Cyanide Leaching Process in Gold Mining: The Complete Process from Dissolution to Recovery

Introduction

Kutulidwa kwa golidi m’matanthwe ake kwakhala nkhani yochititsa chidwi kwambiri kwa zaka mazana ambiri. Mwa njira zosiyanasiyana zomwe zilipo, Kutentha kwa cyanide yatulukira ngati imodzi mwa njira zomwe zimagwiritsidwa ntchito kwambiri pazamalonda Kukumba golide makampani. Njirayi imalola kusungunuka bwino kwa golidi kuchokera ku zipangizo zake zosungiramo, zomwe zimapangitsa kuti zitsulo zamtengo wapatali zipezekenso mumpangidwe wokhazikika. Nkhaniyi ifotokoza momwe cyanide ikuyendera mumigodi ya golide, kuyambira pakutha kwa golide mu njira za cyanide mpaka kuchira komaliza kwa chitsulo.

Kutha kwa Golide mu Cyanide Solutions

Zomwe Zimakhudzidwa ndi Chemical

Kusungunuka kwa golidi muzitsulo za cyanide kumachokera pamagulu ovuta a machitidwe a mankhwala. Kuyankha kwathunthu kumatha kuyimiridwa ndi equation yotsatirayi:

4Au + 8NaCN + O₂ + 2H₂O → 4Na[Au(CN)₂] + 4NaOH

Pochita izi, golide (Au) amachitira ndi Sodium cyanide (NaCN) pamaso pa oxygen (O₂) ndi madzi (H₂O) kupanga sodium dicyanoaurate (Na[Au(CN)₂]) ndi sodium hydroxide (NaOH). Udindo wa okosijeni pakuchita izi ndi wofunikira chifukwa umagwira ntchito ngati okosijeni, kumathandizira kusungunuka kwa golide.

Zoyenera Kuyimitsa Bwino Kwambiri

Kuti golide asungunuke bwino, zinthu zingapo ziyenera kuyang'aniridwa mosamala. Kuchuluka kwa cyanide mu yankho ndi chinthu chofunikira kwambiri. Nthawi zambiri, ndende ya 0.05 - 0.1% NaCN imagwiritsidwa ntchito pakuwongolera. Kuchulukirachulukira kungapangitse kuti cyanide ichuluke popanda kuchulukitsidwa kofananira ndi kusungunuka kwa golide, pomwe kutsika pang'ono kungayambitse kutulutsa pang'onopang'ono komanso kosakwanira.

PH ya yankho imathandizanso kwambiri. Njira yotulutsa mpweya imakhala yothandiza kwambiri pamtundu wa alkaline pang'ono, wokhala ndi pH ya 9.5 - 11. Pa pH iyi, ma ion a cyanide alipo mu mawonekedwe awo osagwirizana (HCN), omwe amawotchera kwambiri ku golidi. Kusintha pH nthawi zambiri kumatheka powonjezera laimu (CaO) ku njira yothetsera leaching.

Kutentha ndi chinthu china chofunikira. Ngakhale zomwe zimachitika pa kutentha kozungulira, kutentha kokwera pang'ono kozungulira 25 - 35 ° C kumatha kupititsa patsogolo kusungunuka kwa golide. Komabe, kuwonjezera kutentha kwambiri kungayambitse kuwonongeka kwa cyanide, kuchepetsa mphamvu yake.

Pre-mankhwala a Ores

Kuphwanya ndi Kupera

Ntchito yotulutsa cyanide isanayambe, miyala yokhala ndi golide iyenera kukonzedwa kale. Gawo loyamba la chithandizo ichi chisanadze nthawi zambiri Kuswa ndi akupera. Miyalayo imaphwanyidwa kuti ichepetse kukula kwake ndipo kenako imadulidwa kukhala tinthu tating’onoting’ono. Izi zimawonjezera pamwamba pa ore, zomwe zimapangitsa kuti pakhale kulumikizana koyenera pakati pa tinthu tating'ono ta golide ndi yankho la cyanide panthawi ya leaching.

Mlingo wa akupera umayendetsedwa mosamala. Kupukuta mopitirira muyeso kungayambitse kupanga slimes zabwino, zomwe zingayambitse mavuto panthawi yolekanitsa madzi olimba. Kumbali inayi, kugaya pang'onopang'ono kungapangitse kuti tinthu tating'ono ta golide tisamawonedwe mokwanira, zomwe zimatsogolera kutulutsa kosakwanira.

Kuwotcha ndi Bio-oxidation

Nthawi zina, miyala ya golide imatha kukhala ndi mchere womwe umalepheretsa kusungunuka kwa golide ndi cyanide. Kwa ore otere, njira zowonjezera zochizira kale monga kuwotcha kapena bio-oxidation zingafunike.

Kuwotcha kumaphatikizapo kutenthetsa miyalayi pamaso pa mpweya kuti iwononge mchere wa refractory, monga sulfides. Njira ya okosijeni imeneyi imaphwanya mchere, kutulutsa tinthu tating'ono ta golide ndikupangitsa kuti tipezeke mosavuta ndi cyanide solution.

Komano, biooxidation imagwiritsa ntchito tizilombo toyambitsa matenda kuti tiyike mchere wa refractory. Iyi ndi njira yabwino kwambiri yowotchera zinthu zachilengedwe chifukwa imagwira ntchito potentha ndipo imatulutsa mpweya woipa wocheperako. Tizilombo tating'onoting'ono, nthawi zambiri mabakiteriya kapena mafangasi, amasankhidwa kutengera kuthekera kwawo kothirira mchere womwe umapezeka mu ore.

The Leaching Process

Kuthamangitsidwa kwa Tank

Kuthamanga kwa tanki ndi imodzi mwa njira zomwe zimagwiritsidwa ntchito kwambiri pochotsa cyanide. Pochita izi, ore yomwe idakonzedweratu imasakanizidwa ndi yankho la cyanide mu akasinja akulu ogwedezeka. Matankiwa ali ndi zosokoneza zomwe zimatsimikizira kusakaniza bwino kwa ore ndi yankho, kulimbikitsa kulumikizana pakati pa tinthu tagolide ndi ayoni a cyanide.

The leaching nthawi zingasiyane malinga ndi chikhalidwe cha ore ndi zikhalidwe ntchito. Nthawi zambiri, njira ya leaching imatha kutenga maola angapo mpaka masiku angapo. Panthawiyi, zitsanzo za leachate zimatengedwa nthawi ndi nthawi kuti ziwone momwe golide akuyendera.

Kuchuluka kwa Leaching

Njira inanso yomwe imagwiritsidwa ntchito kwambiri, makamaka pa miyala ya golide yotsika kwambiri. Pochita izi, miyala yophwanyidwayo imaunikidwa mu milu ikuluikulu pa chingwe chosatha. Kenako madzi a cyanide amawapopera pamwamba pa muluwo ndipo amawalola kuti adutse mu matopewo. Pamene yankho likudutsa mulu, limasungunula tinthu tagolide, ndipo njira yothetsera mimba imasonkhanitsidwa pansi pa mulu.

Kudulira milu ndi njira yotsika mtengo poyerekeza ndi Kuthamangitsidwa kwa tanki chifukwa zimafuna ndalama zochepa zogulira zida. Komabe, ndi njira yapang'onopang'ono ndipo ndi yoyenera kwa ore omwe ali ndi golide wochepa.

Kupatukana Kolimba-Zamadzimadzi

Kusungunula

Pambuyo pakutha kwa leaching, sitepe yotsatira ndiyo kulekanitsa zotsalira zolimba (tailings) kuchokera ku njira yoyembekezera, yomwe ili ndi golidi wosungunuka. Sefa ndi imodzi mwa njira zomwe zimagwiritsidwa ntchito kwambiri pakulekanitsa madzi olimba. Pochita izi, slurry (kusakaniza kolimba ndi madzi) amadutsa muzitsulo zosefera, monga nsalu ya fyuluta kapena makina osindikizira. Tinthu tolimba timasungidwa pa fyuluta sing'anga, pamene madzi (oyembekezera) amadutsa ndikusonkhanitsidwa.

Kusankhidwa kwa sing'anga ya fyuluta kumadalira chikhalidwe cha tinthu tating'onoting'ono ndi momwe zimagwirira ntchito. Mwachitsanzo, ngati tinthu tating'ono tating'ono tating'ono tating'ono tating'ono tating'ono tating'ono tating'ono tingafunike.

Kuchotsa

Kuchepetsa ndi njira ina yomwe ingagwiritsidwe ntchito polekanitsa, makamaka ngati tinthu tokhazikika tikhala yayikulu ndikukhazikika mosavuta. Pochita izi, slurry amaloledwa kuyima mu thanki yokhazikika kwa kanthawi. Tinthu tating'onoting'ono timakhazikika pansi pa thanki chifukwa cha mphamvu yokoka, ndipo madzi omveka bwino (omwe ali ndi pakati) amachotsedwa mosamala.

Decantation ndi njira yosavuta komanso yochepa mphamvu - yozama kwambiri poyerekeza ndi kusefera. Komabe, sizingakhale zogwira mtima pakulekanitsa tinthu tating'onoting'ono tolimba.

Kubwezeretsa Golide kuchokera ku Njira Yapakati

Adayambitsa Carbon Adsorption

Imodzi mwa njira zodziwika bwino zopezera golidi kuchokera ku njira yoyembekezera ndi Kutsatsa kwa carbon activated. Pochita izi, carbon activated imawonjezeredwa ku njira yapakati. Golide - cyanide complex ili ndi mgwirizano wamphamvu pamwamba pa carbon activated, ndipo chifukwa chake, golidiyo amakongoletsedwa pa carbon particles.

Mpweya wa kaboni umasiyanitsidwa ndi yankho, nthawi zambiri poyang'ana kapena kusefera. Mpweya wodzaza golide umakonzedwanso kuti uwononge golide. Izi zimachitika poika mpweya wa carbon pa kutentha kwambiri kwa nthunzi kapena kugwiritsa ntchito mankhwala osokoneza bongo.

Kuchuluka kwa Zinc

Kuchuluka kwa zinc, komwe kumadziwikanso kuti Merrill - Crowe process, ndi njira ina yobwezeretsa golide. Pochita izi, fumbi la zinc limawonjezeredwa ku njira yoyembekezera. Zinc ndi electropositive kwambiri kuposa golide, ndipo chifukwa chake, imachotsa golide kuchokera ku golide - cyanide complex. Zomwe zimachitika zitha kuyimiridwa ndi equation yotsatirayi:

2Na[Au(CN)₂] + Zn → 2Au + Na₂[Zn(CN)₄]

Golide wonyezimira, pamodzi ndi zinc iliyonse yosagwiritsidwa ntchito, imapanga matope olimba. Dothi limeneli limasiyanitsidwa ndi yankho, ndipo golideyo amayengedwanso kuti apeze mankhwala abwino.

Kuyenga Golide

Kusungunula

Golidiyo atapezeka kuti ali ndi pakati, nthawi zambiri amafunika kuyengedwa kuti achotse zonyansa zonse. Kusungunula ndi imodzi mwa njira zodziwika kwambiri zoyenga golide. Pochita izi, golide - zomwe zili ndi zinthu zimatenthedwa ndi kutentha kwakukulu pamaso pa kutuluka, monga borax. Kuthamanga kumathandiza kuchepetsa kusungunuka kwa golidi komanso kumachitanso ndi zonyansa, kupanga slag yomwe imatha kupatukana ndi golide wosungunuka.

Golidi wosungunukayo amathiridwa mu nkhungu kuti apange ingots. Ingots izi zitha kukonzedwanso kapena kugulitsidwa ngati chinthu chomaliza.

Electrolytic Refining

Electrolytic refining ndi njira yapamwamba kwambiri yoyenga golide. Pochita izi, golide - yomwe ili ndi anode imayikidwa mu cell electrolytic pamodzi ndi cathode yoyera yagolide. Electrolyte nthawi zambiri imakhala yankho la golide wa chloride kapena mchere wina wagolide. Mphamvu yamagetsi ikadutsa mu selo, golidi wochokera ku anode amasungunuka mu electrolyte ndikuyika pa cathode.

Zonyansa zomwe zimakhala ndi electropositive kuposa golide zimasungunuka mu electrolyte koma osayika pa cathode, pamene zonyansa zomwe zimakhala zochepa kwambiri kuposa golide zimakhalabe ngati matope pansi pa selo. Izi zimabweretsa mtengo wapamwamba kwambiri - chiyero chagolide.

Zoganizira Zachilengedwe

Kuwongolera kwa Cyanide

Cyanide ndi chinthu chapoizoni kwambiri, ndipo kasamalidwe koyenera ka cyanide mu migodi ya golidi ndiyofunikira kwambiri. Kugwiritsiridwa ntchito kwa cyanide mu migodi ya golidi kumayendetsedwa mosamalitsa m'mayiko ambiri kuti achepetse kukhudzidwa kwake pa chilengedwe ndi thanzi la anthu.

Chimodzi mwazinthu zofunika kwambiri pakuwongolera cyanide ndikupewa kutayika kwa cyanide. Ntchito za migodi zikuyenera kukhala ndi zida zoyenera zoteteza kuti cyanide - yomwe ili ndi njira zothetsera kutayikira ku chilengedwe. Kuphatikiza apo, chithandizo cha cyanide - chomwe chili ndi madzi oyipa ndikofunikiranso. Pali njira zingapo zopangira mankhwala a cyanide - okhala ndi madzi otayira, monga makutidwe ndi okosijeni wamankhwala, chithandizo chachilengedwe, ndi kusinthana kwa ayoni.

Kutaya Michira

Zotsalira zolimba (zotsalira) zomwe zimapangidwa pambuyo pobwezeretsa golide ziyeneranso kutayidwa bwino. Michira imatha kukhala ndi cyanide ndi zitsulo zina zolemera, zomwe zitha kuwononga chilengedwe ngati sizikuyendetsedwa bwino.

Njira imodzi yodziwika bwino yotayira tailings ndiyo kuwasunga m'madamu a tailings. Madamuwa adapangidwa kuti azikhala ndi michira ndikuletsa kutulutsa zowononga m'chilengedwe. Nthawi zina, ma tailings amathanso kukonzedwanso kuti apezenso mchere wotsalira kapena kuchepetsa kuwonongeka kwa chilengedwe.

Kutsiliza

Njira ya cyanide leaching mu migodi ya golide ndi njira yovuta komanso yambiri yomwe imaphatikizapo kusungunuka kwa golide muzitsulo za cyanide, mankhwala opangira ores, leaching, olimba - kulekanitsa madzi, kubwezeretsa golide, kuyenga, ndi kuyang'anira chilengedwe. Gawo lirilonse la ndondomekoyi limayang'aniridwa mosamala kuti liwonetsetse kuti golide amachotsedwa bwino komanso kuchepetsa kuwonongeka kwa chilengedwe. Ngakhale kuti pali zovuta zokhudzana ndi kugwiritsa ntchito cyanide, ndondomekoyi imakhalabe njira yofunikira komanso yogwiritsidwa ntchito kwambiri m'mafakitale a migodi ya golide wamalonda chifukwa chapamwamba komanso mtengo wake wotsika mtengo. Komabe, kufufuza kosalekeza ndi chitukuko chikuchitika kuti apange njira zina zomwe zimakhala zotetezeka komanso zokhazikika.