Chemistry yog lub hauv paus ntawm peb lub neej. Txhua yam khoom siv hauv tsev muaj cov khoom sib txuas ntawm cov ntsiab lus ntawm lub rooj zaum. Txhua feeb hauv tib neeg lub cev muaj cov kev hloov pauv uas cov tshuaj koom nrog. Kab lus no yuav tham txog cov hlau xws li molybdenum: qhov twg nws siv, nws cov khoom thiab lub luag haujlwm hauv tib neeg lub cev.
Zoo rau keeb kwm
Minerals uas muaj molybdenum tau paub hauv tebchaws Greece thaum ub. Cov tebchaw ntuj no muaj cov qauv zoo ib yam li graphite. Yog li ntawd, lawv feem ntau tau siv nrog rau nws los tsim cov hlau lead. Molybdenite MoS₂ muaj grey-ntsuab tint thaum sau rau ntawm daim ntawv. Rau nws cov yam ntxwv ci ntsa iab, nws tau muab lub npe molybdaena - "zoo li txhuas."
Karl Wilhelm Scheele tau tshawb fawb, ua tsaug rau qhov nws tau tsim cov MoO₃ trioxide, tab sis vim tsis muaj lub qhov cub tsim nyog, nws tsis tuaj yeem cais cov hlau hauv nws daim ntawv ntshiab. Jöns Jakob Berzelius ua tiav tau txais molybdenum hauv xyoo 1817 los ntawmoxide txo tsis yog carbon, tab sis nrog hydrogen. Cov tshuaj synthesized tau ua tib zoo kawm thiab piav qhia hauv kev ua haujlwm ntawm tus kws tshawb fawb.
Lub cev muaj zog
molybdenum yog dab tsi? Nws yog lub teeb grey hlau uas, nyob rau hauv nws daim ntawv ntshiab, yog resistant rau oxidation (nyob rau hauv ib txwm tej yam kev mob). Nrog rau qhov kub nce mus txog 400-600 degrees, qhov peev xwm no txo qis, thiab MoO₃ trioxide tsim.
Molybdenum yog ductile thiab malleable, yooj yim stamped. Hlau ntom 10.2 g / cm 3, melting point 2620 ⁰С, boiling point - 4800 ⁰С. Los ntawm cov ntsuas no, nws tuaj yeem pom tias nws yog refractory heev. Lub xub ntiag ntawm carbon, nitrogen los yog sulfur contaminants cuam tshuam rau lub cev lub cev, tshwj xeeb tshaj yog, cov khoom yuav nkig thiab nkig. Molybdenum yog paramagnetic. Nrog rau qhov kub thiab txias, nws lub zog nce ntxiv.
Natural molybdenum compounds, tau txais
Koj yuav tsum paub tias molybdenum tsis tshwm sim hauv nws daim ntawv ntshiab, nws yog tam sim no nyob rau hauv qhov tsuas yog nyob rau hauv cov tebchaw nrog lwm yam. Cov ntsiab lus kwv yees ntawm cov hlau nyob hauv lub ntiaj teb crust yog 3∙10-4%. Muaj txog 15 cov zaub mov, uas feem ntau yog:
- disulfide MoS2 - molybdenite;
- CaMoO4 – powellite;
- PbMoO4 – wulfenite.
Lub ntsiab deposits ntawm cov tebchaw yog ze ze rau cov txheej txheem ntawm nag lossis daus nyob rau hauv hydrothermal vents.
Molybdenum disulphide yog mined rau kev lag luam. Nws siv kom tau cov hlau ntshiab yog heevtseem ceeb. Qhov no tshwm sim nrog kev pab ntawm ore beneficiation los ntawm flotation. Qhov no yog yuav ua li cas kom muaj concentrated, uas yog tom qab raug rho tawm haujlwm.
2MoS2+7O2=2MoO3+4SO 2
Cov oxide cais tau huv thiab txo los ntawm qhov qhuav tam sim no ntawm hydrogen ntawm qhov kub ntawm 700 degrees. Cov khoom siv tshuaj tiv thaiv yog molybdenum hmoov. Yav tom ntej, nws tuaj yeem siv rau hauv nws daim ntawv dawb huv lossis ua cov khoom siv rau kev tsim cov khoom dov thiab stamped.
Kev tsim cov hlau alloys
Ferrous metallurgy siv molybdenum hmoov. Nws siv qhov twg? Rau alloying steels thiab cam khwb cia hlau. Qhov sib ntxiv ntawm cov khoom no rau cov muaj pes tsawg leeg ntawm alloys ho txhim kho lawv zoo. Elasticity, hnav tsis kam, cuam tshuam tsis kam nce. Kwv yees li 0.5% molybdenum ntxiv rau cov qauv hlau, vim qhov no lawv cov qauv ua zoo-grained thiab ntau yam sib xws, thiab brittleness ntawm cov khoom kawg txo.
Qhov sib ntxiv ntawm lwm yam khoom ua rau nws tuaj yeem tau txais cov khoom sib xyaw tshwj xeeb uas siv dav hauv ntau yam lag luam. Alloys, uas suav nrog cob alt thiab npib tsib xee (50-60%), nrog rau chromium (kwv yees 20-28%), yog alloyed los ntawm kev ntxiv molybdenum. Cov khoom siv no siv nyob qhov twg? Cov lus teb nyob rau hauv nws cov khoom tshwj xeeb - siab kub tsis kam. Nws yog siv rau hauv kev tsim cov dav hlau thiab cov foob pob hluav taws ntawm daim tawv nqaij.
Kev thov ntawm molybdenum alloys
Thaum niobium, titanium thiab lwm yam hlau hnyav ntxiv rau molybdenum, qhov kub tsis kam ncealloys. Xws li ib tug muaj pes tsawg leeg yuav siv tau los tsim qhov chaw rau roj turbines thiab combustion chambers nyob rau hauv foob pob ua ntxaij science.
Nyob rau hauv cov alloys nrog cov ntsiab lus siab ntawm molybdenum (17-28%), corrosion kuj nce. Lawv tsis ntshai txawm tias muaj kev cuam tshuam nrog cov kua qaub (tshwj tsis yog hydrofluoric acid).
Lub zog refractory ntawm molybdenum thiab nws siv hauv kev tsim cov kav dej tshwj xeeb yog qhov tseem ceeb hauv nuclear zog. Xws li cov khoom muaj peev xwm tiv taus raug rau molten lithium. Nws ua raws li ib tug coolant nyob rau hauv uranium reactors. Tsis tas li ntawd, molybdenum nws tus kheej, nyob rau hauv daim ntawv ntawm Mo-99 isotope, tau pom kev siv los ua qhov taw qhia hauv kev lag luam nuclear.
Vim vim tsis muaj molybdenum, molybdenum yog siv los tsim pwm rau casting qhov chaw ntawm tooj liab, txhuas thiab zinc. Lub zog siab ntawm cov hlau tso cai rau cov txheej txheem nyob rau hauv siab.
Rolling thiab stamping, daim ntawv thov
Los ntawm qhov khoob tau los ntawm cov hmoov smelting, cov khoom dov yog tsim - rods thiab hlau. Lawv yog tsim los ntawm cov hlau ntshiab hu ua molybdenum. Cov khoom no siv qhov twg? Nws yog feem ntau siv rau hauv kev tsim cov thermocouples, uas yog siv los ntsuas qhov kub siab tshaj 2000 ⁰C. Hooks thiab cores rau winding ib tungsten filament nyob rau hauv lub teeb incandescent kuj yog tsim los ntawm molybdenum hlau. Cathode coj thiab tsom electrodes nyob rau hauv X-ray raj thiab generator teeb yuav tsum txhim khu kev qha thiab ua tau raws li cov kev cai ntawm high hlau refractoriness. Rolled molybdenum yog qhov zoo heev rau cov hom phiaj no.
Qws thiab daim phiajyog siv los ntawm electrodes nyob rau hauv high kub melting rauv. Lawv yuav tsum nyob rau hauv ib qho chaw tshwj xeeb uas muaj argon, hydrogen lossis lub tshuab nqus tsev. Vim qhov tseeb tias molybdenum tsis nkag mus rau hauv cov tshuaj tiv thaiv nrog iav, nws yog siv los ua ib feem ntawm lub qhov cub melting.
Daim ntawv thov hauv lwm qhov kev lag luam
Molybdenum tau pom daim ntawv thov hauv kev lag luam roj. Nyob ntawd nws yog siv los ua ib qho catalyst muaj peev xwm ntxuav cov khoom los ntawm leej faj impurities. Lubricants yog tsim los ntawm aluminium disulfide. Lawv ruaj khov rau kev ua haujlwm ntawm ntau yam khoom siv thiab tiv thaiv qhov chaw los ntawm cov neeg kho tshuab kev ntxhov siab ntawm qhov kub thiab txias. Nws muaj xws li lubricant thiab tiv thaiv corrosion.
Hauv kev tsim cov xim thiab cov kua roj vanish, qhov twg molybdenum thiab nws cov oxides tau siv, cov xim tsis tu ncua ntawm cov xim daj-txiv kab ntxwv tau txais. Lub synthesis ntawm cov khoom siv fiber ntau kuj tsis ua haujlwm yam tsis muaj cov tshuaj no. Txhawm rau nce cov ntsiab lus nitrogen hauv cov av, siv microfertilizers, uas suav nrog molybdenum.
YLub luag haujlwm ntawm molybdenum hauv lub cev
Molybdenum ua lub luag haujlwm tseem ceeb hauv tib neeg lub cev. Nws koom nrog hauv kev sib txuas ntawm hemoglobin, nitrogen thiab purine metabolism. Lub luag haujlwm rau kev nqus hlau thiab vitamin C, yog ib qho muaj zog antioxidant. Cov kab hauv qab muaj cov nyhuv oncoprotective, rejuvenating.
Cov khoom noj uas muaj molybdenum yog legumes thiab cereals, nplooj zaub. Qhov xav tau ntawm micronutrients txhua hnubnkag mus rau hauv lub cev yog tias koj noj txoj cai. Nws qhov tsis muaj tuaj yeem rov ntxiv siv cov ntxhia complexes.
