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 heev hauv ntau yam lag luam. Hauv kev lag luam tsheb, lawv ua lub luag haujlwm tseem ceeb hauv catalytic converters, uas yog qhov tseem ceeb rau kev txo cov pa phem los ntawm cov pa tsheb. Txawm li cas los xij, PGMs tsis tshua muaj thiab tsis sib npaug hauv qhov xwm txheej, thiab lawv cov kev rho tawm los ntawm cov pob zeb thawj zaug feem ntau nyuaj thiab kim. Yog li ntawd, kev rov qab tau PGMs los ntawm cov chaw thib ob, xws li cov catalysts tsheb siv , tau txais kev saib xyuas ntau ntxiv. Kev siv cyanide kub siab yog qhov tshwm sim ua ib txoj hauv kev rau lub hom phiaj no.

Lub luag haujlwm ntawm PGMs hauv Automobile Catalysts

Cov khoom siv hloov pauv catalytic hauv tsheb yog tsim los hloov cov pa phem hauv cov pa tso 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 khoom siv hloov pauv no. Piv txwv li, Pt thiab Pd ua haujlwm 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 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 qhov 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

Thaum lub sijhawm leaching, cov catalysts uas tau kho ua ntej lawm yuav muab tso rau hauv lub thawv tshuaj uas muaj cov kua cyanide, feem ntau yog Sodium Cyanide (NaCN). Lub thawv tshuaj yuav raug cua sov rau qhov kub siab, feem ntau yog li ntawm 120 - 180 °C, thiab qhov siab yuav raug kho raws li qhov yuav tsum tau ua. Feem ntau yuav siv oxygen los yog oxidizing agent los txhawb kev oxidation ntawm PGMs thiab ua kom cov tshuaj sib xyaw ua ke zoo dua. Lub sijhawm leaching yuav txawv nyob ntawm seb cov tshuaj catalyst muaj pes tsawg leeg thiab cov xwm txheej ntawm cov tshuaj, feem ntau yog txij li ob peb teev mus txog 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

Kev siv cyanide leaching kub siab qhia tau tias muaj peev xwm zoo rau kev rov qab tau cov hlau muaj nqis , tshwj xeeb tshaj yog PGMs, los ntawm cov catalysts tsheb. Nws muab kev ua haujlwm rov qab zoo thiab kev xaiv, uas yog qhov tseem ceeb rau kev lag luam thiab kev siv rov qab ntawm cov peev txheej muaj nqis no. Txawm hais tias muaj teeb meem xws li kev lom ntawm cyanide thiab kev siv hluav taws xob ntau, kev tshawb fawb tas mus li thiab kev tsim kho tshiab thev naus laus zis tau ua tiav los daws cov teeb meem no. Nrog rau kev thov PGMs ntau ntxiv thiab kev tsom mus rau kev siv cov peev txheej rov qab thiab kev tiv thaiv ib puag ncig, kev siv cyanide kub siab yuav tsum ua lub luag haujlwm tseem ceeb ntxiv rau yav tom ntej ntawm kev lag luam rov ua dua rau cov catalysts tsheb.