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Materials Data on FeCO3 by Materials Project
FeCO3 is Calcite structured and crystallizes in the trigonal R-3c space group. The structure is three-dimensional. Fe2+ is bonded to six equivalent O2- atoms to form corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles are 60°. All Fe–O bond lengths are 2.17 Å. C4+ is bonded in a trigonal planar geometry to three equivalent O2- atoms. All C–O bond lengths are 1.30 Å. O2- is bonded in a distorted trigonal planar geometry to two equivalent Fe2+ and one C4+ atom.
Materials Data on FeCo3 by Materials Project
FeCo3 is Uranium Silicide structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Fe is bonded to twelve equivalent Co atoms to form FeCo12 cuboctahedra that share corners with twelve equivalent FeCo12 cuboctahedra, edges with twenty-four equivalent CoFe4Co8 cuboctahedra, faces with six equivalent FeCo12 cuboctahedra, and faces with twelve equivalent CoFe4Co8 cuboctahedra. All Fe–Co bond lengths are 2.50 Å. Co is bonded to four equivalent Fe and eight equivalent Co atoms to form CoFe4Co8 cuboctahedra that share corners with twelve equivalent CoFe4Co8 cuboctahedra, edges with eight equivalent FeCo12 cuboctahedra, edges with sixteen equivalent CoFe4Co8 cuboctahedra, faces with four equivalent FeCo12 cuboctahedra, and faces with fourteen equivalent CoFe4Co8 cuboctahedra. All Co–Co bond lengths are 2.50 Å.
Materials Data on FeCo3 by Materials Project
FeCo3 is alpha La-derived structured and crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. Fe is bonded to four equivalent Fe and eight equivalent Co atoms to form FeFe4Co8 cuboctahedra that share corners with four equivalent FeFe4Co8 cuboctahedra, corners with eight equivalent CoCo12 cuboctahedra, edges with twenty-four CoFe4Co8 cuboctahedra, faces with eight equivalent FeFe4Co8 cuboctahedra, and faces with ten CoFe4Co8 cuboctahedra. All Fe–Fe bond lengths are 2.47 Å. All Fe–Co bond lengths are 2.50 Å. There are two inequivalent Co sites. In the first Co site, Co is bonded to four equivalent Fe and eight Co atoms to form CoFe4Co8 cuboctahedra that share corners with twelve equivalent CoFe4Co8 cuboctahedra, edges with eight equivalent FeFe4Co8 cuboctahedra, edges with sixteen CoFe4Co8 cuboctahedra, faces with four equivalent FeFe4Co8 cuboctahedra, and faces with fourteen CoFe4Co8 cuboctahedra. There are four shorter (2.46 Å) and four longer (2.47 Å) Co–Co bond lengths. In the second Co site, Co is bonded to twelve Co atoms to form CoCo12 cuboctahedra that share corners with four equivalent CoCo12 cuboctahedra, corners with eight equivalent FeFe4Co8 cuboctahedra, edges with eight equivalent FeFe4Co8 cuboctahedra, edges with sixteen equivalent CoFe4Co8 cuboctahedra, faces with two equivalent FeFe4Co8 cuboctahedra, and faces with sixteen CoFe4Co8 cuboctahedra. All Co–Co bond lengths are 2.47 Å.
Materials Data on FeCo3(PO4)4 by Materials Project
Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations
Grain boundary widening controls siderite (FeCO3) replacement of limestone (CaCO3)
Abstract The microstructure of minerals and rocks can significantly alter reaction rates. This study focuses on identifying transport paths in low porosity rocks based on the hypothesis that grain boundary widening accelerates reactions in which one mineral is replaced by another (replacement reaction). We conducted a time series of replacement experiments of three limestones (CaCO 3 ) of different microstructures and solid impurity contents using FeCl 2 . Reacted solids were analyzed using chemical imaging, small angle X-ray and neutron scattering and Raman spectroscopy. In high porosity limestones replacement is reaction controlled and complete replacement was observed within 2 days. In low porosity limestones that contain 1–2% dolomite impurities and are dominated by grain boundaries, a reaction rim was observed whose width did not change with reaction time. Siderite (FeCO 3 ) nucleation was observed in all parts of the rock cores indicating the percolation of the solution throughout the complete core. Dolomite impurities were identified to act as nucleation sites leading to growth of crystals that exert force on the CaCO 3 grains. Widening of grain boundaries beyond what is expected based on dissolution and thermal grain expansion was observed in the low porosity marble containing dolomite impurities. This leads to a self-perpetuating cycle of grain boundary widening and reaction acceleration instead of reaction front propagation.
Corrosion of Stainless and Carbon Steel in Aqueous Piperazine for CO2 Capture
Current obstacles that prevent commercial implementation of amine-scrubbing CO2 capture are the high costs. Reducing capital costs by appropriate selection of construction materials, which requires knowledge of material corrosion performance for the process, will improve the economic feasibility of this technology. Corrosion was evaluated in three pilot plant campaigns using aqueous piperazine with the Advanced Stripper (PZAS). 316L stainless steel (SS) experienced higher corrosion than 304 SS and 2205 duplex SS, and the corrosion rate showed strong dependence on the temperature. 304 and 2205 performed well at all locations and should be good construction materials for PZAS. Degraded PZ exacerbated 316L corrosion, and removal of PZ degradation products using a carbon adsorption bed significantly reduced corrosion. Carbon steel (CS) corrosion showed a weak temperature effect because the corrosion was more dependent on the protective siderite film. The protectiveness of the films was related to fluid velocity. Ni-based alloys corroded in PZ, and the rate increased with temperature. Corrosion of C1010 CS and SS (304, 316L, 430) was measured at absorber and water wash conditions on the bench-scale. Corrosion rate decreases with increasing PZ. 8 With more than 0.003 m PZ in solution, CS has acceptable corrosion performance. Corrosion of CS increases with increasing partial pressure of CO2, suggesting loading is another dominant parameter for carbon steel corrosion. Temperature has a less significant effect than PZ concentration and loading. CS corrosion increases with increasing flow velocity at both absorber and water wash conditions. SS had little corrosion at this lower temperature. Performance of siderite (FeCO3) protective films on CS was studied at representative stripper conditions on the bench-scale. Siderite films can deposit on the surface of CS in CO2-loaded PZ solution at temperatures >100 °C and protect CS from corrosion. The protection may fail in degraded PZ. Ethylenediamine (EDA) is one of the major contributors for the loss of film protectiveness or can be the surrogate for the effect of PZ degradation on siderite film protection. A link between protectiveness and the apparent density of siderite films was discovered. The apparent density of siderite films decreases with increasing flow velocity and decreasing CO2 loading, resulting in higher corrosion of CS.