Extraction of rare earth elements from coal fly ash by alkali fusion–acid leaching: Mechanism analysis

Tang, Mengcheng; Zhou, Changchun; Pan, Jinhe; Cao, Shenggen; Hu, Tingting; Ji, Wanshun; Wen, Zhiping; Nie, Tiancheng

doi:10.1080/19392699.2019.1623206

Cited by 29 publications

(12 citation statements)

References 29 publications

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“…The existence of nano-sized REE-bearing particles in carbon was reported in fly ashes derived from bituminous coals [20,114,115]. Even so, most of the studies show that the REEs in coal combustion ashes are mainly associated with aluminosilicate glass (e.g., [9,15,24,27,96,107,[116][117][118][119]). This association could be the result of the incorporation of the REE-bearing phases, or, less probably, to the REE diffusion into the glass phase [41].…”

Section: Geochemical Associationsmentioning

confidence: 99%

“…Currently, the supply of REEs in Europe is dominated by China, at 98% [5], a total of 8% more than in 2006/2007 [6]. The growing demand rate (3.7-8.6% per year) and their supply risk led to the classification of REEs as "critical" raw materials and has stimulated the search for alternative sources [6][7][8][9][10][11]. Coal, and especially coal combustion ashes, have been pointed out as promising sources of REEs, and many studies have been conducted concerning the REE contents, the modes of occurrence, and the extraction potential [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30].…”

Section: Introductionmentioning

confidence: 99%

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Integrative Study Assessing Space and Time Variations with Emphasis on Rare Earth Element (REE) Distribution and Their Potential on Ashes from Commercial (Colombian) Coal

et al. 2022

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The increasing demand for rare earth elements (REEs), which is associated with their economic importance and the supply risk, has motivated the research for alternative secondary sources of these elements. Coal and coal combustion ash have been pointed out as promising REE raw materials. This research seeks to understand REE fractionation, from feed coals to ashes, considering seasonal variations, and to assess the trends within the ash fractions that can be used for further beneficiation processes. Colombian commercial feed coals, combustion ashes, and their respective fractions were sampled from a Portuguese power plant and were characterized via petrographical, mineralogical, and chemical analyses. The total REE concentrations in the feed coals studied range between 6.97 and 23.15 ppm, while, in the ashes, they vary from 159.9 to 266.6 ppm. Fly ash (FA) from electrostatic precipitator (ESP) presented higher concentrations than the bottom (BA) and economizer (ECO) ashes. Furthermore, REEs and the LREE/HREE ratio increased slightly towards the back rows of the ESP. In the feed coals, the REEs are significantly correlated with ash, and they occur in micrometric phosphate minerals intermixed with clays. In the ashes, the REEs were mostly detected in micrometric particles, with P and Al-Si as the major components. The results from the fractioned samples show that the REEs were enriched in the fine (<25 µm) and nonmagnetic fractions of the ESP FA. A single trial combining sieving and magnetic separation enabled the attainment of a REE recovery of 53%, and a final enrichment factor of 1.25. Coal combustion ashes and their respective size fractions are promising REE raw materials; however, the REE oxide concentrations are below the economical cutoff of 1000 ppm.

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Section: Geochemical Associationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Integrative Study Assessing Space and Time Variations with Emphasis on Rare Earth Element (REE) Distribution and Their Potential on Ashes from Commercial (Colombian) Coal

et al. 2022

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“…At the first stage of processing ash and slag materials, the method of leaching them with mineral acids is traditionally used. Sulfuric or nitric acids are most often used as reagents [6][7][8][9][10][11][12][13][14][15]. In order to increase the concentration of valuable components to recoverable rate, it is necessary to process the waste, considering it in the same quality as conventional mineral raw materials.…”

Section: Introductionmentioning

confidence: 99%

Recovery of valuable components from coal consumption waste

Cherkasova

Tikhomirova

et al. 2021

E3S Web Conf.

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Today, more than 56% of all coal in Russia is mined in Kuzbass. As a result of its burning, about half a million ash and slag waste (ASW) is generated per year. Ash dumps with such waste are constantly dusting; mobile ions of inorganic substances are washed away by precipitation, polluting the environment. Burned coals, being natural sorbents, contain impurities of many valuable elements, including rare-earth and precious metals, while their content in ash increases several times and can reach payable concentrations. Therefore, it is necessary to develop a technology for recovery of valuable components from ash and slag and using the remaining ash mass in construction and fertilizer industries. The efficiency of flotoextraction and chemical concentration methods for recovery of valuable components is assessed in the paper. The composition of the initial ash and slag samples and the resulting products of their processing were analyzed using infrared spectroscopic and optical emission methods.

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“…About 2.5 million tons/year or 10% of ash and slag waste are utilized in the country. 22.5 million tons of waste are annually disposed in ash dumps of coal-fired thermal power plants; 1.5 billion tons being already accumulated [1][2][3][4][5][6][7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Study of the content of rare and rare earth elements in ash and slag waste of the Kemerovo state district power plant

et al. 2021

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In the context of restrictions due to the sanctions imposed, a key factor in the country's development is the development of new Russian high-tech materials and their production technologies. The study of ash and slag waste from the Kemerovo State District Power Plant was carried out in this work using the methods of inductively coupled plasma optical emission spectrometry (ICP-OES) and inductively coupled plasma mass spectrometry (ICP-MS). It has been established that matrix elements make up the predominant share of ash and slag waste. Rare and rare earth elements in terms of their content are classified as trace elements, however, some of them either have commercial values, or are close to it.

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Extraction of rare earth elements from coal fly ash by alkali fusion–acid leaching: Mechanism analysis

Cited by 29 publications

References 29 publications

Integrative Study Assessing Space and Time Variations with Emphasis on Rare Earth Element (REE) Distribution and Their Potential on Ashes from Commercial (Colombian) Coal

Integrative Study Assessing Space and Time Variations with Emphasis on Rare Earth Element (REE) Distribution and Their Potential on Ashes from Commercial (Colombian) Coal

Recovery of valuable components from coal consumption waste

Study of the content of rare and rare earth elements in ash and slag waste of the Kemerovo state district power plant

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