Ua ʻike ʻia ka alumina ma ka liʻiliʻi he 8 ʻano, ʻo ia ʻo α- Al2O3, θ-Al2O3, γ- Al2O3, δ- Al2O3, η- Al2O3, χ- Al2O3, κ- Al2O3 a me ρ- Al2O3, ʻokoʻa hoʻi ko lākou mau waiwai macroscopic. ʻO ka alumina i hoʻoulu ʻia ʻo Gamma he pahu aniani i hoʻopili ʻia, ʻaʻole hiki ke hoʻoheheʻe ʻia i ka wai, akā hiki ke hoʻoheheʻe ʻia i ka waikawa a me ka alkali. ʻO ka alumina i hoʻoulu ʻia ʻo Gamma kahi kākoʻo waikawa nāwaliwali, loaʻa kahi helu hoʻoheheʻe kiʻekiʻe 2050 ℃, hiki ke hana ʻia ka alumina gel i loko o ka hydrate form i loko o ka oxide me ka porosity kiʻekiʻe a me ka ʻili kikoʻī kiʻekiʻe, aia nā pae hoʻololi i kahi ākea ākea. Ma ka wela kiʻekiʻe, ma muli o ka dehydration a me ka dehydroxylation, ʻike ʻia ka Al2O3surface i ka hui ʻana o ka oxygen unsaturated (ke kikowaena alkali) a me ka alumini (ke kikowaena waikawa), me ka hana catalytic. No laila, hiki ke hoʻohana ʻia ka alumina e like me ka mea lawe, catalyst a me ka cocatalyst.
ʻO ka alumina i hoʻoikaika ʻia ʻo Gamma he pauda, granules, strips a i ʻole nā mea ʻē aʻe. Hiki iā mākou ke hana e like me kāu koi.γ-Al2O3, ua kapa ʻia ʻo "alumina hoʻāla", he ʻano porous kiʻekiʻe dispersion paʻa mea paʻa, ma muli o kona ʻano pore hiki ke hoʻololi ʻia, kahi ākea ākea nui, hana adsorption maikaʻi, ʻili me nā pono o ka acidity a me ke kūpaʻa thermal maikaʻi, microporous ili me nā waiwai pono o ka catalytic hana, no laila e lilo i ka mea lawe nui a me ka catalyst. He hana koʻikoʻi ia i ka ʻaila hydrocracking, hydrogenation refining, hydrogenation reforming, dehydrogenation reaction a me ka hoʻomaʻemaʻe kaʻa kaʻa. Ke hoʻohana ʻia ʻo γ- Al2O3 ma ke ʻano he mea lawe, ʻoi aku ka hiki ke loaʻa i nā hopena e hoʻopuehu a hoʻopaʻa i nā mea hana, hiki ke hāʻawi i ke kikowaena alkali ikaika, ka hopena synergistic me nā mea hana catalytic. ʻO ke ʻano o ka pore a me nā waiwai ʻili o ka catalyst e pili ana i ka mea lawe γ-Al2O3, no laila e ʻike ʻia ka mea lawe hana kiʻekiʻe no ka hopena catalytic kikoʻī ma o ka hoʻomalu ʻana i nā waiwai o ka mea lawe gamma alumina.
Hana ʻia ka gamma activated alumina i kona precursor pseudo-boehmite ma o 400 ~ 600 ℃ dehydration wela kiʻekiʻe, no laila ua hoʻoholo nui ʻia nā waiwai physicochemical o ka honua e kona precursor pseudo-boehmite, akā he nui nā ala e hana ai i ka pseudo-boehmite, a me nā kumu like ʻole o ka pseudo-boehmite leadsO. Eia nō naʻe, i kēlā mau catalysts me nā koi kūikawā i ka lawe alumina, e hilinaʻi wale i ka mana o ka precursor pseudo-boehmite paʻakikī e hoʻokō, pono e lawe ʻia e wānana i ka hoʻomākaukau a me ka hoʻoili ʻana ma hope o ka hui ʻana i nā ala e hoʻoponopono ai i nā waiwai o ka alumina e hoʻokō i nā koi like ʻole. Ke kiʻekiʻe ka mahana ma mua o 1000 ℃ i ka hoʻohana ʻana, hiki ke alumina ma hope o ka hoʻololi ʻana o ka pae: γ→δ→θ→α-Al2O3, ma waena o lākou γ、δ、θ he cubic kokoke packing, aia wale nō ka ʻokoʻa i ka hāʻawi ʻana i nā ion alumini i ka tetrahedral a me ka octahedral, no laila ʻaʻole nui ka hoʻololi ʻana o ka hale. ʻO nā ion oxygen i loko o ka alpha phase he hexagonal hoʻopili pili, alumini oxide particles he grave reunion, kikoʻī o ka ʻili i emi nui.
lE pale i ka makū, pale i ka ʻōwili ʻana, hoʻolei a me ka haʻalulu ʻoi i ka wā o ka lawe ʻana, pono e hoʻomākaukau ʻia nā mea ua.
Pono e mālama ʻia i loko o kahi hale kūʻai maloʻo a hoʻoheheʻe ʻia i mea e pale ai i ka haumia a i ʻole ka makū.
