G. V. Korpusov

Use of Extraction Generator for Preparing a 99mTc Radiopharmaceutical

Data are reported on the use of extraction generator for preparing high-purity 99mTc from 99Mo, and the quality of the solution of 99mTc is studied. The radiolysis products of the extractant, methyl ethyl ketone (MEK), are examined; the major products are MEK dimers, and their content under operating conditions does not exceed 0.005%. A high degree of removal of both inorganic and organic impurities from the 99mTc eluate obtained from the extraction generator (Radium Institute) is achieved. This ensures a high quality of radiopharmaceuticals prepared from this 99mTc solution. The 99mTc solution prepared with the extraction generator surpasses in quality the similar solution prepared with the sorption generator. When a centrifugal extractor is used for separating 99Mo and 99mTc, the concentration of MEK in the solution of 99mTc does not exceed 0.04 mg ml-1.

Production of High-Purity 90Y on Specially Developed Centrifugal Semicounterflow Extractors

The developed process for producing 90Y is based on semicountercurrent extraction separation with phase inversion on two series-connected blocks of centrifugal extractors. The main advantage of the suggested process over the known procedures is the practically unlimited output capacity of the installation: from trace amounts to several tens of curie in cycle; the possible limitations are only imposed by the chemical or radiation resistance of the materials and chemicals used. Production of 90Y takes from 30 to 60 min. The warranted degree of 90Y separation from the parent 90Sr (with respect to activity) is 10-9% by the day of calibration.

Scintillators Based on Ytterbium Chloride Adducts with Neutral Organophosphorus Extractants for Detecting Solar Neutrino for LENS (Low-Energy Neutrino Spectroscopy) Experiment

The main features of extraction of ytterbium chloride with dibutyl butylphosphonate (DBBP) and triisoamylphosphine oxide (TIAPO) were studied. The effects of temperature, DBBP and TIAPO concentrations in 1,2,4-trimethylbenzene (TMB), and concentrations of salting-out agents LiCl and NH4Cl and mineral acid (HCl) on the ytterbium distribution coefficient were determined. The isotherms of extraction of HCl and YbCl3 with 50% DBBP and TIAPO in TMB were obtained. The composition of the extractable complexes of ytterbium chloride with DBBP and TIAPO (S), YbCl3·3S, was determined by saturation and dilution methods. The saturation of 50% solutions of DBBP and TIAPO in TMB with ytterbium chloride was modeled. Two samples of scintillators with ytterbium concentration of 90 g l-1 were prepared, and their physical parameters were measured. The stability of sample properties was tested for 18 months.

Extraction of Mineral Acids with Neutral Organophosphorus Extractants

Extraction of HNO3, HCl, H2SO4, H3PO4, H3AsO4, HF, and H2C2O4 with triisoamyl phosphate (TiAP), diisooctyl methylphosphonate (DiOMP), isoamyldialkyl(C7-C9)phosphine oxide (DRPO), and cyclohexyldialkyl(C7-C9)phosphine oxide (DRPO-1Ts) was studied, and the extraction isotherms were obtained. The solvation numbers of certain acids and extractants were determined by dilution and saturation methods. Purification of wet-process phosphoric acid to remove arsenic was studied. Distribution of Cu, Zn, Ni, Co, Fe, and Mn microamounts in the oxalic acid-neutral organophosphorus compound (NOPC) extraction systems was measured, and the feasibility of purification of oxalic acid to remove these metals to a 10-7% content was demonstrated.

Extraction of Sc from various media with triisoamyl phosphate: 2. Extraction of Sc from aqueous perchloric and hydrochloric acid solutions

The extraction of Sc from aqueous perchloric and hydrochloric acid solutions with triisoamyl phosphate (TIAP) was studied. The stoichiometry of the extractable complexes (ScA3 · 3TIAP, A = ClO4/− and Cl−) was determined by the saturation and dilution technique. The isotherms of extraction of Sc from aqueous HClO4 and HCl solutions were obtained. The extraction of impurity metals (Zn, Fe, Mo, Zr, Th, REE) was studied over wide HClO4 and HCl concentration ranges.

Application of a semicountercurrent extraction method to waste solution treatment

General data and methods for calculations of the principal parameters of semicountercurrent extraction processes are presented. Examples of solving practical problems, based on application of the semicountercurrent extraction method to treatment of waste solutions containing various valuable components, are given. Deep purification of concentrated zinc chloride solutions to remove iron impurity with the aim of utilization of fluxing solutions was carried out. The process was performed in two semicountercurrent steps filled with VIK-II extractant in the form of zinc soap, through which the initial solution containing 250 g l−1 ZnCl2 and 0.25 g l−1 FeCl3 was passed (βFe/Zn ≥ 1500). The 100-fold amount of the solution relative to the working volume of the extractor was passed. The Fe concentration in the purified solution did not exceed 0.0025 g l−1 (<10−5%). A scheme of treatment of electrolytic chromic acid solution to remove iron was developed. Technical-grade HDEHP was used as extractant (βFe/Cr > 200). The process was performed in one semicountercurrent step filled with a solution containing 250 g l−1 chromic acid, 8.4 g l−1 Cr(III), and 13 g l−1 Fe(III), through which the extractant was passed in a volume equal to 0.66 of the initial aqueous solution volume. The Fe recovery was 98.5%. With Wo = Va, the Fe recovery was as high as 99.9%. A minor fraction of Cr (<8%) coextracted with Fe can be returned to the process.

Extraction of Scandium from Various Media with Triisoamyl Phosphate: 3. Development of Extractive Refining of Scandium

Scandium refining to remove both more and less extractable impurity metals from hydrochloric acid solutions using semicountercurrent and countercurrent extraction with triisoamyl phosphate is modeled. A process for preparing high-purity scandium is developed, involving removal of more and less extractable impurity metals by semicountercurrent extraction and full countercurrent extraction, respectively, at a limited number of separation steps. From the initial scandium oxide (98% purity), 99.97% scandium oxide was prepared (99.995% purity with respect to REEs), i.e., the decontamination factors from both REEs and other impurity metals exceed 100.