Abstract
The mineralizing action of iron in amorphous silica was investigated by firing mixtures of silica gel and iron oxides at 1100 and 1150°C. Silica gel did not crystallize in the absence of ferrous ion below 1200°C. When silica gel mixed with ferrous oxalate was heated at 1100°C in a mildly reducing atmosphere(N 2 , CO 2 , CO), quartz, cristobalite and ferrous silicate (Fe 2 SiO 4 ) were formed. Application of the reducing atmosphere from room temperature promoted the crystallization to quartz, while that from the soaking temperature after heating in N 2 accelerated the formation of cristobalite. Chemical analysis revealed that the N 2 atmosphere acted as a mildly oxidizing atmosphere to FeO possibly due to the coexistence of water vapor released from silica gel and impurity O 2 . Furthermore, tentative crystallization mechanism is proposed where mildly reduced and mildly oxidized Fe 2 SiO 4 produced nuclei for quartz and cristobalite, respectively.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
