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•Enrichment of rare earth elements (REE) from coal and coal by-products.•Particle size, magnetic and density (float-sink) separations were investigated.•Density separation showed the ...highest enrichment of REE.•Elemental analysis suggests that REE are associated with the Al/Si group.•A combination of physical separation methods is recommended for REE enrichment.
Rare earth elements (REE) are of strategic importance because they find numerous applications in various sectors of the global economy. The concern about the REE supply challenge has led to increasing interest and research in the recovery of REE from end-of-life products and secondary sources such as coal and coal by-products. The work reported here was focused on examining the technical feasibility of physical separation techniques for the enrichment of REE from coal and coal by-products. Particle size, magnetic and density separations were performed on coal, coal ash, clay and shale samples. It was found that the samples responded to particle size separation differently. For all ash samples, higher REE concentrations were found in the finer fractions. For the clay and shale samples, however, the REE concentrations decrease as the particle size reduces possibly because RE minerals were not effectively released by grinding. Magnetic separation showed that REE are enriched in non-magnetic fractions for all ash samples. All samples responded similarly to density separation. Among the three methods, density separation showed the highest enrichment of REE. A combination of these methods is recommended. Finally, correlations between elements were demonstrated, which leads to the classification of three groups containing mainly Al/Si, Fe and Ca, respectively. REE are strongly associated with the Al/Si group.
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•Seven-step sequential extraction of coal fly ash (CFA) was performed.•86% of REE in CFA were associated with the glassy phase.•A process was proposed for enrichment of REE from ...CFA.•REE were enriched from 325 mg/kg to 877 mg/kg.
Rare earth elements (REE) play a critical role in the global economy. The concern about the REE supply challenge has stimulated global interest in recovering REE from alternative non-conventional REE sources such as coal fly ash. In this paper, sequential extraction, physical separations and hydrothermal alkaline treatment were explored for characterization and enrichment of REE from coal fly ash. Seven-step sequential extraction of coal fly ash has demonstrated that 86.1% of total REE were associated with the glassy phase of the fly ash, with the remaining REE mainly distributed in the organic and sulfides phase (8.3%), the exchangeable phase (3.7%), and the carbonates phase (1.5%). A process combining physical separations, namely, particle size separation and magnetic separation, and hydrothermal alkaline treatment was proposed for enrichment of REE from coal fly ash. The optimal hydrothermal alkaline treatment condition was determined. It was demonstrated that NaOH concentration, solid-to-liquid ratio, temperature, and reaction duration had significant influence on ash dissolution in NaOH solution. Grinding could also enhance ash dissolution during subsequent hydrothermal alkaline treatment. REE were enriched from coal fly ash from 325 mg/kg to 877 mg/kg via the proposed process under optimal hydrothermal alkaline treatment conditions.
Objective: To determine whether community-level social determinants of health are associated with hypertensive disorders of pregnancy (HDP).
Methods: This is a secondary analysis from the prospective ...Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-To-Be. We evaluated three community-level exposures using home addresses geocoded at the census-tract level: 1) socioeconomic disadvantage by the 2015 Area Deprivation Index (ADI); 2) food insecurity by the USDA Food Access Research Atlas; and 3) less walkability by the EPA National Walkability Score. The outcome was new onset HDP. Poisson regression was used to estimate adjusted relative risks (aRR).
Results: Of 9,062 individuals, 33.6% were in the highest tertile of ADI, 24.5% lived with food insecurity, and 66.3% lived in a less walkable neighborhood. 13.0% were diagnosed with HDP. Individuals living in a community with higher socioeconomic disadvantage, (aRR T2: 1.26; 95% CI: 1.10, 1.44; and T3: 1.19; 95% CI: 1.02, 1.38), food insecurity (aRR: 1.15; 95% CI: 1.02, 1.29), and less walkability (aRR: 1.21; 95 CI: 1.07, 1.36) were at higher risk of developing HDP compared with those who did not.
Conclusions: Community-level social determinants of health, including socioeconomic disadvantage, food insecurity, and low walkability, were associated with increased risk of HDP among nulliparous individuals.
Disclosure
T.Bank: None. W.Grobman: None. J.Wu: None. C.Lynch: None. K.K.Venkatesh: None.
The concentrations of rare earth elements in Alberta, Canada oil sands and six oil sand waste streams were determined using inductively coupled plasma mass spectrometry (ICP–MS). The results indicate ...that the rare earth elements (REEs) are largely concentrated in the tailings solvent recovery unit (TSRU) sample compared to the oil sand itself. The concentration of lanthanide elements is ∼1100 mg/kg (1100 ppm or 0.11 wt %), which represents a >20× increase in the concentration compared to the oil sand itself and a >7× increase compared to the North American Shale Composite (NASC). The process water, which is used to extract the oil from oil sands, and the water fraction associated with the different waste streams had very low concentrations of REEs that were near or below the detection limits of the instrument, with the highest total concentration of REEs in the water fraction being less than 10 μg/L (ppb). Size and density separations were completed, and the REEs and other potentially interesting and valuable metals, such as Ti and Zr, were concentrated in different fractions. These results give insights into the possibility of recovering REEs from waste streams generated from oil sand processing.
Coagulation disorders are rare causes of postpartum hemorrhage. Disturbances in coagulation should be suspected in patients with a family history of coagulopathy, those with a personal history of ...heavy menstrual bleeding, and those with persistent bleeding despite correction of other causes. The coagulopathic conditions discussed include disseminated intravascular coagulation, platelet disorders, and disturbances of coagulation factors. These should not be overlooked in the evaluation of obstetric hemorrhage, as diagnosis and appropriate treatment may prevent severe maternal morbidity and mortality.
We have utilized an environmentally friendly synthesis approach for the accelerated growth of a selective inorganic membrane on a polymeric hollow fiber support for postcombustion carbon capture. ...Specifically, continuous defect-free ZIF-8 thin films were grown and anchored using continuous flow synthesis on the outer surface of porous supports using water as solvent. These membranes demonstrated CO2 permeance of 22 GPU and the highest reported CO2/N2 selectivity of 52 for a continuous flow synthesized ZIF-8 membrane.
Recovering aqueous rare earth elements (REEs) from domestic water sources is one key strategy to diminish the U.S.’s foreign reliance of these precious commodities. Herein, we synthesized an array of ...porous, amine–epoxy monolith and particle REE recovery sorbents from different polyamine, namely tetraethylenepentamine, and diepoxide (E2), triepoxide (E3), and tetra-epoxide (E4) monomer combinations via a polymer-induced phase separation (PIPS) method. The polyamines provided −NH2 (primary amine) plus −NH (secondary amine) REE adsorption sites, which were partially reacted with C–O–C (epoxide) groups at different amine/epoxide ratios to precipitate porous materials that exhibited a wide range of apparent porosities and REE recoveries/affinities. Specifically, polymer particles (ground monoliths) were tested for their recovery of La3+, Nd3+, Eu3+, Dy3+, and Yb3+ (Ln3+) species from ppm-level, model REE solutions (pH ≈ 2.4, 5.5, and 6.4) and a ppb-level, simulated acid mine drainage (AMD) solution (pH ≈ 2.6). Screening the sorbents revealed that E3/TEPA-88 (88% theoretical reaction of −NH2 plus −NH) recovered, overall, the highest percentage of Ln3+ species of all particles from model 100 ppm- and 500 ppm-concentrated REE solutions. Water swelling (monoliths) and ex situ, diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) (ground monoliths/particles) data revealed the high REE uptake by the optimized particles was facilitated by effective distribution of amine and hydroxyl groups within a porous, phase-separated polymer network. In situ DRIFTS results clarified that phase separation, in part, resulted from polymerization of the TEPA-E3 (N-N-diglycidyl-4-glycidyloxyaniline) species in the porogen via C–N bond formation, especially at higher temperatures. Most importantly, the E3/TEPA-88 material cyclically recovered >93% of ppb-level Ln3+ species from AMD solution in a recovery–strip–recovery scheme, highlighting the efficacy of these materials for practical applications.
Reference standard NIST SRM 1633b and FA 345, a fly ash sample from an eastern U.S. coal power plant, were analyzed to determine and quantify the mineralogical association of rare earth elements ...(REE). These analyses were completed using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and a scanning electron microscope, equipped with an energy-dispersive X-ray spectrometer (SEM-EDS). Internal standardization was avoided by quantifying elemental concentrations by normalizing to 100% oxides. Mineral grains containing elevated REE concentrations were found in diverse chemical environments, but were most commonly found in regions where Al and Si were predominant. Dividing the spot analyses into time segments yielded plots that showed the REE content changing over time as individual mineral grains were being ablated. SEM-EDS images of FA 345 confirmed the trends that were found in the LA-ICP-MS results. Small grains of apatite, monazite, or zircon were frequently observed as free mineral grains or embedded in amorphous aluminosilicate glass and were not associated with ferrous particles. This finding is consistent with previous reports that magnetic enrichment may be an effective way of concentrating non-magnetic REE phases. Furthermore, aggressive mechanical and chemical-based separation schemes will be required to separate and recover REE from aluminosilicate glass.
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•Mineral grains containing elevated REE were located within fly ash samples, usually in regions where Al and Si were predominant.•Dividing the LA-ICP-MS spots into time segments yielded plots showing REE content changing over time as individual mineral grains were ablated.•SEM-EDS images confirmed that small free REE mineral grains were frequently observed or embedded in amorphous glass, but not with ferrous particles.•Findings are consistent with previous reports that magnetic enrichment of fly ash may be an effective way of concentrating non-magnetic REE phases.
Inductively coupled plasma‐mass spectrometry after lithium metaborate fusion and digestion was used to measure the rare earth element (REE) mass fractions of several reference materials including ...NIST SRM 1632a, a historical bituminous Pennsylvania seam coal. While most of the REE mass fractions measured in this study were consistent with the published consensus data, the measured mass fraction of thulium for NIST SRM 1632a was consistently lower compared with the published data. Chondrite normalisation of the published consensus data for NIST SRM 1632a produced a positive thulium anomaly (Tm = 1.78), which is inconsistent with a terrestrial source of sediment. Normalisation of REE mass fractions collected in this study produced no significant Tm anomaly (Tm = 0.93), which agrees with the sedimentary depositional environment of coal. Therefore, a revised mass fraction of 0.16 mg kg−1 Tm in NIST SRM 1632a is recommended.
Published consensus data for coal SRM 1632a exhibits a thulium anomaly.
New ICP‐MS mass fraction data for coal SRM 1632a shows no thulium anomaly, consistent with expected REE distribution patterns for coal.
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The supply and price of rare earth elements (REEs) have become a concern to many countries in the world, which has led to renewed interest in exploration and recovery of REEs from ...secondary or waste sources. Potential high REE waste sources that are of particular interest are coal mining, preparation, combustion, and other fossil energy by-products, including those from natural gas production. In this work, we have examined a set of five solid samples from the treatment of produced and flowback water containing elevated concentrations of barium. In order to confirm the correct concentrations of Eu, we studied these materials using sector field inductively coupled plasma mass spectrometry (SF-ICP-MS), which is capable of resolving species of nearly identical masses, including Eu and BaO. While the use of quadrupole inductively coupled plasma mass spectrometry (Q-ICP-MS) for the REE analysis of most geological sample matrices should pose no problem, the presence of large amounts of Ba, as encountered in water treatment solids from natural gas produced and flowback samples may require SF-ICP-MS for accurate determination of all REEs.
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