Cov txheej txheem kub kub cyanidation kom rov qab tau cov hlau zoo nkauj los ntawm cov khoom siv hluav taws xob tsheb

Introduction

Platinum - pawg hlau (PGMs), suav nrog platinum (Pt), palladium (Pd), thiab rhodium (Rh), yog qhov tseem ceeb hauv ntau yam lag luam. Hauv kev lag luam automotive, lawv ua lub luag haujlwm tseem ceeb hauv catalytic converters, uas yog qhov tseem ceeb rau kev txo qis cov pa phem los ntawm cov pa tawm hauv tsheb. Txawm li cas los xij, PGMs tsis tshua muaj thiab tsis sib npaug hauv qhov xwm txheej, thiab lawv qhov kev rho tawm los ntawm cov ntsiab lus tseem ceeb feem ntau nyuaj thiab kim. Yog li ntawd, kev rov qab los ntawm PGMs los ntawm lwm qhov chaw, xws li siv Tsheb catalysts, tau txais kev xav ntau ntxiv. Kub kub cyanide leaching yog tshwm sim raws li cov txheej txheem muaj peev xwm rau lub hom phiaj no.

Lub luag haujlwm ntawm PGMs hauv Automobile Catalysts

Cov catalytic converters hauv tsheb yog tsim los hloov cov pa phem hauv cov pa tawm, xws li carbon monoxide (CO), hydrocarbons (HC), thiab nitrogen oxides (NOx), mus rau hauv cov tshuaj uas tsis muaj teeb meem xws li carbon dioxide (CO₂), nitrogen (N₂), thiab dej (H₂O). PGMs yog cov khoom tseem ceeb hauv cov converters no. Piv txwv li, Pt thiab Pd muaj txiaj ntsig zoo rau kev oxidizing CO thiab HC, thaum Rh feem ntau yog siv rau kev txo NOx. Qhov kev thov rau PGMs hauv kev lag luam tsheb yog qhov loj heev. Xyoo 1990. 1.3 lab ooj ntawm platinum, 230.000 ooj ntawm palladium, thiab 330.000 ooj ntawm rhodium tau siv rau hauv kev tsim cov catalysts tsheb. Xav txog kev loj hlob tas mus li ntawm kev lag luam tsheb dhau xyoo, cov nyiaj ntawm PGMs hauv cov catalysts siv yog loj heev, ua rau lawv yog cov khoom siv thib ob muaj txiaj ntsig.

Cov ntsiab lus ntawm Kev Kub Kub Kub Cyanide Leaching

Cyanide complexation

Cyanide leaching tau siv dav hauv kev lag luam mining, tshwj xeeb tshaj yog rau kev rho tawm kub. Lub hauv paus ntsiab lus yog nyob rau hauv lub peev xwm ntawm cyanide ions (CN⁻) tsim kom ruaj khov complexes nrog tej yam hlau. Nyob rau hauv cov ntaub ntawv ntawm PGMs, nyob rau hauv high - kub thiab tsim nyog alkaline tej yam kev mob, CN⁻ tuaj yeem hnov ​​​​mob nrog Pt, Pd, thiab Rh los ua cov soluble cyanide complexes. Cov tshuaj tiv thaiv complexation no tso cai rau PGMs kom yaj los ntawm cov khoom matrix ntawm cov catalyst mus rau hauv cov kev daws teeb meem, ua kom yooj yim rau kev sib cais thiab cov txheej txheem rov qab.

Siab - Kub Txhim Kho

Cov xwm txheej kub kub ua lub luag haujlwm tseem ceeb hauv kev txhawb nqa cov txheej txheem leaching. Ua kom kub ceev ceev cov tshuaj tiv thaiv kinetics. Ntawm qhov kub siab dua, qhov sib txawv ntawm cyanide ions mus rau saum npoo ntawm PGM hais, thiab cov tshuaj lom neeg tshwm sim sai dua. Piv txwv li, cov kev tshawb fawb tau pom tias nyob rau hauv qhov kub-kub cyanide leaching ntawm PGMs los ntawm lub tsheb catalysts, nce qhov kub ntawm 100 ° C mus rau 150 ° C tuaj yeem ua rau kom cov leaching efficiency ntawm Pd thiab Pt. Txawm li cas los xij, nws yuav tsum tau muab sau tseg tias qhov kub siab heev kuj tseem tuaj yeem ua rau qee qhov teeb meem, xws li kev siv hluav taws xob ntau ntxiv thiab muaj peev xwm tshwm sim.

Txheej Txheem Kub - Kub Cyanide Leaching rau Tsheb Catalysts

Pretreatment ntawm Catalysts

Ua ntej qhov kub kub cyanide leaching txheej txheem, lub tsheb siv catalysts feem ntau yuav tsum tau pretreated. Cov kauj ruam no yog qhov tseem ceeb los txhim kho cov kev ua haujlwm leaching. Ua ntej, cov catalysts yog lub cev crushed thiab hauv av kom txo cov particle loj, uas ua rau kom cov cheeb tsam tshwj xeeb thiab nthuav tawm ntau PGMs rau cov tshuaj tiv thaiv. Tom qab ntawd, lawv yuav raug kev kho cua sov, xws li roasting, tshem tawm cov pa roj carbon thiab lwm yam impurities nyob rau saum npoo ntawm cov catalyst, ua rau PGMs nkag mus rau cov tshuaj cyanide.

Kev Ua Haujlwm Leaching

Nyob rau hauv lub leaching theem, cov pretreated catalysts yog muab tso rau hauv ib tug tshuaj tiv thaiv hlab ntsha nrog ib tug cyanide - muaj cov tshuaj, feem ntau Sodium Cyanide (NWS). Tom qab ntawd cov tshuaj tiv thaiv cov hlab ntsha yog rhuab mus rau qhov tsim nyog siab - kub, feem ntau nyob rau hauv thaj tsam ntawm 120 - 180 ° C, thiab lub siab yog kho raws li qhov yuav tsum tau. Oxygen lossis oxidizing tus neeg sawv cev feem ntau tau qhia los txhawb oxidation ntawm PGMs thiab txhim kho cov tshuaj tiv thaiv complexation. Lub sij hawm leaching nws txawv nyob ntawm seb muaj pes tsawg leeg ntawm cov catalyst thiab cov tshuaj tiv thaiv kab mob, feem ntau yog los ntawm ob peb teev mus rau ntau tshaj kaum teev.

Kev sib cais thiab rov qab ntawm PGMs

Tom qab cov txheej txheem leaching, cov tshuaj muaj cov yaj PGM - cyanide complexes. Txhawm rau rov qab PGMs, ntau txoj kev sib cais tuaj yeem ua haujlwm. Ib txoj hauv kev zoo tshaj plaws yog kev tshem tawm cov kuab tshuaj, qhov uas tsim nyog cov organic extractant yog siv los xaiv extract PGMs los ntawm cyanide leach cawv. Piv txwv li, qee cov kua ionic tau pom tias muaj kev xaiv zoo rau kev sib cais Pt thiab Pd los ntawm cov dej cawv. Lwm txoj kev yog nag lossis daus. Los ntawm kev kho tus nqi pH ntawm cov tshuaj los yog ntxiv cov neeg ua hauj lwm precipitating, PGMs tuaj yeem raug precipitated tawm ntawm cov tshuaj nyob rau hauv daim ntawv ntawm cov hlau ntsev los yog complexes, uas yuav tau ntxiv refined kom tau cov ntshiab PGMs.

Qhov zoo ntawm High - Kub Cyanide Leaching

Kev ua haujlwm siab rov qab

Piv nrog rau qee txoj hauv kev rau kev rov qab PGMs los ntawm lub tsheb catalysts, siab kub cyanide leaching tuaj yeem ua tiav cov txiaj ntsig zoo. Cov kev tshawb fawb tau pom tias nyob rau hauv cov kev kho kom zoo, cov leaching tus nqi ntawm Pt, Pd, thiab Rh tuaj yeem ncav cuag ntau dua 90%, thiab qee zaum, txawm tias ze li 100%. Piv txwv li, hauv kev tshawb fawb txog kev kub siab cyanide leaching ntawm PGMs los ntawm cov pa autocatalytic converters, lub autoclave leaching ntawm 150 ° C, nrog ib tug oxygen ib nrab siab ntawm 200 psi thiab ib lub sij hawm ntawm 120 min, yielded> 90% PGMs 'ssolution.

Xaiv Xaiv

Cyanide muaj qee qhov kev xaiv hauv kev ua haujlwm nrog PGMs. Raws li cov xwm txheej tsim nyog, nws tuaj yeem nyiam qhov cuam tshuam nrog Pt, Pd, thiab Rh thaum muaj kev cuam tshuam tsawg dua nrog ntau lwm yam hauv catalyst matrix, xws li cov khoom siv ceramic thiab qee cov hlau hauv paus. Qhov kev xaiv no ua kom yooj yim rau cov txheej txheem sib cais tom qab thiab pab kom tau txais PGMs nrog kev purity siab dua.

Kev sib tw thiab kev daws teeb meem

Toxicity ntawm Cyanide

Kev siv cov cyanide hauv cov txheej txheem leaching yog txuam nrog kev txhawj xeeb ntawm ib puag ncig thiab kev nyab xeeb vim nws cov tshuaj toxicity siab. Cyanide tuaj yeem tsim kev puas tsuaj rau tib neeg kev noj qab haus huv thiab ib puag ncig yog tias tsis tswj xyuas kom zoo. Txhawm rau daws qhov teeb meem no, kev ntsuas kev nyab xeeb nruj yog siv hauv cov txheej txheem kev lag luam. Piv txwv li, kaw - voj tshuab yog tsim los txo qhov tso tawm ntawm cyanide mus rau ib puag ncig. Tsis tas li ntawd, kev kho mob ntawm cyanide - muaj cov dej khib nyiab yog qhov tseem ceeb. Cov thev naus laus zis thev naus laus zis kho dej khib nyiab, xws li tshuaj oxidation thiab kev kho mob lom neeg, tuaj yeem siv los decompose cyanide rau hauv cov khoom tsis zoo ua ntej tso cov dej pov tseg.

Kev siv hluav taws xob siab

Qhov siab-kub qhov yuav tsum tau ua ntawm cov txheej txheem ua rau muaj kev siv zog heev. Yuav kom txo tau qhov teeb meem no, kev siv zog ua kom zoo rau cov kev mob tshwm sim. Piv txwv li, los ntawm kev tswj xyuas qhov kub thiab txias, siab, thiab lub sijhawm tshuaj tiv thaiv, lub zog tawm tswv yim tuaj yeem txo qis thaum tswj kev ua haujlwm siab leaching. Tsis tas li ntawd, kev txhim kho lub zog ntau dua - cov cuab yeej siv cua sov kom zoo thiab kev siv cov khoom siv hluav taws xob pov tseg tuaj yeem pab txhim kho lub zog ntawm cov txheej txheem kub cyanide leaching.

xaus

High- kub cyanide leaching qhia tau hais tias muaj peev xwm rov zoo zoo zoo nkauj tshooj, tshwj xeeb tshaj yog PGMs, los ntawm lub tsheb catalysts. Nws muaj kev rov qab ua haujlwm zoo thiab kev xaiv, uas yog qhov tseem ceeb rau kev lag luam thiab kev rov ua dua tshiab ntawm cov peev txheej tseem ceeb no. Txawm hais tias muaj teeb meem xws li toxicity ntawm cyanide thiab kev siv hluav taws xob siab muaj nyob, kev tshawb fawb txuas ntxiv thiab thev naus laus zis tshiab tau ua los daws cov teeb meem no. Nrog rau qhov kev thov nce ntxiv rau PGMs thiab qhov tseem ceeb ntawm kev rov ua dua tshiab thiab kev tiv thaiv ib puag ncig, kev kub siab cyanide leaching yuav tsum ua lub luag haujlwm tseem ceeb ntxiv rau yav tom ntej ntawm kev lag luam rov ua dua tshiab rau lub tsheb catalysts.