in this process, the cathode supplies the electrons the metallic ion to convert them to their
corresponding atoms
2
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g using carbon
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g for the extraction of sodium from Nacl, at the cathode
the Na+ is reduced to sodium atom Na+ = Na
Reduction of sulphide
This is done by oxidizing the sulphide to the oxide of the element and then to reduction of the
oxide by the sulphide e
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2CuS + 3O = 2CuO + 2SO Second step
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Metals And Their Compounds
1
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They include lithium sodium potassium but K & Na have the most resemblance in reactivity as
follow
* Both are univalents & powerful reducing agents and good conductor of electricity
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g Na + H2O = Na + OH + ½H2
* Both from strongly basic oxide with Oxygen 2Na + O = NaO (K2O slar) forming soluble
hydroxides NaOH, KOH which are strong alkali
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The trioxonitrate V of both metals when heated, librate O2 and have Dioxonitrate VI of the
metal
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it is roasted in
air to remove the sulphur, arsenic and antimony impurities as volatile oxides
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Sn+2C=Sn+2CO
The tin at this stage is still in pure for further purification heat gently on a scoping surface
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This process gives us 99
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Uses Of Tin
1
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2
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3
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4
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