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Lin, Ronghong

Publications and source records attributed to Lin, Ronghong.

At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Leaching of lanthanide and yttrium from a Central Appalachian coal and the ashes obtained at 550–950 °C

Here in this work, we investigated leaching of lanthanide and yttrium (REY) from a Central Appalachian coal and its ashes obtained at 550–950 °C with the main purpose of understanding the impact of ashing temperature on REY leachability in water, ammonium sulfate, and hydrochloric acid. It is found that the coal contains a negligible amount of water-soluble REY, less than 1% ion-exchangeable REY, and about 28% of HCl-soluble REY. Ashing leads to dramatic changes in REY leachability in both ammonium sulfate and hydrochloric acid solutions, which is believed to be related to transformation and redistribution of organically-associated REY in coal during the ashing process. Ashing temperature significantly affects REY leaching from coal ashes; higher ashing temperature results in lower REY leachability in both solutions. Clay minerals may play a significant role in changing the leachability of REY after ashing. In addition, the results also suggest that the organic matter in the coal is relatively enriched in heavy REY.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2018

Application of sequential extraction and hydrothermal treatment for characterization and enrichment of rare earth elements from coal fly ash

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. Furthermore 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.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2018

Evaluation of trace elements in U.S. coals using the USGS COALQUAL database version 3.0. Part II: Non-REY critical elements

Coal is a potential source of some valuable elements. In this work, concentrations of 25 critical elements in U.S. coals were evaluated using the COALQUAL Database Version 3.0 aiming to identify best coal sources for potential recovery of critical element. A method was proposed to calculate the mean concentrations of critical elements in U.S. coals, including Li (11.5 ppm), Be (1.9 ppm), Ti (721 ppm), V (21.6 ppm), Mn (50.8 ppm), Co (4.5 ppm), Ga (5.1 ppm), Ge (7.2p pm), Se (2.4 ppm), Zr (30.4 ppm), Nb (3.3 ppm), Sn (1.8 ppm), Sb (1.0 ppm), Ba (266 ppm), Hf (0.77 ppm), and Ta (0.19 ppm).Based on the calculated mean concentrations, a rough estimate indicates that U.S. coals contain a large amount of critical elements that are enough to meet U.S. demands for many years to come, if these elements can be commercially extracted. By comparing with the suggested cut-off grades, we found that 5.8% of the coal samples have Ga concentrations higher than the suggested cut-off grade. The percentages of promising coal samples (higher than cut-off grades) of other elements are below 3%. Results further indicate that despite some variations among elements, bituminous coals from the Appalachian region are likely to have high concentrations of Li, Ga, Be, Se, and Sb which make them a potential source of these critical elements. Bituminous coals from the Interior Coal Province, both Eastern and Western, were found to have relatively high probabilities of having high Ge concentrations. Furthermore very limited coal samples were found from mixed regions to have V and Zr concentrations higher than the corresponding suggested cut-off grades.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2018

Evaluation of trace elements in U.S. coals using the USGS COALQUAL database version 3.0. Part I: Rare earth elements and yttrium (REY)

Coal is a potential source of valuable elements such as rare earth elements and yttrium (REY). In this work, REY concentrations in U.S. domestic coals were evaluated using data from the USGS COALQUAL Database Version 3.0. The database contains a total of 7657 non-weathered, full-bed coal samples. The number of samples containing REY data points varies among elements. Assessment of data quality indicates that some of the REY data are semi-quantitative and should be used with caution. Different analytical instruments and methods with varying accuracies and precisions are thought to be the main sources of errors. Inclusion of qualified data also accounts for the sawtooth pattern of the UCC-normalized REY distribution. A new set of Q factor values was thus proposed to adjust qualified data. Consequently, mean concentrations of REY in U.S. coals were obtained with a total REY concentration of 65.5 ppm on a moisture-free whole coal basis. Further evaluation of REY in 5378 selected coal samples indicates that about 9–13% of the samples fall into the combined category of promising and highly promising coals for REY, according to the classification of Dai et al. (2017). Taking sampling bias into consideration, we further found that bituminous coal, particularly from the central Appalachian region, has the highest probability of being a source for beneficial recovery of REY. More specifically, bituminous coal from eastern Kentucky is likely to be the best option. Lastly, we conclude that U.S. domestic coal is a promising, alternative source for beneficial recovery of REY to meet the U.S. REY demand for economic growth.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2017

Permeability and Mineral Composition Evolution of Primary Seal and Reservoir Rocks in Geologic Carbon Storage Conditions

It has been reported that deep saline aquifers represent the largest geologic CO 2 storage resource. To better predict containment effectiveness and long-term reservoir behavior of these formations, it is important to understand the potential geochemically induced changes to the porosity and permeability of both the primary sealing formation and CO 2 storage formation rocks. To investigate these potential changes, an experimental study to probe the geochemical interactions of CO 2 /brine/rock system under geologic CO 2 storage conditions was conducted in a static reaction system. Marine shale (primary sealing formation) and Lower Tuscaloosa sandstone (CO 2 storage formation) core samples taken from the Plant Daniel CO 2 storage test site (Jackson County, Mississippi) were exposed to CO 2 -saturated brine in a batch reactor at relevant geologic storage conditions (85°C and 23.8 MPa CO 2 pressure) for 6 months. X-ray diffraction, scanning electron microscopy, computed tomography, and brine chemistry analyses were performed before and after the exposure. Permeability measurements from the marine shale and sandstone core samples before and after CO 2 /brine exposure indicated a significant effective permeability change. Sealing marine shale permeability increased following exposure while the permeability of the sandstone from the storage formation was observed to decrease. Analysis results of the primary sealing formation sample (marine shale) at the Plant Daniel CO 2 storage test site have not been reported before. In conclusion, the permeability decrease of the Lower Tuscaloosa sandstone sample reported in this study verifies the results reported in a previous study. These results have implications for the integrity of the primary seal in a CO 2 storage setting.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2017

A mechanistic modeling framework for gas-phase adsorption kinetics and fixed-bed transport

Adsorption is a complex physicochemical process involving interparticle transport, interphase mass-transfer, intraparticle diffusion, and surface reactions. Although the exact description of the adsorption process will inevitably vary from system to system, it will always be governed by those primary mechanisms. Thus, by devising a model framework that can inherently include those mechanisms, it would be possible to create a modeling platform on which many different adsorption problems could be solved numerically. In order to accomplish this task, a generalized 1-D conservation law model was created to include the necessary mechanisms of adsorption on several different geometrical domains. Specific model applications for adsorption were developed under that framework and validated using experimental data available in literature or obtained in this work. This modeling platform makes it easier to model various adsorption problems and develop new adsorption models because of the common treatment of the mathematics governing the physical processes.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗