Platinum pab pawg hlau: txheej txheem cej luam, npe, khoom thiab daim ntawv thov

2024 Tus sau: Howard Calhoun | [email protected]. Kawg hloov kho: 2024-01-02 13:55

Platinum pab pawg hlau yog rau cov tshuaj muaj txiaj ntsig zoo uas nyob ib sab ntawm lub rooj zaum. Tag nrho cov no yog cov hlau hloov pauv ntawm 8–10 pawg ntawm 5–6 lub sijhawm.

Platinum pab pawg hlau npe

Cov pab pawg muaj rau cov tshuaj lom neeg hauv qab no, txheej txheem nce qib ntawm atomic hnyav:

• Ru – ruthenium.
• Rh – rhodium.
• Pd – palladium.
• Os – osmium.
• Ir – iridium.
• Pt – platinum.

Platinum pawg hlau muaj cov xim dawb dawb, tshwj tsis yog osmium, uas yog xim dawb. Lawv cov cwj pwm tshuaj lom neeg yog qhov tsis txaus ntseeg vim tias lawv muaj peev xwm tiv taus rau feem ntau cov reagents, tab sis yog siv los ua catalysts, yooj yim accelerating los yog tswj tus nqi ntawm oxidation, txo, thiab hydrogenation tshua.

Ruthenium thiab osmium crystallize rau hauv hexagonal kaw-packed system, thaum lwm tus muaj lub ntsej muag-centered cubic qauv. Qhov no tau tshwm sim hauv qhov hardness ntau dua ntawm ruthenium thiab osmium.

Discovery keeb kwm

Txawm hais tias cov khoom siv kub kub platinum muaj hnub rov qab mus rau 700 BC. e., lub xub ntiag ntawm cov hlau no yog kev sib tsoo ntau dua li cov qauv. Cov neeg Jesuits nyob rau xyoo pua 16th tau hais txog cov pob zeb grey ntom ntom txuam nrog cov pob zeb kub. Cov pob zeb no tsis tuaj yeem yaj, tab sis lawv tsim ib qho hlau nrog kub, thaum lub ingots ua nkig, thiab nws tsis tuaj yeem ntxuav lawv. Cov pob zeb tau hu ua platina del Pinto, granules ntawm silvery khoom los ntawm Pinto River, uas ntws mus rau hauv San Juan River hauv Colombia.

Malleable platinum, uas tuaj yeem tau txais tom qab ua tiav cov hlau huv, raug cais los ntawm Fab Kis tus kws kho mob Chabano xyoo 1789. Los ntawm nws tau ua ib lub goblet nthuav tawm rau Pope Pius VI. Qhov kev tshawb pom ntawm palladium hauv xyoo 1802 tau tshaj tawm los ntawm Askiv chemist William Wollaston, uas hu ua chem. keeb ntawm platinum hlau pawg nyob rau hauv kev hwm ntawm lub asteroid. Wollaston tom qab thov kom tau pom lwm yam khoom muaj nyob hauv platinum ore. Nws hu ua rhodium vim yog xim liab ntawm cov hlau ntsev. Cov kev tshawb pom ntawm iridium (lub npe hu ua zaj sawv vajtswv poj niam Iris vim yog xim variegated ntawm nws cov ntsev) thiab osmium (los ntawm Greek lo lus "tsim" vim hais tias ntawm chlorine tsis hnov tsw ntawm nws volatile oxide) tau tsim los ntawm Askiv chemist Smithson Tennant nyob rau hauv. 1803. Fabkis cov kws tshawb fawb Hippolyte-Victor Collet-Descoti, Antoine-Francois Fourcroix, thiab Nicolas-Louis Vauquelin cais ob lub hlau tib lub sijhawm. Ruthenium, lub xeem cais thiab txheeb xyuas, tau txais nws lub npe los ntawm Latin lub npe rau Russia los ntawm Lavxias teb sab chemist Karl Karlovich Klaus nyob rau hauv 1844.

Tsis zoo lilos ntawm xws li yooj yim cais nyob rau hauv ib tug kuj ntshiab lub xeev los ntawm tej yam yooj yim hluav taws refining tshuaj xws li kub, nyiaj, platinum pab pawg neeg hlau yuav tsum complex dej-tshuaj kho mob. Cov txheej txheem no tsis muaj kom txog rau thaum lub xyoo pua puv 19, yog li kev txheeb xyuas thiab kev sib cais ntawm pawg platinum poob qab nyiaj thiab kub los ntawm ntau txhiab xyoo. Tsis tas li ntawd, lub siab melting point ntawm cov hlau no txwv tsis pub lawv siv kom txog rau thaum cov kws tshawb fawb hauv tebchaws Askiv, Fabkis, Lub Tebchaws Yelemees thiab Russia tau tsim txoj hauv kev los hloov platinum rau hauv daim ntawv ua haujlwm. Yuav ua li cas cov hlau tseem ceeb ntawm pab pawg platinum pib siv cov hniav nyiaj hniav kub txij li xyoo 1900. Txawm hais tias daim ntawv thov no tseem muaj feem cuam tshuam rau niaj hnub no, kev lag luam tau dhau mus dhau nws. Palladium tau dhau los ua cov khoom siv sib txuas lus hauv xov tooj thiab lwm cov xov tooj sib txuas lus, muab lub neej ntev thiab kev ntseeg siab, thaum platinum, vim nws tsis kam mus rau qhov hluav taws xob yaig, tau siv rau hauv kev sib ntaus sib tua aircraft spark plugs thaum Ntiaj Teb Tsov Rog II.

Tom qab tsov rog, kev nthuav dav ntawm cov txheej txheem hloov pauv molecular hauv roj av refining tsim ib qho kev thov loj rau cov khoom catalytic ntawm platinum pawg hlau. Los ntawm xyoo 1970s, kev noj haus tau nce ntau dua thaum cov qauv tsheb emission nyob rau hauv Teb Chaws Asmeskas thiab lwm lub teb chaws tau coj mus rau kev siv cov tshuaj no hauv catalytic tso pa hloov pauv.

Ores

Tsis suav nrog me me qhov tso nyiaj ntawm platinum, palladiumthiab osmic iridium (ib qho alloy ntawm iridium thiab osmium), muaj suab tsis muaj ore nyob rau hauv uas lub ntsiab tivthaiv yuav yog ib tug tshuaj lom neeg - ib tug platinum pab pawg neeg hlau. Minerals feem ntau pom muaj nyob rau hauv sulfide ores, tshwj xeeb tshaj yog pentlandite (Ni, Fe) ₉S₈. Feem ntau yog laurite RuS_{2, irarsite, (Ir, Ru, Rh, Pt)AsS, osmiridium (Ir, Os), cooperite, (PtS) thiab braggite (Pt, Pd) S.}

Lub ntiaj teb qhov nyiaj tso nyiaj loj tshaj plaws ntawm platinum pawg hlau yog Bushveld complex hauv South Africa. Cov nyiaj khaws cia loj ntawm cov ntaub ntawv raw yog concentrated hauv Sudbury deposits hauv Canada thiab Norilsk-Talnakhskoye deposits nyob rau hauv Siberia. Nyob rau hauv lub tebchaws United States, qhov loj tshaj plaws deposits ntawm platinum pab pawg neeg minerals nyob rau hauv Stillwater, Montana, tab sis ntawm no lawv muaj tsawg dua nyob rau hauv South Africa thiab Russia. Cov neeg tsim khoom platinum loj tshaj plaws hauv ntiaj teb yog South Africa, Russia, Zimbabwe thiab Canada.

Lub ntsiab ntawm South African thiab Canadian deposits yog ua los ntawm mine txoj kev. Zoo tag nrho cov platinum pab pawg hlau tau zoo los ntawm tooj liab lossis npib tsib xee sulfide cov zaub mov siv flotation sib cais. Smelting cov concentrate ua ib qho sib tov uas tau ntxuav tawm ntawm tooj liab thiab npib tsib xee sulfides hauv ib lub autoclave. Cov kua qaub kua qaub muaj 15 txog 20% platinum pawg hlau.

Qee zaum kev sib cais lub ntiajteb txawj nqus yog siv ua ntej flotation. Qhov tshwm sim yog ib qho concentrate uas muaj txog li 50% platinum hlau, tshem tawm qhov xav tau rau smelting.

Mechanical Properties

Metals ntawm pab pawg platinum sib txawv hauv cov khoom siv kho tshuab. Platinum thiab palladium yog cov mos mos thiab zoo heev. Cov hlau thiab lawv cov alloys tuaj yeem ua haujlwm kub thiab txias. Rhodium yog thawj zaug ua haujlwm kub thiab tom qab ntawd tuaj yeem txias ua haujlwm nrog ntau zaus annealing. Iridium thiab ruthenium yuav tsum tau ua kom sov, lawv tsis tuaj yeem ua haujlwm txias.

Osmium yog qhov nyuaj tshaj plaws ntawm pab pawg thiab muaj qhov siab tshaj plaws melting point, tab sis nws nyiam oxidize imposes nws tus kheej txwv. Iridium yog qhov corrosion-resistant tshaj plaws ntawm cov hlau platinum, thiab rhodium yog khoom plig rau nws qhov kub thiab txias.

kev siv cov qauv tsim

Vim tias huv si annealed platinum yog mos heev, nws yog ib qho yooj yim mus khawb thiab deterioration. Ua kom nws hardness, nws yog alloyed nrog ntau lwm yam. Platinum hniav nyiaj hniav kub yog nrov heev nyob rau hauv Nyiv qhov twg nws yog hu ua "hakkin" thiab "dawb kub". Cov hniav nyiaj hniav kub muaj 90% Pt thiab 10% Pd, uas yog ib qho yooj yim rau tshuab thiab solder. Qhov sib ntxiv ntawm ruthenium nce lub hardness ntawm cov hlau thaum tswj oxidation kuj. Alloys ntawm platinum, palladium thiab tooj liab yog siv nyob rau hauv forgings vim hais tias lawv nyuaj tshaj platinum palladium thiab tsis kim.

Crucibles siv rau kev tsim cov khoom siv lead ua ib leeg hauv kev lag luam semiconductor xav tau kev tiv thaiv corrosion thiab ruaj khov ntawm qhov kub thiab txias. Rau daim ntawv thov no, platinum, platinum-rhodium thiabiridium. Platinum-rhodium alloys yog siv rau hauv kev tsim cov thermocouples, uas yog tsim los ntsuas kub siab txog 1800 ° C. Palladium yog siv ob qho tib si hauv daim ntawv ntshiab thiab sib xyaw hauv cov khoom siv hluav taws xob (50% ntawm kev noj), hauv cov hniav hlau (30%). Rhodium, ruthenium thiab osmium tsis tshua muaj siv nyob rau hauv lawv cov ntshiab daim ntawv - lawv ua hauj lwm raws li ib tug alloying additive rau lwm platinum pab pawg neeg hlau.

Catalysts

Raws li 42% ntawm tag nrho cov platinum uas tsim nyob rau sab hnub poob yog siv los ua cov catalyst. Ntawm cov no, 90% yog siv nyob rau hauv automotive tso systems, qhov twg platinum (nrog rau palladium thiab rhodium) coated refractory pellets los yog honeycombs pab hloov unburned hydrocarbons, carbon monoxide thiab nitrogen oxides rau hauv dej, carbon dioxide thiab nitrogen.

Ib alloy ntawm platinum thiab 10% rhodium nyob rau hauv daim ntawv ntawm liab-kub hlau mesh catalyzes cov tshuaj tiv thaiv ntawm ammonia thiab cua los tsim nitrogen oxides thiab nitric acid. Thaum noj ua ke nrog kev sib xyaw ntawm ammonia, methane hydrocyanic acid tuaj yeem tau. Hauv roj av refining, platinum nyob rau saum npoo ntawm alumina pellets nyob rau hauv lub reactor catalyzes hloov dua siab tshiab ntawm ntev saw roj molecules rau branched isoparaffins, uas yog ntshaw nyob rau hauv siab octane roj av blends.

Electroplating

Txhua pawg platinum hlau tuaj yeem ua electroplated. Vim lub hardness thiab brilliance ntawm lub resulting txheej, rhodium feem ntau yog siv. Txawm tias nwstus nqi siab dua platinum, qhov qis dua tso cai rau kev siv cov khoom me me nrog cov tuab sib piv.

Palladium yog cov platinum pab pawg hlau uas yooj yim tshaj plaws rau kev siv txheej txheej. Vim qhov no, lub zog ntawm cov khoom siv tau nce ntxiv. Ruthenium tau pom siv nyob rau hauv cov cuab yeej tsis tshua muaj siab sib txhuam machining.

tshuaj lom neeg

Organic platinum pawg hlau complexes, xws li alkylplatinum complexes, yog siv los ua catalysts nyob rau hauv lub polymerization ntawm olefins, zus tau tej cov polypropylene thiab polyethylene, thiab oxidation ntawm ethylene rau acetaldehyde.

Platinum ntsev tau siv ntau ntxiv hauv kev kho mob qog noj ntshav. Piv txwv li, lawv yog ib feem ntawm cov tshuaj xws li Carboplatin thiab Cisplatin. Ruthenium oxide coated electrodes yog siv los tsim cov tshuaj chlorine thiab sodium chlorate. Rhodium sulfate thiab phosphate yog siv nyob rau hauv rhodium plating da dej.