Unveiling the Process of Gold Extraction using Sodium Cyanide

I. Pib Qhia

Hauv lub niaj hnub kub mining kev lag luam, Sodium cyanide plays lub luag haujlwm tseem ceeb. Tsis zoo li cov txheej txheem kub niaj hnub niaj hnub no, cov txheej txheem kev lag luam kub niaj hnub no tuaj yeem rho tawm cov kub los ntawm cov pob zeb ore nrog cov ntsiab lus kub tsis tshua muaj, qee zaum minuscule li 0.005%, qhov kub tsis pom ntawm qhov muag liab qab. Sodium cyanide yog tus neeg sawv cev tseem ceeb hauv cov txheej txheem tshem tawm txoj haujlwm no, ua kom muaj kev sib cais ntawm cov kub ntawm cov ore zoo. Kab lus no yuav tshawb nrhiav hauv kev nthuav dav li cas Sodium Cyanide yog siv nyob rau hauv kub mining.

II. Lub hauv paus ntawm Sodium Cyanide

A. Chemical Properties

Sodium cyanide, nrog rau cov tshuaj formula NaCN, yog dawb crystalline khoom. Nws zoo nkaus li granules los yog hmoov thiab yog nquag deliquescence. Cov tshuaj no muaj cov ntxhiab tsw tsw ntawm iab almonds. Nyob rau hauv cov nqe lus ntawm solubility, nws yog heev soluble nyob rau hauv dej, thaum tsuas yog me ntsis soluble nyob rau hauv ethanol. Tshuaj, sodium cyanide yog lub hauv paus muaj zog thiab tsis muaj zog acid ntsev. Nws cov tshuaj aqueous hydrolyzes los tsim hydrocyanic acid, ua rau cov tshuaj muaj zog alkaline. Tshwj xeeb, sodium cyanide yog tshuaj lom heev. Txawm tias ib qho me me, txawm tias los ntawm kev sib cuag ntawm daim tawv nqaij, nqus pa, lossis nqus tau, tuaj yeem ua rau muaj kev lom neeg hnyav thiab ua rau tuag taus. Nws ua rau nws ua rau tuag taus los ntawm kev tso tawm cyanide ions (CN-) uas muaj kev sib raug zoo rau cov hlau ions ntau dua li cov pa oxygen. Qhov no cuam tshuam cov txheej txheem oxidative ib txwm ntawm cov hlwb, thaum kawg ua rau cell asphyxia thiab cov ntaub so ntswg hypoxia.

B. Kev lag luam tseem ceeb

Tshaj nws lub luag haujlwm hauv kev khawb kub, sodium cyanide tuav qhov tseem ceeb hauv ntau yam kev lag luam. Hauv kev lag luam electroplating, nws ua haujlwm tseem ceeb rau plating tooj liab, nyiaj, cadmium, thiab zinc. Nws pab txo cov anodic polarization, kom ntseeg tau qhov kev sib cais ntawm cov anode, stabilizing cov txheej txheem plating, thiab txhim kho cov cathodic polarization kom tau txais cov txheej txheem zoo thiab cov txheej txheem plating zoo. Hauv metallurgy, nws yog dav siv nyob rau hauv extraction ntawm precious hlau xws li kub thiab nyiaj. Ntxiv mus, nws yog ib qho tseem ceeb raw khoom nyob rau hauv kev lag luam tshuaj rau kev tsim ntau yam inorganic cyanides thiab tsim hydrocyanic acid. Nws kuj tseem ua lub luag haujlwm tseem ceeb hauv kev tsim cov khoom siv organic xws li iav organic, ntau yam khoom siv hluavtaws, nitrile roj hmab, thiab hluavtaws fiber ntau copolymer. Nyob rau hauv kev lag luam dyeing, nws yog siv nyob rau hauv zus tau tej cov cyanuric chloride, ib qho tseem ceeb nruab nrab rau reactive dyes thiab ib tug precursor rau whitening agents. Tsis tas li ntawd, kev lag luam kws tshuaj siv sodium cyanide hauv kev sib txuas ntawm cov tshuaj xws li cyanoacetic acid methyl ester thiab diethyl malonate. Zuag qhia tag nrho, sodium cyanide's versatility thiab reactivity ua rau nws ib tug indispensable tshuaj nyob rau hauv niaj hnub kev lag luam txheej txheem.

III. Cov Txheej Txheem Kub Kub nrog Sodium Cyanide

A. Ore Kev Npaj

Thawj kauj ruam ntawm kev siv sodium cyanide rau Kub rho tawm tab tom npaj cov ore. Cov chunks loj ntawm cov kabmob kub yog thawj zaug crushed rau hauv cov khoom me me uas siv cov crushers hnyav. Qhov thawj crushing no txo ​​cov ore loj mus rau ib tug ntau tswj qhov ntev, feem ntau nyob ib ncig ntawm 150-300 millimeters. Tom qab ntawd, cov crushed ore tau dhau los ntawm kev sib tsoo, feem ntau nrog lub khob hliav qab crushers lossis cuam tshuam crushers, ntxiv txo qhov me me mus txog 20-50 millimeters. Tom qab ntawd, cov ore yog hauv av rau hauv cov hmoov zoo los ntawm cov pob zeb los yog cov pas nrig mills, kom ntseeg tau tias feem ntau ntawm cov khoom muaj tsawg dua 0.074 millimeters. Qhov kev sib tsoo zoo no yog qhov tseem ceeb heev vim nws ua rau thaj tsam ntawm cov ore nce ntxiv, ua kom muaj kev sib cuag zoo dua thiab cov tshuaj tiv thaiv nrog cov tshuaj cyanide hauv cov txheej txheem leaching tom ntej. Tsis tas li ntawd, cov ore tuaj yeem dhau los ntawm cov txheej txheem tshuaj ntsuam kom cais qhov sib txawv ntawm qhov ntau thiab tsawg, tso cai rau kev tswj xyuas cov tshuaj lom neeg ntau dua thiab ua kom muaj txiaj ntsig zoo tshaj plaws.

B. Txheej txheem Leaching

Thaum cov ore npaj tau zoo, nws nkag mus rau theem leaching, uas yog lub plawv ntawm cov txheej txheem rho tawm kub nrog sodium cyanide. Cov hmoov ore yog tov nrog ib tug ua tib zoo formulated cyanide tov, feem ntau nrog ib tug sodium cyanide concentration li ntawm 0.05% mus rau 0.1%. Nyob rau theem no, cov tshuaj tiv thaiv tshuaj tshwm sim qhov twg cov kub hauv cov ore reacts nrog cov cyanide ions (CN-) nyob rau hauv lub xub ntiag ntawm oxygen. Tag nrho cov tshuaj tiv thaiv tuaj yeem sawv cev los ntawm qhov sib npaug: 4Au + 8NaCN + O₂ + 2H₂O → 4Na[Au(CN)₂] + 4NaOH. Ntawm no, cov atoms kub tsim ib qho yooj yim soluble nrog cov cyanide ions, tsim sodium kub cyanide (Na[Au(CN)₂]), uas dissolves nyob rau hauv cov tshuaj. Cov txheej txheem leaching xav tau kev tswj hwm nruj ntawm ntau yam tsis muaj. Cov pH ntawm cov tshuaj yog khaws cia nyob ib ncig ntawm 10-11 los xyuas kom meej qhov ruaj khov ntawm cyanide thiab tiv thaiv kev tsim cov tshuaj lom hydrogen cyanide gas. Kub kuj ua lub luag haujlwm tseem ceeb; Feem ntau, nws khaws cia nyob rau hauv thaj tsam ntawm 20-30 ° C. Qhov kub qis dhau qeeb qeeb ntawm cov tshuaj tiv thaiv tus nqi, thaum tshav kub ntau dhau tuaj yeem ua rau evaporation sai ntawm cov tshuaj thiab cov cuab yeej muaj peev xwm corrosion. Txaus agitation thiab aeration yog tsis tu ncua muab los xyuas kom meej kev sib xyaw ntawm cov ore thiab cov tshuaj cyanide, txhawb kev kub dissolution.

C. Ntug dej nag

Tom qab cov txheej txheem leaching, cov kub tam sim no nyob rau hauv daim ntawv ntawm soluble kub cyanide complexes nyob rau hauv cov tshuaj. Yuav kom rov qab tau cov kub, ib theem nag lossis daus yog nqa tawm. Qhov no feem ntau suav nrog ntxiv zinc hmoov lossis cov pa roj carbon activated rau cov tshuaj. Thaum siv zinc hmoov, muaj kev hloov pauv hloov pauv. Cov zinc, ua ntau reactive tshaj kub, displaces cov kub los ntawm kub cyanide complex. Cov tshuaj tiv thaiv tuaj yeem qhia tau tias: 2Na[Au(CN)₂] + Zn → Na₂[Zn(CN)₄] + 2Au. Cov atoms kub yog tom qab ntawd txo mus rau lawv daim ntawv hlau thiab precipitate tawm ntawm cov tshuaj. Yog tias cov pa roj carbon activated ua haujlwm, nws qhov chaw siab saum npoo thiab adsorption zog tuaj rau hauv kev ua si. Cov kub cyanide complexes adsorb mus rau saum npoo ntawm cov pa roj carbon activated, zoo cais cov kub ntawm cov tshuaj. Lub loaded activated carbon yog tom qab ntawd ua tiav ntxiv kom rov qab tau cov adsorbed kub. Thaum cov nag lossis daus tiav lawm, cov slurry tshwm sim yog lim los yog centrifuged cais cov khoom kub precipitate los ntawm cov kua seem, uas tej zaum yuav muaj residual cyanide thiab lwm yam impurities.

D. Cov txheej txheem kho kom zoo

Cov kub tau los ntawm cov nag lossis daus tseem muaj qee qhov impurities thiab yuav tsum tau ua kom zoo kom ua tiav qhov siab purity xav tau hauv khw. Cov txheej txheem refining feem ntau pib nrog smelting, qhov twg kub precipitate yog rhuab mus rau ib tug kub kub nyob rau hauv lub cub tawg. Qhov no melts cov kub, cia denser impurities mus rau hauv qab thaum lub molten kub yuav skimmed tawm los yog poured rau hauv pwm. Tom qab ntawd, electrolysis tuaj yeem ua haujlwm rau kev ua kom huv ntxiv. Nyob rau hauv ib tug electrolytic cell, lub impure kub yog ua lub anode, thiab ib tug nyias daim ntawv ntawm ntshiab kub ua lub cathode. Thaum cov hluav taws xob tam sim no dhau los ntawm lub xov tooj ntawm tes, cov kub ions los ntawm lub anode tsiv mus rau cathode thiab tso nyiaj ua cov kub ntshiab, tawm hauv qab cov impurities seem ntawm lub anode. Los ntawm cov kauj ruam ua kom zoo dua no, cov kub tuaj yeem ncav cuag qib purity txog li 99.99%, ua tau raws li cov qauv rau ntau yam kev lag luam, kev tsim cov hniav nyiaj hniav kub, thiab kev siv peev.

IV. Daim ntawv thov kev nyab xeeb thiab Environmental Considerationsment

A. Kev Nyab Xeeb Kev Ua Haujlwm

Muab cov tshuaj toxicity ntawm sodium cyanide, kom ntseeg tau tias kev nyab xeeb ntawm cov neeg ua haujlwm yog qhov tseem ceeb tshaj plaws. Cov neeg ua haujlwm koom nrog hauv cov txheej txheem kub mining siv sodium cyanide yuav tsum tau muab kev cob qhia txog kev nyab xeeb. Lawv yuav tsum ua tib zoo saib xyuas cov tshuaj, nkag siab txog nws cov kev phom sij, thiab paub txog cov txheej txheem xwm txheej ceev. Cov cuab yeej tiv thaiv tus kheej (PPE) tsis tuaj yeem sib tham. Cov neeg ua haujlwm yuav tsum hnav cov hnab looj tes uas tsis tuaj yeem tiv thaiv kev sib cuag ntawm daim tawv nqaij, tsom iav los tiv thaiv lawv lub qhov muag, thiab lub tshuab ua pa kom tsis txhob nqus cov pa uas muaj cyanide tso tawm. Ntxiv rau, cov txheej txheem kev nyab xeeb nruj yuav tsum nyob hauv qhov chaw. Piv txwv li, cov chaw ua hauj lwm yuav tsum tau ua kom zoo-ventilated kom txo tau cov concentration ntawm tej huab cua cyanide. Cov neeg ua haujlwm tseem yuav tsum tau txwv tsis pub noj, haus, lossis haus luam yeeb hauv thaj chaw uas muaj sodium cyanide los tiv thaiv kev noj tsis zoo. Kev kuaj mob tsis tu ncua yuav tsum yog qhov yuav tsum tau saib xyuas kev noj qab haus huv ntawm cov neeg ua haujlwm, tshwj xeeb tshaj yog cov neeg siv tshuaj ncaj qha, txhawm rau txheeb xyuas cov tsos mob ntxov ntawm cyanide raug.

B. Kev cuam tshuam ib puag ncig

Kev siv sodium cyanide hauv kev khawb kub kuj ua rau muaj kev txhawj xeeb txog ib puag ncig. Tom qab cov txheej txheem rho tawm kub, cov ntaub ntawv pov tseg uas tseem tshuav, hu ua Cyanide tailings, muaj residual cyanide. Yog tias tsis tswj xyuas kom zoo, cov tailings tuaj yeem ua rau muaj kev hem thawj rau ib puag ncig. Cyanide tuaj yeem nkag mus rau hauv av thiab dej hauv av, kis kab mob hauv dej thiab ua rau lub neej nyob hauv dej. Hauv cov dej saum npoo av, txawm tias me me ntawm cyanide tuaj yeem cuam tshuam qhov kev tshuav ntawm ecological, ua rau ntses tua thiab lwm yam kev cuam tshuam tsis zoo rau biodiversity. Txhawm rau txo cov kev pheej hmoo ntawm ib puag ncig, cov tuam txhab mining yuav tsum siv cov tswv yim tswj hwm ib puag ncig zoo. Ib txoj hauv kev yog kho cov cyanide tailings kom txo cov ntsiab lus cyanide kom muaj kev nyab xeeb. Qhov no tuaj yeem koom nrog cov txheej txheem kev kho tshuaj, xws li oxidation lossis nag lossis daus, los hloov cov tshuaj lom cyanide rau hauv cov tshuaj tsis zoo. Lwm qhov kev ntsuas tseem ceeb yog kev pov tseg kom raug thiab tswj cov tailings kho. Kev ruaj ntseg pov tseg los yog cov pas dej tailings nrog cov ntaub ntawv tsim nyog tuaj yeem tiv thaiv kom tsis txhob muaj cov kab mob seem hauv ib puag ncig. Tsis tas li ntawd, kev soj ntsuam tas li ntawm ib puag ncig ib puag ncig, suav nrog cov dej zoo thiab cov av, yog qhov tseem ceeb los xyuas kom muaj kev puas tsuaj ib puag ncig thaum ntxov thiab kho kom raug sai.

V. Xaus

Sodium cyanide yog undeniably ib tug tseem ceeb tshuaj nyob rau hauv niaj hnub kub mining, ua kom lub extraction ntawm kub los ntawm ores nrog tsawg kub ntsiab lus. Nws tau ua lub hauv paus ntawm cov kub Mining kev lag luam tau ntau xyoo lawm, pab txhawb kev tsim cov kub uas ua rau muaj kev lag luam ntau yam, los ntawm kev tsim cov hniav nyiaj hniav kub mus rau kev siv high-tech. Txawm li cas los xij, nws txoj kev siv xav tau kev saib xyuas zoo tshaj plaws rau kev nyab xeeb thiab kev tiv thaiv ib puag ncig. Cov tuam txhab lag luam mining yuav tsum tau nqis peev hauv cov cuab yeej siv kev nyab xeeb hauv lub xeev, muab kev cob qhia zoo rau cov neeg ua haujlwm, thiab siv cov txheej txheem kev nyab xeeb nruj kom tiv thaiv lub neej. Tib lub sijhawm, lawv muaj lub luag haujlwm ncaj ncees thiab raug cai los tswj kev cuam tshuam ib puag ncig, kho cyanide tailings lub luag haujlwm thiab saib xyuas cov ecosystem kom tiv thaiv kev puas tsuaj mus ntev. Raws li kev siv thev naus laus zis, kev tshawb fawb txog kev nyab xeeb thiab ntau dua ib puag ncig tus phooj ywg lwm txoj hauv kev rau sodium cyanide yuav tsum txuas ntxiv mus. Tsuas yog los ntawm kev tawm tsam qhov sib npaug ntawm qhov txiaj ntsig ntawm kev rho tawm kub, kev nyab xeeb ntawm cov neeg ua haujlwm, thiab kev saib xyuas ib puag ncig tuaj yeem ua rau kev lag luam kub ua kom muaj txiaj ntsig zoo rau yav tom ntej.