Study On The Interaction And Extraction Mechanism Among Ce（Ⅳ）、F And P During The Process Of Roasting Baotou Rare Earth Ores By Na₂CO₃

Baotou rare earth ores play an important role in the rare earth resoures. Theresearch of the process in the clean hydrometally of Baotou rare earth ores has beenthe important subject that uses the rare earth resources efficiently and protects theenvironment. Inoic liquids（ILs） has remarkable advantages such as high stability,green and property can be designed. Due to the advantages, ILs has been widelyapplied in metal ions separation. In this work, the process of roasting Baotou rareearth ores by Na2CO3and leaching with H₂SO₄, the application of rare earth solventextraction using ILs have been investigated. The details are as follows:1. The high rate of Ce（Ⅳ） oxidation can be obtained by roasting Baotou rare earthores by Na2CO3. The selective extraction of Ce（Ⅳ） can reduce the process cost. Theeffects of roast time, the adding amount of Na2CO3, roast temperature and the addingof reaction promoter based on Na2CO3have been observed in detail. Furthermore, theremove of F、P during the washing process and its effect on the extraction rate of RE、Ce（Ⅳ） and Th have also been studied. The results indicate that the amount of F、P hada great influence on the extraction rate of RE and Ce（Ⅳ）.2. The leaching liquor obtained by roasting Baotou rare earth ores by Na2CO3andthen leaching with H₂SO₄is a complex system containing Ce（Ⅳ）, F, P and S.Extraction of Ce（Ⅳ） in this complex system exists many problems, which largelyrestrict the industrialization of decomposing Baotou rare earth ores by Na2CO3. Tostudy the extraction of Ce（Ⅳ） in H₂SO₄/H₃PO₄system and H₂SO₄/HF system has theimportant meaning. In this work, the leaching liquor including Ce（Ⅳ） and P has beensimulated and investigated. The extraction of Ce（Ⅳ） in H₂SO₄/H₃PO₄system has been investigated systematically using bifunctional ionic liquids [A336][P507],[A336][P204] and [A336][C272] in n-heptane as extractants. The effects of H₂SO₄concentration, extractant concentration and salting-out agent concentration have beeninvestigated in detail. The extraction mechanism of Ce（Ⅳ） in H₂SO₄/H₃PO₄systemhas been obtained. The comparison with other extractants such as Cyanex923、TBPhas also been studied. Thermodynamic functions of the extraction reaction has beencalculated, showing that the extraction is an exothermic process. The separation ofCe（Ⅳ） from RE（Ⅲ） and Th（Ⅳ） has also been investigated. The result indicated thatCe（Ⅳ） can be extracted selectively in this system. CePO4nanoparticles have beenobtained in the process of stripping using H₂O₂in H₂SO₄/H₃PO₄system. XRD、SEMand spectroscopy have been adopted for the characterization of the sample.