Leaching of REY from Non-magnetic Coal Fly Ash with Acetic Acid

Abstract

The escalating demand of REY in various industrial applications becomes an important issue nowadays. REY has prominent evidence to improve material properties such as high electropositive and good conductivity. In addition REY can be classified as one of renewable and clean energy resources. Due to the increasing demand of REY, exploration of alternative sources such as red mud, spent catalyst, and coal fly ash has been conducted. Coal fly ash is one of the promising alternative sources of REY in regarding to the low radioactive material concentration. The conventional method to recover REY from coal fly ash using inorganic acids produces harmful by-product to the environment. In this research, two steps experimental methods were conducted. The first step was silicate digestion which was performed using sodium hydroxide 8 M in which REY is concentrated, with solid to liquid ratio of 1:4 and temperature of 90°C for 120 minutes. The second step was leaching the REY using citric acid. The variables studied were pH, temperature and solid to liquid ratio. The optimum condition was at the temperature of 90°C, pH 1.7 and solid to liquid ratio (15%) for each element. The maximum recovery for each elements are 77.33% Lanthanum (La), 83.47 % Cerium (Ce), 88.78% Dysprosium (Dy) and 55% Neodymium(Nd). In addition, temperature does not have any significant efect at pH 3.8.

A Product Diffusion Model for the Extraction of Cerium and Yttrium from Magnetic Coal Fly Ash Using Citric Acid Solution

“…Magnetic fly ash from the Tanjung Awar-Awar power plant mainly consists of SiO2, Fe2O3, and Al2O3 with fewer CaO, MgO, and others (Handoyo, 2019). The concentration of Fe2O3 in the magnetic fraction is much greater than in non-magnetic and raw fly ash, which only contain 5.58% and 9.04%, respectively (Manurung et al, 2020;Rosita et al, 2020b). It also has less SiO2 and Al2O3 concentration (Prihutami, 2020).…”

“…Acid leaching is the most common method to extract rare earth elements from fly ash. Not only inorganic acids like H2SO4 and HCl, some researchers have also recovered rare earth elements by employing organic acids like acetic and citric acid (Manurung et al, 2020;Prihutami et al, 2020;Rosita et al, 2020a;Wen et al, 2020). Many have used citric acid as its utilization gives an excellent performance in extracting rare earth elements, prevents mineral acid leakage, and averts the release of toxic gasses generated by inorganic acid (Tang et al, 2016;Gergoric et al, 2018).…”