Cyanide Gold Extraction Cov Txheej Txheem Kev Kho Dej Dej

Tam sim no, txoj kev rho kub cyanide yog ib qho ntawm cov txheej txheem loj tshaj plaws rau kev sib xyaw kub hauv Suav teb. Nws siv cov kua cyanide los rho kub ntawm cov pob zeb, uas muaj qhov nrawm rov qab tau zoo, muaj zog hloov pauv tau rau cov khoom siv ore, thiab muaj peev xwm tsim kub ntawm qhov chaw. Txij li thaum thawj zaug siv cov kua cyanide los leach kub ntawm cov pob zeb hauv xyoo 1887, txoj kev no tau siv dav dav txog tam sim no. Txawm li cas los xij, kev rho kub cyanide tsim ntau cov tshuaj lom thiab cov tshuaj lom, ua rau muaj kev hem thawj loj rau ib puag ncig thiab tib neeg. Yog li ntawd, txhawm rau kom txo qhov kev puas tsuaj, nws yog qhov tsim nyog los kawm txog cov txheej txheem kho cov dej khib nyiab rho kub cyanide. Muaj ntau tus kws tshawb fawb tau sau cov txheej txheem kho, cov ntsiab cai tshuaj lom neeg, thiab cov qauv kev txhim kho ntawm cov dej khib nyiab uas muaj cyanide, tab sis feem ntau ntawm lawv tsuas yog tham txog ib lossis ob txoj hauv kev. Yog li ntawd, tsab xov xwm no ua qhov kev tshuaj xyuas ntxaws ntxaws ntawm ntau txoj hauv kev kho rau cov dej khib nyiab rho kub cyanide uas siv tam sim no hauv kev lag luam, piv cov txiaj ntsig, qhov tsis zoo, thiab cov xwm txheej ntawm txhua txoj hauv kev, uas muaj qee qhov tseem ceeb rau cov ntawv thov zoo sib xws hauv kev tsim khoom tiag tiag.

I. Cov peev txheej thiab kev phom sij ntawm Cyanide Gold Extraction Wastewater

Lub hauv paus ntsiab lus tseem ceeb ntawm kev rho tawm kub cyanide yog tias nyob rau hauv ib puag ncig aerobic, sodium cyanide reacts nrog kub los tsim cov kub complexes, uas tom qab ntawd yaj. Tom qab ntawd, kub tuaj yeem rho tawm los ntawm kev nplua nuj los ntawm kev ua kom muaj Carbon adsorption lossis tshem tawm los ntawm zinc hmoov los ntawm kub cyanide. Tib lub sijhawm, lwm yam hlau hnyav xws li nyiaj, tooj liab, thiab zinc kuj tsim cov complexes thiab yaj.

Cov cyanides siv rau hauv cov tshuaj tiv thaiv thiab cov tshuaj sib xyaw ua ke yog cov tshuaj lom thiab cov tshuaj ua rau muaj kev phom sij. Sodium cyanide yooj yim rau hydrolyze thiab yog Pawg 1 tshuaj lom heev, nrog rau qhov tshuaj lom tuag ntawm 0.10g. Thaum Cyanides xau rau hauv cov dej, nws ua rau muaj kev puas tsuaj loj heev rau cov kab mob hauv dej, thiab yuav ua rau muaj kev hem thawj loj rau tib neeg thiab ib puag ncig. Yog li ntawd, kev kho cov dej khib nyiab cyanide kub yog qhov tseem ceeb heev.

II. Txoj kev kho tseem ceeb rau Cyanide Gold Extraction Wastewater

Txoj kev Alkaline Chlorination

Txoj kev alkaline chlorination tam sim no yog ib txoj hauv kev siv ntau tshaj plaws los kho cyanide - muaj cov dej khib nyiab los ntawm kev rho tawm kub cyanide. Nws tsuas yog siv cov tshuaj chlorine - raws li oxidants los oxidize cov cyanides nyob rau hauv cov dej khib nyiab nyob rau hauv alkaline tej yam kev mob, converting lawv mus rau hauv tsis muaj tshuaj lom. Lub cyanide - tawg txheej txheem ntawm alkaline chlorination tau muab faib ua ob theem:

Thawj theem yog oxidize cyanide rau cyanate, uas yog hu ua "tsis tiav oxidation" theem. CN⁻ reacts nrog OCl⁻ rau thawj daim ntawv CNCl, thiab tom qab ntawd nws hydrolyzes rau CNO⁻. Nws yuav tsum tau muab sau tseg tias CNCl yog heev volatile thiab lom nyob rau hauv acidic tej yam kev mob. Yog li ntawd, thaum lub sij hawm ua hauj lwm, tus nqi pH yuav tsum nruj me ntsis tswj kom nyob rau hauv ib tug alkaline xeev.

Qhov thib ob theem yog ntxiv oxidize cyanate rau carbon dioxide thiab nitrogen, uas yog hu ua "tag nrho oxidation" theem. Thaum lub sij hawm cyanide - tawg txheej txheem, tus nqi pH muaj kev cuam tshuam zoo rau cov tshuaj tiv thaiv oxidation. Tus nqi pH ntawm thawj - theem oxidation yuav tsum tau tswj ntawm 10 - 11. thiab lub sij hawm tshuaj tiv thaiv yog 10 - 15 feeb. Tus nqi pH ntawm qhov thib ob - theem oxidation yuav tsum tau tswj ntawm 6.5 - 7.0. thiab lub sijhawm tshuaj tiv thaiv yog 10 - 15 feeb.

Ib qho mine siv txoj kev alkaline chlorination los kho cov supernatant ntawm cyanide tail slurry (nrog cov ntsiab lus cyanide ntawm 200mg / L) thiab cov dej seepage los ntawm lub tank sedimentation (nrog rau cov ntsiab lus cyanide ntawm 5mg / L). Tus nqi pH yog tswj ntawm 10 - 11. thiab bleaching hmoov yog ntxiv ntawm qhov piv ntawm 35 - 40 npaug ntawm cov ntsiab lus cyanide rau kev sib tov thiab nplawm. Tom qab sedimentation hauv cov thickener, tag nrho cov ntsiab lus cyanide tuaj yeem txo mus rau 0.1mg / L.

Txoj kev alkaline chlorination yog txoj kev siv ntau tshaj plaws rau kev kho cov cyanide - muaj cov dej khib nyiab, thiab cov hmoov bleaching yog cov tshuaj chlorine feem ntau - raws li oxidant. Txoj kev no tsim nyog rau kev kho cov dej kub ntawm cyanide extraction khib nyiab uas muaj qhov siab lossis qis qis. Nws tuaj yeem tshem tawm thiocyanate thiab cyanide - muaj cov complexes (tshwj tsis yog cov ferrocyanide complexes). Cov tshuaj muaj dav dav, cov khoom pov tseg uas tsim tau yooj yim lim, thiab kev ua haujlwm yooj yim. Txawm li cas los xij, qhov chaw ua haujlwm yog qhov hnyav heev thaum siv cov tshuaj dawb los kho cov dej khib nyiab. Tam sim no qee lub tuam txhab siv cov kua tshuaj dawb los yog cov tshuaj chlorine dioxide xwb, uas txhim kho qhov chaw ua haujlwm rau qee qhov. Tab sis cov pa roj carbon monoxide raug tsim tawm thaum lub sij hawm cov txheej txheem tshuaj tiv thaiv, thiab nws muaj qhov loj corrosiveness rau cov khoom siv. Cov nqi kho mob thiab cov nqi kho mob kuj tseem siab.

Ferrous Salt Complexation Method

Txoj kev ferrous ntsev complexation yog ib txoj kev kho rau cyanide kub extraction dej khib nyiab uas tau tshwm sim nyob rau hauv xyoo tas los no. Los ntawm kev tswj cov tshuaj tiv thaiv pH tus nqi ntawm 7 - 8. ferrous ions react nrog dawb cyanide thiab ib co cyanide complexes nyob rau hauv lub cyanide kub extraction dej khib nyiab los ua precipitates.

Cov kev sim tau pom tias feem ntau, tsuas yog ntxiv ferrous sulfate los kho cov dej kub ntawm cyanide extraction tsis tuaj yeem ua rau cov dej khib nyiab ua tau raws li cov qauv tso tawm. Yog li ntawd, ib tug dav oxidant yuav tsum tau ntxiv rau cov dej khib nyiab kho kom tob - cyanide tshem tawm. Ntev npaum li cov xwm txheej zoo - tswj tau, cov oxidant tuaj yeem ncaj qha ntxiv rau kev kho mob yam tsis muaj kev sib cais ntawm cov precipitate, thiab cov qauv tso tawm kuj tuaj yeem ua tiav. Qhov no muaj qhov tseem ceeb zoo piv nrog cov txheej txheem kev sib cais ua ntej thiab tom qab ntawd kho.

Ib lub smelter kub siv cov sodium sulfide - ferrous sulfate txoj kev kho cyanide - cov kua tsis zoo. Lub zog muaj cov ntsiab lus cyanide ntawm 2500mg / L. Tom qab kev kho mob, cov dej ntws tawm muaj cov ntsiab lus cyanide tsawg dua 20mg / L, nrog kev tshem tawm ntawm 99.2%, uas qhia tau zoo heev. Tom qab sib sib zog nqus - kev kho mob siv cov sodium metabisulfite - cua txoj kev los txo tag nrho cov cyanide kom tsawg dua 0.4mg / L.

Txoj kev ferrous ntsev complexation yog ib txoj kev kho tshiab tshiab, feem ntau yog siv los kho siab - concentration cyanide - muaj cov dej khib nyiab. Nws cov txheej txheem yog yooj yim, ib-lub sij hawm peev me me, nws yog ib qho yooj yim rau kev khiav lag luam, cov tshuaj (feem ntau ferrous sulfate) yog dav, pheej yig, thiab yooj yim rau siv. Txawm li cas los xij, vim hais tias cov tshuaj ferrous sulfate yog acidic, thaum nws tov nrog cyanide kub extraction dej khib nyiab, lub zos cheeb tsam yuav acidic, thiab muaj peev xwm tsim hydrogen cyanide gas. Tsis tas li ntawd, nws tsis tuaj yeem tshem tawm thiocyanate, thiab cov dej khib nyiab kho tseem xav tau kev kho tob kom ua tau raws li cov qauv tso tawm.

Sodium Metabisulfite - Txoj Kev Cua

Sodium metabisulfite - cua txoj kev yog tsim los ntawm sulfur dioxide - cua txoj kev. Nws tsuas yog siv cov nyhuv synergistic ntawm sodium metabisulfite thiab huab cua ntawm cov cyanides hauv cov dej khib nyiab nyob rau hauv ib qho pH ntau, nrog rau cov nyhuv catalytic ntawm tooj liab ions, oxidize CN⁻ rau CNO⁻.

Yog hais tias cov ntsiab lus cyanide hauv cyanide - muaj cov dej khib nyiab siab, kev kho mob ua ntej tuaj yeem ua ntej kom txo tau tag nrho cov cyanide concentration kom tsawg dua 100mg / L. Tom qab ntawd, sodium metabisulfite thiab tooj liab sulfate tau ntxiv, cua txaus yog qhia, thiab pH tus nqi yog tswj (feem ntau tswj ntawm 7 - 8), yog li ntawd cyanide yog oxidized rau cyanate, uas yog ces hydrolyzed rau bicarbonate ions thiab ammonia.

Cov sodium metabisulfite - huab cua txoj kev yog tsim rau kev kho mob tsawg - concentration cyanide kub extraction dej khib nyiab. Qhov ntau npaum ntawm cov tshuaj yog me me, kev siv zog tsawg, tab sis kev nqis peev ua ntej yog qhov loj, thiab cov khoom siv xws li tshuab tshuab yuav tsum tau ntxiv. Cov kev cai rau cov txheej txheem ntsuas yog qhov nruj, thiab tswj tus nqi pH yog qhov tseem ceeb heev. tooj liab sulfate kuj yuav tsum tau ntxiv raws li ib tug catalyst. Lub sijhawm tshuaj tiv thaiv yog ntev. Yog tias qhov kev kho mob tsis tsim nyog, ib qho loj ntawm ammonium ions yuav raug tsim tawm, thiab cov slag generated tsis yooj yim rau lim. Muaj ib qho me me ntawm cov pa roj ammonia tsim rau ntawm qhov chaw, thiab nws tsis muaj qhov cuam tshuam rau kev tshem tawm thiocyanides.

Hydrogen Peroxide Oxidation Method

Txoj kev oxidation hydrogen peroxide yog oxidize cyanide rau CNO⁻ nyob rau hauv ib txwm kub, alkaline (pH = 10 - 11) tej yam kev mob, nrog Cu²⁺ raws li ib tug catalyst, thiab ces hydrolyze lawv mus rau hauv tsis muaj tshuaj lom. Complex cyanides (cov complexes ntawm Cu, Zn, Pb, Ni, Cd) kuj dissociated vim kev puas tsuaj ntawm cyanide nyob rau hauv lawv. Ferrocyanide ions thiab lwm yam hlau hnyav ions tsim ferrocyanide complex ntsev thiab raug tshem tawm. Thaum kawg, tag nrho cov cyanide concentration hauv cov dej khib nyiab tuaj yeem raug txo kom tsawg dua 0.5mg / L.

Txoj kev no tsim nyog rau kev kho qis - concentration cyanide - muaj cov dej khib nyiab. Cov khoom siv kho mob hydrogen peroxide yog qhov yooj yim thiab yooj yim rau kev tswj tsis siv neeg. Txawm li cas los xij, cov cyanate generated yuav tsum nyob twj ywm rau qee lub sijhawm kom decompose rau CO₂ thiab NH₃. Qhov tsis zoo yog tias siv tooj liab los ua cov khoom siv hluav taws xob tuaj yeem ua rau tooj liab hauv cov dej tso tawm kom dhau tus qauv, cov khoom siv raw khoom yog tus nqi siab, thiocyanides tsis tuaj yeem oxidized, thiab ammonium ions raug tsim. Qhov tseeb, cov dej khib nyiab tseem muaj qee yam toxicity. Ntxiv mus, vim hydrogen peroxide yog oxidant, nws muaj corrosiveness loj, thiab muaj qee yam teeb meem thiab kev phom sij hauv kev thauj mus los thiab siv.

Txoj kev Acidification

Thaum siv cov txheej txheem acidification los kho cyanide - kua tsis zoo, nws cov tshuaj tiv thaiv mechanism yog qhov nyuaj, feem ntau suav nrog peb txheej txheem: cov txheej txheem acidification ntawm cyanide - muaj cov dej khib nyiab, cov txheej txheem stripping thiab nqus ntawm HCN roj, thiab cov txheej txheem neutralization ntawm cov kua stripped.

(1) Acidification cov tshuaj tiv thaiv: Cov cyanide - cov kua tsis zoo yog acidified thiab purified nrog acid. Cov cyanides nyuaj hauv cov kua dej tsis zoo yuav tsim cov dej tsis sib haum xws li CuCN, CuSCN, thiab Zn₂Fe (CN)₆ thiab raug tshem tawm, thiab tib lub sijhawm, hydrogen cyanide tsim tawm.

(2) Volatilization thiab nqus cov tshuaj tiv thaiv: Cov kua tsis zoo yog pre-rhuab mus txog 30 ℃ ua ntej acidification. Txij li thaum lub boiling point ntawm HCN tsuas yog 26.5 ℃, nws yog volatile heev. Yog li ntawd, ib tug packed ntauwd yog siv raws li qhov loj - hloov khoom siv rau kev sib cuag ntawm cov roj - kua ob - theem nyob rau hauv lub acidification txoj kev, uas yog ib qho yooj yim mus cuag lub stripping thiab nqus ntawm HCN.

(3) Kev ua kom tsis muaj zog: Cov kua qaub lossis kua alkali yog siv los ua kom cov kua qaub uas seem tshuav tsis muaj zog. Cov HCN molecules seem hauv cov tshuaj yuav raug hloov mus ua daim ntawv CN⁻. Txoj kev ua kom tsis muaj zog tuaj yeem rov qab tau Sodium Cyanide los ntawm cov dej khib nyiab uas muaj cyanide thiab ua kom rov qab tau cov peev txheej. Txawm li cas los xij, nws muaj qhov yuav tsum tau ua kom cov khoom siv kaw, kev nqis peev loj heev, xav tau kev txawj ua haujlwm siab, thiab kev saib xyuas cov khoom siv nyuaj. Kuj tseem muaj qee qhov kev phom sij rau kev nyab xeeb. Cov dej khib nyiab uas tsim tawm tom qab rov qab tau tseem xav tau kev kho mob tob kom ua tau raws li cov qauv tso tawm.

Txoj Kev Electrolysis

Cov txheej txheem electrolysis siv cov tshuaj electrochemical redox los rhuav tshem cov cyanide hauv cov dej khib nyiab. Thaum lub sij hawm ion electrolysis, cyanide poob electrons ntawm lub anode thiab oxidized rau cyanate, carbonate, nitrogen, los yog ammonium. Cyanate yog ntxiv oxidized rau CO₂ thiab H₂O. Cov tshuaj tiv thaiv tseem ceeb yog:

CN⁻ + 2OH⁻ - 2e → CNO⁻ + H₂O (24)

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

Kev sim electrolysis siv tus kheej-ua ceramic - raws li cov hlau lead dioxide electrode pas nrig thiab stainless hlau cathode phaj tau ua pov thawj tias los ntawm kev siv cov txheej txheem electrolysis los kho cyanide - muaj cov dej khib nyiab, tom qab 2 teev ntawm electrolysis, CN⁻ concentration tuaj yeem txo los ntawm 385mg / L txog 58mg / L, thiab Cu²⁺ concentration tuaj yeem txo 450mg / L. Tsis tas li ntawd, Hunan Zhongnan Kub Smelter siv cov txheej txheem electrochemical los kho cov dej khib nyiab ntawm cyanide kub, uas tuaj yeem txo tag nrho cov cyanide ntawm 48g / L txog 4g / L. Qhov txawv ntawm qhov saum toj no yog tias ob qho tib si anode thiab cathode daim hlau yog ua los ntawm cov hlau phaj. Thaum lub sijhawm ua haujlwm, tsis yog siv hluav taws xob nkaus xwb, tab sis kuj tseem siv cov hlau phaj.

Txoj kev electrolysis feem ntau yog siv los kho siab - concentration cyanide - muaj cov dej khib nyiab. Cov khoom siv nyob rau hauv ib cheeb tsam me me, cov txheej txheem yog yooj yim thiab yooj yim rau kev tswj, tab sis nws siv ib tug loj npaum li cas ntawm hluav taws xob lub zog, thiab cov nqi khiav hauj lwm yog siab dua li ntawm alkaline chlorination txoj kev. Tus nqi tshem tawm cyanide yog qhov nruab nrab, thiab nws tsis muaj qhov cuam tshuam rau kev tshem tawm cyanide complexes.

Tam sim no, ntawm cov kev kho mob rau cyanide kub extraction dej khib nyiab, alkaline chlorination txoj kev, acidification txoj kev, thiab sodium metabisulfite - huab cua txoj kev yog dav siv. Cov txheej txheem electrolysis thiab ferrous ntsev complexation txoj kev yog cov txheej txheem tshiab uas tau ua tiav hauv kev kho mob. Txoj kev hydrogen peroxide oxidation feem ntau yog txoj kev kho mob xwm txheej ceev. Muaj ntau ntau lwm txoj kev kho mob rau kev kho cov cyanide kub extraction cov dej khib nyiab, xws li ntuj purification method, biological method, membrane cais txoj kev, ion - exchange method, thiab lwm yam. Txawm li cas los xij, raws li kev siv hauv kev lag luam, lawv txhua tus muaj qee yam kev txwv thiab tseem xav tau kev txhim kho txuas ntxiv.