Cov cua sov ruaj khov ntawm kev txhawb nqa alumina
Qhib alumina tau siv dav hauv thaj chaw catalytic raws li kev txhawb nqa catalyst thauj khoom vim nws qhov tshwj xeeb cov qauv pore thiab cov khoom nto. Ib feem tseem ceeb ntawm cov tshuaj tiv thaiv catalytic tau ua nyob rau hauv ib puag ncig hydrothermal, xws li amination, hydration, dehydration, oxychlorination, carbonylation, catalytic combustion thiab selective catalytic oxidation ntawm methane. Hauv cov txheej txheem ntawm qhov ntsuas kub qis catalytic cov tshuaj tiv thaiv, cov khoom siv alumina muaj peev xwm tuaj yeem rov ua dej hauv qab cov dej txias. Cov khoom boehmite tau tsim hauv qab 100 ℃, cov khoom muaj dej ntawm 100 ~ 110 ℃ yog sib xyaw ntawm boehmite thiab boehmite, thiab cov khoom saum toj no 110 ℃ yog boehmite; Thaum kub siab, γ- Kev kub kub ua kom sov thiab hloov pauv ntawm Al2O3 qhib cov khoom siv alumina yuav ua rau txo qis kev thauj khoom tshwj xeeb thaj chaw, kev puas tsuaj ntawm cov qauv pore lossis kev ua kom tsis muaj zog ntawm catalyst. Ib qho ntxiv, cov dej ua pa yuav txuas ntxiv txuas ntxiv nrog alumina, txhawb kev tsim txuas ntxiv ntawm al-o-al choj sib txuas ntawm alumina hais, ua rau cov sintering nto hnyav ntxiv, ua rau txo qhov tshwj xeeb ntawm thaj chaw thiab ua rau lub catalyst tsis ua haujlwm. Yog li, nws yog qhov tseem ceeb heev los npaj ua kom muaj zog alumina txhawb nrog kev ruaj ntseg hydrothermal siab rau catalytic cov tshuaj tiv thaiv hauv ib puag ncig hydrothermal.
Cov kws tshawb fawb tau ua tiav kev tshawb fawb dav dav ntawm cov thermal stability ntawm activated alumina. Cov txheej txheem ntawm kev ua txhaum thiab hloov pauv ntawm alumina yog tias muaj ntau lub tetrahedral thiab octahedral txoj haujlwm tsis nyob hauv nws qhov ntau. Nyob rau tib lub sijhawm, kev sib koom ua ke ntawm aluminium hais rau saum npoo yog tsis txaus. Thaum muaj qhov kub thiab txias thiab muaj dej ua pa, cov haujlwm no tau dhau los ua haujlwm, thiab cov pab pawg hydroxyl nruab nrab ntawm alumina hais tawm, ua rau txo qis ntawm thaj chaw tshwj xeeb thiab hloov pauv zaum kawg rau se Phase. Yog li ntawd, txhim kho cov txheej txheem kev npaj, ntxiv cov tshuaj ruaj khov thiab tsim cov tshuaj tshiab tuaj yeem tiv thaiv kev ua txhaum thiab hloov pauv ntawm alumina.