Exploring a promising technology for the extraction of gallium from coal fly ash

Huang, Jing; Wang, Yingbin; Zhou, Guanxuan; Gu, Yu

doi:10.1080/19392699.2020.1755662

Cited by 7 publications

(5 citation statements)

References 31 publications

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“…Meanwhile, the 5 wt% nitric acid was the blank sample, and the standard samples were provided by the National Center for Standard Substances. Three parallel experiments were performed on each sample to ensure the accuracy of the results [31].…”

Section: (F5) Residualmentioning

confidence: 99%

Experimental Investigation on Gallium and Germanium Migration in Coal Gangue Combustion

Wu,

Zhou,

Zhou

2024

Minerals

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Gallium (Ga) and germanium (Ge) critical elements have a wide range of applications and market value. Extracting critical elements from coal gangue and combustion products can alleviate pressures on primary mining resources. Understanding the transformation behavior of Ga and Ge during coal gangue combustion processes is significant for resource utilization and environmental protection. Coal gangue from Xing’an League, Inner Mongolia, was chosen to explore how combustion temperatures (600 °C to 1000 °C) and particle sizes (50, 80, 10, 140, and 200 mesh) influence Ga and Ge migration during combustion. Techniques such as ICP-MS, XRD, XRF, SEM, TG−DSC, and sequential chemical extraction were employed to analyze the transformation of minerals and to quantify the contents and occurrence forms of Ga and Ge. Smaller gangue particle sizes were associated with higher concentrations of Ga and Ge. Approximately 99.19% of Ga and Ge in coal gangue were found in the residual, organic/sulfide-bound, and metal-oxide-bound modes. High temperatures promoted element volatilization and changed the reactions and interactions between elements and minerals. As combustion temperatures rose from 600 °C to 1000 °C, Ga and Ge contents in the products declined progressively. Under high temperatures, minerals like kaolinite, illite, and pyrite in gangue converted to silicate glass phases, mullite, and hematite. Minerals like kaolinite, calcite, and pyrite melted, leading to increased cohesion and agglomeration in the products. Over 90% of Ga and Ge in the combustion products existed in the residual, organic/sulfide-bound, and metal-oxide-bound forms. Moreover, Ga was enriched in combustion products, with its content exceeding critical extraction levels. The results may provide a useful reference for developing critical elements enrichment, extraction, and separation technologies from coal gangue.

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Section: (F5) Residualmentioning

confidence: 99%

Experimental Investigation on Gallium and Germanium Migration in Coal Gangue Combustion

Wu,

Zhou,

Zhou

2024

Minerals

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“…The majority of gallium coexists with various minerals, the most important of which are bauxite, zinc ore and coal. Because it is uneconomical to extract gallium minerals alone, gallium is currently recovered primarily from secondary resources, such as solid or liquid waste from the Bayer process [6][7][8][9], coal fly ash [10,11], phosphorus dust [12], E-waste [13][14][15] and various tailings [16][17][18]. With the growth in global industries such as power electronics [19][20][21], semiconductors [22][23][24], medicine [25][26][27], aerospace [28,29], and so on, the use of gallium is becoming more and more widespread, and thus the market demand for gallium is expanding.…”

Section: Introductionmentioning

confidence: 99%

Extraction of Gallium from the Brown Corundum Dust with a One-Step Alkaline Leaching Process

Zhang,

Gao,

Hui

et al. 2023

Separations

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Brown corundum dust, which is created during the manufacturing of brown corundum using bauxite as the raw material, is a vital carrier of gallium. To ascertain the presence of the contained gallium, the brown corundum dust was measured and characterized (XRF, XRD, ICP-OES, EPMA, SEM-EDS, etc.). Gallium was extracted from the brown corundum dust using a one-step alkali leaching process, and thermodynamic calculations were utilized to assess the viability of the leaching reactions. The effects of leaching parameters (NaOH solution concentration, leaching time, leaching temperature, solid–liquid ratio and stirring speed) on the recovery of gallium during the leaching process were investigated. A gallium recovery of 96.83% was discovered to be possible with the following parameters: 200 g/L of NaOH, 363 K for the leaching temperature, 60 min for the leaching time, 1:10 g/mL for the solid–liquid ratio, and 850 rpm for the stirring rate. Gallium extraction was negatively impacted by raising the leaching temperature above 363 K and the concentration of NaOH solution above 200 g/L due to the accelerated side reactions between Na+, K+, SiO44− and AlO2−, which led to the precipitation of aluminosilicates that absorbed gallium from the solution. The influences of leaching parameters such as the temperature, NaOH solution concentration, and solid–liquid ratio on the leaching kinetics were examined. It was demonstrated that the leaching process followed the unreacted shrinking core model, that the interfacial diffusion associated with the contacting surface area served as the controlling step, and that the apparent activation energy was 42.83 kJ/mol. It turned out that the final kinetic equation was 1/(1 − α)1/3 − 1 = 4.34 × 104 × (CNaOH)2.12 (L/S)0.43exp[−42835/(RT)] t.

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“…Therefore, at present, gallium is usually recovered and extracted from secondary resources or obtained as a by-product during the aluminum oxide production process [10,11]. Commonly, the secondary resources for extracting gallium include red mud [12,13], fly ash [14,15], electronic waste [16,17], phosphorus flue dust [18,19], and zinc refinery residues [20,21].…”

Section: Introductionmentioning

confidence: 99%

Extraction of Gallium from Brown Corundum Dust by Roasting—Acid Leaching Process

et al. 2023

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Brown corundum dust is a solid waste produced during the preparation of brown corundum with bauxite as the raw material. The dust has a relatively high gallium content; therefore, it is of great value to recover the gallium from this kind of dust. In this paper, a range of analysis and characterization methods, including XRD, XRF, SEM-EDS, and EPMA, were used to determine the occurrence of gallium. It was found that gallium was mainly present in the potassium-rich phase, wrapped by amorphous silicate and the corundum phase. Roasting activation followed by an acid leaching process was proposed to extract gallium from brown corundum dust. An investigation was carried out on the effects of roasting temperature, roasting time, and additive dosage on the recovery of gallium and the evolution of the phase composition of the dust. The results show that the roasting activation of sodium carbonate was better than that of calcium oxide. After roasting at 1073 K for 40 min with a sodium carbonate dosage of 0.5 (mass ratio of sodium carbonate to dust), the phase composition changed completely to mainly consist of sodium silicate, sodium aluminosilicate, and potassium aluminosilicate. In that case, around 93% of Ga could be recovered from the roasted dust through H2SO4 (4.6 mol/L) leaching for 90 min. The leaching process was described well by the kinetic equation of k3t = 1/(1 − α)1/3 − 1, with an apparent activation energy of 16.81 kJ/mol, suggesting that the leaching rate was limited by the transfer of leaching agent across the contacting interface of the dust particles.

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Exploring a promising technology for the extraction of gallium from coal fly ash

Cited by 7 publications

References 31 publications

Experimental Investigation on Gallium and Germanium Migration in Coal Gangue Combustion

Experimental Investigation on Gallium and Germanium Migration in Coal Gangue Combustion

Extraction of Gallium from the Brown Corundum Dust with a One-Step Alkaline Leaching Process

Extraction of Gallium from Brown Corundum Dust by Roasting—Acid Leaching Process

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