Njerwa za Magnesia alumina spinel

Njerwa za Magnesia alumina spinel zimagwiritsa ntchito njerwa zoyambirira za magnesia ndi sintered magnesia alumina spinel mchenga wokhala ndi C / S chiyerekezo cha 0.4 ngati zopangira, zomwe zimakhala ndi kukula kwa 3mm. The magnesia tinthu kukula utenga 3 ~ 1mm tinthu lalikulu, <1mm tinthu sing’anga ndi <0.088mm ufa wosalala monga zosakaniza atatu mlingo. Gwiritsani ntchito sulpiti zamkati mwa zinyalala zamadzimadzi monga zomangirira, kusakaniza ndi mphero yonyowa, ndi mawonekedwe a makina osanjikiza njerwa a 300t. Thupi lobiriwira litauma, limachotsedwa pa 1560 ~ 1590 ° C. Mpweya wofooka wa okosijeni uyenera kuwongoleredwa panthawi yoombera.

Mitengo yotentha kwambiri komanso kutentha kwa njerwa za periclase-spinel ndibwino kuposa njerwa wamba za magnesia alumina. Mphamvu yolemetsa pam firiji ndi 70-100MPa, ndipo kutentha kwamphamvu (1000 ℃, kuzirala kwamadzi) ndi nthawi 14-19. Njerwa za periclase-spinel zitha kugwiritsidwa ntchito pamalo otentha otentha oyaka ma lime oyenda ndi ma simenti oyenda.

spinel yanga ya magnesium-aluminium yatenga njira ziwiri zopangira: sintering ndi fusion. Zipangizozo makamaka magnesite ndi mafakitale aluminiyamu ufa kapena bauxite. Malinga ndi zikhalidwe zosiyanasiyana za magnesia ndi alumina, spinel yolemera ya magnesia ndi spinel yolemera ya aluminiyamu imagawidwa ndikugwiritsidwa ntchito m’malo osiyanasiyana.

1. Malinga ndi kapangidwe kake kapena njirayi: sintered magnesium aluminium spinel (sintered spinel) ndi fused aluminium magnesium spinel (fused spinel).

2. Malinga ndi zopangira, zitha kugawidwa mu: bauxite-based magnesia-aluminium spinel ndi alumina-based magnesia-aluminium spinel. (Sintering kapena electrofusion)

3. Malinga ndi zomwe zili ndi magwiridwe antchito, imagawidwa: spinel yolemera ya magnesium, spinel ya aluminiyamu komanso spinel yogwira ntchito.

Njerwa ya Magnesia alumina spinel imatchedwanso kuti periclase-spinel njerwa, yomwe imapangidwa ndi magnesia osakanikirana kwambiri kapena kuyerekezera kwapamwamba kwambiri kwa magnesia komanso kuyeretsa kwambiri magnesia-aluminium spinel ngati zida zoyambira, pogwiritsa ntchito zosakaniza zenizeni Forming Kupanga kochita bwino kwambiri komanso makina otentha kwambiri. Poyerekeza ndi njerwa za magnesia-chromium, njerwa yamagnesia-aluminiyumu iyi sikuti imangothetsa kuvulala kwa chromium, komanso imakhala ndi kukana kwa dzimbiri, kukana kuchepa kwa okosijeni, kutentha kwa kutentha komanso kutentha kwakanthawi. Ndi simenti yayikulu komanso yapakatikati Yoyenera kwambiri yopanda chromium yopanda kanthu pamalo osinthira uvuni. Amagwiritsidwanso ntchito pazida zotentha kwambiri monga ma kilimu a mandimu, ma galasi, ndi zida zowotchera m’ng’anjo, ndipo zapindulanso.

Zolemba zakuthupi ndi zamagetsi za njerwa zopangidwa ndi magnesium-aluminium spinel ndi izi: MgO 82.90%, Al2O3 13.76%, SiO2 1.60%, Fe2O3 0.80%, porosity 16.68%, kuchuluka kwakachulukidwe 2.97g / cm3, kutentha kwapakatikati mphamvu 54.4MPa, 1400 ℃ kusintha mphamvu 6.0MPa.

Njerwa za Magnesium-aluminium spinel zakhala zikugwiritsidwa ntchito bwino m’malo osinthira ma simenti oyenda, koma amatha kugwiritsidwa ntchito popanga kuwombera, zovuta kupachika pakhungu la uvuni, komanso kusalimbana ndi nthunzi ya alkali ndi kupindika kwa simenti clinker madzi gawo. Ndipo kusowa kolimba kukana kupsinjika kwamakina komwe kumachitika chifukwa cha kusintha kwa thupi lamoto kumalepheretsa kugwiritsa ntchito malo owombera. Pachifukwa ichi, ofufuza apanga njerwa zosintha magnesia-aluminium spinel oyenera kuwotcha oyatsira simenti. Mukamawombera ndikugwiritsa ntchito, gawo la Fe2 + mu kapangidwe kake ka periclase-spinel limaphatikizidwa ndi Fe3 +. Pambuyo pake, gawo la Fe2 + ndi Fe3 + mu iron-aluminium spinel limafalikira m’matrix a periclase kuti apange MgOss. Nthawi yomweyo, Mg2 + ina m’matrix imayambukiranso ndi tinthu tating’onoting’ono tating’onoting’onoting’ono tating’onoting’ono tating’onoting’ono, tomwe timagwira ndi otsala a Al2O3 kuchokera pakuwonongeka kwa chitsulo-aluminiyamu spinel kuti apange magnesium-aluminium spinel. Zotsatirazi zikutsatiridwa ndi kukulitsa kwa voliyumu, zomwe zimabweretsa mapangidwe azinthu zazing’ono. Kuti

Njerwa zachitsulo-zotayidwa zopangira njerwa zimakhala ndi zinthu zabwino zopachikika ndi uvuni. Mwa iwo, chifukwa chomwe chitsulo chosungunuka chachitsulo chimapachikidwa bwino pakhungu la uvuni ndikofanana ndi njerwa ya mafic-iron spinel. Zimayambanso chifukwa cha CaO mu simenti clinker ndi Fe2O3 yolimba kwambiri mu periclase kuti apange makhiristo omwe amatha kunyowetsa periclase. , Calcium ferrite yomwe imamangirira zolumikizana ndi moto palimodzi. Zomwe zimapangitsa kuti pakhale matenthedwe abwino ndikupanga ma microcracks.

Mu dongosolo la MgO-Al2O3, njira yolimba yothetsera Al2O3 mu periclase pa 1600 ° C ili pafupi 0; yankho lolimba lomwe lili pa 1800 ° C ndi 5% yokha, yomwe ndi yocheperako kuposa Cr2O3. M’dongosolo la MgO-Al2O3, chinthu chokhacho chomwe chimakhala ndi magnesium aluminium spinel. Malo osungunuka a magnesium aluminium spinel ndi okwera mpaka 2135 ℃, ndipo kutentha kotsika kwambiri kwa MgO-MA kulinso 2050 ℃. Magnesium-aluminium spinel ndi mchere wachilengedwe, womwe umapezeka kwambiri mumchenga wa mchenga, chifukwa chake umakhala ndi bata pazinthu zachilengedwe.

Ma modulus of elasticity ndi ochepa, magnesia alumina njerwa (0.12 ～ 0.228) × 105 MPa, pomwe magnesia njerwa ndi (0.6 ～ 5) × 105MPa; MA amatha kusamutsa MF kuchokera ku periclase, ndipo atha kusesa FeO. Zomwe zimachitika ndi izi: FeO + MgO • AI2O3 → MgO + FeAl2O4, FeO + MgO → (Mg • Fe) O, MA imayamwa Fe2O3 ndikukula pang’ono ndikukhala ndi malo osungunuka kwambiri. Spinel imakhala ndi malo osungunuka a 2135 ° C, ndipo kutentha kwake koyamba ndi periclase ndikokwera kuposa 1995 ° C. Kuphatikizidwa kwa ziwirizi kumathandizira magwiridwe antchito a njerwa za magnesia. Kutentha kochepetsa katundu ndikokwera, koma mapangidwe a spinel amatsagana ndi kukulitsa kwa voliyumu, ndipo mphamvu zowerengera ndi kuyesanso mphamvu ndizofooka, motero kutentha kwakukulu kumafunika. Wabwino matenthedwe kukana. mkulu mphamvu. Kukana kwamphamvu kwamphamvu.