nkhani

Mawu Oyamba
Cristobalite ndi low density SiO2 homomorphous variable, ndipo thermodynamic stability range yake ndi 1470 ℃~1728 ℃ (pansi pa kukakamizidwa kwabwino). β Cristobalite ndi gawo lake lotentha kwambiri, koma likhoza kusungidwa mu mawonekedwe osakanikirana mpaka kutentha kwambiri mpaka kusintha kwa mtundu wa kusintha kumachitika pafupifupi 250 ℃ α Cristobalite. Ngakhale cristobalite imatha kusungunuka kuchokera ku SiO2 kusungunuka m'dera lake lokhazikika la thermodynamic, ma cristobalite ambiri m'chilengedwe amapangidwa pansi pamikhalidwe yosinthika. Mwachitsanzo, diatomite imasintha kukhala cristobalite chert kapena microcrystalline opal (opal CT, opal C) panthawi ya diagenesis, ndipo magawo awo akuluakulu a mchere ndi α Cristobalite), omwe kutentha kwake kumakhala m'dera lokhazikika la quartz; Pansi pa granulite facies metamorphism, cristobalite yochokera ku olemera Na Al Si melt, idakhalapo mu garnet ngati chophatikizira ndipo imakhala ndi albite, kupanga kutentha ndi kupanikizika kwa 800 ℃, 01GPa, komanso m'malo okhazikika a quartz. Komanso, metastable cristobalite amapangidwanso ambiri sanali zitsulo mchere zipangizo pa kutentha kutentha, ndi mapangidwe kutentha lili mu thermodynamic bata zone ya tridymite.
Njira yopangira
Diatomite amasintha kukhala cristobalite pa 900 ℃ ~ 1300 ℃; Opal amasintha kukhala cristobalite pa 1200 ℃; Quartz imapangidwanso mu kaolinite pa 1260 ℃; The synthetic MCM-41 mesoporous SiO2 molecular sieve idasinthidwa kukhala cristobalite pa 1000 ℃. Metastable cristobalite imapangidwanso munjira zina monga ceramic sintering ndi kukonzekera mullite. Kufotokozera za njira yopangira metastable ya cristobalite, zimavomereza kuti ndi njira yosagwirizana ndi thermodynamic, yomwe imayendetsedwa ndi machitidwe a kinetics. Malinga ndi mawonekedwe a metastable mapangidwe a cristobalite otchulidwa pamwambapa, pafupifupi onse amakhulupirira kuti cristobalite amasandulika kuchokera ku amorphous SiO2, ngakhale panthawi ya mankhwala a kaolinite kutentha, kukonzekera kwa mullite ndi ceramic sintering, cristobalite imasinthidwanso kuchokera ku amorphous SiO2.
Cholinga
Kuyambira kupangidwa kwa mafakitale m'ma 1940, zinthu zakuda zakuda za kaboni zakhala zikugwiritsidwa ntchito kwambiri ngati kulimbikitsa zinthu za rabara. Kuphatikiza apo, zitha kugwiritsidwanso ntchito m'makampani opanga mankhwala, mankhwala ophera tizilombo, inki, utoto, utoto, mankhwala otsukira mano, mapepala, chakudya, chakudya, zodzoladzola, mabatire ndi mafakitale ena.
Mankhwala amtundu wakuda wakuda wa carbon mu njira yopangira ndi SiO2nH2O. Chifukwa chakuti ntchito yake ndi yofanana ndi ya carbon yakuda ndi yoyera, imatchedwa white carbon black. Malinga ndi njira zosiyanasiyana zopangira, kaboni wakuda wakuda ukhoza kugawidwa kukhala wakuda wakuda wa kaboni (precipitated hydrated silica) ndi fumed white carbon black (fumed silica). Zogulitsa ziwirizi zimakhala ndi njira zopangira zosiyana, katundu ndi ntchito. Njira ya gasi imagwiritsa ntchito silicon tetrachloride ndi silicon dioxide yomwe imapezeka ndi kuyaka kwa mpweya. Tinthu tating'onoting'ono tating'onoting'ono tating'onoting'ono tating'ono tating'ono tating'ono tating'ono tating'ono tating'ono tating'ono tating'ono 5. Njira ya mpweya ndiyo kutsitsa silika powonjezera sulfuric acid ku sodium silicate. Kukula kwa tinthu tapakati ndi pafupifupi 7-12 microns. Silika ya fumed ndi yokwera mtengo ndipo si yosavuta kuyamwa chinyezi, choncho imagwiritsidwa ntchito ngati chopondera popaka.
Njira yothetsera magalasi a nitric acid imakhudzidwa ndi nitric acid kuti ipange silicon dioxide, yomwe imakonzedwanso kukhala silicon dioxide yamagetsi kudzera mukutsuka, pickling, rinsing madzi rinsing ndi kutaya madzi m'thupi.