Ein neues Verfahren zur Trennung der seltenen Erden

Solvent Extraction of Inorganic Species.

“…However, Blaustein and Bryder (37) showed that no ionizable protons accompany the cerium into the ether, so that a directly solvated species such as Ce (ether) 2(N03)4 is the main form of cerium in the organic phase. Some extraction of trivalent lanthanide nitrates by ether has been found, and this has been suggested a considerable time ago as a basis for their separation (95,96). The extraction of neptunium (317) and of uranium, plutonium and various fission products by hexone from nitric acid and calcium nitrate solutions (336) follows the same pattern of behavior.…”

“…Since the anion attached to the ammonium cation may be exchanged for others, or for complex metal anions, these solvents are often called liquid anion exchangers, resembling the resin exchangers in many of their properties. An example is the extraction of uranyl sulfate by triisooctylamine (TIOA) from sulfuric acid forming (fOc3-NH)4U02(S04)2 (96). Quaternary amines extract by a similar mechanism, but are effective also in nonacid solutions.…”

The The Separation of Thorium and Rare Earth Salts by Solvent Extraction.

“…The literature dealing with the solvent fractionation of thorium and rare earths is quite meager. Fischer et al (2) report briefly on the distribution of rare earth halides between water and such organic solvents as alcohols, ketones, and ethers. Selwood and Appleton (5) present preliminary data on the solubility of a variety of rare earth salts in a large number of organic solvents.…”

Separation Factor

“…It does not involve an analysis of the initial material and is independent mathematically of the original ratio, the presence of other elements, the extent to which a separation process has taken place, or the units of measurement employed. The term is not new, as it has been used to evaluate liquid-liquid extraction methods for the separation of rare earths (1,10,17,22). In extractions it is simply the ratio of distribution coefficients for the two elements involved.…”