Ke Kaʻina Hana a me ka Hana ʻana o ka Pepa Keleawe

ʻO ka pepa keleawe, ʻo kēia pepa keleawe lahilahi loa, he hana hana palupalu a paʻakikī hoʻi. ʻO kēia kaʻina hana nui e pili ana i ka unuhi ʻana a me ka hoʻomaʻemaʻe ʻana i ke keleawe, ka hana ʻana i ka pepa keleawe, a me nā ʻanuʻu hana ma hope.

ʻO ka hana mua, ʻo ia ka unuhi ʻana a me ka hoʻomaʻemaʻe ʻana i ke keleawe. Wahi a ka ʻikepili mai ka United States Geological Survey (USGS), ua hōʻea ka hana honua o ka ore keleawe i 20 miliona tons i ka makahiki 2021 (USGS, 2021). Ma hope o ka unuhi ʻana i ka ore keleawe, ma o nā ʻanuʻu e like me ka kuʻi ʻana, ka wili ʻana, a me ka flotation, hiki ke loaʻa ka concentrate keleawe me kahi o 30% o ka nui o ke keleawe. A laila e hele ana kēia mau concentrate keleawe i kahi kaʻina hana hoʻomaʻemaʻe, me ka hoʻoheheʻe ʻana, ka hoʻomaʻemaʻe ʻana i ka mea hoʻololi, a me ka electrolysis, a laila e loaʻa ai ke keleawe electrolytic me ka maʻemaʻe e like me 99.99%.

ʻO ka mea aʻe ke kaʻina hana ʻana o ka pepa keleawe, hiki ke hoʻokaʻawale ʻia i ʻelua ʻano ma muli o ke ʻano hana ʻana: pepa keleawe electrolytic a me ka pepa keleawe i ʻōwili ʻia.

Hana ʻia ka pepa keleawe electrolytic ma o ke kaʻina hana electrolytic. I loko o kahi cell electrolytic, hoʻoheheʻe mālie ka anode keleawe ma lalo o ka hana a ka electrolyte, a neʻe nā ion keleawe, i hoʻokele ʻia e ke au, i ka cathode a hana i nā waihona keleawe ma ka ʻili cathode. ʻO ka mānoanoa o ka pepa keleawe electrolytic maʻamau mai 5 a 200 micrometers, hiki ke hoʻokele pololei ʻia e like me nā pono o ka ʻenehana papa kaapuni paʻi (PCB) (Yu, 1988).

ʻO ka pepa keleawe i ʻōwili ʻia, ma ka ʻaoʻao ʻē aʻe, hana ʻia me ka mīkini. E hoʻomaka ana mai kahi pepa keleawe he mau milimita ka mānoanoa, e hoʻomāmā mālie ʻia ma ka ʻōwili ʻana, a laila e hana i ka pepa keleawe me ka mānoanoa ma ka pae micrometer (Coombs Jr., 2007). ʻOi aku ka laumania o kēia ʻano pepa keleawe ma mua o ka pepa keleawe electrolytic, akā ʻoi aku ka nui o ka ikehu e hoʻopau ai kāna hana hana.

Ma hope o ka hana ʻia ʻana o ka pepa keleawe, pono ia e hana ma hope o ka hana ʻana, me ka annealing, ka mālama ʻana i ka ʻili, a me nā mea ʻē aʻe, e hoʻomaikaʻi i kāna hana. No ka laʻana, hiki i ka annealing ke hoʻonui i ka ductility a me ka paʻakikī o ka pepa keleawe, ʻoiai ʻo ka mālama ʻana i ka ʻili (e like me ka oxidation a i ʻole ka uhi ʻana) hiki ke hoʻonui i ke kūpaʻa i ka pala a me ka hoʻopili ʻana o ka pepa keleawe.

I ka hōʻuluʻulu manaʻo, ʻoiai he paʻakikī ke kaʻina hana a me ka hana ʻana o ka pepa keleawe, he hopena koʻikoʻi ka hopena o ka huahana i ko kākou ola hou. He hōʻike kēia o ka holomua ʻenehana, e hoʻololi ana i nā kumuwaiwai kūlohelohe i nā huahana ʻenehana kiʻekiʻe ma o nā ʻano hana hana pololei.

Eia nō naʻe, lawe mai ke kaʻina hana o ka hana ʻana i ka pepa keleawe i kekahi mau pilikia, me ka hoʻohana ʻana i ka ikehu, ka hopena o ke kaiapuni, a me nā mea ʻē aʻe. Wahi a kahi hōʻike, ʻo ka hana ʻana o 1 tone o ke keleawe e pono ai ma kahi o 220GJ o ka ikehu, a hoʻopuka i 2.2 tone o nā hoʻokuʻu kalapona dioxide (Northey et al., 2014). No laila, pono mākou e ʻimi i nā ala ʻoi aku ka maikaʻi a me ke aloha i ke kaiapuni e hana ai i ka pepa keleawe.

ʻO kahi hopena kūpono, ʻo ia ka hoʻohana ʻana i ke keleawe hana hou ʻia e hana i ka pepa keleawe. Ua hōʻike ʻia ʻo ka hoʻohana ʻana i ka ikehu o ka hana ʻana i ke keleawe hana hou ʻia he 20% wale nō o ke keleawe mua, a hoʻemi ia i ka hoʻohana ʻana i nā kumuwaiwai keleawe (UNEP, 2011). Eia kekahi, me ka holomua o ka ʻenehana, hiki iā mākou ke hoʻomohala i nā ʻenehana hana pepa keleawe ʻoi aku ka maikaʻi a me ka mālama ikehu, e hoʻemi hou ana i ko lākou hopena i ke kaiapuni.

I ka hopena, ʻo ke kaʻina hana a me ka hana ʻana o ka pepa keleawe he kahua ʻenehana piha i nā pilikia a me nā manawa kūpono. ʻOiai ua holomua nui mākou, nui nō ka hana e hana ʻia e hōʻoia i ka hiki i ka pepa keleawe ke hoʻokō i kā mākou mau pono o kēlā me kēia lā me ka pale ʻana i ko mākou kaiapuni.