Cyanide Gold M'zigawo Zochizira Madzi Onyansa

Pakalipano, a cyanide Njira yochotsera golide ndi imodzi mwamachitidwe okhwima pakusungunula golide ku China. Imagwiritsa ntchito njira ya cyanide kuchotsa golide ku ore, yokhala ndi kubweza kwambiri, kusinthika kolimba kuzinthu za ore, komanso kuthekera kopanga golide pamalopo. Chiyambireni kugwiritsa ntchito njira ya cyanide kutulutsa golide kuchokera ku ores mu 1887. Njirayi yakhala ikugwiritsidwa ntchito kwambiri mpaka pano. Komabe, kutulutsa golide wa cyanide kumatulutsa zinthu zambiri zapoizoni komanso zovulaza, zomwe zimawopseza kwambiri chilengedwe komanso anthu. Choncho, pofuna kuchepetsa kuvulaza, m'pofunika kuphunzira njira zochizira za cyanide gold m'zigawo za madzi otayira. Ofufuza ambiri afotokozera mwachidule njira zochizira, mfundo zamakina, ndi njira zachitukuko za cyanide - zomwe zili ndi madzi onyansa, koma ambiri amangokambirana njira imodzi kapena ziwiri. Chifukwa chake, nkhaniyi ikuwunika mwatsatanetsatane njira zosiyanasiyana zochizira madzi otayira a cyanide golide omwe akugwiritsidwa ntchito panopa m'makampani, kuyerekeza ubwino, kuipa, ndi zochitika za kagwiritsidwe ntchito ka njira iliyonse, yomwe ili ndi zofunikira zina zomwe zimagwiritsidwa ntchito popanga zenizeni.

I. Magwero ndi Zowopsa za M'zigawo Zagolide za Cyanide

Mfundo yayikulu yochotsa golide wa cyanide ndikuti m'malo a aerobic, sodium cyanide Amachita ndi golide kupanga mitundu ya golide, yomwe kenako imasungunuka. Pambuyo pake, golide amatha kuchotsedwa mwa kuwonjezera mphamvu kudzera mu ntchito yochitidwa Carbon kulowetsedwa kapena kusunthidwa ndi ufa wa zinc kuchokera ku gold cyanide. Nthawi yomweyo, zitsulo zina zolemera monga siliva, mkuwa, ndi zinc zimapanganso zinthu zosakanikirana ndikusungunuka.

The cyanides zomwe zimagwiritsidwa ntchito pochita zomwe zimapangidwira komanso zovuta zomwe zimapangidwa ndizinthu zapoizoni komanso zovulaza. Sodium cyanide ndi yosavuta kuyiyika pa hydrolyze ndipo ndi chinthu chapoizoni cha Class 1, chokhala ndi mlingo wakupha wa 0.10g. Liti Cyanides Kuchulukira m'madzi, kumawononga kwambiri zamoyo zomwe zili m'madzi, ndipo zingayambitse chiwopsezo chachikulu kwa anthu komanso chilengedwe. Chifukwa chake, chithandizo chamadzi onyansa a cyanide golide ndikofunikira kwambiri.

II. Njira Zazikulu Zachidziwitso Zam'zigawo Zagolide za Cyanide

Njira ya Alkaline Chlorination

Njira ya alkaline chlorination pakali pano ndi imodzi mwa njira zomwe zimagwiritsidwa ntchito kwambiri pochizira cyanide - okhala ndi madzi onyansa ochokera ku golide wa cyanide. Amagwiritsa ntchito kwambiri ma chlorine - oxidants opangidwa ndi oxidize ma cyanides m'madzi onyansa pansi pamikhalidwe yamchere, kuwasandutsa zinthu zopanda poizoni. The cyanide - kuswa ndondomeko ya alkaline chlorination imagawidwa m'magawo awiri:

Gawo loyamba ndikupangitsa kuti cyanide ikhale cyanide, yomwe imatchedwa "incomplete oxidation" siteji. CN⁻ imachita ndi OCl⁻ kupanga CNCl koyamba, kenako imasungunuka kukhala CNO⁻. Ndikoyenera kudziwa kuti CNCl imakhala yosasunthika komanso yowopsa pansi pa acidic. Chifukwa chake, pakugwira ntchito, pH mtengo uyenera kuyendetsedwa mosamalitsa kuti ukhale wamchere.

Gawo lachiwiri ndikuwonjezera oxidize cyanate ku carbon dioxide ndi nitrogen, yomwe imatchedwa "complete oxidation" siteji. Pakusweka kwa cyanide, mtengo wa pH umakhudza kwambiri momwe ma oxidation amachitira. The pH mtengo woyamba - siteji makutidwe ndi okosijeni ayenera kulamulidwa pa 10 - 11. ndi anachita nthawi 10 - 15 Mphindi. Phindu la pH lachiwiri - siteji ya okosijeni iyenera kuyendetsedwa pa 6.5 - 7.0. ndipo nthawi yochitira ndi 10 - 15 mphindi.

Mgodi wina umagwiritsa ntchito njira ya alkaline chlorination pochiza slurry wamchira wa cyanide (wokhala ndi cyanide wokwanira 200mg/L) ndi madzi otuluka kuchokera mu thanki ya sedimentation (yokhala ndi cyanide yokwanira 5mg/L). Phindu la pH limayendetsedwa pa 10 - 11. ndi ufa wa bleaching umawonjezedwa pa chiŵerengero cha 35 - 40 nthawi ya cyanide yosakaniza ndi kusonkhezera. Pambuyo pa matope mu thickener, kuchuluka kwa cyanide kumatha kuchepetsedwa kukhala 0.1mg/L.

Njira yothira mchere wamchere ndiyo njira yomwe imagwiritsidwa ntchito kwambiri popangira mankhwala a cyanide - okhala ndi madzi otayira, ndipo ufa wothira ndi mankhwala omwe amagwiritsidwa ntchito kwambiri ndi chlorine - oxidant. Njirayi ndi yoyenera kuchiza madzi otayira a cyanide golide okhala ndi kuchuluka kapena kutsika. Ithanso kuchotsa thiocyanate ndi cyanide - okhala ndi zovuta (kupatula ma ferrocyanide complexes). The medicament imapezeka kwambiri, zotsalira za zinyalala zomwe zimapangidwa ndizosavuta kusefa, ndipo ntchitoyo ndi yosavuta. Komabe, malo ogwirira ntchito amakhala ovuta kwambiri mukamagwiritsa ntchito ufa wothira madzi otayira. Tsopano mabizinesi ena amagwiritsa ntchito bleaching madzi kapena chlorine dioxide m'malo mwake, zomwe zimapangitsa kuti malo ogwirira ntchito azikhala bwino. Koma mpweya wapoizoni umapangidwa panthawiyi, ndipo zimakhala ndi corrosiveness yaikulu ku zipangizo. Mtengo wa mankhwala ndi mtengo wokonza ndi wokwera kwambiri.

Ferrous Salt Complexation Njira

Njira yophatikizira mchere wamchere ndi njira yochizira madzi onyansa a cyanide omwe atuluka m'zaka zaposachedwa. Ndi kulamulira anachita pH mtengo pa 7 - 8. ayoni yachitsulo amachita ndi sianidi ufulu ndi ena sianidi maofesi mu sianidi golide m'zigawo m'zinyansi madzi kupanga precipitates.

Kuyesera kwawonetsa kuti nthawi zambiri, kuwonjezera ferrous sulfate kokha kuti athetse madzi otayira a cyanide golide sikungapangitse madzi onyansawo kuti akwaniritse miyezo yotayira. Chifukwa chake, oxidant wamba ayenera kuwonjezeredwa m'madzi otayidwa kuti achotsedwe mozama - cyanide. Malingana ngati mikhalidwe ikuyendetsedwa bwino, oxidant akhoza kuwonjezeredwa mwachindunji kuti athandizidwe popanda kulekanitsa mpweya, ndipo muyezo wotuluka ukhoza kuthekanso. Izi zili ndi tanthauzo labwino poyerekeza ndi njira yachikhalidwe yolekanitsa poyamba ndiyeno chithandizo.

Wosungunula golide wina amagwiritsa ntchito njira ya sodium sulfide - ferrous sulfate pochizira cyanide - madzi osakwanira. Mphamvuyi imakhala ndi 2500mg/L ya cyanide. Pambuyo pa mankhwala, madzi otsekemera amakhala ndi cyanide yocheperapo 20mg/L, ndi kuchotsedwa kwa 99.2%, kusonyeza zotsatira zodabwitsa. The wotsatira kuya - mankhwala amagwiritsa sodium metabisulfite - mpweya njira kuchepetsa cyanide okwana zosakwana 0.4mg/L.

Njira yophatikizira mchere wamchere ndi njira yatsopano yochizira, yomwe imagwiritsidwa ntchito kwambiri pochiza cyanide wambiri - wokhala ndi madzi oipa. Njira yake ndi yophweka, ndalama za nthawi imodzi ndizochepa, ndizosavuta kugwiritsa ntchito, mankhwala (makamaka ferrous sulfate) amapezeka kwambiri, otsika mtengo, komanso osavuta kugwiritsa ntchito. Komabe, chifukwa ferrous sulfate solution ndi acidic, ikasakanizidwa ndi cyanide gold m'zigawo zamadzi otayira, dera la m'deralo limakhala acidic, ndipo pali kuthekera kopanga mpweya wa hydrogen cyanide. Kuphatikiza apo, sichingachotse thiocyanate, ndipo madzi otayira oyeretsedwa amafunikirabe chithandizo chakuya kuti akwaniritse miyezo yotulutsa.

Sodium Metabisulfite - Njira ya Air

The sodium metabisulfite - mpweya njira amapangidwa kuchokera sulfure dioxide - mpweya njira. Amagwiritsa ntchito kwambiri synergistic zotsatira za sodium metabisulfite ndi mpweya pa cyanides m'madzi otayira mkati mwa mtundu wina wa pH, ndi mphamvu ya ayoni yamkuwa, kuti oxidize CN⁻ ku CNO⁻.

Ngati cyanide zili mu cyanide - munali madzi oipa ndi mkulu, chisanadze mankhwala akhoza kuchitidwa choyamba kuchepetsa okwana sianidi ndende zosakwana 100mg/L. Kenako, sodium metabisulfite ndi mkuwa sulphate amawonjezeredwa, mpweya wokwanira umayambitsidwa, ndipo pH mtengo umayendetsedwa (nthawi zambiri umayendetsedwa pa 7 - 8), kotero kuti cyanide ndi oxidized kukhala cyanate, yomwe imapangidwa ndi hydrolyzed kuti ipange ayoni bicarbonate ndi ammonia.

Njira ya sodium metabisulfite - mpweya ndiyoyenera kuchotsera madzi otsika a cyanide golide. Mlingo wa mankhwalawo ndi wochepa, kuchuluka kwa anthu ogwira ntchito kumakhala kochepa, koma ndalama zoyambirapo ndizokulirapo, ndipo zida monga zowombera ziyenera kuwonjezeredwa. Zofunikira pazizindikiro zamachitidwe ndizokhazikika, ndipo kuwongolera mtengo wa pH ndikofunikira kwambiri. Copper sulphate iyeneranso kuwonjezeredwa ngati chothandizira. Zomwe zimachitika nthawi yayitali. Ngati chithandizo sichili choyenera, ma ion ammonium ambiri amapangidwa, ndipo slag yopangidwa sivuta kusefa. Pali mpweya wochepa wa ammonia wopangidwa pamalopo, ndipo ilibe mphamvu pakuchotsa thiocyanides.

Hydrogen Peroxide Oxidation Njira

Njira ya hydrogen peroxide oxidation ndi yothira ma cyanides kukhala CNO⁻ pansi pa kutentha kwabwino, zamchere (pH = 10 - 11), Cu²⁺ monga chothandizira, kenaka amazisungunula kukhala zinthu zopanda poizoni. Ma cyanides ovuta (zovuta za Cu, Zn, Pb, Ni, Cd) zimasiyanitsidwanso chifukwa cha kuwonongedwa kwa cyanides mwa iwo. Ferrocyanide ions ndi ayoni ena heavy metal amapanga mchere wovuta wa ferrocyanide ndipo amachotsedwa. Pomaliza, kuchuluka kwa cyanide m'madzi otayidwa oyeretsedwa kumatha kuchepetsedwa mpaka 0.5mg/L.

Njirayi ndi yoyenera kuchiza otsika - ndende cyanide - munali madzi oipa. Zida zothandizira hydrogen peroxide ndizosavuta komanso zosavuta kuziwongolera zokha. Komabe, cyanate yopangidwa imayenera kukhala kwakanthawi kuti iwonongeke kukhala CO₂ ndi NH₃. Zoyipa zake ndizakuti kugwiritsa ntchito mkuwa ngati chothandizira kungayambitse mkuwa m'madzi otayidwa kupitilira muyezo, mtengo wazinthu zopangira ndi wokwera kwambiri, ma thiocyanides sangathe kukhala oxidized, ndipo ma ion ammonium amapangidwa. Ndipotu, madzi onyansa akadali ndi poizoni wina. Komanso, popeza hydrogen peroxide ndi oxidant, imakhala ndi dzimbiri, ndipo pali zovuta ndi zoopsa zina pamayendedwe ndi kugwiritsa ntchito.

Njira ya Acidification

Mukamagwiritsa ntchito njira ya acidification pochiza cyanide - madzi osauka, momwe zimachitikira zimakhala zovuta, makamaka kuphatikizapo njira zitatu: ndondomeko ya acidification ya cyanide - yomwe imakhala ndi madzi onyansa, kuvula ndi kuyamwa kwa mpweya wa HCN, ndi ndondomeko ya neutralization yamadzimadzi ochotsedwa.

(1) Kuchita kwa Acid: The cyanide - madzi osauka amapangidwa acidified ndi kuyeretsedwa ndi asidi. Ma cyanides ovuta m'madzi osowa amatha kupanga mpweya wosasungunuka monga CuCN, CuSCN, ndi Zn₂Fe(CN)₆ ndikuchotsedwa, ndipo nthawi yomweyo, hydrogen cyanide imapangidwa.

(2) Volatilization ndi mayamwidwe kachitidwe: Madzi osauka amatenthedwa mpaka pafupifupi 30 ℃ asanakhale acidification. Popeza kuwira kwa HCN ndi 26.5 ℃ kokha, kumakhala kosakhazikika. Choncho, nsanja yodzaza ndi ntchito ngati misa - kutengerapo zida kukhudzana pakati pa mpweya - madzi awiri - gawo mu njira acidification, amene n'zosavuta kukwaniritsa kuvula ndi mayamwidwe HCN.

(3) Neutralization reaction: laimu kapena madzi alkali ntchito neutralize asidi - anavula zotsalira madzi. Mamolekyu otsalira a HCN mu yankho adzasinthidwa kukhala mawonekedwe a CN⁻. Njira ya acidization imatha kuchira Sodium Cyanide kuchokera ku cyanide - yomwe ili ndi madzi onyansa ndikuzindikira kuchira. Komabe, ili ndi zofunika kwambiri pakusindikiza zida, ndalama zokulirapo zam'tsogolo, zimafunikira luso lapamwamba kwambiri, ndipo kukonza zida kumakhala kovuta. Palinso zoopsa zina zachitetezo. Madzi owonongeka omwe amapangidwa pambuyo pochira amafunikirabe chithandizo chakuya kuti akwaniritse miyezo yotulutsa.

Electrolysis Njira

Njira ya electrolysis imagwiritsa ntchito ma electrochemical redox reaction kuti iwononge ma cyanides m'madzi onyansa. Panthawi ya ion electrolysis, ma cyanides amataya ma elekitironi pa anode ndipo amapangidwa ndi okosijeni kukhala cyanate, carbonate, nitrogen, kapena ammonium. Cyanate imawonjezeredwa ku CO₂ ndi H₂O. Zomwe zimachitika kwambiri ndi:

CN⁻ + 2OH⁻ - 2e → CNO⁻ + H₂O (24)

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

Kuyesera kwa Electrolysis pogwiritsa ntchito ndodo ya ceramic yopangidwa ndi lead dioxide electrode ndi chitsulo chosapanga dzimbiri - mbale yachitsulo ya cathode yatsimikizira kuti pogwiritsa ntchito njira ya electrolysis pochiza cyanide - yomwe ili ndi madzi oipa, pambuyo pa maola 2 a electrolysis, CN⁻ ndende ikhoza kuchepetsedwa kuchoka pa 385mg / L mpaka 58mg / L, ndipo Cu²/L kuchokera ku 450mg / L ikhoza kuchepetsedwa 48mg / L. Komanso, Hunan Zhongnan Gold Smelter amagwiritsa electrochemical njira kuchitira cyanide golide m'zigawo madzi zinyalala, amene angathe kuchepetsa cyanide okwana 4g/L kuti 0.8g/L. Kusiyanitsa kuchokera pamwambapa ndikuti mbale zonse za anode ndi cathode zimapangidwa ndi mbale zachitsulo. Panthawi yogwira ntchito, osati mphamvu yamagetsi yokha yomwe imagwiritsidwa ntchito, komanso mbale zachitsulo zimadyedwa.

Njira ya electrolysis imagwiritsidwa ntchito kwambiri pochiza cyanide yapamwamba - yomwe ili ndi madzi onyansa. Zipangizozi zimakhala ndi malo ang'onoang'ono, ndondomekoyi ndi yosavuta komanso yosavuta kulamulira, koma imagwiritsa ntchito mphamvu zambiri zamagetsi, ndipo ndalama zogwiritsira ntchito zimakhala zapamwamba kuposa njira ya alkaline chlorination. Kuchulukitsa kwa cyanide ndikokwanira, ndipo sikumakhudza kuchotsa ma cyanide.

Pakalipano, pakati pa njira zochizira cyanide golide m'zigawo madzi zinyalala, ndi alkaline chlorination njira, acidification njira, ndi sodium metabisulfite - mpweya njira ntchito kwambiri. Njira ya electrolysis ndi ferrous salt complexation njira ndi njira zatsopano zomwe zakhala zikugwiritsidwa ntchito bwino pochiza mafakitale. Njira ya hydrogen peroxide oxidation ndiyo njira yochizira mwadzidzidzi. Palinso njira zina zambiri zochiritsira zochizira cyanide golide m'zigawo zamadzi otayira, monga njira yoyeretsera zachilengedwe, njira yachilengedwe, njira yolekanitsa nembanemba, njira ya ion - kusinthanitsa, ndi zina zambiri.