Kev teeb tsa thiab hardening ntawmtsawg cement refractory castablesFeem ntau yog vim coagulation thiab kev sib txuas. Yog li ntawd, lub luag haujlwm ntawm ultrafine hmoov yog qhov tseem ceeb, yog qhov tseem ceeb ntawm kev txiav txim siab thiab cuam tshuam nws cov kev ua tau zoo. Nyob rau tib lub sijhawm, qhov cuam tshuam ntawm kev sib xyaw ntawm nws qhov kev ua tau zoo tsis tuaj yeem tsis quav ntsej.
NO.01 Ultrafine hmoov
Cov hmoov ultrafine nyob rau hauv qis cement castables feem ntau suav nrog silica fume, -Al₂O₃ hmoov, thiab Cr₂O₃ hmoov, nrog cov ntsiab lus (%) ntawm 93.2%, ntau dua 90%, thiab ntau dua 99%, feem. Qhov loj me me faib ntawm peb hom ultrafine hmoov yog qhia nyob rau hauv cov lus hauv qab no. Cov lus qhia tau hais tias cov khoom me me dua 1.0 hli suav rau ntau dua 71%.
Lub refractory castables muaj tib qhov sib xyaw ua ke, nrog rau CaO cov ntsiab lus kwv yees li 0.6%. Peb pawg ntawm cov qauv tau npaj los ntawm kev ntxiv SiO₂ active, -Al₂O₃ ( -alumina hmoov), thiab ib qho kev sib xyaw ntawm ob qho tib si ultrafine hmoov, feem, nyob rau hauv tib tus nqi. Raws li cov cua kub kub nce, lub zog ntawm castables nrog txawv ultrafine hmoov tag nrho nce.
Nws kuj tseem pom tau tias cov hmoov sib txawv ultrafine pab sib txawv rau lub zog ntawm cov castables. Lub castable nrog tus nqi sib npaug ntawm cov nquag SiO₂ thiab -Al₂O₃ cov hmoov sib xyaw ultrafine pom lub zog siab tshaj plaws, ua raws li cov castable nrog active SiO₂ ultrafine hmoov, thaum lub castable nrog alumina ultrafine hmoov muaj lub zog qis tshaj. Ntawm qhov cua kub ntawm 1500 degree, lub zog ntawm castables nrog peb hom ultrafine hmoov yog qhov zoo sib xws. Qhov no txhais tau hais tias thaum npaj cov cement refractory castables tsawg, cov hmoov sib xyaw ultrafine yog qhov zoo tshaj plaws, thiab thaum siv ib leeg, active SiO₂ ultrafine hmoov yuav tsum zoo dua.
Txawm li cas los xij, kev nce qib ntawm SiO₂ ultrafine hmoov yuav txo cov Al₂O₃ cov ntsiab lus hauv castable thiab nce dawb quartz, inevitably ua rau txo qis hauv slag kuj ntawm cov castable. Piv txwv li, qhov sib xyaw ntawm cov castable refractory rau hlau troughs yog: 70% siab- alumina aggregate, 14.2% SiC, 5.8% C, 0.2% dispersant, 6.5% dej, thiab 10% siab- alumina hmoov thiab SiO₂ ultrafine ua ke hmoov Slag resistance tests tau ua los ntawm cov txheej txheem crucible nyob rau hauv ib tug txo qhov cua. Cov xwm txheej xeem: tus qauv slag pib 1.105, cua sov thiab tuav lub sij hawm 1500 degree, 4h. Nrog nce SiO₂ ultrafine hmoov cov ntsiab lus, muaj qhov zoo tshaj plaws tus nqi rau slag kuj; uas yog, qhov zoo tshaj plaws slag tsis kam yog ua tiav thaum lub ultrafine hmoov ntsiab lus nyob ib ncig ntawm 5%.
Nrog rau cov castable mix proportions thiab cov ntsiab lus ntawm refractory nplua hmoov thiab ultrafine hmoov seem tas mus li, lub zog compressive tom qab firing ntawm 1600℃kuj nce nrog nce ultrafine hmoov cov ntsiab lus, tab sis muaj qhov zoo tshaj tus nqi. Nrog SiO₂ ultrafine hmoov suav txog kwv yees li 5%, thiab Al₂O₃ thiab Cr₂O₃ ultrafine hmoov suav txog kwv yees li 7%, lub zog zoo, thiab lwm yam khoom kuj zoo heev. Nyob rau hauv cov nqe lus ntawm ultrafine hmoov hom, SiO₂ ultrafine hmoov muaj qhov zoo tshaj plaws reinforcing nyhuv, ua raws li los ntawm Al₂O₃ ultrafine hmoov, thaum Cr₂O₃ ultrafine hmoov muaj cov nyhuv tsis zoo. Nws kuj tseem pom tau tias cov nyhuv txhawb zog ntawm SiO₂ ultrafine hmoov yog 2.5 txog 4.4 npaug siab dua ob hom tom kawg.
NO.02 Admixtures
Muaj ntau hom kev sib xyaw. Ntawm no, peb muab cov tshuaj dispersants thiab dej- txo cov neeg ua hauj lwm ua piv txwv los qhia txog lawv qhov kev cuam tshuam ntawm kev ua haujlwm ntawm cov cement refractory castables tsawg.
Thaum qhov sib xyaw ua ke ntawm cov castable yog tas li, ntxiv qhov sib txawv ntawm cov dispersant tuaj yeem txo cov dej tsim tsim. Thaum tus nqi ntawm kev tsim kho cov dej tsis tu ncua, nws muaj qhov zoo tshaj plaws rau qhov ziab compressive zog raws li tus nqi ntawm dispersant nce. Ntawd yog, lub zog yog qhov zoo tshaj plaws thaum cov ntsiab lus dispersant yog 0.15% txog 0.2%. Thaum tsis muaj dej- txo tus neeg sawv cev ntxiv lossis ntau npaum li 0.5%, lub zog deteriorates lossis cov qauv tawg. Qhov no yog vim tsis zoo fluidity ntawm lub castable thiab tsis muaj qhov ntom ntawm lub cev molded.
Muaj ntau hom dej- txo cov neeg ua haujlwm, thiab kev xaiv tsim nyog yuav tsum tau ua los ntawm kev sim. Tom qab txiav txim siab qhov sib xyaw ua ke ntawm ultra- qis cement corundum castable, sodium polyphosphate, polycyanamide condensates, thiab naphthalene sulfonate condensates tau siv los ua dej- txo cov neeg ua haujlwm, thiab cov tshuaj tsim nyog tau tshuaj xyuas los npaj cov castable refractory. Castables tsis muaj dej-txo cov neeg ua haujlwm raug kev txom nyem los ntawm kev sib sau ua ke ntawm cov hmoov ultrafine, uas tsis tuaj yeem ua rau lub qhov hws zoo thiab muaj kev faib tawm tsis sib xws. A large amount of water is trapped in the flocs or fills the pores, resulting in increased water consumption, low bulk density, high porosity, and low strength after heat treatment, and is also unfavorable for sintering. Polyphosphates muaj qee qhov sib cais thiab dej-txo cov nyhuv, uas tuaj yeem, rau qee qhov, tiv thaiv cov agglomeration ntawm cov hmoov ultrafine, uas tso cai rau lawv kom muaj kev sib faib ntau dua hauv qhov pores, txhim kho kev siv dej thiab txo cov dej siv li ntawm 17%.
Therefore, the increased bulk density and decreased porosity of the castable, compared to the untreated castable, resulted in a 0.6-1.9 times increase in compressive strength after firing and a 1.25 times increase in high-temperature flexural strength. Cov neeg sawv cev B thiab C yog cov organic siab - dej ua tau zoo- txo cov neeg ua haujlwm, nrog rau cov dej sib txawv tshwj xeeb tseem ceeb - txo cov teebmeem, ua kom cov dej txo qis ntawm 25% thiab 28% raws li. Piv nrog rau qhov tsis kho castable, lawv qhov ntom ntom tau nce li ntawm 3.5%, porosity poob los ntawm 15%, compressive zog tom qab tua tau nce los ntawm 1-4 zaug, thiab siab - kub flexural zog nce ntau dua 3.5 npaug. Nws kuj tseem pom tau tias tus neeg sawv cev C muaj txiaj ntsig zoo dua li tus neeg sawv cev B. Hauv qhov xaus, cov dej- txo cov neeg ua haujlwm yuav tsum tau ntxiv thaum npaj cov cement refractory castables tsawg, thiab cov organic high-efficiency dej-txo cov neeg ua haujlwm yuav tsum nyiam dua.
NO.03 Aluminium hmoov
Nyob rau hauv cov hlau trough refractory castables, nws yog xim hlau txhuas hmoov feem ntau ntxiv kom ceev kom qhuav thiab ntxiv dag zog rau cov casting. Nws qhov loj me me thiab ntau npaum li cas muaj feem cuam tshuam rau kev ua haujlwm ntawm castable thiab yuav tsum tau xaiv kom tsim nyog.
Hauv Al₂O₃-SiC-C ultra- qis cement castables, qhov me me ntawm cov hmoov txhuas me me thiab siab dua qhov kub thiab txias thaum lub sij hawm tsim kho, qhov muaj zog ntawm cov tshuaj tiv thaiv, cov roj ntau dua, thiab cov khoom siv kub ntau dua. Qhov no muaj txiaj ntsig zoo rau lub cev qhuav dej ntawm cov castable, tso cai rau kev ci sai sai; Txawm li cas los xij, cov tshuaj tiv thaiv sai heev tuaj yeem ua rau qhov teeb meem tsis tseeb, uas ua rau muaj kev puas tsuaj rau lub zog. Qhov sib tov proportions ntawm castable tseem zoo ib yam. Cov hmoov txhuas loj me me yog qhov cuam tshuam rau lub zog, thaum qhov loj me me me me muaj qee qhov txiaj ntsig rau compressive zog thaum ziab, tab sis lwm yam kev ua tau zoo txo. Ib qho me me ntawm 88-44mm ua rau muaj zog zoo dua. Tus nqi ntawm cov hmoov txhuas siv yuav tsum tau txiav txim siab raws li qhov ua tau zoo ntawm cov khoom siv refractory castable thiab kev tsim kho; nws yuav tsum tau siv tsawg li tsawg tau thaum ua kom lub qhov cua zoo thiab ziab sai.
NO.04 Additives
Hauv Al₂O₃-SiC-C ultra- qis cement castables, SiC thiab cov ntaub ntawv carbon yuav tsum tau ntxiv los txhim kho lawv cov slag kuj thiab thermal stability. Kev sim thiab kev siv tau ua pov thawj tias qib thiab ntau npaum li cas ntawm SiC thiab cov khoom siv carbon muaj qhov cuam tshuam loj rau kev ua haujlwm ntawm cov castables thiab yuav tsum tau xaiv kom muaj nuj nqis. Tsis tas li ntawd, qib thiab ntau npaum li cas sib txawv nyob ntawm qhov loj ntawm qhov cub tawg thiab qhov chaw ntawm daim ntawv thov. Feem ntau, siab -SiC thiab carbon cov ntaub ntawv zoo yog siv nyob rau hauv lub ntsiab hlau trough los yog slag trough ntawm loj thiab nruab nrab- loj moj tej tawg rauv, thaum qis dua -qib SiC thiab carbon cov ntaub ntawv yog siv nyob rau hauv nruab nrab thiab me me blast furnaces; Qhov ntau npaum ntawm SiC feem ntau yog 5% mus rau 35%. Cov ntaub ntawv carbon feem ntau suav nrog suab, flake graphite, electrode hmoov, thiab earthy graphite, nrog rau ntau npaum li cas ntawm 2% mus rau 6%.
Hauv cov hlau trough refractory castables, SiC thiab cov ntaub ntawv carbon feem ntau ntxiv rau hauv cov hmoov zoo, nrog rau ultrafine SiC nyiam. Vim tias cov khoom no muaj SiC thiab cov ntaub ntawv carbon, nws cov oxidation kuj raug txo. Carbon oxidation tawm ntau micropores, tso cai rau molten hlau los yog slag mus txuas ntxiv mus rau sab hauv, tsim ib tug decarburized txheej thiab ua rau hauv ob sab phlu puas. Ntxiv cov hmoov hlau txhuas tuaj yeem txhim kho oxidation tsis kam ntawm castable. Kev sim tau pom tias kev sib xyaw ua ke ntawm cov hmoov hlau silicon hmoov, piv txwv li, Al hmoov thiab Si hmoov, ua rau oxidation zoo dua thiab txhim kho lub zog ntawm cov castable. Qhov no yog vim hais tias cov tshuaj tiv thaiv ntawm cov xim hlau silicon thiab txhuas nrog cov pa roj carbon ntawm qhov kub thiab txias los ua SiC thiab Al₄C₃ ua rau lub denser microstructure thiab nto.
Hauv Al₂O₃-SiO₂ qis cement refractory castables, qhov sib ntxiv ntawm 2% -8% kyanite hmoov zoo ntawm qhov kub ntawm 1200-1400℃txhawb kev tsim ntawm mullite, yog li ua kom nws lub zog. Qhov no txhais tau hais tias kyanite ua tsis tau tsuas yog raws li tus neeg sawv cev nthuav tab sis kuj yog ib tus neeg sawv cev mineralizing.
