Effect of Sulfuric Acid Baking and Caustic Digestion on Enhancing the Recovery of Rare Earth Elements from a Refractory Ore
| Autor: | Ji Hye Kim, Sugyeong Lee, Heechan Cho, Kyeong Woo Chung, Jinan Jeong, Chul-Joo Kim, Ho-Sung Yoon, Rina Kim |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Goethite
lcsh:QE351-399.2 0211 other engineering and technologies Oxide 02 engineering and technology 010501 environmental sciences caustic digestion 01 natural sciences water leaching Apatite acid leaching chemistry.chemical_compound sulfuric acid baking Chemical decomposition 021102 mining & metallurgy 0105 earth and related environmental sciences lcsh:Mineralogy Geology Sulfuric acid Geotechnical Engineering and Engineering Geology REE chemistry visual_art Monazite visual_art.visual_art_medium Phosphate minerals Leaching (metallurgy) Nuclear chemistry |
| Zdroj: | Minerals, Vol 10, Iss 532, p 532 (2020) Minerals Volume 10 Issue 6 |
| Popis: | To improve the recovery of rare earth elements (REEs) from a refractory ore, this study investigated two different chemical decomposition methods, namely sulfuric acid baking and caustic digestion, with their respective leaching processes. The studied lateritic ore contained goethite (FeOOH) as a major constituent with REEs scattered around and forming submicron grains of phosphate minerals, such as apatite and monazite. Therefore, despite the substantially high content of REEs (3.4% total rare earth oxide), the normal acidic leaching efficiency of REEs reached only 60&ndash 70%. By introducing sulfuric acid baking and caustic digestion, the REE-leaching efficiency was significantly improved. After sulfuric acid baking at 2.0 acid/solid ratio and 200 ° C for 2 h, the leaching efficiency reached 97&ndash 100% in the subsequent water-leaching. When the ore was digested with a solid/liquid ratio of 100 g/L in a 30 wt% NaOH solution at 115 ° C and 300 rpm for 3 h, the REE-leaching efficiency of 99&ndash 100% was attained at 80 ° C using a 3.0 M HCl solution. The correlation between the REE and the Fe-leaching was determined. The improvements in REE-leaching in both methods were mostly attributed to the mineral phase and crystallinity changes of Fe-bearing minerals due to the ore pretreatments. Such findings were also supported by X-ray diffraction and scanning electron microscopy analyses. |
| Databáze: | OpenAIRE |
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