Alumina waxaa la ogaaday inay ugu yaraan jiraan 8 qaab, waa α- Al2O3, θ-Al2O3, γ- Al2O3, δ- Al2O3, η- Al2O3, χ- Al2O3, κ- Al2O3 iyo ρ- Al2O3, sifooyinka qaab-dhismeedka macroscopic-ga ah ee ay leeyihiin sidoo kale way kala duwan yihiin. Alumina-da firfircoon ee Gamma waa kiristaalo ku xiran cubic closed, oo aan ku milmin biyaha, laakiin ku milma aashitada iyo alkali. Alumina-da firfircoon ee Gamma waa taageero aashito oo daciif ah, waxay leedahay dhibic dhalaalid sare 2050 ℃, jel alumina ah oo qaab hydrate ah ayaa laga samayn karaa oksaydhka oo leh dalool sare iyo dusha sare oo gaar ah, waxay leedahay marxalado kala-guur ah oo heerkul ballaaran ah. Heerkulka sare, sababtoo ah fuuq-baxa iyo dehydration, dusha sare ee Al2O3 waxay u muuqataa isku-dubarid oksijiin aan dheregsanayn (xarunta alkali) iyo aluminium (xarunta aashitada), oo leh firfircooni katalytic ah. Sidaa darteed, alumina waxaa loo isticmaali karaa sidii side, kiciye iyo kokatalyst.
Alumina-da firfircoon ee Gamma waxay noqon kartaa budo, granules, strips ama kuwa kale. Waxaan u samayn karnaa sida aad u baahan tahay. γ-Al2O3, oo loogu magac daray "alumina firfircoon", waa nooc ka mid ah walxaha adag ee kala firdhisan ee daloolada sare leh, sababtoo ah qaab-dhismeedka daloolada la hagaajin karo, bedka dusha sare ee weyn, waxqabadka nuugista wanaagsan, dusha sare ee leh faa'iidooyinka aashitada iyo xasilloonida kulaylka wanaagsan, dusha sare ee microporous leh sifooyinka lagama maarmaanka u ah ficilka catalytic, sidaas darteed waxay noqotaa kaaliyeyaasha ugu badan ee loo isticmaalo, kaaliyeyaasha qaada iyo kaaliyeyaasha chromatography ee warshadaha kiimikada iyo saliidda, waxayna door muhiim ah ka ciyaartaa hydrocracking saliidda, sifeynta hydrogenation, dib-u-habaynta hydrogenation, falcelinta dehydrogenation iyo habka nadiifinta qiiqa baabuurta. Gamma-Al2O3 waxaa si weyn loogu isticmaalaa sida kaaliyeyaasha sababtoo ah la hagaajin karo qaab-dhismeedka daloolada iyo aashitada dusha sare. Marka γ-Al2O3 loo isticmaalo sida kaaliyeyaasha, marka laga reebo waxay yeelan kartaa saameynta kala firdhinta iyo xasilinta qaybaha firfircoon, waxay sidoo kale bixin kartaa xarun firfircoon oo alkali ah, falcelin isku-dhafan oo leh qaybaha firfircoon ee kaaliyeyaasha. Qaab-dhismeedka daloolka iyo sifooyinka dusha sare ee kiciyaha waxay ku xiran yihiin side γ-Al2O3, sidaa darteed side waxqabad sare leh ayaa loo heli doonaa falcelinta catalytic gaar ah iyadoo la xakameynayo sifooyinka side gamma alumina.
Alumina-da firfircoon ee Gamma waxaa guud ahaan laga sameeyaa pseudo-boehmite-keeda horudhaca ah iyada oo loo marayo fuuq-bax heerkul sare ah oo ah 400 ~ 600℃, sidaa darteed sifooyinka fiisikokimikada dusha sare waxaa inta badan lagu go'aamiyaa pseudo-boehmite-ka horudhaca ah, laakiin waxaa jira siyaabo badan oo loo sameeyo pseudo-boehmite, ilo kala duwan oo pseudo-boehmite ahna waxay horseedaa kala duwanaanshaha gamma - Al2O3. Si kastaba ha ahaatee, kiciyeyaashaas leh shuruudo gaar ah oo loogu talagalay side-ka alumina, kaliya waxay ku tiirsan yihiin xakamaynta pseudo-boehmite-ka horudhaca ah way adag tahay in la gaaro, waa in loo qaato hab isku-darka diyaarinta iyo ka dib habaynta si loo hagaajiyo sifooyinka alumina si loo daboolo shuruudaha kala duwan. Marka heerkulku ka sarreeyo 1000 ℃ ee la isticmaalo, alumina waxay dhacdaa ka dib isbeddelka wejiga: γ→δ→θ→α-Al2O3, oo ay ka mid yihiin γ、δ、θ waa xirmo ku dhow cubic, farqigu wuxuu ku jiraa oo keliya qaybinta ion-yada aluminium ee tetrahedral iyo octahedral, sidaa darteed isbeddelka wejigani ma keeno kala duwanaansho badan oo qaab-dhismeedka ah. Aayooyinka oksijiinta ee marxaladda alfa waa xirmo isku xiran oo lix-geesood ah, walxaha aluminium oksaydhka ah waa dib-u-mideyn weyn, aagga dusha sare ee gaarka ah ayaa si weyn hoos ugu dhacay.
Iska ilaali qoyaanka, iska ilaali rogrogmada, tuurista iyo gariirka fiiqan inta lagu jiro gaadiidka, waa in la diyaariyaa goobaha roobka ka hortaga.
Waa in lagu kaydiyaa bakhaar qalalan oo hawo leh si looga hortago wasakhowga ama qoyaanka.
