Document Type : Original Research Paper
Authors
1 Shahrood university of technology
2 Shahrood University of Technology
Abstract
This research investigates the process of cerium extraction from tailings that have been separated from iron using a magnetic drum separator, through both acid leaching and solvent extraction methods. Initially, the mineralogical characteristics of the samples were analysed using microscopic studies. The main minerals identified were feldspar, garnet, calcite, gypsum, amphibole, and secondary minerals such as chlorite, quartz, and apatite. The metallic minerals were included pyrite, chalcopyrite, magnetite, and hematite. The sample was taken from the tailing’s damps, then it was crushed to a particle size of less than 800 microns. The sample was then placed in a stirred tank along with water, fed into a spiral separator, and subsequently into a shaking table. The analysis results showed that the cerium grade increased from 320 ppm in the feed to 1364 ppm. In the leaching experiments, the influence of various parameters including temperature, acid concentration, type of acid, leaching time, and particle size on cerium leaching recovery rate was evaluated. The results indicated that temperature and acid concentration had the greatest impact on the leaching rate of cerium. In this stage, 95% of cerium was dissolved. Optimization tests for leaching conditions showed that the best conditions for cerium leaching were using hydrochloric acid at a 1:3 concentration with water (concentration of hydrochloric acid became 9 Molar), at a temperature of 90°C and a leaching time of 4 hours. In the subsequent phase, an optimization experiment was conducted with the same parameters. Under these conditions, 96.5% of cerium was dissolved. Then, the solvent extraction process was examined using organic solvents, di(2-ethylhexyl) phosphoric acid and tributyl phosphate. The results showed that the highest cerium extraction rate (81%) was achieved when di(2-ethylhexyl) phosphoric acid was used, considering parameters such as pH 3, organic-to-aqueous phase ratio of 1:1, 20-minute extraction time, 25°C temperature, and stirring speed of 300 rpm. Finally, the results of this research contribute to the optimization of the cerium extraction process and provide suggestions for improving the efficiency of this process.
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