Ts'ebetso ea Phekolo ea Metsi a Litšila ea Cyanide Gold

Hona joale, ea cyanide mokhoa oa ho ntša khauta ke e 'ngoe ea mekhoa ea mantlha ea ho qhibilihisa khauta Chaena. E sebelisa tharollo ea cyanide ho ntša khauta ho ores, e nang le sekhahla se phahameng sa ho hlaphoheloa, ho ikamahanya le maemo ka matla ho thepa ea ore, le bokhoni ba ho hlahisa khauta setšeng. Ho tloha ts'ebelisong ea pele ea tharollo ea cyanide ho tlosa khauta ho tloha ores ka 1887. mokhoa ona o sebelisitsoe haholo ho fihlela joale. Leha ho le joalo, ho ntšoa ha khauta ea cyanide ho hlahisa lintho tse chefo le tse kotsi tse ngata, tse bakang tšokelo e kholo tikolohong e haufi le batho. Ka hona, e le ho fokotsa kotsi, hoa hlokahala ho ithuta mekhoa ea phekolo ea metsi a litšila a cyanide khauta. Palo e kholo ea bafuputsi e akarelitse mekhoa ea phekolo, melao-motheo ea lik'hemik'hale, le mekhoa ea ntlafatso ea cyanide - e nang le metsi a litšila, empa boholo ba bona ba buisana ka mokhoa o le mong kapa tse peli feela. Ka hona, sengoloa sena se etsa tlhahlobo e qaqileng ea mekhoa e fapaneng ea kalafo bakeng sa metsi a litšila a cyanide a ntseng a sebelisoa indastering, se bapisa melemo, mathata, le maemo a ts'ebeliso ea mokhoa o mong le o mong, o nang le tataiso e itseng bakeng sa lits'ebetso tse ts'oanang tlhahisong ea 'nete.

I. Mehloli le Likotsi tsa Cyanide Gold Extraction Metsi a litšila

Molao-motheo o ka sehloohong oa ho ntšoa ha khauta ea cyanide ke hore tikolohong ea aerobic, sodium cyanide e kopana le khauta ho etsa metsoako ea khauta, ebe e qhibiliha. Kamora moo, khauta e ka ntšoa ka ho e ntlafatsa ka ho e kenya tšebetsong k'habone ho monngoa kapa ho tlosoa ke phofo ea zinki ho tsoa ho cyanide ea khauta. Ka nako e ts'oanang, litšepe tse ling tse boima tse kang silevera, koporo le zinki le tsona li theha metsoako le ho qhibiliha.

The li-cyanides e sebelisoang karabelong le li-complexes tse hlahisoang kaofela ke lintho tse chefo le tse kotsi. Sodium cyanide e bonolo ho hydrolyze 'me ke ntho e chefo ea Sehlopha sa 1, e nang le tekanyo e bolaeang ea 0.10g. Neng Li-cyanides e lutla ka metsing, e kotsi haholo ho lintho tse phelang metsing, 'me e tla baka tšokelo e kholo ho batho le tikolohong e haufi. Ka hona, kalafo ea metsi a litšila a cyanide e tsoang ho khauta e bohlokoa haholo.

II. Mekhoa e ka Sehloohong ea Kalafo ea Cyanide Gold Extraction Metsi a litšila

Alkaline Chlorination Mokhoa

Mokhoa oa alkaline chlorination hajoale ke o mong oa mekhoa e sebelisoang haholo ho alafa cyanide - e nang le metsi a litšila a tsoang mocheng oa khauta ea cyanide. Haholo-holo e sebelisa li-oxidants tse thehiloeng ho chlorine ho oxidize cyanides metsing a litšila tlas'a maemo a alkaline, e li fetola lintho tse seng chefo. Mokhoa oa ho pshatla cyanide oa alkaline chlorination o arotsoe ka mekhahlelo e 'meli:

Mohato oa pele ke ho oxidize cyanide ho cyanate, e bitsoang "incomplete oxidation stage". CN⁻ e sebetsana le OCl⁻ ho theha CNCl pele, 'me e be hydrolyzes ho CNO⁻. Hoa lokela ho hlokomeloa hore CNCl e fetoha haholo ebile e chefo tlas'a maemo a acidic. Ka hona, nakong ea ts'ebetso, boleng ba pH bo tlameha ho laoloa ka thata hore bo be boemong ba alkaline.

Mohato oa bobeli ke ho tsoela pele ho oxidize cyanate ho carbon dioxide le nitrogen, e bitsoang "complete oxidation stage". Nakong ea ho robeha ha cyanide, boleng ba pH bo na le tšusumetso e kholo ho karabelo ea oxidation. Boleng ba pH ba mohato oa pele oa oxidation bo lokela ho laoloa ho 10 - 11. 'me nako ea ho arabela ke metsotso e 10 - 15. Boleng ba pH ea oxidation ea mohato oa bobeli bo lokela ho laoloa ho 6.5 - 7.0. 'me nako ea ho arabela ke metsotso e 10 - 15.

Morafo o itseng o sebelisa mokhoa oa alkaline chlorination ho phekola seretse se chesang sa cyanide tail (ka cyanide content ea 200mg/L) le metsi a phallang ho tloha tanka ea sedimentation (ka cyanide content ea 5mg/L). Boleng ba pH bo laolwa ho 10 - 11. mme phofshoana ya bleaching e kenngwa ka tekanyo ya 35 - 40 makhetlo a cyanide bakeng sa ho kopanya le ho sisinya. Ka mor'a hore sedimentation e teteaneng, kakaretso ea cyanide e ka fokotsoa ho 0.1mg/L.

Mokhoa oa alkaline chlorination ke mokhoa o sebelisoang haholo oa ho phekola cyanide - e nang le metsi a litšila, 'me phofo e soeufatsang ke eona e sebelisoang haholo ka chlorine - based oxidant. Mokhoa ona o loketse ho phekola metsi a litšila a cyanide a tsoang ka khauta e nang le maemo a holimo kapa a tlase. E ka boela ea tlosa thiocyanate le cyanide - e nang le li-complexes (ntle le li-complexes tsa ferrocyanide). Meriana e fumaneha hohle, masalla a litšila a hlahisoang a bonolo ho sefa, 'me ts'ebetso e bonolo. Leha ho le joalo, tikoloho ea ts'ebetso e batla e le thata ha ho sebelisoa phofo e soeufatsang ho hloekisa metsi a litšila. Hona joale likhoebo tse ling li sebelisa mokelikeli o soeufatsang kapa chlorine dioxide ho e-na le hoo, e leng se ntlafatsang tikoloho ea tšebetso ho isa bohōleng bo itseng. Empa likhase tse chefo li hlahisoa nakong ea ts'ebetso, 'me li na le ho senyeha ho hoholo ha lisebelisoa. Litsenyehelo tsa meriana le litšenyehelo tsa tlhokomelo li batla li phahame.

Mokhoa oa ho Kopanya Letsoai la Ferrous

Mokhoa oa ho kopanya letsoai ke mokhoa oa kalafo oa metsi a litšila a cyanide o hlahileng lilemong tsa morao tjena. Ka ho laola karabelo pH ea boleng ho 7 - 8. ferrous ions e sebetsana le cyanide e sa lefelloeng le li-complexes tse ling tsa cyanide ka har'a metsi a litšila a cyanide a mochong oa khauta ho etsa precipitates.

Liteko li bonts'itse hore ka kakaretso, ho kenyelletsa ferrous sulfate feela ho phekola metsi a litšila a cyanide khauta e ke keng ea etsa hore metsi a litšila a fihlelle maemo a ho qhala. Ka hona, oxidant e akaretsang e hloka ho kenyelletsoa metsing a litšila a hloekisitsoeng bakeng sa ho tlosoa ho tebileng - cyanide. Hafeela maemo a ntse a laoloa hantle, oxidant e ka ekeletsoa ka ho toba bakeng sa phekolo ntle le ho arola precipitate, 'me tekanyo ea ho ntša metsi e ka finyelloa hape. Sena se na le moelelo o motle ha o bapisoa le mokhoa oa setso oa karohano pele ebe oa phekolo.

Mokelikeli o itseng oa khauta o sebelisa sodium sulfide - ferrous sulfate mokhoa ho phekola cyanide - mokelikeli o fokolang. Tšusumetso e na le cyanide content ea 2500mg/L. Ka mor'a phekolo, metsi a litšila a na le cyanide e ka tlaase ho 20mg / L, e nang le tekanyo ea ho tlosoa ha 99.2%, e bontšang liphello tse tsotehang. Kalafo e latelang e tebileng e sebelisa sodium metabisulfite - mokhoa oa moea ho fokotsa kakaretso ea cyanide ho ea tlase ho 0.4mg/L.

Mokhoa oa ho kopanya letsoai ke mokhoa o sa tsoa hlaha oa kalafo, o sebelisoang haholo ho alafa cyanide e phahameng - e nang le metsi a litšila. Ts'ebetso ea eona e bonolo, matsete a nako e le 'ngoe a nyane, a bonolo ho sebetsa, meriana (haholo-holo ferrous sulfate) e fumaneha hohle, e theko e tlaase, ebile e bonolo ho e sebelisa. Leha ho le joalo, kaha motsoako oa ferrous sulfate o na le asiti, ha o kopane le metsi a litšila a motsung oa khauta ea cyanide, sebaka seo se fetoha asiti, ’me ho na le monyetla oa ho hlahisa khase ea hydrogen cyanide. Ho feta moo, e ke ke ea tlosa thiocyanate, 'me metsi a litšila a hloekisitsoeng a ntse a hloka phekolo e tebileng ho finyella litekanyetso tsa ho ntša metsi.

Sodium Metabisulfite - Mokhoa oa Moea

Mokhoa oa sodium metabisulfite - moea o hlahisoa ho tloha ho sulfur dioxide - moea mokhoa. Haholo-holo e sebelisa phello ea synergistic ea sodium metabisulfite le moea ho cyanides metsing a litšila ka har'a mefuta e itseng ea pH, ka phello ea catalytic ea li-ion tsa koporo, ho oxidize CN⁻ ho CNO⁻.

Haeba litaba tsa cyanide tse ka har'a cyanide - tse nang le metsi a litšila li le holimo, kalafo ea pele e ka etsoa pele ho fokotsa bongata ba cyanide ka tlase ho 100mg/L. Ka mor'a moo, metabisulfite ea sodium le sulfate ea koporo li kenngoa, moea o lekaneng oa hlahisoa, 'me boleng ba pH bo laoloa (ka kakaretso bo laoloa ho 7 - 8), e le hore cyanide e be oxidized ho cyanate, e ntan'o hydrolyzed ho theha bicarbonate ion le ammonia.

Sodium metabisulfite - mokhoa oa moea o loketse ho phekola metsi a litšila a cyanide ea khauta e tlase. Tekanyo ea meriana e nyane, matla a basebetsi a tlase, empa letsete la pele le batla le le leholo, 'me lisebelisoa tse kang li-blower li hloka ho eketsoa. Litlhoko tsa matšoao a ts'ebetso li batla li le thata, 'me ho laola boleng ba pH ho bohlokoa haholo. Copper sulfate e boetse e hloka ho eketsoa e le sesosa. Nako ea ho arabela e telele. Haeba phekolo e sa nepahale, palo e kholo ea li-ion tsa ammonium e tla hlahisoa, 'me slag e entsoeng ha e bonolo ho e hloekisa. Ho na le khase e nyane ea ammonia e hlahisoang sebakeng sa marang-rang, 'me ha e na phello ea ho tlosa thiocyanides.

Hydrogen Peroxide Oxidation Mokhoa

Mokhoa oa hydrogen peroxide oxidation ke ho oxidize cyanides ho CNO⁻ tlas'a maemo a tloaelehileng a mocheso, alkaline (pH = 10 - 11), 'me Cu²⁺ e le ntho e susumetsang, ebe o li kenya ka hydrolyze hore e be lintho tse seng chefo. Li-cyanides tse rarahaneng (li-complexes tsa Cu, Zn, Pb, Ni, Cd) li boetse li arohane ka lebaka la ho timetsoa ha li-cyanides ho tsona. Li-ion tsa Ferrocyanide le li-ion tse ling tse boima li theha matsoai a rarahaneng a ferrocyanide ebe lia tlosoa. Qetellong, kakaretso ea cyanide ka metsing a litšila a hloekisitsoeng e ka fokotsoa ho ba ka tlase ho 0.5mg/L.

Mokhoa ona o loketse ho phekola cyanide e tlase - e nang le metsi a litšila. Thepa ea phekolo ea hydrogen peroxide e bonolo ebile e bonolo ho fihlella taolo ea othomathike. Leha ho le joalo, cyanate e hlahisoang e hloka ho lula nako e itseng ho bola ho CO₂ le NH₃. Mefokolo ke hore ho sebelisa koporo e le sesosa ho ka etsa hore koporo e ka metsing a lahliloeng e fete maemo, theko ea thepa e tala e batla e phahame, li-thiocyanides ha li khone ho etsoa oxidized, 'me li-ion tsa ammonium lia hlahisoa. Ha e le hantle, metsi a litšila a ntse a e-na le chefo e itseng. Ho feta moo, kaha hydrogen peroxide ke oxidant, e na le ho bola ho hoholo, 'me ho na le mathata le likotsi tse itseng lipalangong le tšebelisong.

Mokhoa oa Acidification

Ha o sebelisa mokhoa oa acidification ho phekola cyanide - mokelikeli o fokolang, mokhoa oa eona oa ho itšoara o batla o rarahane, haholo-holo o kenyelletsa mekhoa e meraro: mokhoa oa acidification oa cyanide - o nang le metsi a litšila, mokhoa oa ho hlobolisa le ho monya ha khase ea HCN, le mokhoa oa ho se nke lehlakore oa mokelikeli o tlositsoeng.

(1) Karabelo ea asiti: The cyanide - mokelikeli o futsanehileng o na le asiti le ho hloekisoa ka asiti. Li-cyanide tse rarahaneng ka har'a mokelikeli o futsanehileng li tla etsa li-precipitates tse sa tsitsang tse kang CuCN, CuSCN, le Zn₂Fe(CN)₆ 'me li tlosoe,' me ka nako e ts'oanang, hydrogen cyanide e hlahisoa.

(2) Volatilization le absorption reaction: Mokelikeli o fokolang o futhumatsoa pele ho hoo e ka bang 30 ℃ pele ho asiti. Kaha ntlha e belang ea HCN e 26.5 ℃ feela, e fetoha e fetohang haholo. Ka hona, tora e tletse e sebelisoa e le boima - lisebelisoa tsa phetisetso bakeng sa ho kopana pakeng tsa khase - metsi a mabeli - mohato ka mokhoa oa acidification, o leng bonolo ho finyella ho hlobola le ho monya ha HCN.

(3) Boitšoaro ba Neutralization: Lime kapa alkali ea metsi e sebelisoa ho fokotsa mokelikeli o setseng oa asiti. Limolek'hule tse setseng tsa HCN ka tharollo li tla fetoloa ka mokhoa oa CN⁻. Mokhoa oa acidization o ka hlaphoheloa Sodium cyanide ho tsoa ho cyanide - e nang le metsi a litšila le ho hlokomela ho hlaphoheloa ha mehloli. Leha ho le joalo, e na le litlhoko tse phahameng bakeng sa ho tiisa lisebelisoa, letsete le batlang le le leholo ka pele, le hloka tsebo ea boemo bo holimo ea ts'ebetso, 'me tlhokomelo ea lisebelisoa e thata. Ho boetse ho na le likotsi tse itseng tsa polokeho. Metsi a litšila a hlahisoang ka mor'a ho hlaphoheloa a ntse a hloka phekolo e tebileng ho finyella litekanyetso tsa ho ntša metsi.

Mokhoa oa Electrolysis

Mokhoa oa electrolysis o sebelisa electrochemical redox reactions ho senya li-cyanides metsing a litšila. Nakong ea electrolysis ea ion, li-cyanide li lahleheloa ke lielektrone ho anode 'me li na le oxidized ho cyanate, carbonate, nitrogen, kapa ammonium. Cynate e tšeloa hape ho CO₂ le H₂O. Maikutlo a mantlha ke:

CN⁻ + 2OH⁻ - 2e → CNO⁻ + H₂O (24)

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

Liteko tsa electrolysis ka ho sebelisa mochini o entsoeng ka ceramic-based lead lead electrode electrode rod le stainless - steel cathode plate li pakile hore ka ho sebelisa mokhoa oa electrolysis ho phekola cyanide - e nang le metsi a litšila, kamora lihora tse 2 tsa electrolysis, mahloriso a CN⁻ a ka fokotsoa ho tloha ho 385mg/L ho ea ho 58mg/L, le Cu²⁺ ho tloha ho 450mg ho ea ho 48mg. Ho feta moo, Hunan Zhongnan Gold Smelter e sebelisa mokhoa oa electrochemical ho phekola metsi a litšila a cyanide a tsoang ho khauta, e ka fokotsang kakaretso ea cyanide ho tloha ho 4g/L ho ea ho 0.8g/L. Phapang ho tloha ka holimo ke hore lipoleiti tsa anode le cathode li entsoe ka lipoleiti tsa tšepe. Nakong ea ts'ebetso, ha ho sebelisoe matla a motlakase feela, empa le lipoleiti tsa tšepe lia jeoa.

Mokhoa oa electrolysis o sebelisoa haholo ho phekola high-concentration cyanide - e nang le metsi a litšila. Thepa e nka sebaka se senyenyane, mokhoa ona o bonolo ebile o bonolo ho o laola, empa o sebelisa matla a mangata a motlakase, 'me litšenyehelo tsa ts'ebetso li phahame ho feta mokhoa oa alkaline chlorination. Sekhahla sa ho tlosoa ha cyanide ke karolelano, 'me ha se na phello ea ho tlosa li-cyanide complexes.

Hona joale, har'a mekhoa ea phekolo ea metsi a litšila a cyanide khauta, mokhoa oa alkaline chlorination, mokhoa oa acidification, le sodium metabisulfite - mokhoa oa moea o sebelisoa haholo. Mokhoa oa electrolysis le mokhoa oa ho kopanya letsoai le ferrous ke mekhoa e sa tsoa hlaha e sebelisitsoeng ka katleho kalafo ea indasteri. Mokhoa oa hydrogen peroxide oxidation haholo-holo ke mokhoa oa phekolo ea tšohanyetso. Ho na le mekhoa e meng e mengata ea phekolo ea ho phekola metsi a litšila a cyanide khauta, joalo ka mokhoa oa tlhaho oa tlhoekiso, mokhoa oa likokoana-hloko, mokhoa oa ho arohana ha membrane, mokhoa oa ion - phapanyetsano, joalo-joalo Leha ho le joalo, e le likopo tsa indasteri, kaofela li na le mefokolo e itseng 'me li ntse li hloka ntlafatso e tsoelang pele.