Highly disordered ionic distribution in α‐dicalcium silicate for structure relaxation

Abstract

Dicalcium silicate (Ca 2 SiO 4 , C2S) is a typical compound that appears in different fields related to ceramic materials such as building (e.g., cements and clinker), 1-5 biomaterials, [6][7][8] nuclear waste depository, [9][10][11] and metallurgical slag in metal production, [12][13][14][15] and plays significant roles due to its unique characteristic in accepting many kinds of doping elements. 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. Although various kinds of doping elements have been investigated for these polymorphs, the solid solubility of these elements are very limited. However, the α polymorph, which exists as a stable phase

Influence of the Basicity on Phosphorus Enrichment Properties of Decarbonization Slag in Low‐Carbon Double Slag Converter Steelmaking Process with Industrial Experiments, Mineralogy, and Ion–molecule Coexistence Theory

“…Within the temperature range of the LCDSP decarbonization stage, C 2 S is in the high‐temperature crystalline state of α‐C 2 S, [ 46 ] which mainly exists in the form of 2Ca 2+ and [SiO 4 ] 4− , and C 3 P mainly exists in the form of 3Ca 2+ and 2[PO 4 ] 3− . [ 46 ] Among them, the radii of [SiO 4 ] 4− and [PO 4 ] 3− are similar, which are 2.79 and 2.76 Å, respectively, and the crystal structures of them both tetrahedral, which makes a part of Si in tetrahedral structure can be replaced by P, [ 46,47 ] resulting in changes in its coordination structure. In the C 2 S lattice, part of the [SiO 4 ] 4− is replaced by [PO 4 ] 3− , which initially forms the n C 2 S‐C 3 P solid solution.…”

“…Equation (15-1)-(15-3) represents the The C 2 S-C 3 P solid solutions play a major role on phosphorus enrichment in decarburization slag, and its formation process can be reasonably explained by the structure theory of molten slag. Within the temperature range of the LCDSP decarbonization stage, C 2 S is in the high-temperature crystalline state of α-C 2 S, [46] which mainly exists in the form of 2Ca 2þ and [SiO 4 ] 4À , and C 3 P mainly exists in the form of 3Ca 2þ and 2[PO 4 ] 3À . [46] Among them, the radii of [SiO 4 ] 4À and [PO 4 ] 3À are similar, which are 2.79 and 2.76 Å, respectively, and the crystal structures of them both tetrahedral, which makes a part of Si in tetrahedral structure can be replaced by P, [46,47] resulting in changes in its coordination structure.…”