Alumina tau pom muaj tsawg kawg yog 8 daim ntawv, lawv yog α- Al2O3, θ-Al2O3, γ- Al2O3, δ- Al2O3, η- Al2O3, χ- Al2O3, κ- Al2O3 thiab ρ- Al2O3, lawv cov qauv macroscopic. kuj txawv.Gamma activated alumina yog lub cubic kaw ntim siv lead ua, insoluble hauv dej, tab sis soluble hauv acid thiab alkali.Gamma activated alumina tsis muaj zog acidic kev txhawb nqa, muaj lub siab melting point 2050 ℃, alumina gel nyob rau hauv daim ntawv hydrate tuaj yeem ua rau hauv cov oxide nrog cov porosity siab thiab siab tshwj xeeb nto, nws muaj qhov hloov pauv hauv qhov kub thiab txias.Thaum kub siab dua, vim lub cev qhuav dej thiab dehydroxylation, Al2O3surface zoo li kev sib koom ua ke unsaturated oxygen (alkali center) thiab aluminium (acid center), nrog rau kev ua haujlwm catalytic.Yog li ntawd, alumina tuaj yeem siv los ua cov cab, catalyst thiab cocatalyst.
Gamma activated alumina tuaj yeem yog hmoov, granules, strips lossis lwm yam.Peb tuaj yeem ua raws li qhov koj xav tau.γ-Al2O3, hu ua "activated alumina", yog ib yam ntawm cov khoom ntxeem tau siab dispersion khoom, vim nws cov qauv pore adjustable, qhov loj ntawm qhov chaw, kev ua haujlwm zoo adsorption, nto nrog qhov zoo ntawm acidity. thiab zoo thermal stability, microporous nto nrog cov khoom tsim nyog ntawm catalytic kev txiav txim, yog li ntawd dhau los ua cov catalyst feem ntau siv, catalyst carrier thiab chromatography cab kuj nyob rau hauv cov tshuaj thiab roj kev lag luam, thiab plays ib tug tseem ceeb luag hauj lwm nyob rau hauv cov roj hydrocracking, hydrogenation refining, hydrogenation reforming, Cov tshuaj tiv thaiv dehydrogenation thiab tsheb purification txheej txheem.Gamma-Al2O3 yog dav siv los ua catalyst cab kuj vim qhov adjustability ntawm nws pore qauv thiab nto acidity.Thaum γ- Al2O3 siv los ua tus nqa khoom, dhau li ntawd tuaj yeem muaj qhov cuam tshuam rau kev tawg thiab ruaj khov cov khoom siv, kuj tuaj yeem muab cov kua qaub alkali active chaw, synergistic cov tshuaj tiv thaiv nrog cov catalytic active Cheebtsam.Lub pore qauv thiab cov khoom nto ntawm catalyst nyob ntawm γ-Al2O3 cov cab kuj, yog li cov neeg nqa khoom ua haujlwm siab yuav pom muaj cov tshuaj tiv thaiv catalytic tshwj xeeb los ntawm kev tswj cov khoom ntawm gamma alumina carrier.
Gamma activated alumina feem ntau yog ua los ntawm nws cov precursor pseudo-boehmite los ntawm 400 ~ 600 ℃ siab kub lub cev qhuav dej, yog li lub nto physicochemical zog yog loj txiav txim los ntawm nws precursor pseudo-boehmite, tab sis muaj ntau ntau txoj kev los ua pseudo-boehmite, thiab ntau qhov chaw. ntawm pseudo-boehmite ua rau muaj ntau haiv neeg ntawm gamma - Al2O3.Txawm li cas los xij, rau cov catalysts nrog cov kev cai tshwj xeeb rau alumina carrier, tsuas yog tso siab rau kev tswj hwm ntawm precursor pseudo-boehmite yog qhov nyuaj rau kev ua tiav, yuav tsum tau coj mus rau kev npaj thiab kev ua tiav tom qab kev sib txuas ua ke los kho cov khoom ntawm alumina kom tau raws li cov kev xav tau sib txawv.Thaum qhov kub siab tshaj 1000 ℃ hauv kev siv, alumina tshwm sim tom qab hloov pauv theem: γ → δ → θ → α-Al2O3, ntawm lawv γ, δ, θ yog cubic kaw, qhov sib txawv tsuas yog nyob rau hauv kev faib tawm ntawm txhuas ions hauv tetrahedral thiab octahedral, yog li cov kev hloov pauv theem no tsis ua rau muaj kev hloov pauv ntau ntawm cov qauv.Oxygen ions nyob rau hauv alpha theem yog hexagonal kaw packing, txhuas oxide hais yog grave reunion, tej thaj chaw deg poob considerably.
lAv tsis txhob ya raws, tsis txhob scrolling, pov thiab ntse shocking thaum lub sij hawm kev thauj mus los, rainproof chaw yuav tsum tau npaj..
Nws yuav tsum tau muab cia rau hauv qhuav thiab ventilated warehouse kom tsis txhob muaj kab mob los yog ya raws.
