Preliminary Study on Leaching Capacity of Rare Earth Elements from Coal Fly Ash by Using Citric Acid Solution

Gilbert Winoto; Panut Mulyono; Suyanti Suyanti; Agus Prasetya

doi:10.22146/ijc.99763

Preliminary Study on Leaching Capacity of Rare Earth Elements from Coal Fly Ash by Using Citric Acid Solution

https://doi.org/10.22146/ijc.99763

Gilbert Winoto⁽¹⁾, Panut Mulyono⁽²⁾, Suyanti Suyanti⁽³⁾, Agus Prasetya^(4*)

(1) Sustainable Mineral Processing Research Group, Department of Chemical Engineering, Faculty of Engineering, Universitas Gadjah Mada, Jl. Grafika No. 2, Yogyakarta 55281, Indonesia
(2) Sustainable Mineral Processing Research Group, Department of Chemical Engineering, Faculty of Engineering, Universitas Gadjah Mada, Jl. Grafika No. 2, Yogyakarta 55281, Indonesia
(3) Research Center of Mining Technology, National Research and Innovation Agency (BRIN), Jl. Ir. Sutami Km. 15, Tanjung Bintang, Lampung Selatan 35361, Indonesia
(4) Sustainable Mineral Processing Research Group, Department of Chemical Engineering, Faculty of Engineering, Universitas Gadjah Mada, Jl. Grafika No. 2, Yogyakarta 55281, Indonesia
(*) Corresponding Author

Abstract

Rare earth elements (REEs) are chemical elements in the III B and lanthanide groups on the chemical periodic table. Extracting REEs from secondary resources (such as coal fly ash) could be environmentally friendlier than extracting REEs from primary resources. Coal fly ash was chosen because of its attractive REE availability and to minimize the pollution problem created by coal fly ash dumping. Citric acid is used as the leaching agent because of its biodegradability, relatively safe vis-à-vis mineral acid commonly used in the REE leaching, and its non-damaging nature to coal fly ash’s properties as construction material. The leaching experiment was conducted at temperature variations of 30, 50, and 85 °C, with liquid-solid ratio (L/S) of 5, 10, and 15 mL/g in 50 mL of 0.01 mol/L citric acid solution. The leaching experiments were conducted in a water bath shaker. It was found that increasing L/S and temperature mainly contributed to increasing cerium leaching capacity.

Keywords

rare earth elements; citric acid; coal fly ash; leaching; leaching capacity

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DOI: https://doi.org/10.22146/ijc.99763