Chemical extraction of rare earth elements from coal ash

Peiravi, Meisam; Ackah, Louis Akainya; Guru, Rashmiranjan Behera Raghunath Satpathy Rajesh Ku; Mohanty, Manoj Kumar; Liu, J.; Xu, Bing; Zhu, Xiaobo; Chen, L.

doi:10.19150/mmp.7856

Cited by 43 publications

(38 citation statements)

References 6 publications

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“…Several studies prepared coal ash samples by combusting coals in muffle furnaces, which were used to simulate fly ash and bottom ash produced from pulverized coal-fired boilers [97,103]. Relatively high leaching recoveries were achieved from artificially prepared coal ashes.…”

Section: Acid Leaching Of Rees From Coal Combustion Ashesmentioning

confidence: 99%

A Comprehensive Review of Rare Earth Elements Recovery from Coal-Related Materials

et al. 2020

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Many studies have been published in recent years focusing on the recovery of rare earth elements (REEs) from coal-related materials, including coal, coal refuse, coal mine drainage, and coal combustion byproducts particularly fly ash. The scientific basis and technology development have been supported by coal geologists and extractive metallurgists, and through these efforts, the concept has progressed from feasibility assessment to pilot-scale production over the last five years. Physical beneficiation, acid leaching, ion-exchange leaching, bio-leaching, thermal treatment, alkali treatment, solvent extraction, and other recovery technologies have been evaluated with varying degrees of success depending on the feedstock properties. In general, physical beneficiation can be a suitable low-cost option for preliminary upgrading; however, most studies showed exceedingly low recovery values unless ultrafine grinding was first performed. This finding is largely attributed to the combination of small RE-bearing mineral particle size and complex REE mineralogy in coal-based resources. Alternatively, direct chemical extraction by acid was able to produce moderate recovery values, and the inclusion of leaching additives, alkaline pretreatment, and/or thermal pretreatment considerably improved the process performance. The studies reviewed in this article revealed two major pilot plants where these processes have been successfully deployed along with suitable solution purification technologies to continuously produce high-grade mixed rare earth products (as high as +95%) from coal-based resources. This article presents a systematic review of the recovery methods, testing outcomes, and separation mechanisms that are involved in REE extraction from coal-related materials. The most recent findings regarding the modes of occurrence of REEs in coal-related materials are also included.

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Section: Acid Leaching Of Rees From Coal Combustion Ashesmentioning

confidence: 99%

A Comprehensive Review of Rare Earth Elements Recovery from Coal-Related Materials

et al. 2020

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“…Many research organizations are currently evaluating processes to recover rare earths from coal combustion wastes [43][44][45]. Several techniques for extraction and separation of individual REEs from waste coal ash have been summarized including physical [46] and chemical processes [47,48]. These processes generally start with the dissolution of rare earths using acid as the leaching agent, followed by separation of unwanted minerals from the leachate by filtration, and precipitation through solvent extraction, then recovery of REEs/REOs by hydro metallurgy.…”

Section: Introductionmentioning

confidence: 99%

Leaching Characteristics of Low Concentration Rare Earth Elements in Korean (Samcheok) CFBC Bottom Ash Samples

et al. 2019

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Coal-derived power comprises over 39% of the world’s power production. Therefore, a mass volume of coal combustion byproducts are generated and shifted the extra burden onto the economy and environment. Circulating fluidized bed combustion (CFBC) has been found to be a clean and ultimate technology for Korea’s coal-fired power plants to have effective power generation from low-grade imported coal with reduced emissions. Efforts have been made to broaden the utilization of CFBC coal ash, and to promote sustainable development of CFBC technology. Investigations provided numerous evidences for coal ash to be a potential deposit for rare earths reclamation. However, the basic characteristics and the methods of rare earth mining from the CFBC bottom ash lack detailed understanding and are poorly reported. This study highlighted an insight of the CBFC bottom ash with respect to REEs concentration. Moreover, agents were tested as a means for leaching REEs from Samcheok CFBC bottom ash. The leaching tests were performed in relation to variations in concentration, time and temperature. The results were applied to identify suitable processes to leach REEs from the ash and clarify the potential valuation of CFBC bottom ash. The leaching conditions attained by ANOVA analysis for hydrochloric concentration, temperature, and time of 2 mol L−1, 80 °C, and 12 h, were found to provide a maximum extraction of yttrium, neodymium and dysprosium of 62.1%, 55.5% and 65.2%, respectively.

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“…The initial enrichment process takes an advantage of a gravitational method, using devices such as a jig, a spiral separator, a cone concentrator, a concentration table or a hydrocyclone. The obtained concentrate undergoes further processes, such as: flotation, leaching, magnetic-electrostatic separation or the use of concentrated acid solution and extraction with concentrated sodium hydroxide [4,6,15,17,20,21,23]. The final stage of the work aimed at recovering or obtaining the feed with a significant concentration of rare earth elements (from the selected material with prospective sufficient REE content) in the gravitational beneficiation process.…”

Section: Concept Of Rare Earth Elements Recoverymentioning

confidence: 99%

Determination of Rare Earth Elements Content in Hard Coal Type 31.1

Baron

2020

Management Systems in Production Engineering

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The aim of the article is to present the results of laboratory analyses determining the content of rare earth elements (REE) in hard coal type 31.1. Coal was extracted directly from the mining excavation located in the Upper Silesian Coal Basin. Mass spectrometry tests with ionization in inductively coupled plasma (ICP-MS), were aimed at the quantitative analysis of the share of REE in coal, taking into account the economic aspects of recovery of these elements. Fine ground hard coal samples and ashes obtained after coal burning were assessed for the rare earth elements concentration. Results of the rare earth elements concentration (lanthanum and cerium) in hard coal are similar in the values obtained in previous tests. The current analyses present higher concentration of europium or neodymium. The article also contains the concept of possible future research work, consisting in the recovery of rare earth elements using, among others, a classifying hydrocyclone.

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Chemical extraction of rare earth elements from coal ash

Cited by 43 publications

References 6 publications

A Comprehensive Review of Rare Earth Elements Recovery from Coal-Related Materials

A Comprehensive Review of Rare Earth Elements Recovery from Coal-Related Materials

Leaching Characteristics of Low Concentration Rare Earth Elements in Korean (Samcheok) CFBC Bottom Ash Samples

Determination of Rare Earth Elements Content in Hard Coal Type 31.1

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