$crystaldiffract export diffraction pattern$

$crystaldiffract export diffraction pattern$

Thus, it could be presumed that the formation of α–C2S in molten steelmaking slag contributes to enhancing the phosphorus distribution to the slag due to its high solubility of phosphorus as C3P. For both cases, the diffraction patterns of the precipitates were successfully obtained, and they were recognized as the α–C2S polymorph. Recently, some of the authors attempted to identify the crystal structure of the dicalcium silicate compound precipitated from the C2S–C3P liquid 25 and molten CaO–SiO 2–FeO x–P 2O 5 slag 26 by high-temperature in situ X-ray diffraction analysis. Because C2S shows rapid phase transition during quenched, 25 phase identification could not be done when the quenched sample was analyzed at room temperature. However, the crystal structure of the C2S–C3P solid solution had not been identified in these previous works. Many previous studies have been performed to investigate the formation behavior of the C2S–C3P solid solution during the dephosphorization 19- 21 and the thermodynamic properties of the C2S–C3P solid solution and coexisting molten slag, 22- 24 all of which experimentally support the high solubility of phosphorus in dicalcium silicate. Because dicalcium silicate accepts many phosphate ions as a dopant, dicalcium silicate significantly contributes to the efficiency of dephosphorization. To improve the efficiency of phosphorus distribution to the slag, solid particles of dicalcium silicate are dispersed in the molten slag because it forms a solid solution with C3P. g., P 2O 5) is distributed to molten slag. In this dephosphorization, oxygen is blown into molten iron to oxidize solvable phosphorus, and the phosphate species ( e. The dephosphorization is often performed during the steelmaking process to remove phosphorus as an impurity from molten iron until the remaining phosphorus amount is as less as the order of several tens ppm by weight. In the steelmaking process, C2S is an important material necessary to promote phosphorus removal from molten iron. Such a high solubility of phosphorus in the α–C2S has been effectively utilized in the steelmaking process, as explained below. Concerning phosphorus as a typical dopant, several researchers 16- 18 have reported that the α polymorph forms solid solution between dicalcium silicate and tricalcium phosphate (Ca 3 (PO 4) 2, C3P) in the entire composition range. However, the α polymorph, which exists as a stable phase at high temperatures than 1698 K, is known to exhibit very high solubility of dopants. Although various kinds of doping elements have been investigated for these polymorphs, the solid solubility of these elements are very limited. Among different kinds of C2S polymorphs ( α: hexagonal, α': orthorhombic, β: monoclinic, γ: orthorhombic), most of the above fields focus on the β or γ polymorphs, which are metastable or stable phase at lower temperatures than 1123 K. g., cements and clinker), 1- 5 biomaterials, 6- 8 nuclear waste depository, 9- 11 and metallurgical slag in metal production, 12- 15 and plays significant roles due to its unique characteristic in accepting many kinds of doping elements. Electronic-state calculation and MD simulation indicated that a highly disordered ionic arrangement spontaneously forms in the α-phase crystal for structure relaxation when held at high temperatures, or when phosphorus is incorporated.ĭicalcium silicate (Ca 2SiO 4, C2S) is a typical compound that appears in different fields related to ceramic materials such as building ( e. The results indicated that the completely symmetric ionic arrangement, as reported for the α phase, is the most unstable. In this study, the ionic distribution in the α polymorph of dicalcium silicate was evaluated by first-principles calculation based on density functional theory (DFT), as well as by molecular dynamics (MD) simulation with a polarizable ion model optimized by DFT calculation. However, because the occupation probability of each atomic site in the α polymorph is not limited to unity, it has not been qualified how these ions are exactly arranged. It has previously been reported that the crystal structure of α-dicalcium silicate consists of a symmetric arrangement of Ca 2+ ions and SiO 4 4− tetrahedra, although other polymorphs exhibit asymmetric arrangements. The α-dicalcium silicate forms a solid solution with tricalcium phosphate in the entire composition range, although the reason for high solubility of phosphorus remains unclear in view of the crystal structure. Dicalcium silicate, which is found in steelmaking slag for dephosphorization, exists as the hexagonal α phase at high temperatures.

$crystaldiffract export diffraction pattern$

Crystaldiffract export diffraction pattern