Subsequent separation and selective extraction of thorium (IV), iron (III), zirconium (IV) and cerium (III) from aqueous sulfate medium

Abstract

Regarding to their presence as an important constituent in some ores such as monazite, this work aims for selective solvent extraction of thorium (IV), zirconium (IV), iron (III) and cerium (III) from aqueous sulfate medium using different basic and acidic extractants. To elucidate the extractability of these elements, different effective parameters were studied such as contact time, pH value, extractant concentration and the diluents type. In a single element system, Th (IV) was extracted by the primary amines (octylamine and tert.octylamine) and the acidic extractnts [di-(2-ethylhexyl) phosphoric acid (D2EHPA) and (bis(2,4,4-trimethyl pentyl) phosphinic acid (Cyanex 272))]. Moreover, secondary amine (N-methylaniline) is effective for Fe (III) extraction while, the primary amines are suitable for Zr (IV) extraction. Ce (III) can be extracted with the primary amines and D2EHPA. In a mixed elements system, Th (IV) was extracted firstly with Cyanex 272 (65 %) at pH 1 followed by the extraction of Fe (III) with N-methylaniline (95 %), then Zr (IV) was precipitated at pH 2.5 (84 %) while Ce (III) remains in the final aqueous phase.

Oksidasi Serium Berdasarkan Agen Pengoksidasi

“…Dengan pH berbeda dari 1,5 sampai 7, waktu berbeda dari 0-180 menit, dan voltase berbeda dari 4,5 -20 V. Hasil oksidasi langsung menunjukkan bahwa pada penambahan langsung hidrogen peroksida ke Ce(III) hanya bertindak sebagai oksidan, mengubah Ce(III) menjadi Ce(IV) dalam larutan tanpa pembentukan gugus OHseperti Persamaan (10), sedangkan dengan oksidasi elektrokimia, pada Persamaan (11) menunjukkan jalur reduksi empat elektron di mana O2 sepenuhnya direduksi menjadi ion hidroksida (OH -) dan Persamaan ( 12) menunjukkan jalur dua elektron di mana O2 direduksi menjadi ion OHdan H2O2. Oksidasi langsung menghasilkan recovery Ce sebesar 2% pada pH 1,5 dan 50% pada pH 3, sedangkan recovery oksidasi elektrokimia: 67% pada pH 1,25 [24] Bao et al [25] melakukan penelitian dari sampel rare earth polishing powder wastes (REPPWs) yang mengandung komposisi limbah kimia, yang terutama mengandung Ce dan La, bersama dengan pengotor tertentu LTJ-karbonat dilarutkan menggunakan asam nitrat, oksidasi Ce(III) menjadi Ce(IV) dan pemisahan Ce(IV) dilakukan dengan menambahkan campuran hidrogen peroksida dan amonium hidroksida. pH dikontrol (pH=5,5-6) selama percobaan dengan penambahan larutan amonium hidroksida secara manual.…”

Purification of Carrier-Free 47Sc of Biomedical Interest: Selective Separation Study from natCa(n,γ)

“…Several factors influence the extraction of metal ions using organic extractants; for example, the impact on mass transfer, solubility, diluents, and sometimes even participation of the diluent in the extraction process itself can play a role due to their aggregation in the organic phase [34]. In this respect, kerosene, chloroform, and benzene were examined as diluents for Cyanex 272 to elucidate the extraction efficiency of 47 Sc and 47 Ca at a 1:1 phase ratio, pH 1.8 (0.015 M HCl), extraction time of 30 min, and 25 ± 1 • C. Based on the obtained data presented in Figure 4, the extraction efficiency of 47 Sc is extremely similar for kerosene and chloroform (E = 89.5%); however, there was a decrease in the extraction of 47 Sc when benzene was used as a diluent (E = 79%).…”

Electrochemical oxidation of terbium(III) in aqueous media: influence of supporting electrolyte on oxidation potential and stability

“…However, a change in oxidation state leads to significant changes in chemical properties. This offers the opportunity to develop new separation processes of neighboring lanthanides [6][7][8][9][10][11]. The availability of other valence states can therefore be advantageous in industrial processes such as reprocessing of spent nuclear fuel, purification of medical radiolanthanides or recovery of lanthanides from ores.…”