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At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

ATOMIC Simulations and Experimental Data for CaCO3 Mixtures

This data consists of simulations and experimental measurements of laser-induced breakdown spectroscopy (LIBS). The simulations are produced by ATOMIC, a general purpose plasma modeling and kinetics code that has been designed to compute emission (or absorption) spectra from plasmas [1] and are used to develop a statistical characterization of matrix effects. Our overall suite of simulations includes contains several sets of simulations: training and validation sets of simulations for three and four element mixtures of calcium, carbon, oxygen, and nitrogen (included to account for atmosphere) along with simulations of the individual elements. The 4-element simulations include the mixture of all four elements mentioned and for each of the four individual elements. The 3-element simulations include output for the mixture of calcium, carbon, oxygen and for these three individual elements. The training data were produced using a 600-run design, shown in Figure 1, that varies input parameters temperature (T), electron density (Ne), and proportion of the elements calcium, carbon, oxygen, and nitrogen (Ca; C; O; N) for the 4 element output. The 3-element output includes all parameters except for the proportion of nitrogen. The element proportions (all the variables but T and Ne) sum to one and are unused in the single-element simulations. The validation data was produced with a 80-run design shown in Figure 2. The training and validation simulation outputs for the 4-element simulations for the mixture and for the single element calcium are shown as sample simulations in Figures 3 and 4 respectively. The simulations produce spectra over a range of 190nm - 950nm that roughly mimics the range collected by the SciAps Z-300 LIBS instrument that was used for the experimental data. The measured spectra for a CaCO3 (which may include contribution from Earth's atmosphere) in the experiment is shown in in Figure 5. All files are kept in directories whose names indicate the elemental composition (CaCO3, Ca, C, O, or N), number of elements (3 or 4), and purpose (training, which is not labeled in the file name, or validation) with file names numbered to indicate the line in the design files used to produce the simulation. The designs are provided as text files with names indicating their purpose. The experimental data is provided as a CSV file. [1] J Colgan, EJ Judge, DP Kilcrease, and JE Barefield II. Ab-initio modeling of an iron laser-induced plasma: Comparison between theoretical and experimental atomic emission spectra. Spectrochimica Acta Part B: Atomic Spectroscopy, 97:65{73}, 2014.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Materials Data on CaCO3 by Materials Project

CaCO3 crystallizes in the orthorhombic Pmmn space group. The structure is three-dimensional. Ca2+ is bonded in a 12-coordinate geometry to twelve O2- atoms. There are a spread of Ca–O bond distances ranging from 2.47–3.03 Å. C4+ is bonded in a trigonal planar geometry to three O2- atoms. There is two shorter (1.29 Å) and one longer (1.31 Å) C–O bond length. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to four equivalent Ca2+ and one C4+ atom. In the second O2- site, O2- is bonded in a distorted single-bond geometry to four equivalent Ca2+ and one C4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CaCO3 by Materials Project

CaCO3 is Calcite structured and crystallizes in the trigonal R-3c space group. The structure is three-dimensional. Ca2+ is bonded to six equivalent O2- atoms to form corner-sharing CaO6 octahedra. The corner-sharing octahedral tilt angles are 62°. All Ca–O bond lengths are 2.39 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 trigonal planar geometry to two equivalent Ca2+ and one C4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CaCO3 by Materials Project

CaCO3 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Ca2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Ca–O bond distances ranging from 2.43–2.69 Å. C4+ is bonded in a trigonal planar geometry to three O2- atoms. There is one shorter (1.29 Å) and two longer (1.30 Å) C–O bond length. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to three equivalent Ca2+ and one C4+ atom. In the second O2- site, O2- is bonded in a distorted single-bond geometry to three equivalent Ca2+ and one C4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CaCO3 by Materials Project

CaCO3 is Calcite-like structured and crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Ca2+ is bonded to six O2- atoms to form corner-sharing CaO6 octahedra. The corner-sharing octahedra tilt angles range from 61–63°. There are a spread of Ca–O bond distances ranging from 2.38–2.40 Å. C4+ is bonded in a trigonal planar geometry to three O2- atoms. All C–O bond lengths are 1.30 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Ca2+ and one C4+ atom. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Ca2+ and one C4+ atom. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Ca2+ and one C4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CaCO3 by Materials Project

CaCO3 is Calcite-like structured and crystallizes in the monoclinic C2 space group. The structure is three-dimensional. there are two inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded to six O2- atoms to form corner-sharing CaO6 octahedra. The corner-sharing octahedra tilt angles range from 60–62°. There are three shorter (2.38 Å) and three longer (2.39 Å) Ca–O bond lengths. In the second Ca2+ site, Ca2+ is bonded to six O2- atoms to form distorted corner-sharing CaO6 pentagonal pyramids. The corner-sharing octahedra tilt angles range from 59–63°. There are a spread of Ca–O bond distances ranging from 2.39–2.41 Å. There are two inequivalent C4+ sites. In the first C4+ site, C4+ is bonded in a trigonal planar geometry to three O2- atoms. All C–O bond lengths are 1.30 Å. In the second C4+ site, C4+ is bonded in a trigonal planar geometry to three O2- atoms. All C–O bond lengths are 1.30 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to two Ca2+ and one C4+ atom. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to two Ca2+ and one C4+ atom. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to two Ca2+ and one C4+ atom. In the fourth O2- site, O2- is bonded in a trigonal planar geometry to two equivalent Ca2+ and one C4+ atom. In the fifth O2- site, O2- is bonded in a trigonal planar geometry to two equivalent Ca2+ and one C4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CaCO3 by Materials Project

CaCO3 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional and consists of four formaldehyde molecules and one CaO2 framework. In the CaO2 framework, Ca2+ is bonded in a distorted square co-planar geometry to four equivalent O2- atoms. There are two shorter (2.43 Å) and two longer (2.44 Å) Ca–O bond lengths. O2- is bonded in a 3-coordinate geometry to two equivalent Ca2+ and one O2- atom. The O–O bond length is 1.47 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CaCO3 by Materials Project

CaCO3 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. Ca2+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Ca–O bond distances ranging from 2.37–2.61 Å. C4+ is bonded in a trigonal planar geometry to three O2- atoms. There is two shorter (1.29 Å) and one longer (1.31 Å) C–O bond length. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to three equivalent Ca2+ and one C4+ atom. In the second O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent Ca2+ and one C4+ atom. In the third O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent Ca2+ and one C4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2023

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.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2026

A mild calcium carbonate treatment improves moisture resistance and mechanical/interfacial properties of jute and hemp fibers

Natural fibers are attractive, sustainable reinforcements, but often exhibit high moisture uptake and weak bonding with polymer matrices. In this study, jute and hemp were treated by immersion in aqueous calcium carbonate (CaCO3) suspensions (10–40?wt.%, 1.5?h, room temperature) and were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), moisture sorption testing, single-fiber tensile testing, and bundle pull-out testing. SEM showed granular CaCO3 deposition on fiber surfaces, with particulates bridging surface voids and microcracks. At 40 wt.% CaCO3, equilibrium moisture uptake decreased to ~5% (hemp) and ~3% (jute), while tensile strength increased to ~904 MPa (hemp) and ~960 MPa (jute). Apparent interfacial shear strength from pull-out testing increased up to ~1.35 MPa (hemp) and ~0.56 MPa (jute). These results indicate that CaCO3 deposition is a mild, scalable surface treatment that improves moisture resistance, fiber tensile strength, and interfacial load transfer relevant to semi-structural composite applications, including interior and secondary automotive components.

Calcium carbonate treatment↗
DOE OSTI2026

Aragonite saturation horizon variability along North Pacific seamounts and implications for deep-sea coral reefs

The 2014 discovery of living deep-sea coral reefs along the Northwest Hawaiian Islands (NWHI) and lower Emperor Seamount Chain (ESC), despite the North Pacific’s shallow aragonite saturation horizon (ASH) and high CaCO3 dissolution rates, underscores the need to understand the local seawater chemistry that allows these reefs to persist. We investigated seawater carbonate chemistry using discrete samples along the NWHI and ESC from two cruises ~1 year apart (08/26/21 – 09/26/21, 09/09/22 – 10/24/22). Across the two cruises, ASH depth difference ranged from 15 to 77 m. Since the Pacific ASH shoals by 1–2 m yr?¹, this long-term trend cannot explain the magnitude of ASH change observed between cruises. Temperature-salinity plots similarly indicate no major shifts in intermediate water masses that could account for these changes. Instead, ASH depth variability was primarily governed by localized biogeochemical processes, namely changes in intermediate water respiration and CaCO3 dissolution. Indicators for dissolution (TA*) and respiration (AOU) suggest changes in ASH depth were driven by changes in dissolution at the northern- and southern-most sites, whereas respiration exerted stronger control at central sites. Combining 2021 and 2022 data with data from 2014 – 2019 (excluding 2018) revealed high interannual ASH variability, by as much as >200 m at one site. Deep-sea coral reefs across the NWHI and ESC currently reside close to the ASH depth and likely experience seasonal and interannual shifts between under- and supersaturation. As ocean acidification progresses however, persistent exposure to undersaturated seawater could further threaten these critical deep-sea ecosystems.

coral reefs↗
DOE OSTI2021

CO2 Capture Strategies via Mineralization with Industrial Waste Brines

Large coal-fired power plants (>500 MW) account for 30% of global CO2 emissions, and long-term management of this CO2 to is urgently needed mitigate global temperature increases. Sequestration of CO2 within stable mineral carbonates (e.g., CaCO3) represents an attractive emission reduction strategy because it offers a leakage-free alternative to geological storage of CO2 in an environmentally friendly form. We have previously described a mineralization process in which divalent cations are sourced from various waste streams (e.g., produced water and brackish water) and alkalinity is induced via regenerable ion-exchange materials (Bustillos et. al. Frontiers in Energy Research. 2020, 8, 352). In our process, aqueous carbonate-bearing streams with pH > 8 are produced by contacting fresh water and carbon dioxide with various ion-exchange materials (e.g., Na form zeolites or ion exchange resins). These streams are mixed with produced water containing varying concentrations (~0.01 – 1.0 M) of Ca2+ leading to the precipitation of solid calcium carbonate (PCC). This process has the advantages of using regenerable solids in a simple and continuous process to increase the pH of water by ion exchange instead of relying on the consumption of costly and unsustainable sources of alkalinity (e.g., sodium hydroxide). While once-through column experiments showed the above benefits, the same were yet to established in a steady-state process with recycle streams. In this work, we set up a process simulation to quantify the energy requirements and CO2 emissions associated with the process and seek optimal produced water compositions and CO2 concentrations (5 – 20 vol%). The process simulation was set up in ASPEN Plus using eRNTL as the thermodynamic property method and sequential modular strategy. Ion exchange alkaline solution was simulated using sodium hydroxide and validated against the experimental data obtained from once-through kinetic experiments. Nanofiltration and reverse osmosis membrane steps were also implemented for the separation of divalent cations and production of fresh water and a regeneration stream following mineralization. Sensitivity analysis was carried out using a range of produced water compositions (0.01 – 1.0 M Ca2+, 0.001 – 0.15 M Mg2+, 0.5 – 3.5 M Na+ and 0.0004 – 0.002 M Fe2+) according to the United States Geological Survey (USGS) database. Calcium carbonate yields increased with increasing CO2 concentrations and were maximized using produced water compositions with larger Ca2+ concentrations. Maximum calcium carbonate yields produced at 5 vol%, 12 vol% and 20 vol% CO2 were 2.3 mmol/L, 5.5 mmol/L, and 9.3 mmol/L, respectively, with the formation of brucite (a magnesium hydroxide phase, Mg(OH)2) and goethite (an iron hydroxide phase, FeOOH) as the primary contaminant phases (99% calcite, 0.6% brucite, 0.4% goethite), which agree with phases detected by XRD experimentally. These results indicate high purity calcium carbonate can be precipitated using industrial waste streams. Consequentially, energy consumption and net CO2 emissions were minimized where precipitated calcium carbonate was maximized for all produced water compositions and CO2 concentrations. Minimum energy consumptions were 0.21 kWh/ton CO2 processed, with 98% of the energy input required coming from the membrane filtration steps. Produced water compositions with large Na+ concentrations (> 0.5 M) were effective at reducing energy consumptions due to faster regeneration time of ion exchange materials. Additionally, calculated net CO2 emissions were negative for the process and ranged from -0.02 kg/ton CO2 to -0.15 kg/ton CO2 processed, indicating a low emission process. We will also present techno-economic assessment showing the economic benefits of the current process as an alternative to the addition of stoichiometric bases to induce alkalinity for the precipitation of CaCO3.

Simonetti, Dante↗
DOE OSTI2022

Calcium carbonate minerals as scavengers of metals and radionuclides: Their role in natural attenuation and remediation

Calcium carbonates (CaCO3) are ubiquitous naturally occurring minerals in subsurface sediments. Calcium carbonate coatings are common in many terrestrial environments and are known to coat a variety of reactive mineral surfaces in soils and sediments, altering their reactivity and chemical behavior. For these reasons, contaminant interactions with CaCO3 minerals are relevant to contaminant fate and transport. Significant advancements have been made recently toward identifying relevant contaminant (e.g., U, I, and Cr) attenuation mechanisms, which may also serve as a basis for in situ remediation strategies. Hence, the objective of this review paper is to 1) describe the state-of-knowledge of calcium carbonate minerals as universal scavengers of metals and radionuclides; 2) provide a state of the science of how calcium carbonate interactions affect contaminant fate and transport in the subsurface environmental systems; and 2) provide insights on the use of calcium carbonate natural attenuation mechanisms and their application to the remediation of complex sites. Knowledge gaps are also identified that, when closed, can advance the use of carbonate minerals for in situ remedy applications.

Qafoku, Nikolla↗
DOE OSTI2025

Characterizing Hazardous Gases from NMC811 Materials and Coin Cells with TGA and Tube-Furnace FTIR-MS Evolved-Gas-Analysis

Abuse testing is useful for informing the risks of different battery chemistries but has been limited to larger formats. This paper conducted thermal abuse tests at the smaller coin cell level to determine its relevance in specifying vent gas flammability and toxicity. A nitrogen purge carried the evolved gases into a parallel Fourier-transform infrared spectrometer (FTIR) and a mass spectrometer (MS) downstream of the tube furnace. The experimental system was validated by comparing evolved gas data for single components between the tube furnace system and a thermogravimetric analysis (TGA) instrument. Multiple samples were tested during validation, including CaCO3, electrolyte, delithiated NMC 811 cathode, and lithiated graphite anode. Temperature-resolved gas evolution of HF, CO2, CO, H2, and hydrocarbons from isolated components helped to characterize the emission sources. A previously unreported H2 generation mechanism was found. It was shown that the reduced NMC cathode acts as a catalyst to crack polypropylene-decomposed hydrocarbons into H2 at around 450 degrees C. It was also shown, while studying LiPF6 thermal decomposition, that using the tube furnace with a coin cell casing as the sample holder has some advantages for evolved-gas analysis of environmentally sensitive samples relative to testing in TGA instruments. After validation with single components, a fully charged NMC 811 coin cell was failed in the tube furnace. The measured evolved gases were found to be a combination of the species measured from the single component tests. H2 formation related to the reduced cathode was found to have greater abundance than H2 formed from the anode. Hydrogen fluoride emission factors and diethyl carbonate conversion emission factors assist in understanding the gaseous hazards for larger format cells.

25 ENERGY STORAGE↗
DOE OSTI2021

Produced water softening using high-pH catholyte from brine electrolysis: reducing chemical transportation and environmental footprints

This study evaluates the benefits of using brine electrolysis for generating caustic soda (NaOH) and free chlorine for on-site produced water (PWs 1 ) treatment. A two-compartment electrochemical cell was shown to generate NaOH solutions (pH > 12, faradic efficiency 93%) and chlorine (faradic efficiency 32%) from a NaCl brine solution at a current density of 10 mA/cm2. The catholyte was used for softening field-collected PWs. The degree of Mg removal depends mostly on the catholyte/PW mixture pH with pH 11 achieving >90% removal. Ca removal is poor (<10%) due to low bicarbonate alkalinity in the PWs. Soda ash alone at a dose equivalent to the total hardness of the PWs helps CaCO3 precipitation and Ca removal (>90%). The combined treatment of the catholyte and a reduced quantity of soda ash achieves better or comparable Ca removal compared to the full stoichiometric amounts of soda ash alone. Ba and Sr removal patterns closely follow those of Ca, suggesting co-precipitation of these cations as the primary removal mechanism. Organic removal is negligible during chemical softening; however, activated carbon filtration achieves >90% of total organic carbon (TOC) removal in all PWs. A treatment scheme is proposed for field generation of caustic soda and chlorine from PW. The economic analysis demonstrates the significant cost-effectiveness of the approach compared to purchasing the NaOH.

42 ENGINEERING↗
DOE OSTI2021

Ab Initio Molecular Dynamics Simulations of Amorphous Calcium Carbonate: Interpretation of Pair Distribution Function and X-Ray Absorption Spectroscopy Data

The structure and transformation of hydrous amorphous calcium carbonate (ACC) are key to understanding biomineralization pathways and their relationship with the properties of the resulting material. Quantitative interpretation of scattering experiments aimed at elucidating the structure of ACC is challenging, due to the amorphous nature of this material, and, therefore, requires models for the structure and the scattering physics. Here, we generate physically realistic ensembles of hydrated ACC structures and their vibrational disorder from ab initio molecular dynamics (AIMD) simulations with an emphasis on enabling the consistent interpretation of the finer details of three complementary structural probes: neutron and x-ray pair distribution experiments and x-ray absorption spectroscopy (XAS). In each case, we simulate the signal directly in reciprocal space and then manipulate it into the real-space pair distribution function (PDF) or spectrum using the same procedures for the experimental and theoretical data. Good agreement with experiment was obtained across the three techniques with the simulations accounting well for all features in the spectra. Remaining small discrepancies pointed to differences between real samples and the idealized simulated systems such as deviations from the nominal CaCO3·nH2O stoichiometry. Additionally, the simulations offered a more accurate description of the local coordination environment of calcium than previous shell-by-shell fits to spectra of synthetic ACC and classical molecular dynamics simulations. This work demonstrates that AIMD is a powerful approach for extracting detailed structural information from neutron PDF, x-ray PDF, and XAS of amorphous carbonate phases.

Prange, Micah P.↗