Homogeneous Precipitation of Lanthanide Oxalates

Abstract

Oxalic acid is an important separation agent in the technology of lanthanides, actinides, and transition metals. Thanks to the low solubility of the oxalate salts, the metal ions can be easily precipitated into crystalline material, which is a convenient precursor for oxide preparation. However, it is difficult to obtain oxalate monocrystals due to the fast precipitation. We have developed a synthetic route for homogeneous precipitation of oxalates based on the thermal decomposition of oxamic acid. This work primarily concerns lanthanide oxalates; however, since no information was found about oxamic acid, a brief characterization was included. The precipitation method was tested on selected elements (Ce, Pr, Gd, Er, and Yb), for which the kinetics was determined at 100 °C. Several scoping tests at 90 °C or using different starting concentrations were performed on Ce and Gd. The reaction products were studied by means of solid-state analysis with focus on the structure and morphology. Well-developed microcrystals were successfully synthesized with the largest size for gadolinium oxalate.

Processing, Phase Stability, and Conductivity of Multication-Doped Ceria

“…A small shift in the v CO band to a higher wavenumber is observed with increased doping concentration. This is in line with previously published results that showed smaller dopants lead to a shift in the spectrum to higher wavenumbers [18,19]. Additionally, a peak around 980 cm −1 is observed for all doped samples, which is not observed in the individual oxalates.…”

“…As seen, the a and c lattice parameters shrink while b and β stay relatively constant, and a reduction in volume is observed. This is consistent with previous work on lanthanide oxalates that showed a decrease in the a and c parameters with an increase in atomic number through gadolinium for the lanthanides and only a slight change in b and β [18]. The low doping concentrations used here prevent a noticeable trend from being observed for the b and β parameters.…”

Penggunaan Agen Pengendap terhadap Pengendapan Lantanum dan Neodimium

“…Hal ini karena asam oksalat secara umum memiliki afinitas yang sangat baik dengan LTJ pada umumnya [11]. Oksalat merupakan precursor yang harganya murah tetapi berkualitas tinggi untuk bahan-bahan dengan sifat menarik, seperti bahan bakar nuklir, kerangka logam-organik, oksigen konduktor, atau magnet molecular [12].…”

Complex Oxide Nanoparticle Synthesis: Where to Begin to Do It Right?

“…After dissolving the nitrates in water, they were added to a mixture of dissolved oxalic acid in water to precipitate oxalates. The five elements selected (Ce, Pr, Nd, Sm, and Gd) belong to the lanthanide group and all oxalates form in the same structure as decahydrates with space group P2 1 /c [34,35]. Alemayehu et al recently showed that a cerium-gadolinium oxalate could be formed to produce a single phase, homogeneous oxalate [36].…”