Abstract
Abstract The volume stability caused by the hydration of f-CaO is one of the main obstacles to the comprehensive utilization of steel-making slag. In view of the f-CaO produced by incomplete dissolution of lime, it is necessary to strengthen the dissolution behavior of lime in the converter process. The reactivity of lime determines the dissolution efficiency and is closely related to its microstructure. The experimental results show that the reactivity and porosity of quick lime decrease and the average diameter of pore increases with an increase in temperature. The CaO crystals gradually grow up under the action of grain boundary migration. When the temperature increased from 1,350 to 1,600°C, the lime reactivity decreased from 237.60 to 40.60 mL, the porosity decreased from 30.55 to 15.91%, the average pore diameter increased from 159.10 to 1471.80 nm, and the average CaO particle size increased from 0.33 to 9.61 µm. The results indicate that reactivity is decreased because of the deformation and growth of CaO crystals and the decrease in porosity in reactive lime. This will cause an obstacle to the dissolution of lime and is not conducive to the control of f-CaO in slag.
Highlights
The volume stability caused by the hydration of f-calcium oxide (CaO) is one of the main obstacles to the comprehensive utilization of steel-making slag
On the basis of the testing results of 28 converterslag samples obtained from 25 iron and steel enterprises in China, Xu and Huang [8] found that f-CaO existed in slag in two different forms: one is that f-CaO distributed around dicalcium silicate with a size of about 50 μm, which is derived from incompletely dissolved reactive lime; the other is that the f-CaO covering the calcium
According to the XRD analysis results of the samples (Figure 1a), the reactive lime raw material lime sample was 36.09% (L0), which had been calcined at high temperature, was composed of calcite (CaCO3) and calcium oxide (CaO), and CaO is the dominant mineral of L0
Summary
Abstract: The volume stability caused by the hydration of f-CaO is one of the main obstacles to the comprehensive utilization of steel-making slag. The results indicate that reactivity is decreased because of the deformation and growth of CaO crystals and the decrease in porosity in reactive lime This will cause an obstacle to the dissolution of lime and is not conducive to the control of f-CaO in slag. On the basis of the testing results of 28 converterslag samples obtained from 25 iron and steel enterprises in China, Xu and Huang [8] found that f-CaO existed in slag in two different forms: one is that f-CaO distributed around dicalcium silicate with a size of about 50 μm, which is derived from incompletely dissolved reactive lime; the other is that the f-CaO covering the calcium. The evolution behaviors of both reactivity and microstructure of the quick lime calcinated at different temperatures were investigated in this paper to reveal the relationship between the size of CaO crystal and the lime reactivity
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