Abstract

Rare earth elements (REEs) are a group of fifteen chemical elements in the periodic table. They are 15 lanthanides besides (scandium and yttrium). These elements are commonly found in the same mineral assemblages because of similar physical and chemical properties. REEs are critical for several high technologically industries such as hybrid cars, batteries, electronics, clean energy (wind turbines). The presence of REEs in Jordanian phosphate waste which currently dumped to the desert may have an economic value since large amount of phosphate rock are used in fertilizers industry annually. REE extraction from phosphate mine waste will not only improve the profitability of phosphate mine but conserve the natural resources. Furthermore, REEs extraction from phosphate tailings and slime will reduce the cost of mining and beneficiation as well as reduces the environmental impact of these effluents. In this work, we digested dried and finely ground phosphate slime and tailings by diluted phosphoric acid and sodium carbonate in specially designed reactor at temperature 72 Co for 3 hours. Then the leachate was filtered and TBP solvent was used to extract REE. Finally phosphoric acid was produced from the raffinate by conventional method i.e. addition of concentrated sulfuric acid. It was found that that Jordanian phosphate have 59.8 ppm TREE (Ce, La, Y, Eu). HREE (Y, Eu ) represents 83% while 17 % are LREE( Ce, La) . A linear relationship was also found between phosphate and REE which may be due to isomorphism of REE- ions with other ions in apatite / Francolite crystal, most likely Ca+2. The results also showed that Slime contain 28% of the phosphate REE while Tailings contain 50 % of REE. Therefore, mixing slime and tailings for REE leaching and extraction may be justified. However, it was found that in high phosphate medium it is better to precipitate REE by oxalic acid instead of TBP solvent. REE recovery was 35% by oxalate precipitation compared to 7 % by TBP extraction.

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/content/papers/10.5339/qfarc.2014.EEPP0152
2014-11-18
2024-03-28
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