Alumina waxaa la ogaaday inay jiraan ugu yaraan 8 qaab, waxay yihiin α- Al2O3, θ-Al2O3, γ- Al2O3, δ- Al2O3, η- Al2O3, χ- Al2O3, κ- Al2O3 iyo ρ- Al2O3, sidoo kale sifooyinka qaab-dhismeedka macroscopic ee kala duwan. Gamma activated alumina waa kiristaalo cubic ah oo ku dhow, 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 jel ee foomka hydrate waxaa lagu samayn karaa oksaydhka 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 awgeed, dusha sare ee Al2O3 wuxuu u muuqdaa 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 daloolin, sababtoo ah ay qaab-dhismeedka dalool hagaajin karo, aagga weyn oo gaar ah, waxqabadka adsorption wanaagsan, dusha leh faa'iidooyinka aysidhka iyo xasilloonida kulaylka wanaagsan, dusha microporous la guryaha u baahan ee tallaabo carystritic, Sidaa darteed waxay noqon kartaa carystriper chromographer ee ugu ballaaran ee loo isticmaalo. warshadaha kiimikada iyo saliidda, oo waxay door muhiim ah ka ciyaara hydrocracking saliidda, hydrogenation sifaynta, hydrogenation dib u habaynta, falcelinta fuuqbaxa iyo habka nadiifinta qiiqa baabuurta.Gamma-Al2O3 waxaa si ballaaran loo isticmaalaa sida side kicin sababtoo ah hagaajinta ee ay qaab-dhismeedka dalool iyo acidity dusha. 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 guryaha physicochemical ee dusha sare ayaa inta badan lagu go'aamiyaa precursor-boehmite, laakiin waxaa jira siyaabo badan oo loo sameeyo been-boehmite, iyo ilo kala duwan oo been abuur ah -boehmite. Si kastaba ha ahaatee, kuwa kicinta shuruudaha gaarka ah si ay alumina side, kaliya ku tiirsan tahay kantaroolka 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 ay u hagaajiyaan sifooyinka alumina si ay u buuxiyaan shuruudaha kala duwan. Marka heerkulku ka sarreeyo 1000 ℃ isticmaalka, alumina waxay dhacdaa soo socota isbeddelka wajiga: γ→δ→θ→α-Al2O3, iyaga ka mid ah γ、δ、θ waa xirmo dhow oo cubic ah, farqiga u dhexeeya kaliya wuxuu ku jiraa qaybinta aluminium aluminium ee tetrahedral iyo octahedral, sidaas darteed isbeddelka qaabdhismeedkani ma keeno qaab-dhismeedka. 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.
