Arsenic distillation thiab purification txheej txheem

arsenic distillation thiab purification txheej txheem yog ib txoj kev uas siv qhov sib txawv ntawm volatility ntawm arsenic thiab nws cov tebchaw los cais thiab purify, tshwj xeeb tshaj yog haum rau tshem tawm sulfur, selenium, tellurium thiab lwm yam impurities nyob rau hauv arsenic.Nov yog cov kauj ruam tseem ceeb thiab kev xav txog:

1.Raw khoom pretreatment

• Qhov chaw ntawm crude arsenic: feem ntau yog los ntawm cov khoom lag luam ntawm smelting ntawm arsenic-muaj cov zaub mov (xws li arsenite, realgar) lossis cov khoom pov tseg uas muaj arsenic.
• Oxidative roasting(optional): Yog tias cov khoom siv raw yog arsenic sulfide (xws li As₂S₃), nws yuav tsum tau roasted ua ntej hloov mus rau volatile As₂O₃

As 2S3+9O2 →As2O3+3SO2As2S3+9O2 →As2O3 + 3SO2

2.Distillation unit

• Khoom siv: Quartz lossis ceramic tseem (corrosion resistant, kub resistant), nruab nrog condenser raj thiab txais lub raj mis.
• Inert kev tiv thaiv: Nitrogen los yog carbon dioxide yog qhia los tiv thaiv arsenic oxidation los yog explosion txaus ntshai (arsenic vapor yog flammable).

3.Cov txheej txheem distillation

• Kev tswj qhov kub thiab txias:
  • Arsenic sublimation: As₂O₃ sublimation ntawm 500-600 ° C (ntshiab arsenic sublimation ntawm txog 615 ° C).
  • Kev sib cais impurity: low-boiling impurities xws li sulfur thiab selenium yog qhov zoo tshaj plaws volatilized thiab tuaj yeem sib cais los ntawm segmented condensation.
• Condensation collection: Arsenic vapor condenses rau hauv high-purity As₂O₃ los yog elemental arsenic nyob rau hauv condensation cheeb tsam (100-200 ° C).

4.Tom qab ua tiav

• Kev txo qis(yog tias yuav tsum muaj arsenic elemental): Txo ntawm As₂O₃ nrog carbon lossis hydrogen

As 2O3 + 3H2 → 2As + 3H2OAs 2 O3 + 3H2 → 2As + 3H2O

• Nqus distillation: ntxiv purification ntawm elemental arsenic kom tshem tawm residual volatile impurities.

5.Cov kev ceev faj

• Kev tiv thaiv toxicity: Tag nrho cov txheej txheem yog kaw ua haujlwm, nruab nrog arsenic to detection thiab cov cuab yeej kho mob xwm txheej ceev.
• Tail kho gas: Tom qab condensation, tus Tsov tus tw roj yuav tsum tau absorbed los ntawm lye tov (xws li NaOH) los yog activated carbon adsorption kom tsis txhob As₂O₃tso pa tawm.
• arsenic hlau cia: khaws cia nyob rau hauv ib qho chaw inert los tiv thaiv oxidation los yog deliquescent.

6. Kev ntshiabTxhim kho

• Multi-theem distillation: Rov qab distillation tuaj yeem txhim kho qhov purity ntau dua 99.99%.
• Zone melting (optional): Zone refining ntawm elemental arsenic kom txo cov hlau impurities ntxiv.

Cov teb ntawm daim ntawv thov

High-purity arsenic yog siv rau hauv cov khoom siv semiconductor (xws li GaAscrystals), alloy additives, los yog nyob rau hauv kev tsim cov tsom iav tshwj xeeb. Processes yuav tsum tau ua raws li cov cai nruj ib puag ncig kom muaj kev nyab xeeb thiab ua raws li kev pov tseg pov tseg.