Njerwa za Magnesia alumina

Njerwa za Magnesia alumina zimapangidwa ndi sintered magnesia wapamwamba ndipo pafupifupi 8% ya ufa wosalala wa Al2O3 kapena mtundu wapamwamba kwambiri wa alumina bauxite (Al2O3> 78%, SiO2 <20%, pang’ono Fe2O3 ndi zonyansa zina), pogwiritsa ntchito sulfite zamkati zamkati zamadzimadzi monga zomangira, Zamchere zamatsenga zopangidwa ndi batching, kusakaniza, billeting, kuyanika, kuwombera ndi zina.

Mavitamini a magnesium mu njanji ya magnesia alumina ali pafupifupi 85%. Zomwe zili ndi alumina ndi 5% mpaka 10%, zida zoyambira zomwe zili ndi periclase monga gawo lalikulu la kristalo ndi magnesia-aluminium spinel ngati gawo lachiwiri la kristalo (monga gawo lalikulu lomangirira). Zowoneka ngati porosity nthawi zambiri zimakhala 15-18%. Chowonjezera chakukula kwamatenthedwe ndi 10.6 × 10-6 / ° C. Kutentha kwamatenthedwe kuli bwino kuposa njerwa ya magnesia. Chifukwa chakuti magnesium aluminium spinel yokhala ndi malo osungunuka kwambiri imagawidwa mu matrix, mphamvu yake yotentha kwambiri ndiyokwera, ndipo kutentha koyambira kochepetsa katundu kumakhala pamwamba pa 1580 ° C. Kukana kwa slag ndibwinonso. Nthawi zambiri, sintered magnesia imagwiritsidwa ntchito ngati chimanga, ndipo ufa wabwino wopangidwa ndi magnesia ndi bauxite kapena bauxite clinker kapena alumina wamafuta amawonjezeredwa pamlingo wina, ndipo umapezeka ndikusakaniza, kupanga ndikuwombera.

1. Magnesia alumina njerwa atha kupanga ndi kuwonjezera 5-10% Al2O3 ku sintered magnesia. A12O3 ndi anawonjezera mu ufa wosalala mu mawonekedwe a aluminiyamu mafakitale kapena mkulu aluminiyamu bauxite clinker.

2. Ngati Al2O3 imayambitsidwa ndi nthaka yayikulu ya alumina, imayenera kuyambitsa zodetsa monga SiO2 nthawi yomweyo, motero kumachepetsa kukonzanso kwamphamvu ndi kutentha kwa mankhwala. Chifukwa chake, kuchuluka kwa alumina wowonjezera sikuyenera kukhala kwakukulu kwambiri.

3. Magawo omwe amapanga njerwa za magnesia alumina ali ofanana ndi a njerwa za magnesia. Kungoti kutentha kowala nthawi zambiri kumakhala kwakukulu kuposa kutentha kwa njerwa za magnesia pofika 30-50 ° C, mpaka 1750-1800 ° C.

Njerwa za Magnesia alumina zili ndi izi:

1. Magnesia alumina njerwa ali bwino matenthedwe bata ndi kupirira madzi kuzirala kwa nthawi 20-25 kapena ngakhale apamwamba. Uwu ndiye mwayi wake wodziwika kwambiri. Njerwa Magnesia aluminiyamu ndi wabwino matenthedwe mantha bata. Onse magnesia alumina spinel ndi periclase ndi a cubic crystal system. Kukula kwa matenthedwe mbali iliyonse ya kristalo ndikofanana, chifukwa chake kukulira ndi kupindika kwake ndi komwe kutentha kumasinthasintha. Ndi yunifolomu kwambiri ndipo imatulutsa kupsinjika kocheperako.

2. Katundu wa magnesia alumina njerwa alinso wolimba pang’ono kuposa njerwa za magnesia. Chifukwa cha magnesia-aluminium spinel yomwe imasungunuka kwambiri, kutentha kwa njerwa ya magnesia-aluminium kumakhala bwino kuposa njerwa ya magnesia, kufika 1620 ～ 1690 ℃.

3. Makina a njerwa za magnesia-aluminium amasiyanasiyana ndi zida zosiyanasiyana, makamaka MgO> 81%, Al2O3 8.7%, SiO2 <6.0%, CaO <1.5%, Fe2O3 <1.0%.

4. Mapangidwe amchere a magnesia alumina njerwa. Pazitsulo zake, kristalo wamkulu ndi periclase, ndipo matrix amapangidwa ndi magnesium ferrite, forsterite, forsterite ndi magnesia spinel.

5. Refractoriness ndi katundu softening kutentha kwa magnesia aluminiyamu njerwa. Mu njerwa za magnesia alumina, makhiristo a periclase ndi magnesia alumina spinel amapanga maukonde. Ngakhale zotsika zazing’ono zosungunuka zimadzazidwa ndi maukonde opanda zingwe, maukonde akadali Amatha kulimbana ndi kutentha kwakukulu ndi katundu, chifukwa chake kukonzanso kotsika ndi kutsitsa kutentha kwa njerwa za magnesia alumina ndizokwera kwambiri, Refractoriness itha kufika 2100 ℃, ndipo kutentha kwachepetsa kutentha ndi 1570 ℃.

6. Kukula kwa matenthedwe ndi kukhazikika kwamatenthedwe a njerwa ya magnesia-aluminium. Chifukwa coefficient yowonjezera ya magnesia-aluminium spinel ndi yaing’ono, chiwerengero chowonjezeka cha njerwa ya magnesia-aluminium ndi chochepa kwambiri. Pakati pa 20 ~ 1000 ℃, koyefera kozungulira kwa magnesia alumina njerwa ndi 10.6 × 10-6 ℃ -1 zokha. Chifukwa magnesia alumina spinel amatenga gawo pakukweza kukana kwamphamvu mu njerwa, magnesia alumina njerwa imakhala ndi matenthedwe abwino osakanikirana, ndipo kuchuluka kwamadzi ozizira amapitilira 20.

7. Kukana kwa slag kwa njerwa za magnesia-aluminium. Chifukwa njerwa za magnesia-aluminium zimakhala zolimba kwambiri, poriclase imazunguliridwa ndi magnesia-aluminium spinel, ndipo AI2O3 ndimtundu wosalowerera ndale, chifukwa chake njerwa za magnesia-aluminium Kutha kukana kukokoloka kwa asidi ndi alkaline ndikolimba.

Kukhoza kwa magnesia alumina njerwa kuteteza ma periclase particles ku slag kukokoloka ndi kwamphamvu kuposa kwa forsterite, kotero kuthekera kwa magnesia alumina njerwa yolimbana ndi slagine slag ndi iron oxide slag kumalimbikitsidwa.

Njerwa za ku Magnesia-alumina zili ndi zinthu zabwino kwambiri zomwe zatchulidwazi, chifukwa chake zakhala zikugwiritsidwa ntchito ngati zida zomangira nyumba padenga lazitsulo zotentha kwambiri monga mipando yazitsulo yotentha ndi ng’anjo zotsekemera zamkuwa, ndipo akwaniritsa izi Zotsatira za kutalikitsa moyo wa ng’anjo. Nyumba yayikulu yotseguka imatha kufikira ng’anjo pafupifupi 300, ndipo malo otseguka apakatikati ndi ang’ono amakhala ndi malo opitilira 1000.