Qhov xwm ntawm chromium
Chromium, lub cim cim Cr, atomic naj npawb 24, txheeb ze atomic mass 51.996, belongs rau cov kev hloov hlau hlau ntawm pawg VIB ntawm lub sij hawm ntawm cov ntsiab lus tshuaj. Chromium hlau yog lub cev-centered cubic siv lead ua, silver-dawb, ntom 7.1g / cm³, melting point 1860 ℃, boiling point 2680 ℃, tshwj xeeb kub muaj peev xwm ntawm 25 ℃ 23.35J / (mol·K), tshav kub ntawm vaporization 342.1kJ / mol, thermal conductivity 91.3 W / (m·K) (0-100 ° C), resistivity (20 ° C) 13.2uΩ·cm, nrog cov khoom siv zoo.
Muaj tsib lub ntsiab lus ntawm chromium: +2, +3, +4, +5 thiab +6. Nyob rau hauv cov xwm txheej ntawm endogenous kev txiav txim, chromium feem ntau yog +3 valence. Cov tshuaj nrog + trivalent chromium yog qhov ruaj khov tshaj plaws. + Sixvalent chromium compounds, suav nrog cov ntsev chromium, muaj zog oxidizing zog. Lub ionic radii ntawm Cr3+, AI3+ thiab Fe3+ zoo sib xws, yog li lawv tuaj yeem muaj ntau yam sib xws. Tsis tas li ntawd, cov ntsiab lus uas tuaj yeem hloov nrog chromium yog manganese, magnesium, npib tsib xee, cobalt, zinc, thiab lwm yam, yog li chromium yog dav faib rau hauv magnesium hlau silicate cov zaub mov thiab cov khoom siv ntxiv.
Daim ntawv thov
Chromium yog ib qho ntawm cov hlau siv dav hauv kev lag luam niaj hnub no. Nws yog tsuas yog siv nyob rau hauv zus tau tej cov stainless hlau thiab ntau yam hlau alloys nyob rau hauv daim ntawv ntawm ferroalloys (xws li ferrochrome). Chromium muaj cov yam ntxwv ntawm tawv, hnav-tiv taus, kub-resistant thiab corrosion-resistant. Chrome ore yog dav siv nyob rau hauv metallurgy, refractory cov ntaub ntawv, tshuaj kev lag luam thiab foundry industries.
Hauv kev lag luam metallurgical, chromium ore feem ntau yog siv los ua ferrochrome thiab hlau chromium. Chromium yog siv los ua cov hlau ntxiv los tsim ntau yam muaj zog, corrosion-resistant, hnav-tiv taus, kub kub, thiab oxidation-resistant tshwj xeeb steels, xws li stainless hlau, acid-resistant steel, kub-resistant steel, pob bearing steel, caij nplooj ntoos hlav steel, cuab yeej steel, thiab lwm yam. Chromium tuaj yeem txhim kho cov khoom siv kho tshuab thiab hnav tsis kam ntawm cov hlau. Hlau chromium feem ntau yog siv los smelt tshwj xeeb alloys nrog cobalt, nickel, tungsten thiab lwm yam khoom. Chrome plating thiab chromizing tuaj yeem ua rau cov hlau, tooj liab, txhuas thiab lwm yam hlau tsim ib qho chaw corrosion-resistant, uas yog ci thiab zoo nkauj.
Hauv kev lag luam refractory, chromium ore yog ib qho tseem ceeb refractory khoom siv los ua chrome cib, chrome magnesia bricks, advanced refractories thiab lwm yam khoom tshwj xeeb refractory (chrome qhob). Chromium-based refractories feem ntau suav nrog cib nrog chrome ore thiab magnesia, sintered magnesia-chrome clinker, molten magnesia-chrome cib, molten, finely av thiab ces bonded magnesia-chrome cib. Lawv tau dav siv nyob rau hauv qhib hearth furnaces, induction furnaces, thiab lwm yam. Metallurgical converter thiab rotary furnace hauv ob sab phlu ntawm cement kev lag luam, thiab lwm yam.
Hauv kev lag luam foundry, chromium ore yuav tsis cuam tshuam nrog lwm cov ntsiab lus hauv cov hlau molten thaum lub sij hawm nchuav, muaj cov thermal expansion coefficient tsawg, tiv taus cov hlau nkag, thiab muaj kev ua haujlwm txias dua li zircon. Chrome ore rau foundry muaj cov kev cai nruj ntawm cov tshuaj muaj pes tsawg leeg thiab particle loj tis.
Hauv kev lag luam tshuaj, kev siv chromium ncaj qha tshaj plaws yog los tsim cov tshuaj sodium dichromate (Na2Cr2O7·H2O), thiab tom qab ntawd los npaj lwm cov chromium compounds siv rau hauv kev lag luam xws li pigments, textiles, electroplating, thiab tawv ua, nrog rau catalysts. .
Cov hmoov av chromium ore hmoov zoo yog cov xim ntuj xim hauv kev tsim cov iav, ceramics thiab cov vuas glazed. Thaum sodium dichromate siv los rhuav tshem cov tawv nqaij, cov protein (collagen) thiab carbohydrates nyob rau hauv cov tawv nqaij qub reacts nrog tshuaj lom neeg los tsim ib tug ruaj khov complex, uas yog lub hauv paus ntawm tawv khoom. Hauv kev lag luam textile, sodium dichromate yog siv los ua mordant hauv cov ntaub dyeing, uas tuaj yeem xa cov xim molecules rau cov organic tebchaw; nws tseem tuaj yeem siv los ua oxidant hauv kev tsim cov dyes thiab intermediates.
Chromium ntxhia
Muaj ntau tshaj 50 hom chromium-muaj cov zaub mov uas tau tshawb pom nyob rau hauv cov xwm txheej, tab sis feem ntau ntawm lawv muaj cov ntsiab lus chromium tsawg thiab kev faib tawm, uas muaj cov nqi siv tsawg. Cov zaub mov muaj chromium no suav nrog oxides, chromates thiab silicates, ntxiv rau ob peb hydroxides, iodates, nitrides thiab sulfides. Ntawm lawv, chromium nitride thiab chromium sulfide minerals tsuas pom nyob rau hauv meteorites.
Raws li ib hom pob zeb hauv cov chromium ore subfamily, chromite yog tib qho tseem ceeb ntawm cov ntxhia ntawm chromium. Cov qauv tshuaj theoretical yog (MgFe) Cr2O4, uas Cr2O3 cov ntsiab lus suav nrog 68%, thiab FeO suav rau 32%. Hauv nws cov tshuaj muaj pes tsawg leeg, cov cation trivalent feem ntau yog Cr3+, thiab feem ntau Al3+, Fe3+ thiab Mg2+, Fe2+ isomorphic hloov pauv. Nyob rau hauv qhov tseeb tsim chromite, ib feem ntawm Fe2+ feem ntau yog hloov los ntawm Mg2+, thiab Cr3+ yog hloov los ntawm Al3+ thiab Fe3+ mus rau txawv degrees. Qhov ua tiav ntawm isomorphic hloov pauv ntawm ntau yam ntawm chromite tsis zoo ib yam. Plaub-txoj kev sib koom ua ke cations feem ntau yog magnesium thiab hlau, thiab ua tiav isomorphic hloov ntawm magnesium-hlau. Raws li plaub txoj kev faib, chromite tuaj yeem muab faib ua plaub pawg: magnesium chromite, hlau-magnesium chromite, mafic-iron chromite thiab hlau-chromite. Tsis tas li ntawd, chromite feem ntau muaj me me ntawm manganese, Ib homogeneous sib xyaw ntawm titanium, vanadium thiab zinc. Cov qauv ntawm chromite yog hom spinel ib txwm.
4. Cov qauv zoo ntawm chromium concentrate
Raws li cov txheej txheem sib txawv (mineralization thiab natural ore), chromium ore rau metallurgy muab faib ua ob hom: concentrate (G) thiab pob ore (K). Saib cov lus hauv qab no.
Cov kev cai zoo rau chromite ore rau metallurgy
Chrome ore beneficiation technology
1) Rov xaiv dua
Tam sim no, lub ntiajteb txawj nqus sib cais nyob rau hauv ib qho tseem ceeb txoj hauj lwm nyob rau hauv lub beneficiation ntawm chromium ore. Txoj kev sib cais lub ntiajteb txawj nqus, uas siv cov txheej txheem xoob hauv qhov nruab nrab aqueous raws li tus cwj pwm yooj yim, tseem yog txoj hauv kev tseem ceeb rau kev ntxiv cov chromium ore thoob ntiaj teb. Lub ntiajteb txawj nqus sib cais cov cuab yeej yog ib tug kauv chute thiab ib tug centrifugal concentrator, thiab cov ua particle loj ntau yam kuj dav. Feem ntau, qhov sib txawv ntawm qhov sib txawv ntawm chromium minerals thiab gangue minerals yog ntau tshaj 0.8g / cm3, thiab lub ntiajteb txawj nqus sib cais ntawm tej particle loj dua 100um yuav ua tau txaus siab. qhov tshwm sim ntawm. Coarse lumps (100 ~ 0.5mm) ore yog sorted los yog pre-xaiv los ntawm hnyav-nruab nrab beneficiation, uas yog ib tug heev economical beneficiation txoj kev.
2) Sib nqus sib cais
Sib nqus sib cais yog ib txoj hauv kev tau txais txiaj ntsig uas paub txog kev sib cais ntawm cov zaub mov hauv qhov tsis sib xws ntawm cov hlau nplaum raws li qhov sib txawv ntawm cov pob zeb hauv cov ore. Chromite muaj cov khoom sib nqus tsis muaj zog thiab tuaj yeem sib cais los ntawm ntsug nplhaib siab gradient sib nqus sib nqus cais, ntub phaj sib nqus sib nqus thiab lwm yam khoom siv. Qhov tshwj xeeb sib nqus susceptibility coefficients ntawm chromium minerals uas tsim nyob rau hauv ntau yam chromium ore tsim nyob rau hauv lub ntiaj teb no tsis ntau txawv, thiab zoo ib yam li cov sib nqus susceptibility coefficients ntawm wolframite thiab wolframite tsim nyob rau hauv ntau lub cheeb tsam.
Muaj ob qhov xwm txheej ntawm kev siv sib nqus sib nqus kom tau txais qib siab chromium mloog zoo: ib qho yog tshem tawm cov hlau nplaum muaj zog (feem ntau yog magnetite) hauv cov ore nyob rau hauv qhov chaw tsis muaj zog hlau nplaum kom nce qhov sib piv ntawm ferrochrome, thiab lwm yam yog siv cov hlau nplaum. muaj zog magnetic teb. Kev sib cais ntawm gangue minerals thiab rov qab los ntawm chromium ore (tsis muaj zog hlau nplaum).
3) Kev xaiv hluav taws xob
Kev sib cais hluav taws xob yog ib txoj hauv kev sib cais chromium ore thiab silicate gangue cov zaub mov los ntawm kev siv cov khoom hluav taws xob ntawm cov khoom siv hluav taws xob, xws li qhov sib txawv ntawm cov conductivity thiab dielectric tas li.
4) Flotation
Nyob rau hauv tus txheej txheem ntawm lub ntiajteb txawj nqus sib cais, nplua-grained (-100um) chromite ore feem ntau muab pov tseg raws li tailings, tab sis cov chromite ntawm no loj tseem muaj ib tug siab siv tus nqi, yog li txoj kev flotation yuav siv tau rau cov qib qis zoo Granular chromite ore. rov qab los. Flotation ntawm chromium ore nrog 20% ~ 40% Cr2O3 nyob rau hauv tailings thiab serpentine, olivine, rutile thiab calcium magnesium carbonate minerals li gangue minerals. Cov ore yog finely hauv av rau 200μm, dej iav, phosphate, metaphosphate, fluorosilicate, thiab lwm yam yog siv los disperse thiab inhibit cov sludge, thiab unsaturated fatty acid yog siv los ua ib tug collector. Lub dispersion thiab suppression ntawm gangue sludge yog ib qho tseem ceeb heev rau cov txheej txheem flotation. Cov hlau ions xws li hlau thiab txhuas tuaj yeem qhib chromite. Thaum pH tus nqi ntawm cov slurry qis dua 6, cov chromite yuav tsis ntab. Nyob rau hauv luv luv, lub flotation reagent noj yog loj, cov concentration qib tsis ruaj khov, thiab tus nqi rov qab yog tsawg. Ca2+ thiab Mg2+ yaj los ntawm gangue minerals txo cov kev xaiv ntawm cov txheej txheem flotation.
5) Kev siv tshuaj lom neeg
Cov txheej txheem tshuaj yog ncaj qha kho qee yam chromite ore uas tsis tuaj yeem sib cais los ntawm txoj kev siv lub cev lossis tus nqi ntawm txoj kev siv lub cev yog qhov siab. Cr / Fe piv ntawm cov concentrate uas tsim los ntawm cov txheej txheem tshuaj yog siab dua li cov qauv ntawm lub cev zoo tib yam. Cov txheej txheem tshuaj muaj xws li: xaiv leaching, txo oxidation, melting sib cais, sulfuric acid thiab chromic acid leaching, txo thiab sulfuric acid leaching, thiab lwm yam. tiam sis nyob rau hauv chromite beneficiation hnub no. Cov txheej txheem tshuaj tuaj yeem ncaj qha rho tawm chromium los ntawm cov ore thiab tsim chromium carbide thiab chromium oxide.
Lub sij hawm xa tuaj: Plaub Hlis-30-2021