高中化学个精讲 金属的冶炼（ fine lectures on high school chemistry smelting of metals）

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1、高中化学58个精讲(38)金属的冶炼（58finelecturesonhighschoolchemistry(38)smeltingofmetals）Testsite38smeltingofmetals1.reviewthekeypoints1.thechemicalprincipleofmetalsmeltingandthebasicmethodofmetalsmelting;2.importantroleofmetalrecyclingandresourceprotection,The3.pointistoexaminethebasicmethodsofmetals

2、melting.2.difficultiesfocusFirst,theexistenceofmetalsinnature:1.freestateChemicallyinactivemetalscanexistasfreeforminnature,suchasAu,Ag,Pt,Cu2.chemicalcombinationChemicallyactivemetalsthatexistinnatureintheformofchemicalcompoundssuchasAl,NaExplanation:asmallnumberofmetalsexistinnatureinf

3、reeform,whilemostmetalsexistinacompositeforminnatureTwo.Smeltingofmetals:1.theessenceofmetalsmeltingThemetalcationinametalcompoundisreducedtoelectronsbyreductionMn++ne-=M2.majorstepsinmetalsmelting:OreenrichmentObjective:toremoveimpuritiesandincreasethecontentoftheusefulconstituentsofthe

4、ore;SmeltingObjective:toobtainmetallicsimplesubstancePrinciple:byusingtheprincipleofoxidation-reductionreaction,undercertainconditions,themetalioninmetaloreisreducedintometallicsinglesubstancebyreducingagentRefiningObjective:toimprovethepurityofmetals3.generalmethodsofmetalsmelting:Accor

5、dingtothelivelinessofmetals(1)thermaldecompositionmethod:Scopeofapplication:inactivemetalAg----AuSuchas:2Ag2O==4Ag+O2=2HgO==2Hg+O2=(2)reductionmethod:Scopeofapplication:morelivelymetalZn----CuSuchas:Fe2O3+3CO,==2Fe+3CO2Cr2O3+2Al==2Cr+Al2O3Commonlyusedreducingagents:C,CO,H2andactivemetals

6、,suchasaluminumThethermitreactionisalsoknownasthethermalreductionprocess[thinking]whatmethodshouldbeusedifthesmeltingofveryactivemetalscannotbereducedbythermalreduction?3.electrolysis:Scopeofapplication:livelymetalK-----AlSuchas:2Al2O3=4Al+3O2=+Cl2=2NaCl===2NaComparison:2NaCl+2H2O===2NaO

7、H=+Cl2=+H2=2CuSO4+2H2O===2Cu+2H2SO4+O2Electrolysisisalsousedintherefiningofsomeinertmetals[description]thedisadvantageofelectrolysisisthatitconsumesagreatdealofenergy,andthecostishigherThree,metalrecyclingandenvironmentalprotection1.significanceofmetalrecycling(1)tosavemi