Selenium, ua ib yam khoom siv semiconductor tseem ceeb thiab cov khoom siv raw hauv kev lag luam, nws cov kev ua tau zoo cuam tshuam ncaj qha los ntawm nws qhov kev huv. Thaum lub sijhawm ua kom huv si los ntawm lub tshuab nqus tsev, cov pa oxygen tsis huv yog ib qho ntawm cov yam tseem ceeb uas cuam tshuam rau qhov huv ntawm selenium. Tsab xov xwm no muab kev sib tham ntxaws ntxaws txog ntau txoj hauv kev thiab cov txheej txheem rau kev txo cov pa oxygen thaum lub sijhawm ua kom huv si los ntawm kev nqus tsev.

I. Txo Cov Pa oxygen hauv Cov Khoom Siv Raw Pretreatment Theem

1. Kev Ua Kom Huv Ua Ntej ntawm Cov Khoom Siv Raw

Feem ntau cov selenium nyoos muaj ntau yam tsis huv, suav nrog cov oxides. Ua ntej nkag mus rau hauv lub tshuab nqus tsev, yuav tsum siv cov tshuaj ntxuav kom tshem tawm cov oxides ntawm qhov chaw. Cov tshuaj ntxuav uas siv ntau suav nrog:

• Dilute hydrochloric acid kua (5-10% concentration): Yaj cov oxides xws li SeO₂ tau zoo
• Ethanol los yog acetone: Siv los tshem tawm cov organic contaminants
• Dej Deionized: Ntxuav ntau zaus kom tshem tawm cov kua qaub seem

Tom qab ntxuav tas, yuav tsum ziab kom qhuav hauv qab huab cua uas muaj roj inert (piv txwv li, Ar lossis N₂) kom tiv thaiv kev rov ua dua tshiab.

2. Kev Kho Mob Ua Ntej Txo Cov Khoom Siv Raw

Kev txo cov khoom siv raw ua ntej kev nqus tsev tuaj yeem txo cov pa oxygen ntau heev:

• Kev txo qis Hydrogen: Qhia txog hydrogen uas muaj purity siab (purity ≥99.999%) ntawm 200-300 ° C kom txo SeO₂ rau cov selenium hauv paus.
• Kev txo qis carbothermal: Sib tov selenium raw khoom nrog cov hmoov carbon purity siab thiab cua sov rau 400-500 ° C nyob rau hauv lub tshuab nqus tsev lossis inert huab cua, inducing cov tshuaj tiv thaiv C + SeO₂ → Se + CO₂
• Kev txo cov sulfide: Cov pa roj xws li H₂S tuaj yeem txo cov selenium oxides ntawm qhov kub qis dua.

II. Tsim thiab Kev Ua Haujlwm Zoo Tshaj Plaws ntawm Lub Tshuab Nqus Tsev Distillation

1. Kev Xaiv thiab Kev Teeb tsa ntawm Lub Tshuab Nqus Tsev

Ib puag ncig uas muaj lub tshuab nqus tsev ntau yog qhov tseem ceeb rau kev txo cov pa oxygen:

• Siv lub twj tso kua mis diffusion + lub twj tso kua mis mechanical ua ke, nrog lub tshuab nqus tsev kawg mus txog tsawg kawg 10⁻⁴ Pa
• Lub kaw lus yuav tsum tau nruab nrog lub cuab yeej txias kom tiv thaiv kev rov qab kis ntawm cov pa roj
• Txhua qhov kev sib txuas yuav tsum siv cov hlau foob kom tsis txhob muaj pa tawm ntawm cov roj hmab foob
• Lub kaw lus yuav tsum dhau los ntawm kev ua kom qhuav txaus (200-250 ° C, 12-24 teev)

2. Kev Tswj Xyuas Qhov Kub thiab Siab ntawm Distillation

Cov txheej txheem parameter zoo tshaj plaws ua ke:

• Kub ntawm kev sib xyaw ua ke: Tswj tau hauv qhov ntau ntawm 220-280 ° C (qis dua selenium lub kub npau ntawm 685 ° C)
• Lub zog ntawm lub cev: Tswj ntawm 1-10 Pa
• Tus nqi cua sov: 5-10 ° C / feeb kom tsis txhob muaj kev ua pa thiab kev nkag mus rau hauv tsheb ciav hlau
• Qhov kub ntawm thaj chaw uas muaj dej noo: Khaws cia ntawm 50-80 ° C kom ntseeg tau tias cov selenium sib sau ua ke tag nrho

3. Kev Siv Tshuab Distillation Ntau Theem

Kev sib xyaw ua ke ntau theem tuaj yeem txo cov pa oxygen maj mam:

• Theem Ib: Kev rho tawm cov khoom tsis huv uas yooj yim hloov pauv
• Theem Ob: Kev tswj qhov kub kom raug kom sau tau cov feem tseem ceeb
• Theem Peb: Kub qis, qeeb distillation kom tau txais cov khoom purity siab
  Cov kub sib txawv ntawm cov dej noo tuaj yeem siv tau ntawm cov theem rau cov dej noo sib xyaw ua ke

III. Kev Ntsuas Txheej Txheem Pabcuam

1. Kev Siv Tshuab Tiv Thaiv Pa roj Inert

Txawm hais tias ua haujlwm hauv lub tshuab nqus tsev, kev qhia txog cov roj inert uas muaj cov pa oxygen ntau yuav pab txo cov pa oxygen:

• Tom qab tshem tawm lub kaw lus, sau nrog cov argon purity siab (purity ≥99.9995%) mus rau 1000 Pa
• Siv kev tiv thaiv roj dynamic, txuas ntxiv qhia me me ntawm argon (10-20 sccm)
• Nruab cov tshuab lim roj ua haujlwm zoo ntawm cov qhov nkag roj kom tshem tawm cov pa oxygen thiab cov dej noo seem

2. Ntxiv cov tshuaj Oxygen Scavengers

Ntxiv cov tshuaj oxygen scavengers kom tsim nyog rau cov khoom siv raw tuaj yeem txo cov pa oxygen:

• Magnesium hlau: Muaj zog affinity rau oxygen, tsim MgO
• Hmoov txhuas: Muaj peev xwm tshem tawm cov pa oxygen thiab sulfur tib lub sijhawm
• Cov hlau tsis tshua muaj hauv ntiaj teb: Xws li Y, La, thiab lwm yam, nrog rau cov teebmeem tshem tawm cov pa oxygen zoo heev
  Tus nqi ntawm cov pa oxygen scavenger feem ntau yog 0.1-0.5 wt% ntawm cov khoom siv raw; cov nyiaj ntau dhau yuav cuam tshuam rau selenium purity.

3. Kev Siv Tshuab Lim Dej Molten

Lim cov selenium uas yaj ua ntej distillation:

• Siv cov lim dej quartz lossis ceramic nrog qhov loj me ntawm 1-5 μm
• Tswj qhov kub ntawm kev lim dej ntawm 220-250 ° C
• Yuav tshem tawm cov khoom oxide khov kho
• Cov lim dej yuav tsum tau ua ntej-degassed nyob rau hauv lub tshuab nqus tsev siab

IV. Tom Qab Kho Mob thiab Khaws Cia

1. Kev Sau Khoom thiab Kev Tswj Xyuas

• Tus condenser collector yuav tsum tau tsim los ua ib qho qauv detachable rau cov khoom siv yooj yim nrhiav tau hauv ib puag ncig inert
• Cov selenium ingots uas tau sau los yuav tsum tau ntim rau hauv lub thawv hnab looj tes argon.
• Kev txiav cov nto yuav raug ua yog tias tsim nyog kom tshem tawm cov txheej oxide uas muaj peev xwm

2. Kev Tswj Xyuas Qhov Xwm Txheej Cia Khoom

• Qhov chaw cia khoom yuav tsum khaws cia kom qhuav (dew point ≤-60 ° C)
• Siv cov ntim khoom kaw ob txheej uas muaj cov roj inert siab purity
• Qhov kub cia khoom pom zoo kom qis dua 20°C
• Tsis txhob raug lub teeb kom tiv thaiv kev ua kom tsis txhob muaj cov tshuaj tiv thaiv photocatalytic oxidation

V. Kev Tswj Xyuas Zoo thiab Kev Ntsuas

1. Kev Siv Tshuab Saib Xyuas Hauv Online

• Nruab cov khoom ntsuas roj seem (RGA) los saib xyuas qhov siab ntawm cov pa oxygen hauv lub sijhawm tiag tiag
• Siv cov pa oxygen sensors los tswj cov pa oxygen hauv cov pa roj tiv thaiv
• Siv infrared spectroscopy los txheeb xyuas cov yam ntxwv ntawm kev nqus ntawm Se-O bonds

2. Kev Tshuaj Xyuas Khoom Tiav Lawm

• Siv txoj kev nqus pa inert gas fusion-infrared los txiav txim siab cov pa oxygen
• Kev ntsuas qhov hnyav ntawm cov ion theem ob (SIMS) los tshuaj xyuas kev faib tawm ntawm cov pa oxygen
• X-ray photoelectron spectroscopy (XPS) los ntes cov tshuaj lom neeg ntawm qhov chaw

Los ntawm cov kev ntsuas dav dav uas tau piav qhia saum toj no, cov pa oxygen tuaj yeem tswj tau qis dua 1 ppm thaum lub sijhawm nqus tsev distillation purification ntawm selenium, ua tau raws li qhov yuav tsum tau ua rau cov ntawv thov selenium purity siab. Hauv kev tsim khoom tiag tiag, cov txheej txheem txheej txheem yuav tsum tau ua kom zoo raws li cov xwm txheej ntawm cov khoom siv thiab cov khoom xav tau, thiab yuav tsum tsim kom muaj lub kaw lus tswj xyuas zoo.