Role of acid-base interactions in synthesis of cordierite from talc and sillimanite group minerals

It has been found that the mechanical activation of mixtures of sillimanite group minerals with talc and silica additives in grinding-activating devices with periodic and flow action provides significant acceleration of their interaction with formation of cordierite at the subsequent high-temperatur...

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Bibliographic Details
Published in:Science of sintering 2013, Vol.45 (3), p.273-279
Main Authors: Avvakumov, E.G., Lepezin, G.G., Gusev, A.A., Vinokourova, O.B.
Format: Article
Language:English
Subjects:
cordierite
heat treatment
mechanical activation
quartz
sillimanite group minerals
synthesis
talc
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Summary:It has been found that the mechanical activation of mixtures of sillimanite group minerals with talc and silica additives in grinding-activating devices with periodic and flow action provides significant acceleration of their interaction with formation of cordierite at the subsequent high-temperature treatment. It is shown that the output of cordierite depends on nature of mineral: in mixture with a sillimanite it is considerably higher, than with an andalusite and kyanite, while the rate of mullitization of these minerals has opposite character. It means that the formation of mullite during heat treatment is not a limiting step in synthesis of cordierite. It is shown that the rate of reaction is determined by the difference in the acid-base properties of these minerals, which depend on the coordination of aluminum cations by oxygen ions, different for each of the modifications. Utvrdjeno je da mehanicka aktivacija smesa silimanitne grupe materijala sa aditivima talka i silicijuma u mlinovima utice na znacajno ubrzavanje njihove medjusobne interakcije i nastajanja kordijerita tokom daljeg temperaturnog tretmana. Pokazano je da dobijeni kordijerit zavisi od prirode minerala: vise kordijerita se dobija iz smese sa silimanitom nego iz smesa sa andaluzitom i kijanitom, dok udeo mulitne faze ima suprotan karakter. To znaci da formiranje mulita tokom temperaturnog tretmana nije limitirajuci faktor u sintezi kordijerita. Utvrdjeno je da je brzina reakcije uslovljena razlikom kiselo-baznih svojstava minerala. Svostva zavise od odnosa katjona aluminijuma i anjona kiseonika, koji je razlicit za sve modifikacije.
ISSN:0350-820X
1820-7413
DOI:10.2298/SOS1303273A