Iphrofayili yensimbi: i-Chromium

Insimbi ye-Chromium iyabonakala ngokubanzi ngokusetyenziswa kwayo kwi-chromium plating (edlalwa ngokubhekisele nje ngokuthi 'chrome'), kodwa ukusetyenziswa kwayo kakhulu kunokuba isithako kwii- steels ezingenasici . Ezi zombini zicelo zincedwa ngobunzima be-chromium, ukumelana nokubola , kunye nokukwazi ukuphoswa ngenjongo yokubukeka.

Iipropati

• I-Atomic Symbol: Cr
• Inomic Number: 24
• I-Atomic Mass: 51.996g / mol ¹
• Udidi lwe-Element: iTransition Metal

• Ubuninzi: 7.19g / cm ³ kwi-20 ° C
• I-Melting Point: 3465 ° F (1907 ° C)
• Indawo yokubilisa: 4840 ° F (2671 ° C)
• Ubunzima bukaMoh: 5.5

Iimpawu

I-Chromium yinto enzima, isinyithi esilungileyo esabalulekayo ngokuchasayo okungenakuqhayisa. I-chromium echanekileyo imagnetic ne-brittle, kodwa xa ichitshiweyo ingenziwa yenziwe ingenakunyuka kwaye iphosiwe ekugqibeleni, ekupheleni kwe-silvery.

I-Chromium ithola igama layo ukusuka ku- khrōma, igama lesiGrike elisho umbala, ngenxa yokukwazi ukuvelisa izinto ezicacileyo, ezimibalabala, ezifana ne-chrome oxide.

Imbali

Ngomnyaka we-1797, isazi samachiza saseFransi uNicolas-Louis Vauguelin savelisa i-chromium yentsimbi yokuqala ecocekileyo ngokuphatha i-crocoite (i-chromium-containing containing mineral) kunye ne-potassium carbonate kunye nokunciphisa i-chromic acid eyenza i-chromic acid kunye nekhabhoni kwi-graphite crucible.

Nangona i-chromium compounds isetyenzisiwe kumatshini kunye nopende ngamashumi eminyaka, bekungekho emva kokufunyanwa kweVauguelin ukuba i-chromium isebenzise kwizicelo zetsimbi zaqala ukuphuhlisa.

Ngasekupheleni kwe-19 neyokuqala kwekhulu lama-20, i-metallurgists eYurophu yayizama ukuzisebenzisa ngetsimbi zetsimbi, izama ukuvelisa izitishi ezinamandla kwaye zihlala zizinzileyo.

Ngomnyaka we-1912, ngelixa besebenza kwi-Firth Brown Laboratories e-UK, i-metallurgist uHarry Brearley wayenomsebenzi wokufumanisa isinyithi esinamandla ngakumbi kwimiphongolo yempu.

Wongezelela i-chromium, eyayiziwa ngokuba neqondo eliphezulu lokuqhaqhazela, kwi-carbon steel steel, ukuvelisa insimbi yokuqala engenasici. Nangona kunjalo, malunga nexesha elifanayo, abanye, kuquka u-Elwood Haynes e-US kunye neenjineli eKrupp eJamani, nabo babekhupha i-chromium equkethe i-alloys zensimbi. Ngophuhliso lwesithando somlilo se-arc, ukuveliswa kwemveliso enkulu yensimbi engenasici ilandelwe emva nje koko.

Ngethuba elifanayo, uphando lwaluqhutyelwa kwinqanaba le-electro-metal, elalivumela izityebhe ezincinci, ezinjenge- iron kunye ne- nickel , ukuba zithwale ukuxhatshazwa kwe-chromium yangaphandle ekukhutshweni nasekuhambeni, kunye neempawu zayo zobugcisa. Iimpawu zokuqala ze-Chrome zibonakala kwiimoto kunye namawashi aphezulu ekupheleni kwee-1920.

U ku velisa

Imveliso ye-chromium yezoshishino iquka i-chromium zetsimbi, i-ferrochrome, iikhemikhali ze-chromium kunye neesanti ze-foundry. Kwiminyaka yakutshanje, kuye kwaba nombono wokubambisana okugqithisileyo kwimveliso yezinto zokwakha i-chromium. Oko kukuthi, iinkampani ezininzi ezibandakanyekayo kwimigodi ye-chromite ore zibuye zisebenzise kwi-chromium yensimbi, i-ferrochrome kwaye, ekugqibeleni, insimbi engenasici.

Ngo-2010 ukuveliswa kwemveliso ye-chromite ore (i-FeCr ₂ O- ₄ ), i-mineral primary eyayikhishwe ukuveliswa kwe-chromium yayingu-25 yezigidi zeetoni.

Ukukhiqizwa kwe-Ferrochrome bekuyi-7 yezigidi zeetoni, ngelixa i-chromium yecandelo lemveliso yenziwe ngeetoni ezingama-40,000. I-Ferrochromium ikhiqizwa kuphela usebenzisa izitshixo ze-arc zombane, ngelixa i-chromium zinyithi zingenziwa nge-electrolytic, i-silico-thermic ne-aluminothermic.

Ngexesha lokuveliswa kwe-ferrochrome, ubushushu obudalwe ngumbane we-arc yombane, efikelela kuma-5070 ° F (2800 ° C), ubangela amalahle kunye ne-coke ukunciphisa i-chromium ore ngokusabela kwamathambo. Xa izinto ezaneleyo zithe zanyiswa kwisithandweni somlilo, isinyithi esinyithiweyo sidityanisiweyo kwaye siqiniswe kwi-castings enkulu ngaphambi kokuchotshozwa.

I-Aluminothermic production of purity chromium zinyithi i-akhawunti engaphezulu kwe-95% ye-chromium yenziwe ngunamhla. Isinyathelo sokuqala kule nkqubo sidinga ukuba i-chromite ore igongwe nge-soda kunye ne-lime emoyeni ngo-2000 ° F (1000 ° C), edala i-chromate ye-sodium ene-calcine.

Iyakunqandwa kwizinto eziphathekayo kwaye iyancitshiswa kwaye inqandwe njenge-chromic oxide (Cr ₂ O ₃ ).

I-chromic oxide iyaxutywa kunye ne- aluminium enopulini kwaye ifakwe kwi-crucible enkulu. I-pumxide ye-Barium kunye ne- magnesium powder iyasasazeka kumxube, kwaye i-crucible ijikelezwe yentlabathi (eyenziwa njengesiqulatho).

Umxube uvutha, okwenza i-oksijini isuka kwi-oksidi oxide eyenza i-aluminium ukuvelisa i-aluminium oxide kwaye, ngoko ke, inkululeko ye-chromium ensimbi ene-97-99% ecocekileyo.

Ngokwezibalo ze-US Geological Survey, abavelisi abakhulu be-ore chromite ngo-2009 babengabantu baseMzantsi Afrika (33%), i-India (20%) kunye ne-Kazakhstan (17%). Iinkampani ezinkulu zokukhiqiza i-ferrochrome ziquka i- Xstrata , i-Eurasian Resources Resources Corp (iKazakhstan), iSancanc (South Africa) kunye neHernic Ferrochrome (eMzantsi Afrika).

Izicelo

Ngokwe-International Association Association yeChromium, ye-oromyr ore epheleleyo eyenziwe ngowama-2009, i-95.2% yagqitywa yimboniselo ye-metallurgical, 3.2% yoshishini lokukhanyela kunye ne-foundry, kunye no-1.6% ngabavelisi bamakhemikhali. Iimveliso eziphambili ze-chromium zise-steels ezingenasici, ama-steels alloyed, kunye nama-alloys angenanto.

Iiteli ezingenasiphelo zibhekisela kwimiba yeelayeli eziqulethe phakathi kwe-10% ukuya kwi-30% ye-chromium (ngokulinganisa) kwaye engayibhuduli okanye i-rust ngokulula nje njengama-steels aqhelekileyo. Kuphakathi kwama-150 kunye nama-200 ahlukeneyo entsimbi engenakunqandwa, nangona kuphela malunga ne-10% yezi zinto zisetyenziswa rhoqo.

_Imithombo:

_{Sully, uArthur Henry, no-Eric A. Brandes. Chromium . London: Butterworths, ngo-1954.}

_{Street Street, Arthur. Kunye no-Alexander, WO-1944. Amanzi kwiNkonzo yoMntu . Udidi lwe-11 (1998).}

_{I-International Chromium Development Association (ICDA).}

_{Umthombo: www.icdacr.com}

I-Chromium Superalloy Names Names