Ua ʻike ʻia ka alumina ma kahi o 8 mau ʻano, ʻo ia ka α- Al2O3, θ-Al2O3, γ- Al2O3, δ- Al2O3, η- Al2O3, χ- Al2O3, κ- Al2O3 a me ρ- Al2O3, ko lākou mau waiwai macroscopic. ʻokoʻa nō hoʻi. 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, i kapa ʻia ʻo "alumina hoʻāla ʻia", he ʻano mea paʻa paʻa kiʻekiʻe dispersion porous, no ka mea hiki ke hoʻololi ʻia kona ʻano pore, ʻāpana kikoʻī nui, hana adsorption maikaʻi, ʻili me nā pono o ka acidity. a maikaʻi thermal paʻa, microporous ili me requisite waiwai o catalytic hana, no laila e lilo i ka loa hoʻohana 'ia catalyst, catalyst lawe a me ka chromatography lawe i loko o ka kemika a me ka aila 'oihana, a pāʻani i ka mea nui i loko o ka aila hydrocracking, hydrogenation hoʻomaʻemaʻe, 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 ʻo Gamma activated alumina i kāna 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 pseudo-boehmite alakai i ka like ole o ka gamma - Al2O3. 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, i waena o lākou γ、δ、θ he cubic close packing, aia ka ʻokoʻa i ka hāʻawi ʻana i nā ion alumini i loko. tetrahedral a me ka octahedral, no laila, ʻaʻole e hoʻololi nui kēia mau hoʻololi ʻana i nā 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.
