Neodymium yog cov khoom siv tshuaj nrog lub cim Nd thiab tus lej atomic 60. Nws yog cov hlau mos, silvery hlau uas tarnishes hauv huab cua. Nws tau pom nyob rau hauv 1885 los ntawm Austrian chemist Carl Auer von Welsbach. Cov khoom muaj nyob rau hauv ntau qhov tseem ceeb hauv monazite xuab zeb deposits thiab nyob rau hauv cov ntxhia bastnäsite.
History
Lub ntiaj teb tsis tshua muaj hlau neodymium tau tshawb pom los ntawm Austrian chemist Baron Karl Auer von Welsbach hauv Vienna xyoo 1885. Tus kws tshawb fawb tau cais cov khoom tshiab (nrog rau lub ntsiab lus praseodymium) los ntawm cov khoom hu ua Didymium los ntawm fractional crystallization ntawm ob chav ammonium nitrate tetrahydrate los ntawm nitric acid, tom qab sib cais los ntawm spectroscopic tsom xam. Txawm li cas los xij, txog xyoo 1925 nws tsis tuaj yeem tau txais cov khoom hauv nws daim ntawv purest.
Txog thaum xyoo 1940s, txoj kev lag luam tseem ceeb rau kev tsim cov hlau yog ob chav crystallization ntawm nitrates. Cov txheej txheem tsis muaj txiaj ntsig, thiab cov khoom tau txais me me. Lindsay Chemical Division yog thawj zaug pib tsim cov khoom loj ntawm neodymiumion-pauv purification txoj kev. Txij li thaum xyoo 1950, cov khoom ua kom huv heev (siab dua 99%) tau tsim los ntawm cov txheej txheem ion txauv los ntawm lub ntiaj teb tsis tshua muaj nplua nuj monazite los ntawm electrolysis ntawm nws cov ntsev halide.
Tam sim no, feem ntau nws yog xim hlau neodymium yog muab rho tawm los ntawm bastnäsite. Kev nce qib hauv thev naus laus zis thiab kev txhim kho kev txhim kho kev tu kom zoo tau ua rau nws siv dav hauv kev lag luam.
Kev piav qhia
Cov tshuaj lom neeg tsis tshwm sim nyob rau hauv ib daim ntawv hlau, nws yog cais los ntawm cov tshuaj Didymium, uas nws yog tov nrog lwm yam lanthanides (tshwj xeeb, nrog praseodymium). Txawm hais tias neodymium raug cais raws li cov hlau tsis tshua muaj hauv ntiaj teb, nws yog ib qho khoom siv sib xws, tshwm sim tsawg kawg li ntau zaus xws li cob alt, npib tsib xee, lossis tooj liab, thiab tau muab faib rau hauv lub ntiaj teb crust. Feem ntau ntawm cov khoom yog los ntawm Tuam Tshoj.
Neodymium tebchaw tau xub siv ua lag luam ua cov xim iav hauv xyoo 1927 thiab tseem yog cov khoom siv nrov hauv cov tsom iav. Cov xim ntawm neodymium compounds vim muaj Nd3+ ions feem ntau muaj xim liab-liab, tab sis qhov no txawv nyob ntawm seb hom teeb pom kev zoo.
Daim ntawv thov
Ndodymium-doped lo ntsiab muag yog siv nyob rau hauv lasers uas emit infrared tawg nrog wavelengths ntawm 1047 thiab 1062 nanometers. Lawv yog siv nyob rau hauv cov tshuab uas muaj zog heev, piv txwv li, nyob rau hauv kev sim ntawm inertialntim.
Nd: hlau kuj tseem siv nrog lwm cov muaju (xws li yttrium aluminium garnet) hauv Nd:YAG lasers. Qhov kev teeb tsa no feem ntau emits infrared rays nrog lub wavelength ntawm ib ncig ntawm 1064 nm. Nws yog ib qho ntawm feem ntau siv lub xeev lasers.
Lwm qhov tseem ceeb ntawm kev siv cov hlau neodymium yog ib qho kev txhawb zog hauv cov hlau nplaum siv los ua cov hlau nplaum muaj zog, muaj zog ruaj khov. Lawv tau siv dav hauv cov khoom xws li microphones, cov hais lus tshaj lij, lub mloog pob ntseg hauv pob ntseg, kev ua haujlwm siab DC motors, khoos phis tawj hard drive, qhov twg tsis tshua muaj hlau nplaum (ntim) lossis muaj zog sib nqus yuav tsum tau.
Cov hlau nplaum neodymium loj yog siv rau hauv lub zog siab thiab hnyav hluav taws xob (xws li tsheb hybrid) thiab cov tshuab hluav taws xob (xws li dav hlau thiab cua tshuab hluav taws xob). Tsis tas li ntawd, lub caij yog siv los ua ib co alloys. Piv txwv li, titanium dhau los ua ib thiab ib nrab zaug muaj zog tom qab ntxiv 1.5% ntawm cov khoom no.
Lub cev muaj zog
Metallic neodymium tam sim no nyob rau hauv classic mischmetal (ib qho alloy ntawm lub ntiaj teb tsis tshua muaj cov ntsiab lus), qhov uas nws cov concentration feem ntau yog nyob ntawm qhov kev txiav txim ntawm 18%. Nyob rau hauv nws cov ntshiab daim ntawv, lub caij muaj ib tug kaj silver-kub metallic luster, tab sis sai sai oxidizes nyob rau hauv tej huab cua. Ib txheej oxide tsim thiab flakes tawm, nthuav tawm cov hlau kom ntxiv oxidation. Yog li,centimeter qauv ntawm cov khoom yog oxidized kiag li nyob rau hauv ib xyoos.
Neodymium feem ntau muaj nyob rau hauv ob daim ntawv allotropic, nrog rau qhov nruab nrab-rau-qhov kev hloov pauv los ntawm ob lub hexagonal cubic qauv. Nws pib yaj ntawm 1024 ° C thiab boil ntawm 3074 ° C. Qhov ceev ntawm cov teeb meem nyob rau hauv cov khoom theem yog 7.01 g / cm3, nyob rau hauv cov kua hauv lub xeev yog 6.89 g / cm3.
Atomic properties:
- Oxidation xeev: +4, +3, +2 (basic oxide).
- Electronegativity: 1, 14 (Polling scale).
- Thermal conductivity: 16.5 W / (m K).
- Ionization zog: 1: 533, 1 kJ / mol, 2: 1040 kJ / mol, 3: 2130 kJ / mol.
- Radius ntawm ib lub atom: 181 picometers.
tshuaj muaj zog
Hlau neodymium tarnishes maj mam hauv huab cua thiab hlawv yooj yim ntawm ib ncig ntawm 150 ° C los tsim neodymium (III) oxide:
4Nd + 3O2 → 2Nd2O3
Qhov no yog ib qho electropositive. Nws reacts maj mam nrog dej txias, tab sis sai sai nrog dej kub, tsim neodymium (III) hydroxide:
2Nd(s) + 6H2O(l) → 2Nd(OH)3 (aq) + 3H 2(g)
Cov hlau ua haujlwm hnyav nrog tag nrho cov halogens, yooj yim yaj hauv dilute sulfuric acid los tsim cov kev daws teeb meem uas muaj cov violet Nd(III) ion.
Production
Neodymium hlau yeej tsis tshwm sim raws li cov khoom pub dawb hauv cov xwm txheej. Nws yog mined los ntawm ores xws libastnäsite thiab monazite, nyob rau hauv uas nws yog txuam nrog lwm yam lanthanides thiab lwm yam ntsiab. Cov chaw mining tseem ceeb rau cov zaub mov no nyob hauv Suav teb, Tebchaws Asmeskas, Brazil, Is Nrias teb, Sri Lanka thiab Australia. Cov nyiaj me me kuj tau tshawb nrhiav hauv Russia.
Reserve ntawm neodymium yog kwv yees li ntawm 8 lab tons. Nws cov concentration nyob rau hauv lub ntiaj teb crust yog hais txog 38 mg / kg, uas yog qhov thib ob siab tshaj plaws ntawm lub ntiaj teb tsis tshua muaj ntsiab tom qab cerium. Ntiaj teb hlau ntau lawm yog hais txog 7000 tons. Lub ntsiab ntawm ntau lawm belongs rau Tuam Tshoj. Tsoomfwv PRC tsis ntev los no tau lees paub lub ntsiab lus tseem ceeb thiab tau txwv tsis pub xa tawm, ua rau qee qhov kev txhawj xeeb hauv cov neeg siv khoom lag luam thiab ua rau muaj kev nce nqi ntawm neodymium rau $ 500. Niaj hnub no, tus nqi nruab nrab ntawm ib kilogram ntawm cov hlau ntshiab txawv ntawm $ 300-350, neodymium oxides pheej yig dua: $ 70-130.
Muaj cov xwm txheej thaum tus nqi ntawm cov hlau poob rau $ 40 vim kev lag luam tsis raug cai, hla kev txwv ntawm tsoomfwv Suav. Tus nqi thiab qhov tsis muaj qhov tsis txaus ntseeg tau ua rau cov tuam txhab Nyij Pooj tsim cov hlau nplaum ruaj khov thiab cov hluav taws xob muaj feem xyuam nrog tsawg lossis tsis tshua muaj lub ntiaj teb.
