Existing state and solidification characteristics of heavy metals in glass‐ceramics from Mn‐bearing blast furnace slag

Abstract

In this article, the high performance glass-ceramics were prepared with Mnbearing blast furnace slag as the main raw material, Fe 2 O 3 and Cr 2 O 3 as composite nucleating agents. The existence state of Mn and Cr in glass-ceramics and the mechanisms of solidification of heavy metals in glass-ceramics were studied. The results showed that the high electric field characteristics of Cr ions contributed to the generation of spinel phase, while Mn ions can enter the spinel crystal by replacement method and exist stably in spinel crystal. The Mn ions were mainly

The direct experimental observation and solidification mechanism of heavy metals in blast furnace slag glass‐ceramics

“…At this point, some of the heavy metal ions enter the interstices of the glass network to balance the excess negative charge and form a chemical bond with Al (X–Al, where X is the heavy metal ion). The formation of chemical bonds is more favorable for the immobilization of heavy metals than for those in the free state 36 . As shown above, heavy metals are mostly immobilized in glass‐ceramics by forming chemical bonds with other ions, spinel can be considered as a core for the solidification of heavy metals, while augite and glass phases can act as a double barrier to further prevent the leaching of heavy metal ions, thus giving the glass‐ceramics excellent solidification properties.…”

“…The formation of chemical bonds is more favorable for the immobilization of heavy metals than for those in the free state. 36 As shown above, heavy metals are mostly immobilized in glass-ceramics by forming chemical bonds with other ions, spinel can be considered as a core for the solidification of heavy metals, while augite and glass phases can act as a double barrier to further prevent the leaching of heavy metal ions, thus giving the glass-ceramics excellent solidification properties. Figure 6b illustrates the crystal growth and solidification characteristics of the glass ceramic, combining the SEM and EDS experimental results.…”

“…The comprehensive utilization of BFS includes its use in the production of cement, slag bricks, silicon fertilizer, and glass ceramics. The main constituents of BFS are CaO (35)(36)(37)(38)(39)(40)(41)(42)(43)(44)(45)(46)(47)(48) wt.%), SiO 2 (28-42 wt.%), MgO (3-14 wt.%), and a small amount of Fe 2 O 3 (0-2 wt.%). 5 Glass-ceramic is a polycrystalline solid material consisting of microcrystalline and glass phases.…”

“…In addition, the strong electrical properties of rare earth elements can induce the formation of aggregates and facilitate the densification of the glass network. 11,12 Therefore, the preparation of glass-ceramics by REBFS can further improve the mechanical properties of glass-ceramics.…”

“…The primary crystalline phase of the above glass‐ceramics is mostly augite, and the production of augite is one of the important factors contributing to the excellent physical and chemical properties of the glass‐ceramics. In addition, the strong electrical properties of rare earth elements can induce the formation of aggregates and facilitate the densification of the glass network 11,12 . Therefore, the preparation of glass‐ceramics by REBFS can further improve the mechanical properties of glass‐ceramics.…”