extraction of metals chemistry
TRANSCRIPT
![Page 1: Extraction of metals chemistry](https://reader031.vdocuments.net/reader031/viewer/2022012403/5580ec1fd8b42aec5a8b4fd9/html5/thumbnails/1.jpg)
Extraction of metals
![Page 2: Extraction of metals chemistry](https://reader031.vdocuments.net/reader031/viewer/2022012403/5580ec1fd8b42aec5a8b4fd9/html5/thumbnails/2.jpg)
Topics
• Introduction.• Reactivity series.• Enrichment of ores.• Extracting metals low,
middle,& top of series.• Refining of metals.
![Page 3: Extraction of metals chemistry](https://reader031.vdocuments.net/reader031/viewer/2022012403/5580ec1fd8b42aec5a8b4fd9/html5/thumbnails/3.jpg)
Introduction• Some Metals Are Found In Earth Crust In Free State
And Some In Form Of Their Compounds.• The Metals At Bottom Of Activity Series Are Least
Reactive & Are Found In Free State. Eg: Gold,silver,copper Ect.
• The Metals At Top Of Activity Series As( K, Na, Ca, Mg, Al) Are Very Reactive.
• The Metals At Middle Of Activity Series As (Zn ,Fe ,Pb , Cu) Are Moderately Reactive And Found In Crust Mainly As Oxides, Sulphides, Or Carbonates.
![Page 4: Extraction of metals chemistry](https://reader031.vdocuments.net/reader031/viewer/2022012403/5580ec1fd8b42aec5a8b4fd9/html5/thumbnails/4.jpg)
Reactivity Series
• This Is Reactivity Series Where K, Na, Ca, Mg &Al Are Electrolysis.
• Zn, Fe, Pb, Cu Are Reduction Using Carbon.
• Ag, Au Are Found In Native State.
KNaCaMgAlZnFePbCuAgAu
![Page 5: Extraction of metals chemistry](https://reader031.vdocuments.net/reader031/viewer/2022012403/5580ec1fd8b42aec5a8b4fd9/html5/thumbnails/5.jpg)
Enrichment of ores
• Ores Mined From The Earth Are Usually Contaminated With Large Amounts Of Impurities Such As Soil, Sand Etc.Is Called Gangue.
• The Processes Used For Removing The Gangue From Ore Is Based On Differences B/W The Physical Or Chemical Properties Of The Gangue & The Ore.
![Page 6: Extraction of metals chemistry](https://reader031.vdocuments.net/reader031/viewer/2022012403/5580ec1fd8b42aec5a8b4fd9/html5/thumbnails/6.jpg)
Extracting metals low in series• Metals Low In Series Are Very Unreactive.• Oxides Of These Metals Can Be Reduced To
Metals By Heating Alone.Eg:when Cinnabar Is Heated In Air , First It Is Converted Into Mercuric Oxide. Then It Is Reduced To Mercury On Further Heating.
• 2hg(s) +3o2(g)2hgo(s)+ 2so2(g) 2hgo(s)2hg +O2
![Page 7: Extraction of metals chemistry](https://reader031.vdocuments.net/reader031/viewer/2022012403/5580ec1fd8b42aec5a8b4fd9/html5/thumbnails/7.jpg)
Extracting metals from middle of series• Metals In Middle Of Series Are Moderately Reactive.• They Are Present As Sulphides & Carbonates.• Prior To Reduction, Metal Sulphides & Carbonates
Must Be Converted Into Metal Oxides.• When Sulphide Ores Are Converted Into Oxides By
Heating Strongly In Presence Of Excess O2 Is Known As Roasting.
• When Carbonates Ore Is Changed In Oxides By Heating Strongly In Limited Air Is Known As Calcination.
![Page 8: Extraction of metals chemistry](https://reader031.vdocuments.net/reader031/viewer/2022012403/5580ec1fd8b42aec5a8b4fd9/html5/thumbnails/8.jpg)
Chemical reaction of roasting and calcination of zinc ores
• Roasting:• 2zns(s) +3O2 (G) 2zno(s) + 2SO2 (G)• Calcination:• Znco3(s) Zno(s) + Co2(g)• The Metal Oxides Are Then Reduced To
Corresponding Metals By Suitable Reducing Agents As Carbon. Eg: When Zinc Oxide Is Reduced To Metallic Zinc.
• Zno (S)+ C(s) Zn(s)+ Co(g)
![Page 9: Extraction of metals chemistry](https://reader031.vdocuments.net/reader031/viewer/2022012403/5580ec1fd8b42aec5a8b4fd9/html5/thumbnails/9.jpg)
Reduction agents• Besides Using Carbon (Coke) To Reduce Metal
Oxides To Metal, Sometimes Displacement Reactions Can Also Be Used In Reduction.
• The Highly Reactive Metal As Na, Ca, Al, Ect. Are Used As Reducing Agents As They Can Displace Metals Of Lower Resistivity From Their Compounds.
• For Eg: When Manganese Dioxide Is Heated With Aluminium Powder :
• 3mno2(s) + 4al(s)3mn +2al2o3(s) +Heat
![Page 10: Extraction of metals chemistry](https://reader031.vdocuments.net/reader031/viewer/2022012403/5580ec1fd8b42aec5a8b4fd9/html5/thumbnails/10.jpg)
Substances Getting Oxidized & Reduced
• These Displacements Reactions Highly Exothermic In Nature.
• The Amount Of Heat Produced Is So Large That Metals Are Produced In Molten State.
![Page 11: Extraction of metals chemistry](https://reader031.vdocuments.net/reader031/viewer/2022012403/5580ec1fd8b42aec5a8b4fd9/html5/thumbnails/11.jpg)
Thermit Reaction
• The Reaction Of Iron(iii) Oxide[fe2o3 ] With Aluminium Is Join Railway Tracks Or Cracked Machine Parts This Is Known As Thermit Reaction.
• The Reaction For Thermit Reaction Is:
• Fe2o3[s] + 4al[s] 3mn(i) +2al2o3(s) + Heat
![Page 12: Extraction of metals chemistry](https://reader031.vdocuments.net/reader031/viewer/2022012403/5580ec1fd8b42aec5a8b4fd9/html5/thumbnails/12.jpg)
Extracting metals from top of series
• These Metals Are Very Reactive.
• They Cannot Be Obtained By Their Compounds While Heating By Carbon. For Eg: Carbon Cannot Reduce The Oxide Of Sodium, Magnesium, Calcium, Aluminium Ect. It Is Because They Have More Affinity Of O2 Than CO2 .
![Page 13: Extraction of metals chemistry](https://reader031.vdocuments.net/reader031/viewer/2022012403/5580ec1fd8b42aec5a8b4fd9/html5/thumbnails/13.jpg)
Extracting metals from top of series
• These Metals Are Obtained From Electrolytic Reduction. For Eg:
• Na, Mg, Ca Are Obtained By The Electrolysis Of Their Molten Chlorides.
• The Metals Are Deposited At The Cathode (Negatively Charged Electrode) .And Cl Is Liberated At Anode (Positively Charged Cathode)
![Page 14: Extraction of metals chemistry](https://reader031.vdocuments.net/reader031/viewer/2022012403/5580ec1fd8b42aec5a8b4fd9/html5/thumbnails/14.jpg)
Refining Of Metals
• Metals Are Produced By Various Reduction Process Which Are Not Very Pure.
• They Contain Impurities Which Must Be Removed To Obtain Pure Metals.
• The Most Widely Used Method For Refining Impure Metals Is Electrolytic Refining .
![Page 15: Extraction of metals chemistry](https://reader031.vdocuments.net/reader031/viewer/2022012403/5580ec1fd8b42aec5a8b4fd9/html5/thumbnails/15.jpg)
Electrolytic refining
• Many Metals Such As Cu, Zn, Sn, Ag, Au Etc Are Refined Electrolytically.
• The Impure Metal Is Made Anode & A Thin Strip Of Pure Metal Is Made Of Cathode .
• Solution Of Metal Salt Is Used In Electrolyte.
![Page 16: Extraction of metals chemistry](https://reader031.vdocuments.net/reader031/viewer/2022012403/5580ec1fd8b42aec5a8b4fd9/html5/thumbnails/16.jpg)
Electrolytic refining
• On Passing The Current Through The Electrolyte, The Pure Metal From The Anode Dissolves Into The Electrolyte.
• An Equivalent Amount Of Pure Metal From The Electrolyte Is Deposited On The Cathode.
• The Soluble Impurities Go Into The Solution, Whereas, The Insoluble Impurities Settle Down At The Bottom Of The Anode And Are Known As Anode Mud.
![Page 17: Extraction of metals chemistry](https://reader031.vdocuments.net/reader031/viewer/2022012403/5580ec1fd8b42aec5a8b4fd9/html5/thumbnails/17.jpg)
THANK YOU
BY:NIM
ESH BHATIA
1
0-B