Mullit sintezi

Mullitning sintez usulini sinterlash usuli va elektr eritish usuliga bo'lish mumkin. Sinterlash usuli xom ashyoni tayyorlash usuliga ko'ra quruq usul va nam usulga bo'linishi mumkin. Quruq jarayon - bu ingredientlarni birga maydalash va keyin to'pni yoki ixchamni bosgandan so'ng uni aylanadigan pech yoki tunnel pechida yoqishdir. Nam jarayon aralash materialni suv bilan atala ichiga maydalash, so'ngra bosish va filtrlash uchun loy kekiga suvsizlantirish va loyni loy qismiga yoki loy bo'shligiga vakuum bilan siqish va keyin yoqishdir.
Elektr eritish usuli aralash materialni boshq o'choqqa qo'shish, yoy natijasida hosil bo'lgan yuqori haroratda eritish, sovuq kristallanish, tabiiy xom ashyo tarkibiy qismlaridan (masalan, boksit va boshqalar) foydalanish to'g'ridan-to'g'ri ezilishi mumkin.<1.5mm particles without grinding, and then mixed with other powdered raw materials in the mixer.
Mullitni sinterlash orqali sintez qilish odatda 1650 ~ 1700 darajada amalga oshiriladi. Mullitning sinterlash orqali sinteziga ta'sir qiluvchi asosiy omillar xom ashyoning tozaligi, xom ashyoning nozikligi va kalsinlanish haroratidir. Mullitning sinterlash usuli bilan sintezi asosan Al? O? SiO2 va sio2 o'rtasidagi qattiq faza reaktsiyasi tugallandi, shuning uchun xom ashyoning tarqalishini yaxshilash qattiq faza reaktsiyasi jarayonini tezlashtiradi. Xususan, zarralar<8μm have a great effect on the formation and sintering of synthetic mullite. It can be seen that the full mixing and fine grinding of raw materials is an important process condition to promote the solid phase of the synthesis of mullite. Mullite generally begins to form at 1200 ° C and ends at 1650 ° C. At this time, it is microcrystalline, and the crystallization develops well when the temperature exceeds 1700℃. It can be seen that the combustion temperature directly affects the formation and crystal development of mullite. Therefore, heating to a certain firing temperature and extending a certain holding time are necessary conditions for the synthesis of mullite. The purity of the raw materials used to synthesize mullite is very strict, and a small amount of impurities will reduce the content of mullite. In industrial production, it is inevitable to bring a variety of impurities, mainly Fe? O? TiO? , CaO, MgO, Na? O·K? O, the most harmful of which is Na? O, K? O, they inhibit the formation of mullite and lead to the production of a large number of silicon-rich glass phases, reducing mullite content. Fe? O? It will slow down the mullite process and increase the amount of glass phase. Be TiO? When a small amount of Ti ions exist, part of Ti ions enter the mullite lattice to form a solid solution, promoting the formation of mullite and crystal development and growth, when the TiO2 content is too high, it still acts as a flux.
Elektroerituvchi mullit aralashmani elektr yoy pechida eritib tayyorlanadi va mullit eritmadan sovutiladi. Kristallanish jarayoni Al ning jarayoniga o'xshaydi? O? -SiO? Tizim fazasi diagrammasining kristallanish jarayoni shunga o'xshash. Qachon Al? O? Mullitning nazariy tarkibi 71,8% dan yuqori bo'lsa, erigan ortiqcha Al hosil bo'ladi. O? Mullitning qattiq eritmasi, beta-mullit, faqat Almi? O? Korund fazasi faqat 80% da paydo bo'ladi. Eritilgan mullitning mineral fazali tarkibi odatda mullit kristalli va shisha fazadir. Xitoyning elektr erituvchi mullit sanoat standarti YB/T104-2004 "Elektr erituvchi mullit" Al bo'yicha elektr erituvchi mullit mahsuloti? O? Kontent DM-1 va DM-2 darajalariga bo'lingan va tegishli texnik shartlarni tegishli milliy standartlarda ko'rish mumkin. Sinterlangan mullit bilan solishtirganda, eritilgan mullit kristallari katta donalar va kamroq nuqsonlar bilan yaxshi rivojlangan va kristall hajmi sinterlangan mullitdan yuzlab marta kattaroqdir, shuning uchun yuqori haroratli mexanik xususiyatlar va eroziyaga chidamlilik nisbatan yaxshi.