Cyanide Leaching Txheej Txheem hauv Kub Mining: Cov txheej txheem ua tiav los ntawm kev tawg mus rau rov qab

Introduction

Kev rho tawm ntawm kub los ntawm nws cov ore yog ib qho kev txaus siab rau ntau pua xyoo. Ntawm ntau txoj kev muaj, Cyanide leaching tau tshwm sim los ua ib qho ntawm cov txheej txheem siv dav hauv kev lag luam kub mining kev lag luam. Cov txheej txheem no tso cai rau kom muaj txiaj ntsig zoo ntawm kev sib cais ntawm cov kub los ntawm nws cov ntaub ntawv tswv tsev, ua rau nws muaj peev xwm rov qab tau cov hlau tseem ceeb hauv daim ntawv ntau dua. Kab lus no yuav delve rau hauv cov txheej txheem ua tiav ntawm cyanide leaching nyob rau hauv kub mining, los ntawm thawj zaug dissolution ntawm kub hauv cyanide daws mus rau qhov kawg rov qab ntawm cov hlau.

Lub Dissolution ntawm Kub hauv Cyanide Solutions

Cov tshuaj tiv thaiv muaj feem xyuam

Lub dissolution ntawm kub nyob rau hauv cov kev daws teeb meem cyanide yog raws li ib tug complex series ntawm tshuaj tiv thaiv. Tag nrho cov tshuaj tiv thaiv tuaj yeem sawv cev los ntawm kev sib npaug hauv qab no:

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

Hauv qhov tshuaj tiv thaiv no, kub (Au) reacts nrog Sodium cyanide (NaCN) nyob rau hauv muaj oxygen (O₂) thiab dej (H₂O) tsim sodium dicyanoaurate (Na[Au(CN)₂]) thiab sodium hydroxide (NaOH). Lub luag haujlwm ntawm cov pa oxygen hauv cov tshuaj tiv thaiv no yog qhov tseem ceeb vim nws ua raws li tus neeg sawv cev oxidizing, ua kom yooj yim rau kev tawg ntawm kub.

Tej yam kev mob rau qhov zoo tshaj plaws Dissolution

Txhawm rau kom muaj txiaj ntsig zoo ntawm kev tawg ntawm kub, ntau yam yuav tsum tau ua tib zoo tswj. Qhov concentration ntawm cyanide hauv cov tshuaj yog qhov tseem ceeb. Feem ntau, qhov concentration ntawm 0.05 - 0.1% NaCN yog siv rau hauv cov txheej txheem leaching. Ib qho kev xav ntau dua tuaj yeem ua rau muaj kev noj ntau dua ntawm cyanide yam tsis muaj qhov sib npaug ntawm kev sib cais ntawm cov kub, thaum qhov qis dua tuaj yeem ua rau qeeb thiab tsis tiav leaching.

Cov pH ntawm cov tshuaj kuj tseem ua lub luag haujlwm tseem ceeb. Cov txheej txheem leaching yog zoo tshaj plaws nyob rau hauv ib tug me ntsis alkaline nruab nrab, nrog ib tug pH ntau ntawm 9.5 - 11. Ntawm no pH, cov cyanide ions tam sim no nyob rau hauv lawv un-dissociated daim ntawv (HCN), uas yog ntau reactive rau kub. Kev kho cov pH feem ntau ua tiav los ntawm kev ntxiv cov txiv qaub (CaO) rau cov tshuaj leaching.

Kub yog lwm qhov tseem ceeb parameter. Txawm hais tias cov tshuaj tiv thaiv tuaj yeem tshwm sim ntawm qhov kub thiab txias, qhov kub siab me ntsis ntawm ib ncig ntawm 25 - 35 ° C tuaj yeem txhim kho tus nqi ntawm cov kub yaj. Txawm li cas los xij, qhov ntsuas kub ntau dhau tuaj yeem ua rau decomposition ntawm cyanide, txo nws cov txiaj ntsig.

Kev kho mob ua ntej ntawm Ores

Crushing thiab sib tsoo

Ua ntej cov txheej txheem cyanide leaching tuaj yeem pib, cov pob zeb kub yuav tsum tau kho ua ntej. Thawj kauj ruam hauv qhov kev kho ua ntej no feem ntau yog Crushing thiab Sib tsoo. Cov ores yog crushed kom txo lawv qhov loj me thiab tom qab ntawd hauv av rau hauv cov khoom zoo. Qhov no ua rau thaj tsam saum npoo ntawm cov ore, tso cai rau kev sib cuag zoo ntawm cov khoom kub thiab cov tshuaj cyanide thaum lub sij hawm leaching txheej txheem.

Lub degree ntawm kev sib tsoo yog ua tib zoo tswj. Kev sib tsoo ntau dhau tuaj yeem ua rau tsim cov slimes zoo, uas tuaj yeem ua rau muaj teeb meem thaum cov kauj ruam tom ntej ntawm cov kua dej sib cais. Ntawm qhov tod tes, kev sib tsoo hauv qab yuav ua rau muaj qhov tsis txaus ntawm cov khoom kub, ua rau tsis tiav leaching.

Roasting thiab Bio-oxidation

Qee qhov xwm txheej, cov pob zeb kub tuaj yeem muaj cov khoom siv refractory uas tiv thaiv kev tawg ncaj qha ntawm kub los ntawm cyanide. Rau cov ores zoo li no, kev kho mob ua ntej ntxiv xws li roasting lossis bio-oxidation yuav xav tau.

Roasting muaj cua sov cov ore nyob rau hauv lub xub ntiag ntawm huab cua kom oxidize lub refractory minerals, xws li sulfides. Cov txheej txheem oxidation no rhuav tshem cov zaub mov, tso cov khoom kub thiab ua rau lawv nkag mus rau cov tshuaj cyanide.

Bio-oxidation, ntawm qhov tod tes, siv cov kab mob oxidize cov zaub mov refractory. Qhov no yog lwm txoj hauv kev zoo rau kev ci ci vim nws ua haujlwm ntawm qhov kub thiab txias thiab ua rau muaj kev phom sij tsawg dua. Cov kab mob, feem ntau yog cov kab mob los yog fungi, raug xaiv raws li lawv lub peev xwm los oxidize cov minerals refractory tshwj xeeb tam sim no hauv cov ore.

Txoj Kev Leaching

Stirred Tank Leaching

Stirred tank leaching yog ib txoj hauv kev siv ntau tshaj plaws rau cyanide leaching. Nyob rau hauv cov txheej txheem no, cov ore kho ua ntej yog tov nrog cov tshuaj cyanide nyob rau hauv loj stirred tso tsheb hlau luam. Cov tso tsheb hlau luam tau nruab nrog cov agitators uas ua kom muaj kev sib xyaw ua ke ntawm cov ore thiab cov kev daws teeb meem, txhawb kev sib cuag ntawm cov khoom kub thiab cov cyanide ions.

Lub sijhawm leaching tuaj yeem sib txawv nyob ntawm qhov xwm txheej ntawm cov ore thiab cov haujlwm ua haujlwm. Feem ntau, cov txheej txheem leaching tuaj yeem siv nyob qhov twg los ntawm ob peb teev mus rau ob peb hnub. Nyob rau lub sijhawm no, cov qauv ntawm cov leachate raug coj mus rau ib ntus thiab tshuaj xyuas los saib xyuas qhov kev nce qib ntawm kev tawg ntawm kub.

Heap Leaching

Heap leaching yog lwm txoj kev siv dav, tshwj xeeb tshaj yog rau qib qis kub ores. Nyob rau hauv cov txheej txheem no, lub crushed ore yog stacked nyob rau hauv loj heaps ntawm ib tug impermeable liner. Cov tshuaj cyanide yog tom qab ntawd txau rau saum lub pob thiab tso cai rau percolate los ntawm cov ore. Raws li kev daws teeb meem dhau los ntawm lub pob zeb, nws dissolves cov khoom kub, thiab cov txiaj ntsig cev xeeb tub yog sau rau hauv qab ntawm heap.

Heap leaching yog ib txoj kev siv nyiaj ntau dua piv rau Stirred tank leaching raws li nws xav tau tsawg peev peev hauv cov cuab yeej siv. Txawm li cas los xij, nws yog cov txheej txheem qeeb dua thiab tsim nyog rau ores nrog cov ntsiab lus kub tsawg.

Kev sib cais-kua kua

pom

Tom qab cov txheej txheem leaching tiav lawm, cov kauj ruam tom ntej yog cais cov khoom seem (tailings) los ntawm cov tshuaj cev xeeb tub, uas muaj cov kub yaj. Kev lim dej yog ib txoj hauv kev siv ntau tshaj plaws rau kev sib cais-kua kua. Hauv cov txheej txheem no, cov slurry (sib tov ntawm cov khoom thiab cov kua) yog dhau los ntawm lub lim nruab nrab, xws li cov ntaub lim los yog lim xovxwm. Cov khoom siv tau khaws cia rau ntawm qhov nruab nrab lim, thaum cov kua (cov tshuaj cev xeeb tub) dhau los thiab sau.

Qhov kev xaiv ntawm lim nruab nrab yog nyob ntawm qhov xwm txheej ntawm cov khoom thiab cov kev ua haujlwm. Piv txwv li, nyob rau hauv cov ntaub ntawv uas cov khoom yog zoo heev, yuav tsum tau ib tug zoo dua - meshed lim ntaub.

Decantation

Decantation yog lwm txoj hauv kev uas tuaj yeem siv rau kev sib cais ntawm cov kua-kua, tshwj xeeb tshaj yog thaum cov khoom siv loj loj thiab kho tau yooj yim. Nyob rau hauv cov txheej txheem no, lub slurry raug tso cai sawv ntsug nyob rau hauv ib tug settling tank rau ib lub sij hawm ntawm lub sij hawm. Cov khoom me me nyob rau hauv qab ntawm lub tank vim yog lub ntiajteb txawj nqus, thiab cov kua ntshiab supernatant (cov tshuaj cev xeeb tub) ces ua tib zoo decanted tawm.

Decantation yog ib qho yooj yim dua thiab tsawg zog - siv zog piv rau kev pom. Txawm li cas los xij, nws yuav tsis zoo li kev sib cais cov khoom zoo heev.

Kev rov qab kub los ntawm kev xeeb tub

Cov pa roj carbon activated adsorption

Ib txoj hauv kev zoo tshaj plaws rau kev rov qab kub los ntawm kev cev xeeb tub yog Cov pa roj carbon activated adsorption. Nyob rau hauv cov txheej txheem no, activated carbon yog ntxiv rau lub cev xeeb tub cov tshuaj. Cov kub - cyanide complex muaj ib tug muaj zog affinity rau saum npoo ntawm cov activated carbon, thiab yog li ntawd, cov kub yog adsorbed rau cov pa roj carbon hais.

Cov pa roj carbon monoxide yog tom qab ntawd sib cais los ntawm cov tshuaj, feem ntau yog los ntawm kev tshuaj ntsuam los yog pom. Cov kub-loaded carbon yog tom qab ntawd ntxiv cov txheej txheem kom desorb kub. Qhov no feem ntau yog ua los ntawm kev tso cov pa roj carbon mus rau qhov kub thiab txias los ntawm kev siv tshuaj desorption tus neeg sawv cev.

Zinc nag lossis daus

Zinc nag lossis daus, tseem hu ua Merrill - Crowe txheej txheem, yog lwm txoj hauv kev rau kev rov qab kub. Hauv cov txheej txheem no, zinc plua plav yog ntxiv rau cov tshuaj cev xeeb tub. Zinc yog ntau electropositive tshaj kub, thiab yog li ntawd, nws displaces cov kub ntawm kub - cyanide complex. Cov tshuaj tiv thaiv tuaj yeem sawv cev los ntawm kev sib npaug hauv qab no:

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

Cov kub precipitated, nrog rau cov zinc uas tsis muaj kev cuam tshuam, tsim cov khoom sludge. Cov sludge no ces muab cais tawm ntawm cov tshuaj, thiab cov kub yog ntxiv refined kom tau ib tug ntshiab cov khoom.

Refining ntawm kub

Smelting

Thaum cov kub tau rov qab los ntawm kev cev xeeb tub, nws feem ntau yuav tsum tau ua kom zoo kom tshem tawm cov impurities seem. Smelting yog ib txoj hauv kev zoo tshaj plaws rau kev ua kom zoo nkauj kub. Nyob rau hauv cov txheej txheem no, kub - uas muaj cov khoom yog rhuab mus rau ib tug kub kub nyob rau hauv lub xub ntiag ntawm ib tug flux, xws li borax. Lub flux pab txo qis qhov melting point ntawm cov kub thiab kuj reacts nrog impurities, tsim ib tug slag uas yuav raug cais los ntawm cov molten kub.

Tom qab ntawd cov molten kub yog poured rau hauv pwm los ua ingots. Cov ingots no tuaj yeem ua tiav ntxiv lossis muag raws li cov khoom tiav.

Electrolytic Refining

Electrolytic refining yog ib txoj hauv kev zoo dua rau kev ua kom kub. Nyob rau hauv cov txheej txheem no, cov kub - muaj anode yog muab tso rau hauv ib tug electrolytic cell nrog rau ib tug ntshiab kub cathode. Cov electrolyte feem ntau yog cov tshuaj kub chloride lossis lwm cov ntsev kub. Thaum cov hluav taws xob tam sim no dhau los ntawm lub xov tooj ntawm tes, cov kub los ntawm cov anode dissolves rau hauv electrolyte thiab tom qab ntawd tso rau hauv cathode.

Cov impurities uas muaj electropositive ntau dua li kub yaj rau hauv cov electrolyte tab sis tsis tso rau hauv cathode, thaum impurities uas tsis tshua muaj electropositive tshaj kub nyob twj ywm raws li ib tug sludge nyob rau hauv qab ntawm lub cell. Qhov no ua rau cov khoom kub-purity heev.

Kev Saib Xyuas Ib Puag Ncig

Cyanide Management

Cyanide yog ib yam tshuaj lom heev, thiab kev tswj kom zoo ntawm cyanide hauv cov txheej txheem kub mining yog qhov tseem ceeb tshaj plaws. Kev siv cov cyanide hauv kev khawb kub yog nruj tswj hwm hauv ntau lub teb chaws kom txo nws qhov cuam tshuam rau ib puag ncig thiab tib neeg kev noj qab haus huv.

Ib qho tseem ceeb ntawm kev tswj hwm cyanide yog kev tiv thaiv ntawm cyanide spills. Kev ua haujlwm tsuas yog yuav tsum muaj cov txheej txheem ntim khoom kom zoo los tiv thaiv cyanide - muaj cov kev daws teeb meem los ntawm kev xau mus rau ib puag ncig. Tsis tas li ntawd, kev kho mob ntawm cyanide - muaj cov dej khib nyiab kuj tseem ceeb heev. Muaj ntau txoj hauv kev los kho cyanide - muaj cov dej khib nyiab, xws li tshuaj oxidation, kev kho mob lom neeg, thiab kev sib pauv ion.

Kev tshem tawm tailings

Cov khoom seem (tailings) ua tom qab cov txheej txheem kub rov qab yuav tsum tau muab pov tseg kom zoo. Tailings tuaj yeem muaj cov lej ntawm cyanide thiab lwm yam hlau hnyav, uas tuaj yeem ua rau muaj kev hem thawj rau ib puag ncig yog tias tsis tswj kom raug.

Ib txoj hauv kev zoo rau tailings pov tseg yog khaws cia rau hauv tailings dams. Cov dams no yog tsim los kom muaj cov tailings thiab tiv thaiv kev tso tawm ntawm cov kab mob mus rau ib puag ncig. Qee zaum, cov tailings kuj tseem yuav rov ua dua kom rov qab tau cov khoom muaj txiaj ntsig tseem ceeb lossis txo qhov cuam tshuam ib puag ncig.

xaus

Cov txheej txheem cyanide leaching nyob rau hauv kub mining yog ib tug complex thiab multi-txheej txheej txheem uas muaj cov dissolution ntawm kub nyob rau hauv cyanide tov, pre-kev kho mob ntawm ore, leaching, khoom - kua sib cais, kub rov qab, refining, thiab ib puag ncig kev tswj. Txhua kauj ruam hauv cov txheej txheem no tau ua tib zoo tswj xyuas kom muaj txiaj ntsig zoo ntawm kev rho tawm thiab rov qab kub thaum txo qhov cuam tshuam ib puag ncig. Txawm hais tias muaj teeb meem cuam tshuam nrog kev siv cyanide, cov txheej txheem tseem yog ib qho tseem ceeb thiab siv dav hauv kev lag luam kub mining kev lag luam vim nws cov kev ua haujlwm siab thiab tus nqi qis. Txawm li cas los xij, kev tshawb fawb txuas ntxiv thiab kev txhim kho tau raug ua los tsim lwm txoj hauv kev uas muaj kev nyab xeeb dua thiab muaj txiaj ntsig zoo.