Facile Large‐Scale Synthesis of Nanoscale Fayalite, α‐Fe₂SiO₄

Abstract

Fayalite has been found various applications in many fields. However, it is scarce in Earth's crust. Most of the preparation methods reported earlier are slightly rigorous or complicated and mainly used for preparing large crystal or single crystal fayalite. Because of the potential applications in the field of functional materials and catalysis, nanoscale fayalite would be interesting and attractive. Herein we designed a new method to synthesize nanoscale α‐Fe2SiO4 via a H2‐assisted gas‐solid reaction. We have used three different approaches based on the above method. The highly dispersed precursor, which was prepared by a continuous co‐precipitation method, was heated to a phase‐transition temperature (∼600 °C) under H2 atmosphere to synthesize nanoscale α‐Fe2SiO4. The fayalites were characterized by XAD, XAS and FT‐IR. Comparing with the earlier reported methods, our method largely reduces the reaction temperature, and facilitates large scale synthesis of nanoscale fayalite. It is found that the well distribution of Fe−O and Si−O domains in a nanometer scale plays an important role in the preparation.

Synthesis of Fe2SiO4-Fe7Co3 Nanocomposite Dispersed in the Mesoporous SBA-15: Application as Magnetically Separable Adsorbent

“…The TPR profiles are presented in Figure 2. According to the literature, solids containing iron and cobalt dispersed in silica begin to reduce at temperature between 250 and 300 • C. It usually has two or three peaks related to the reduction of iron and cobalt oxides concerning the phases of cobalt ferrite and fayalite dispersed in the silica matrix as observed in the diffractions of Figure 1 [41][42][43][44][45]. The TPR curves show two distinct reduction stages, the first between 350 and 650 • C and the second between 650 and 850 • C, approximately.…”

“…Previous papers describe the possible reactions that justify the formation of fayalite from iron oxides and silicon. A series of gas-solid reactions in the presence of H 2 may be occurring, which leads to a series of redox reactions such as 2Fe 3+ + 2Fe 0 → 3Fe 2+ and 2α-Fe 3+ + 2Fe + 3SiO 2 → 3α-Fe 2 SiO 4 [40,41].…”

“…The second range referring to the reduction of Fe 2+ to Fe 0 may be related to the reduction of iron silicate. It is worth to highlight that the iron silicate and cobalt ferrite phases, observed in the XRD results before reduction, are very resistant structures to be reduced and, therefore, the complete reduction of these phases may not have been completely observed in the temperature range studied [41,45]. It is important to mention that metal oxides particles located internally in the pores are more difficult to reduce compared to particles positioned on the outer surface [46,47].…”

Mechanism of Cation–Oxygen Bond Activation and K+/Na+ Synergistic Promotion of Silicate Phase Dissociation in Smelting Slag

“…The results of this work could provide more effective solutions for minerals, smelting slag treatment, and resource utilization fields, facilitating developments in related areas. 32 magnesium nitrate hexahydrate (11.1 g) and iron(III) nitrate nonahydrate (1.9 g) were dissolved in 115 mL of deionized water to formulate the Mg−Fe solution. Upon stirring, 10.0 g of TEOS was introduced to the aforementioned solution, establishing the (Fe+Mg)/Si atomic ratio at 2:1 to craft the Mg−Fe−Si solution.…”

Synthetic fayalite Fe2SiO4 by kinetically controlled reaction between hematite and silicon carbide

“…While being fast and simple, the preparation of fayalite by this method can be accompanied by significant contamination from the milling materials . Other methods proposed for the preparation of nanosized fayalite include sol‐gel technique, precipitation method, and sucrose‐PVA‐based synthesis; all the routes involve calcination in a controlled reducing atmosphere for the crystallization of the fayalite phase.…”