A Review of the Occurrence and Promising Recovery Methods of Rare Earth Elements from Coal and Coal By-Products

Zhang, Wencai; Rezaee, Mohammad Ahangarzadeh; Bhagavatula, Abhijit; Li, Yonggai; Groppo, J.G.; Honaker, R.Q.

doi:10.1080/19392699.2015.1033097

Cited by 171 publications

(94 citation statements)

References 107 publications

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“…This is consistent with previous studies showing REE phosphate minerals in coals and coal ashes. 18,23,28,57,58 The stark contrast between YPO 4 -like points (e.g. App-FA3 Map 4) and those resembling the bulk ts (App-FA3 Map 6) highlights the importance of scale when considering Y speciation.…”

Section: Bulk and Micro-scale Yttrium Speciationmentioning

confidence: 99%

“…western U.S.) coals. 7,[16][17][18] However, the mass of acid-extractable REE is oen similar for eastern and western U.S. coal ashes due to the high leachability of REE in Powder River Basin coal ashes. 7,19,20 Appalachian-and Illinois Basinderived ashes require more aggressive methods to decompose the aluminosilicate glasses (such as alkaline extractions) for effective leaching of the REE into solution.…”

Section: Introductionmentioning

confidence: 99%

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Differences in bulk and microscale yttrium speciation in coal combustion fly ash

Taggart

Rivera

Levard

et al. 2018

Environ. Sci.: Processes Impacts

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Section: Bulk and Micro-scale Yttrium Speciationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Differences in bulk and microscale yttrium speciation in coal combustion fly ash

Taggart

Rivera

Levard

et al. 2018

Environ. Sci.: Processes Impacts

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“…The concern about the REE supply challengehas led to increasing interest and research in the recovery of REE from end-of-life products such as permanent REE magnets, nickel metalhydride batteries and lamp phosphors [5] and from secondarysourcessuch as coal and coal mining and combustion by-products [6,7].…”

Section: Introductionmentioning

confidence: 99%

“…The worldwide average total REY(lanthanides and yttrium) concentrations are 68.5 ppm and 404 ppm for coal and coal ash, respectively [7,8]. Recent studies showed that the beneficial recovery of REE from coal requires a minimum rare earth oxide (REO) concentrationof 800-900 ppm in the coal ash [6,[9][10][11]. Based on this datum, Zhang et al [6] further estimated the cut-off grade of REE in coal which is 115-130 ppm on the whole coal basis and 677-762 ppm on the ash basis.…”

Section: Introductionmentioning

confidence: 99%

Enrichment of rare earth elements from coal and coal by-products by physical separations

Lin

Howard

Roth

et al. 2017

Fuel

159

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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 shalesamples, 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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“…The recovery of rare earth elements from coal, through the use of permeable reactive barrier material as evaluated in the present study, can be obtained through solvent extraction, electrowinning, magnetic and electrostatic separation, flotation or precipitation 72 . This aspect can be an opportunity that adds value to the PRB, which should be studied in the future.…”

Section: Resultsmentioning

confidence: 99%

Kraft pulp mill dregs and grits as permeable reactive barrier for removal of copper and sulfate in acid mine drainage

Farage

Quina

Gando-Ferreira

et al. 2020

Sci Rep

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Mining is an essential human activity, but results in several environmental impacts, notably the contamination of ground and surface water through the presence of toxic substances such as metals and sulfates in mine drainage. permeable reactive barriers (pRB) have been applied to remediate this environmental impact, but the high costs associated with the maintenance of this system are still a challenge. the main objective of this study was to evaluate the use of kraft pulp mill alkaline residues, known as dregs and grits, as material for pRB, and to determine their capacity for retaining copper and sulfate. the work was carried out in laboratory adsorption kinetics assays, batch assays and column tests. tests for elemental characterization, point of zero charge, acid neutralization capacity, total porosity, bulk density and moisture of the dregs and grits were conducted. the results showed high retention of Cu due to a chemical precipitation mechanism, notably for dregs (99%) at 5 min in adsorption kinetics. The grits presented similar results after 180 min for the same assay. Sulfate retention was effective at pH below 5, with an efficiency of 79% and 89% for dregs and grits, respectively. Dregs presented the best results for acid drainage remediation, notably with a solid:liquid (S:L) ratio of 1:10.Acid mine drainage (AMD) is caused by the oxidation of sulfur-bearing materials in the presence of oxygen and water, resulting in sulfate and metals solubilization and forming acidic solutions 1-4 . Active and inactive mining activities for metals, such as copper, lead, zinc, gold, silver and uranium, provoke potential degradation of the environment by the presence of different contaminants, particularly due to metals and sulfates in acid drainage 5 . Indeed, the acid drainage formation is an important environmental aspect of mining practices. The sulfate concentrations may reach 2,400 to 20,800 mg/L 6,7 , well above the limit of 250 mg/L established by the World Health Organization 8 . It might cause damage not only to human health but also to the environment, and depreciation of structures and equipment 2,9 , resulting in high costs for control and management by the mining companies 2,10 . Copper concentration may be in the range from 77 to 615 mg/L, with higher values in the Cu mines 1,11 . Other metals such as Al, Mn, Fe, Mg, and Zn are also commonly found in AMD in these mines 10,12 .AMD remediation can be actively accomplished off-site with the pumping of the contamination plume to a treatment plant, or passively on-site with the use of permeable reactive barriers (PRB), with lower installation and maintenance costs. It can be carried out with the flow directed to the system, by the Funnel model, or the grid-type, by the installation of a perpendicular barrier to the contamination plume 13,14 . The PRB was first proposed in Canada in the 1990s 13,15 , with different materials used as adsorbent media, from single barriers with only one material to composites of different materials, or multiple sequential barrier...

show abstract

A Review of the Occurrence and Promising Recovery Methods of Rare Earth Elements from Coal and Coal By-Products

Cited by 171 publications

References 107 publications

Differences in bulk and microscale yttrium speciation in coal combustion fly ash

Differences in bulk and microscale yttrium speciation in coal combustion fly ash

Enrichment of rare earth elements from coal and coal by-products by physical separations

Kraft pulp mill dregs and grits as permeable reactive barrier for removal of copper and sulfate in acid mine drainage

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