Abstract
Steel slag, as industrial solid waste, is difficult to recycle owing to its complex components and poor mechanical properties. However, steel slag can be modified by adding Al2O3–SiO2 through high temperature sintering, which would improve the mechanical properties and expand the scope of its application. The phase changing, morphology evolution and the mechanical properties of the modified steel slag were investigated. The results indicate that the main phase changes to gehlenite occur with increasing temperature. The compressive strength increases to 115 MPa at 1350 °C. The relationship of the quantity of gehlenite and the compressive strength were explored.
Highlights
Recycling and utilization of industrial waste is a current problem, and it is a research hotspot in solid waste utilization [1]
The effects of Fe2O3 on the properties of steel slag ceramics were studied by Li et al.; the results indicate that an increase in Fe2O3 can reduce the sintering temperature and improve the mechanical properties of the ceramics [19]
The amount of gehlenite increases and the impurity peaks gradually decreased, indicating that most of the Ca in the steel slag combined with Al and Si to form gehlenite crystals
Summary
Recycling and utilization of industrial waste is a current problem, and it is a research hotspot in solid waste utilization [1]. The effects of Fe2O3 on the properties of steel slag ceramics were studied by Li et al.; the results indicate that an increase in Fe2O3 can reduce the sintering temperature and improve the mechanical properties of the ceramics [19]. Deng et al investigated the effect of SiO2/MgO ratio on the phase transformation and properties of wollastonite–augite glass-ceramic through the sintering of steel slag [21]. It can be seen from the DTA/TG curve that the steel slag showed an overall weight gain trend during the heating process This may have been due to some low-valence ions or simple substances transformed into high-valence ions during sintering, for example, Fe and FeO may have converted to Fe2O3. When the steel slag is sintered at 1270 ◦C, the sample mainly contains Ca2Fe2O5 and Ca2SiO4; the Ca3SiO5 and amorphous phase disappear, which is unstable at room temperature
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