Alumina waxaa la ogaaday inay jiraan ugu yaraan 8 foom, waxay yihiin α- Al2O3, θ-Al2O3, γ- Al2O3, δ- Al2O3, η- Al2O3, χ- Al2O3, κ- Al2O3 iyo ρ- Al2O3, hantidooda qaab-dhismeedka macroscopic. sidoo kale way kala duwan yihiin.Gamma activated alumina waa kiristaalo cubic ah oo isku dhow, oo aan lagu milmi karin biyaha, laakiin ku milma aashitada iyo alkali.Gamma activated alumina waa taageerada acidic daciif ah, waxay leedahay dhibic dhalaalaysa sare 2050 ℃, alumina gel qaab hydrate waxaa lagu samayn karaa oxide leh porosity sare iyo dusha sare gaar ah, waxay leedahay wejiyada kala guurka ee kala duwanaansho heerkulka ballaaran.Heerkulka sare, fuuq-baxa iyo fuuq-baxa, Al2O3 dusha sare waxay u muuqataa isuduwidda ogsijiinta aan saturated (xarunta alkali) iyo aluminium (xarun acid), oo leh firfircooni firfircoon.Sidaa darteed, alumina waxaa loo isticmaali karaa sida side, kicinta iyo cocatalyst.
Gamma fir-fircoon alumina waxay noqon kartaa budo, granules, strips ama kuwo kale.Waxaan sameyn karnaa sida looga baahan yahay.γ-Al2O3, waxaa loo yaqaan "alumina firfircoon", waa nooc ka mid ah qalabka adag ee kala firidhsan sare, sababtoo ah qaab-dhismeedka daloolka la hagaajin karo, aag gaar ah oo gaar ah, waxqabadka adsorption wanaagsan, dusha sare leh faa'iidooyinka aysidhka iyo xasilloonida kulaylka wanaagsan, dusha microporous oo leh sifooyinka lagama maarmaanka ah ee ficil catalytic, sidaas darteed noqdaan kicinta ugu ballaaran loo isticmaalo, side kiciya iyo side chromatography in warshadaha kiimikada iyo saliidda, iyo door muhiim ah in hydrocracking saliidda, hydrogenation sifaynta, hydrogenation dib u habaynta, falcelinta fuuq-baxa iyo habka nadiifinta qiiqa baabuurta.Gamma-Al2O3 waxaa si weyn loo isticmaalaa sida koriyaha kicinta sababtoo ah hagaajinta qaab dhismeedka daloolka iyo aysidhka dusha sare.Marka γ- Al2O3 loo isticmaalo sida side ah, ka sokow waxay yeelan karaan saamaynta si ay u kala firdhiso iyo xasilinta qaybaha firfircoon, sidoo kale waxay ku siin karaan xarunta firfircoon alkali acid, falcelinta synergistic la qaybaha firfircoon katalytic.Qaab dhismeedka daldaloolada iyo sifooyinka dusha sare ee kicinta waxay ku xiran yihiin sidaha γ-Al2O3, sidaa darteed side wax qabad sare waxaa laga heli karaa falcelin catalytic gaar ah iyadoo la xakameynayo sifooyinka side gamma alumina.
Gamma activated alumina guud ahaan waxaa laga sameeyaa been abuur-boehmite iyada oo loo marayo 400 ~ 600 ℃ fuuqbaxa heerkulka sare, sidaas darteed sifooyinka physicochemical ee dusha sare waxaa lagu go'aamiyaa horudhac-boehmite, laakiin waxaa jira siyaabo badan oo loo sameeyo pseudo-boehmite, iyo ilo kala duwan. ee been abuurka-boehmite waxay keenaysaa kala duwanaanshaha gamma - Al2O3.Si kastaba ha ahaatee, kuwa kicinta leh shuruudo gaar ah si ay alumina side, kaliya ku tiirsan tahay gacanta ku precursor been abuur ah-boehmite waa adag tahay in la gaaro, waa in la qaado si ay prophase diyaarinta iyo post processing isku daraan habab si loo hagaajiyo sifooyinka alumina si ay ula kulmaan shuruudaha kala duwan.Marka heerkulku ka sarreeyo 1000 ℃ isticmaalka, alumina waxay dhacdaa soo socota isbeddelka wajiga: γ→δ→θ→α-Al2O3, oo ay ku jiraan γ,δ, tetrahedral iyo octahedral, markaa isbeddelka wejigani ma keeno kala duwanaansho badan oo dhismayaasha ah.Iunyada ogsijiinta ee wejiga alfa waa xidhidh laba geesood ah, qaybaha aluminium oksaydhku waa dib u midoobid weyn, aag gaar ah oo dusha sare ah ayaa si weyn hoos ugu dhacay.
Ka fogow qoyaanka, iska ilaali duuduubka, tuurista iyo naxdinta fiiqan inta lagu jiro gaadiidka, tas-hiilaadka aan roobka lahayn waa in la diyaariyaa.
Waa in lagu kaydiyaa bakhaar qallalan oo hawo leh si looga hortago wasakh ama qoyaan.
