No ka loaʻa ʻana o ka alumini mai ka bauxite, ʻo ia hoʻi ka haʻalele ʻana i ka alumini trioxide mai ka bauxite. No ka hoʻokō ʻana i ke kumu, aia ʻekolu mau ala e komo pū ana me: ke ʻano waikawa, ke ʻano alkali, ke ʻano hui pū ʻia o ka waikawa-base a me ke ʻano thermal. Eia nō naʻe, ʻaʻole hoʻohana nui ʻia ke ʻano waikawa, ke ʻano hui pū ʻia o ka waikawa-base a me ke ʻano thermal i ka ʻoihana ma muli o ka palekana a me nā pono waiwai. Hoʻohana ʻia ke ʻano alkaline i ka hana ʻoihana.

Aia he 3 mau ʻano hana no ka unuhi ʻana i ka alumina trioxide me ka hoʻohana ʻana i ke ʻano alkaline ʻo ia ke ʻano calcination, ke ʻano bayer a me ke ʻano hui pū ʻia. E lawe mākou i ke ʻano calcination ma ke ʻano he laʻana.

ʻAno Calcination: Ke kau nei i kahi nui o ka calcium carbonate i loko o ka bauxite, kahi mea nona ka sodium aluminate i hoʻokumu ʻia ma hope o ka calcination wela kiʻekiʻe i loko o kahi umu wili. ʻO ka hope loa, loaʻa ka alumina ma hope o ka hoʻoheheʻe ʻana, ka crystallization a me ke kālua ʻana.