Hauv high -kub industries (xws li steel smelting, pov tseg incineration, thiab ceramic kilns), lub neej ntawm cov ntaub ntawv refractory ncaj qha txiav txim siab ntau lawm efficiency.Silicon carbide (SiC), vim nws superior physicochemical zog, tau dhau los ua ib qho tseem ceeb additive rau kev txhim kho qib ntawm refractory cov ntaub ntawv.
Tsab ntawv xov xwm no yuav tshawb nrhiav qhov tob npaum li cas silicon carbide hloov qhov kev ua tau zoo ntawm cov ntaub ntawv refractory ntawm qib microscopic, tsom rau kev txheeb xyuas cov ntsiab lus tseem ceeb tom qab nws txoj kev txhim kho hauv refractoriness thiab slag kuj.
Cov yam ntxwv tseem ceeb ntawm Silicon Carbide: Lub Cev Lub Cev Lub Cev ntawm Refractory Properties
Silicon carbide yog cov khoom siv hluavtaws uas muaj zog heev covalent bonds, thiab nws cov qauv siv lead ua zoo ib yam li pob zeb diamond. Qhov kev cog lus siab zog no muab nws cov txiaj ntsig hauv qab no:
High melting point:Nws tsis yaj ntawm ib txwm siab, tab sis decomposes (sublimates) ntawm kwv yees li 2700 degree.
High thermal conductivity:Ntau dua li aluminosilicate refractories, ua kom yooj yim rau cov cua sov sai sai thiab txo cov kev ntxhov siab thermal.
Tsawg coefficient ntawm thermal expansion:Txo tus nqi ntawm ntim hloov ntawm qhov kub thiab txias, txhim kho thermal shock stability.
Lub hauv paus ntsiab lus 1: silicon carbide txhim kho "refractory resistance" thiab "thermal shock stability" li cas?
Nyob rau hauv cov ntaub ntawv refractory (xws li silicon carbide cib thiab siab -alumina cib nrog ntxiv SiC), silicon carbide lub luag hauj lwm tsis yog raws li ib tug muab tub lim; nws ntxiv dag zog rau cov matrix los ntawm cov txheej txheem hauv qab no:
1. Kev them nyiaj yug Skeletal
Silicon carbide particles tuav lub siab tawv thiab lub zog ntawm qhov kub thiab txias, ua kom muaj zog "skeleton." Txawm hais tias qee qhov binders hauv matrix (xws li av nplaum los yog qis- melting- theem theem) soften, SiC pob txha pob txha tseem tuaj yeem txhawb nqa cov qauv, tiv thaiv siab - kub nkag los yog tawg.
2. Muaj txiaj ntsig zoo ntawm kev ntxhov siab
Qhov laj thawj tseem ceeb ntawm kev puas tsuaj ntawm cov khoom siv refractory yog tawg (thermal shock spalling) tshwm sim los ntawm kev hloov kub ceev.
Txoj Cai:Lub siab thermal conductivity ntawm SiC txo qhov kub ntawm qhov sib txawv ntawm sab hauv thiab saum npoo ntawm cib.
Cov nyhuv:Qhov tsis tshua muaj coefficient ntawm thermal expansion ho txo cov thermal stress generated los ntawm qhov kub thiab txias sib txawv, tso cai rau cov ntaub ntawv los tswj nws cov kev ncaj ncees txawm nyob rau hauv heev heev lub qhov cub shutdowns thiab restarts.
Lub hauv paus ntsiab lus thib ob: "Chemical Barrier" rau Slag thiab Erosion Resistance
Hauv qhov cub tawg lossis cov khib nyiab pov tseg, kev yaig ntawm cov ntaub ntawv refractory los ntawm molten slag (acidic los yog yooj yim slag) yog kev puas tsuaj. Silicon carbide's slag resistance stems los ntawm nws tus kheej tshwj xeeb - kho cov txheej txheem tiv thaiv.
1. Passive Oxidation Mechanism
Thaum silicon carbide raug rau qhov siab -kub oxidizing cua, nws nto tau txais cov tshuaj tiv thaiv hauv qab no:
SiC(s) + 2O2(g) → SiO2(s) + CO2(g)
The generated SiO2 forms a dense, glassy protective film on the particle surface.
Barrier Effect:Cov yeeb yaj kiab no tsis tsuas yog tiv thaiv kev nkag mus rau oxygen ntxiv xwb tab sis tseem thaiv cov pores pom ntawm cov khoom siv refractory.
Imperfection Resistance:Vim hais tias molten slag muaj teeb meem wetting no ntom SiO2 zaj duab xis, kua slag tsis tuaj yeem nkag mus rau hauv cov khoom, yog li tiv thaiv "stripping erosion."
2. Tsis yog-wetting khoom
Silicon carbide muaj lub kaum sab xis loj nrog ntau cov hlau molten (xws li hlau molten) thiab cov kua qaub slags. Qhov no txhais tau hais tias slag, zoo li dej tee ntawm nplooj nplooj, yog qhov nyuaj rau kev ua raws thiab nkag mus. Ntxiv SiC rau torpedo ladle thiab taphole castables tuaj yeem txuas ntxiv lub neej hauv ob sab phlu.
Daim ntawv thov piv txwv ntawm Silicon Carbide nyob rau hauv txawv Refractory Scenario
| Cov cheeb tsam thov | Pom zoo SiC cov ntsiab lus | Ntsiab nta |
| Blast furnace tapping trough castable | 10% - 30% | Siv nws tsis kam mus yaig thiab molten hlau corrosion. |
| Khib nyiab incinerator hauv ob sab phlu | 40% - 85% | Siv nws cov tshuaj tiv thaiv corrosion thiab siab - kub hnav. |
| Ceramic kiln khoom (rooj) | > 90% | Siv nws cov load siab -cov kabmob muaj peev xwm thiab oxidation tsis kam, tso cai rau cov thickness ntawm cov kiln thinner thiab nce kiln ntim. |
Yuav Ua Li Cas Xaiv High -Kev Ua Haujlwm Silicon Carbide Raw Materials?
Raws li tus neeg yuav khoom xa tawm, thaum ntsuas SiC cov neeg xa khoom, tus nqi yuav tsum tsis yog qhov kev txiav txim siab nkaus xwb. Cov ntsuas hauv qab no yuav tsum tau hais txog:
SiC Purity (Qib):
Qib suav nrog 90%, 95%, thiab 98%. Cov purity siab dua ua rau muaj qhov ruaj khov antioxidant tiv thaiv zaj duab xis ntawm qhov kub thiab txias.
Loj Distribution:
Qhov tsim nyog gradation (xws li, cov khoom loj ntawm 1-3mm sib xyaw nrog cov hmoov zoo) tuaj yeem txhim kho cov khoom ntom ntom thiab txo cov porosity pom.
Dawb Carbon thiab Silicon Cov ntsiab lus:
Cov pa roj carbon ntau dhau los txo cov oxidation tsis kam thiab yuav tsum tau tswj nruj me ntsis.
Xaus: Silicon Carbide - "Kev Ua Haujlwm Zoo" hauv cov khoom siv hluav taws xob niaj hnub
Los ntawm kev txhim kho thermal shock stability thiab siv cov oxide zaj duab xis mechanism los tiv thaiv slag yaig, silicon carbide tau dhau los ua tus yuam sij rau txo nqi thiab txhim kho cov khoom siv refractory. Rau steel mills thiab ceramic nroj tsuag, txawm hais tias tus nqi pib ntawm SiC yog siab dua li ntawm cov khoom siv alumina zoo tib yam -silicon raw cov ntaub ntawv, lub tshuab ua kom ntev dua lub neej thiab txo nqi txij nkawm nws ua rau ROI siab heev (Rov qab los ntawm Kev Lag Luam).
