ʻO ke Kaʻina Hana Hoʻomaʻemaʻe Wai ʻino ʻO Cyanide Gold

I kēia manawa, ʻo ke ʻano hana unuhi gula cyanide kekahi o nā kaʻina hana nui no ka hoʻoheheʻe gula ma Kina. Hoʻohana ia i ka hopena cyanide e unuhi i ke gula mai nā ores, e hōʻike ana i ka wikiwiki hoʻōla kiʻekiʻe, ka hiki ke hoʻololi ikaika i nā waiwai ore, a me ka hiki ke hana i ke gula ma kahi. Mai ka hoʻohana mua ʻana o ka hopena cyanide e hoʻokuʻu i ke gula mai nā ores i ka makahiki 1887. ua hoʻohana nui ʻia kēia ʻano hana a hiki i kēia manawa. Eia nō naʻe, hoʻopuka ka unuhi gula cyanide i ka nui o nā mea ʻawahia a me nā mea ʻino, e hoʻoweliweli nui ana i ke kaiapuni a puni a me nā kānaka. No laila, i mea e hōʻemi ai i ka pōʻino, pono e aʻo i nā ʻano hana mālama o ka wai hoʻoheheʻe gula cyanide. Ua hōʻuluʻulu ka nui o nā mea noiʻi i nā ʻano hana mālama, nā loina kemika, a me nā ʻano hoʻomohala o ka wai hoʻoheheʻe cyanide, akā ʻo ka hapa nui o lākou e kūkākūkā wale i hoʻokahi a ʻelua paha mau ʻano. No laila, hana kēia ʻatikala i kahi loiloi kikoʻī o nā ʻano hana mālama like ʻole no ka wai hoʻoheheʻe gula cyanide i hoʻohana ʻia i kēia manawa ma ka ʻoihana, hoʻohālikelike i nā pono, nā hemahema, a me nā hiʻohiʻona noi o kēlā me kēia ʻano hana, nona kekahi alakaʻi koʻikoʻi no nā noi like i ka hana maoli.

I. Nā Puna a me nā pōʻino o ka wai ʻōpala ʻo Cyanide Gold

ʻO ke kumumanaʻo nui o ka unuhi ʻana i ke gula cyanide, ʻo ia ka mea i loko o kahi ʻano aerobic, hana ka sodium cyanide me ke gula e hana i nā hui gula, a laila hoʻoheheʻe ʻia. Ma hope o kēlā, hiki ke unuhi ʻia ke gula ma o ka hoʻonui ʻana ma o ka adsorption Carbon i hoʻāla ʻia a i ʻole i hoʻoneʻe ʻia e ka pauka zinc mai ke gula cyanide. I ka manawa like, ʻo nā metala kaumaha ʻē aʻe e like me ke kālā, ke keleawe, a me ka zinc e hana pū i nā hui a hoʻoheheʻe ʻia.

ʻO nā cyanides i hoʻohana ʻia i ka hopena a me nā hui i hana ʻia he mau mea ʻawahia a hōʻino. He maʻalahi ka hydrolyze ʻana o ka sodium cyanide a he mea ʻawahia loa ia o ka Papa 1, me kahi mahele make o 0.10g. Ke kahe nā Cyanide i loko o nā kino wai, he mea hōʻino loa ia i nā meaola i loko o ka wai, a e hoʻoweliweli nui i nā kānaka a me ke kaiapuni a puni. No laila, he mea nui ka mālama ʻana i ka wai hoʻoheheʻe gula cyanide.

II. ʻO nā ʻano Lapaʻau Nui no ka wai ʻōpala ʻo Cyanide Gold Extraction

ʻO ke ʻano hoʻoheheʻe alkaline

ʻO ke ʻano alkaline chlorination i kēia manawa kekahi o nā ala maʻamau i hoʻohana ʻia no ka mālama ʻana i ka cyanide - loaʻa ka wai ʻōpala mai ka ʻohi gula cyanide. Hoʻohana nui ʻo ia i nā mea hoʻokahe chlorine e hoʻoheheʻe i nā cyanides i loko o ka wai ʻino ma lalo o nā kūlana alkaline, e hoʻohuli iā lākou i mea ʻawaʻawa ʻole. Hoʻokaʻawale ʻia ka cyanide-breaking process o ka alkaline chlorination i ʻelua mau pae:

ʻO ka pae mua ka hoʻoheheʻe ʻana i ka cyanide i ka cyanate, i kapa ʻia ʻo ke ʻano o ka "oxidation incomplete". Hoʻopili ʻo CN⁻ me OCl⁻ e hana mua i CNCl, a laila hydrolyzes i CNO⁻. Pono e hoʻomaopopo ʻia ʻo CNCl he mea maʻalahi a ʻawaʻawa ma lalo o nā kūlana acidic. No laila, i ka wā o ka hana ʻana, pono e mālama pono ʻia ka waiwai pH i loko o kahi kūlana alkaline.

ʻO ka lua o ka pae, ʻo ia ka hoʻomaʻamaʻa hou ʻana i ka cyanate i carbon dioxide a me ka nitrogen, i kapa ʻia ʻo ke ʻano o ka "oxidation piha". I ka wā o ka cyanide-breaking kaʻina, he hopena nui ka pH waiwai i ka hopena oxidation. Pono e ho'omalu 'ia ka pH waiwai o ka mua - pae oxidation ma 10 - 11. a 'o ka manawa pane he 10 - 15 minuke. Pono e ho'omalu 'ia ka waiwai pH o ka lua o ka 'oxidation ma 6.5 - 7.0. a ʻo ka manawa pane he 10 - 15 mau minuke.

Hoʻohana kekahi mine i ke ʻano alkaline chlorination no ka mālama ʻana i ka supernatant o ka slurry huelo cyanide (me ka cyanide maʻiʻo o 200mg/L) a me ka wai kahe mai ka pahu sedimentation (me ka cyanide maʻiʻo o 5mg/L). Hoʻopili ʻia ka waiwai pH ma 10 - 11. a hoʻohui ʻia ka pauka bleaching ma kahi ratio o 35 - 40 mau manawa o ka cyanide content no ka hui ʻana a me ka hoʻoulu ʻana. Ma hope o ka sedimentation i loko o kahi mānoanoa, hiki ke hoʻemi ʻia ka nui o ka cyanide i 0.1mg/L.

ʻO ke ʻano alkaline chlorination ka hana maʻamau i hoʻohana ʻia no ka mālama ʻana i ka cyanide - i loko o ka wai ʻino, a ʻo ka pauka bleaching ka mea hoʻohana maʻamau i ka chlorine-based oxidant. He kūpono kēia ʻano hana no ka mālama ʻana i ka wai ʻōpala cyanide gula me ka haʻahaʻa haʻahaʻa. Hiki iā ia ke wehe i ka thiocyanate a me ka cyanide - loaʻa nā paʻakikī (koe wale nā ​​paʻakikī ferrocyanide). Loaʻa ka lāʻau lapaʻau, maʻalahi ke kānana i ke koena o ka ʻōpala i hana ʻia, a maʻalahi ka hana. Eia nō naʻe, ʻoi aku ka paʻakikī o ka hana i ka wā e hoʻohana ai i ka pauka bleaching e mālama i ka wai ʻino. I kēia manawa, hoʻohana kekahi mau ʻoihana i ka wai bleaching a i ʻole chlorine dioxide, kahi e hoʻomaikaʻi ai i ke kaiapuni hana i kekahi ʻano. Akā, hana ʻia nā kinoea ʻawaʻawa i ka wā o ke kaʻina hana, a he nui kona corrosiveness i nā mea hana. He kiʻekiʻe ke kumukūʻai o ka lāʻau a me ka mālama ʻana.

Hana Paʻakai Paʻakai Ferrous

ʻO ke ʻano paʻakai paʻakai ferrous kahi ʻano lapaʻau no ka wai ʻōpala cyanide gula i puka mai i nā makahiki i hala. Ma ka hoʻomalu ʻana i ka waiwai pH hopena ma 7 - 8. hoʻopili ʻia nā ion ferrous me ka cyanide manuahi a me kekahi mau cyanide complexes i loko o ka wai ʻōpala ʻohi gula cyanide e hoʻohua ai i nā precipitates.

Ua hōʻike ʻia nā hoʻokolohua ma ke ʻano maʻamau, ʻo ka hoʻohui ʻana i ka ferrous sulfate wale nō e mālama i ka wai ʻōpala ʻohi gula cyanide ʻaʻole hiki ke hoʻokō i ka wai ʻōpala i nā kūlana hoʻokuʻu. No laila, pono e hoʻohui ʻia kahi oxidant maʻamau i ka wai ʻino i mālama ʻia no ka wehe hohonu - cyanide. ʻOiai ke hoʻomalu maikaʻi ʻia nā kūlana, hiki ke hoʻohui pololei ʻia ka oxidant no ka mālama ʻana me ka ʻole e hoʻokaʻawale i ka precipitate, a hiki ke hoʻokō ʻia ke kūlana hoʻokuʻu. He koʻikoʻi koʻikoʻi kēia i hoʻohālikelike ʻia me ke ʻano kuʻuna o ka hoʻokaʻawale ʻana ma mua a laila mālama ʻia.

Hoʻohana kekahi mea hoʻoheheʻe gula i ka sodium sulfide - ferrous sulfate ala e mālama ai i ka cyanide - wai maikaʻi ʻole. Loaʻa i ka influent kahi maʻi cyanide o 2500mg/L. Ma hope o ka hoʻomaʻamaʻa ʻana, loaʻa i ka effluent kahi cyanide ma lalo o 20mg/L, me ka nui o ka wehe ʻana o 99.2%, e hōʻike ana i nā hopena kupaianaha. Hoʻohana ka lāʻau hohonu i ka sodium metabisulfite - ea e hōʻemi i ka nui o ka cyanide ma lalo o 0.4mg/L.

ʻO ke ʻano o ka paʻakai paʻakai ferrous kahi ʻano lapaʻau hou e kū nei, i hoʻohana nui ʻia no ka mālama ʻana i ka cyanide kiʻekiʻe - i loko o ka wai ʻōpala. He mea maʻalahi kona kaʻina hana, he liʻiliʻi ka hoʻopukapuka hoʻokahi manawa, maʻalahi ka hana, ʻo ka lāʻau lapaʻau (ʻoi aku ka nui o ka ferrous sulfate) i loaʻa ākea, maʻalahi, a maʻalahi hoʻi e hoʻohana. Eia nō naʻe, no ka mea, he acidic ka hopena ferrous sulfate, i ka wā i hui ʻia me ka cyanide gula extraction wastewater, lilo ka wahi kūloko i acidic, a aia kahi hiki ke hana i ke kinoea hydrogen cyanide. Eia kekahi, ʻaʻole hiki iā ia ke wehe i ka thiocyanate, a ʻo ka wai ʻino i mālama ʻia e pono ai ka mālama hohonu e hoʻokō i nā kūlana hoʻokuʻu.

ʻO Sodium Metabisulfite - Ke ʻano ea

Hoʻokumu ʻia ke ʻano sodium metabisulfite - ea mai ka sulfur dioxide - ea ala. Hoʻohana nui ia i ka hopena synergistic o ka sodium metabisulfite a me ka ea ma nā cyanides i loko o ka wai ʻino i loko o kahi pae pH, me ka hopena catalytic o nā ion keleawe, e oxidize CN⁻ i CNO⁻.

Inā kiʻekiʻe ka maʻiʻo cyanide i loko o ka cyanide - loaʻa ka wai ʻino, hiki ke hana mua ʻia ka mālama ʻana e hoʻemi i ka nui o ka cyanide i lalo o 100mg/L. A laila, hoʻohui ʻia ka sodium metabisulfite a me ke keleawe sulfate, lawa ka ea i hoʻokomo ʻia, a mālama ʻia ka waiwai pH (mālama ʻia ma 7 - 8), no laila ua oxidized ka cyanide i cyanate, a laila hydrolyzed e hana i nā ion bicarbonate a me ka amonia.

ʻO ka sodium metabisulfite - ea ala kūpono no ka mālama ʻana i ka wai ʻōpala cyanide gula haʻahaʻa. He liʻiliʻi ke ʻano o ka lāʻau lapaʻau, haʻahaʻa ka ikaika o ka hana, akā ʻoi aku ka nui o ka hoʻopukapuka mua, a pono e hoʻohui ʻia nā mea hana e like me nā blowers. He koʻikoʻi nā koi no nā hōʻailona kaʻina hana, a he mea koʻikoʻi ka mālama ʻana i ka waiwai pH. Pono e hoʻohui ʻia ka keleawe sulfate ma ke ʻano he catalyst. He lōʻihi ka manawa pane. Inā ʻaʻole kūpono ka mālama ʻana, e hana ʻia ka nui o nā ion ammonium, a ʻaʻole maʻalahi ke kānana i ka slag i hana ʻia. He wahi liʻiliʻi o ke kinoea amonia i hana ʻia ma - kahua, a ʻaʻohe hopena i ka wehe ʻana i nā thiocyanides.

ʻO ke ʻano o ka hydrogen peroxide

ʻO ke ʻano o ka hydrogen peroxide oxidation ʻo ia ka hoʻokahe ʻana i nā cyanides i CNO⁻ ma lalo o ka mahana maʻamau, nā kūlana alkaline (pH = 10 - 11), me Cu²⁺ ma ke ʻano he catalyst, a laila hydrolyze iā lākou i loko o nā mea ʻawaʻawa ʻole. Hoʻokaʻawale ʻia nā cyanides paʻakikī (complexes o Cu, Zn, Pb, Ni, Cd) ma muli o ka luku ʻana o nā cyanides i loko o lākou. ʻO nā ion Ferrocyanide a me nā iona metala kaumaha ʻē aʻe e hana i nā paʻakai paʻakikī ferrocyanide a wehe ʻia. ʻO ka mea hope loa, hiki ke hoʻemi ʻia ka nui o ka cyanide i loko o ka wai ʻino i mālama ʻia ma lalo o 0.5mg/L.

He kūpono kēia ʻano hana no ka mālama ʻana i ka cyanide haʻahaʻa haʻahaʻa - loaʻa ka wai ʻino. He mea maʻalahi a maʻalahi ka hoʻokō ʻana i ka mana o ka hydrogen peroxide. Eia nō naʻe, pono e noho ka cyanate i hana ʻia no kekahi manawa e decompose i CO₂ a me NH₃. ʻO nā hemahema, ʻo ka hoʻohana ʻana i ke keleawe ma ke ʻano he catalyst hiki ke hoʻonui i ke keleawe i loko o ka wai i hoʻokuʻu ʻia ma mua o ka maʻamau, ʻoi aku ka kiʻekiʻe o ke kumu kūʻai maka, ʻaʻole hiki ke hoʻoheheʻe ʻia nā thiocyanides, a hana ʻia nā ion ammonium. ʻOiaʻiʻo, loaʻa i ka wai ʻino kekahi mea ʻona. Eia kekahi, no ka mea he oxidant ka hydrogen peroxide, nui kona corrosiveness, a aia kekahi mau pilikia a me nā pōʻino i ka lawe ʻana a me ka hoʻohana.

Keʻano Acidification

Ke hoʻohana nei i ke ʻano acidification no ka mālama ʻana i ka cyanide - wai maikaʻi ʻole, ʻano paʻakikī kona ʻano hana, ʻoi aku ka nui o nā kaʻina hana ʻekolu: ʻo ke kaʻina acidification o ka cyanide - i loko o ka wai ʻino, ka wehe ʻana a me ka absorption o ke kinoea HCN, a me ke kaʻina hana neutralization o ka wai i wehe ʻia.

(1) Acidification reaction: ʻO ka cyanide - hoʻomaʻemaʻe ʻia ka wai maikaʻi ʻole me ka waikawa. ʻO nā cyanides paʻakikī i loko o ka wai maikaʻi ʻole e hana i nā precipitates insoluble e like me CuCN, CuSCN, a me Zn₂Fe(CN)₆ a hoʻoneʻe ʻia, a i ka manawa like, hana ʻia ka hydrogen cyanide.

(2) Volatilization a absorption reaction: Hoʻomaʻamaʻa mua ka wai ʻilihune ma kahi o 30 ℃ ma mua o ka acidification. No ka mea he 26.5 ℃ wale nō ka paila paila o HCN, he mea hikiwawe loa ia. No laila, hoʻohana ʻia kahi hale kiaʻi i hoʻopaʻa ʻia e like me ka nui - nā mea hoʻoili no ka hoʻopili ʻana ma waena o ke kinoea - wai ʻelua - ʻāpana i ke ʻano acidification, hiki ke maʻalahi i ka wehe ʻana a me ka absorption o HCN.

(3) Hana neutralization: Hoʻohana ʻia ka lime a i ʻole ka alkali wai e neutralize i ke koena wai i hoʻohemo ʻia e ka waikawa. E hoʻololi ʻia nā molekala HCN koena i loko o ka hopena i ke ʻano CN⁻. Hiki i ke ʻano acidification ke hoʻihoʻi i ka Sodium Cyanide mai ka wai hoʻoneoneo i loaʻa i ka cyanide a hoʻokō i ka hoʻōla ʻana o nā kumuwaiwai. Eia nō naʻe, he nui nā koi no ka sila ʻana i nā lako, kahi hoʻopukapuka mua nui, koi i nā mākau hana kiʻekiʻe, a he paʻakikī ka mālama ʻana i nā lako. Aia kekahi mau pōʻino palekana. Pono ka wai hoʻoneoneo i hana ʻia ma hope o ka hoʻōla ʻana i ka mālama hohonu e hoʻokō i nā kūlana hoʻokuʻu.

ʻAno Electrolysis

Hoʻohana ke ʻano electrolysis i nā hopena redox electrochemical e luku i nā cyanides i loko o ka wai ʻino. I loko o ka ion electrolysis, cyanides nalowale electrons ma ka anode a oxidized i cyanate, carbonate, nitrogen, a i ole ammonium. Hoʻopili hou ʻia ka cyanate i CO₂ a me H₂O. ʻO nā hopena nui:

CN⁻ + 2OH⁻ - 2e → CNO⁻ + H₂O (24)

2CN⁻ + 4OH⁻ - 6e → 2CO₂ + N₂ + 2H₂O (25)

Ua hōʻike ʻia nā hoʻokolohua Electrolysis e hoʻohana ana i ke koʻokoʻo electrode lead dioxide i hana ponoʻī ʻia a me kahi pā cathode stainless steel i ka hoʻohana ʻana i ke ʻano electrolysis e mālama ai i ka cyanide - i loko o ka wai ʻino, ma hope o 2 mau hola o ka electrolysis, hiki ke hoʻemi ʻia ka CN⁻ ʻike mai 385mg/L a 58mg/L, a hiki ke hoʻemi ʻia ka Cu²⁺/L450. Eia kekahi, hoʻohana ʻo Hunan Zhongnan Gold Smelter i ke ʻano electrochemical no ka mālama ʻana i ka wai ʻōpala cyanide gula extraction, hiki ke hōʻemi i ka nui o ka cyanide mai 48g/L a i 4g/L. ʻO ka ʻokoʻa mai luna aʻe, ʻo ka anode a me nā papa cathode i hana ʻia i nā papa hao. I ka wā o ke kaʻina hana, ʻaʻole i pau ka ikehu uila wale nō, akā ua pau nā pā hao.

Hoʻohana nui ʻia ke ʻano electrolysis no ka mālama ʻana i ka cyanide kiʻekiʻe - i loko o ka wai ʻōpala. Noho ka mea hana i kahi wahi liʻiliʻi, maʻalahi a maʻalahi ke kaʻina hana, akā hoʻopau ia i ka nui o ka ikehu uila, a ʻoi aku ka kiʻekiʻe o ke kumukūʻai hana ma mua o ke ʻano o ka alkaline chlorination method. He awelika ka nui o ka wehe ʻana o ka cyanide, a ʻaʻohe hopena i ka wehe ʻana i nā paʻakikī cyanide.

I kēia manawa, ma waena o nā kaʻina hana no ka cyanide gold extraction wastewater, ke ʻano alkaline chlorination, ke ʻano acidification, a me ka sodium metabisulfite - hoʻohana nui ʻia ke ʻano ea. ʻO ke ʻano electrolysis a me ke ʻano paʻakai paʻakai ferrous nā ʻano hana hou i hoʻohana maikaʻi ʻia i ka mālama ʻana i nā ʻoihana. ʻO ke ʻano o ka hydrogen peroxide oxidation ka mea maʻamau i ke ʻano lapaʻau pilikia. Nui nā ʻano lāʻau lapaʻau ʻē aʻe no ka mālama ʻana i ka wai ʻōpala cyanide gula, e like me ke ʻano hoʻomaʻemaʻe maoli, ke ʻano biological, ke ʻano o ka wehe ʻana o ka membrane, ion - exchange method, etc.