Separation of niobium and tantalum - a literature survey

During recent years increased interest has been shown in the metal niobium. Because niobium has a high melting point (4376° F) and a low neutron cross-section, the Atomic Energy Commission has encouraged research on new methods of winning the metal from its ores with the ultimate hope of finding a process which would yield niobium metal at a reasonable price. The two areas of endeavor in which·the principal difficulties in finding such an economic process occur are the separation of tantalum from the niobium and the conversion of purified niobium salts to the metal. This report, then, was written to consolidate the more important information available in the literature on one of these troublesome areas, that of the separation of niobium and tantalum. It is to be noted, however, that all the references available in the literature on niobium-tantalum separation are not included in this report, but only those which appear to have the most usefulness for future endeavors on this problem

Effect of phosphate rock particle size on recovery of uranium from superphosphate

The tremendous domestic reserves of phosphate rock together with the large annual production of normal superphosphate from phosphate rock have made the recovery of the small amounts of uranium (0.01 to 0.02 percent) in phosphate rock during the production of superphosphate an important problem. At current superphosphate production rates there exists a uranium potential of approximately 1000 tons per year

Growth of gadolinium single crystals

Single crystals have become vitally important to many areas of research in metallurgy, engineering, physics and chemistry. With the introduction of theories about dislocations and their movement during plastic deformation of metals came a need for single crystals to test these theories. The fact that theoretical yield strengths are almost 1000 times higher than those normally observed needs to be explained to satisfy the curiosity of the metallurgist. The explanation may also have very practical applications. It is interesting to note that whiskers, metallic single crystals in tiny hair-like shape, do have strengths approaching the theoretical. Dr. Halden (13), manager of ceramics research at Stanford Research Institute, reports that techniques are being developed to use this strength in composites and self-bonded structures

Equilibrium distribution studies of dysprosium nitrate-erbium nitrate-nitric acid-tributyl phosphate systems

\u27!be equilibrium distribution of dysprosium nitrate, erbium nitrate, and nitric acid between water and tributyl phosphate was studied in this research. Separate equilibrium data were obtained for the distribution of dysprosium nitrate-nitric acid, erbium nitrate-nitric acid, and dysprosium nitrate-erbium nitrate-nitric acid mixtures. The equilibrium data were obtained by making single stage extractions from aqueous feed solutions using commercial grade tributyl phosphate. Equilibrium distribution of solutes was determined by analysis of each phase from the single stage extractions

A polyethylene box-type mixer-settler extractor

The design features of a small multistage mixer-settler extractor are described. The polyethylene construction permits the use of corrosive systems such as those containing hydrofluoric acid. The design permits precise interface control in each settler. Complete cost data are given

Extraction equipment and sampling technique used in semi-continuous silver-uranium extraction studies

Liquid-liquid aqueous extraction methods for reprocessing metallic fuels have two main disadvantages. First, the process involves many steps such as dissolution in acid; extraction, conversion to a salt, and reduction to the metallic state. Secondly, relatively large volumes of radioactive solutions are obtained. This paper describes small scale, semi-continuous extraction runs for extracting irradiated neodymium from a molten uranium-neodymium alloy using droplets of molten silver at 1250° and 1290°C. Two different silver drop sizes and f\u27low .rates were used. The graphite extractor, silver metering device, and the extract sampling equipment are described. The experimental extraction data obtained are presented. These data were correlated reasonably well with equations developed for multistage batch extractions. The actual neodymium concentrations obtained were compared with equilibrium data to determine extraction efficiencies for the various runs . Extraction efficiencies of 15% to 35% were found, with higher efficiencies resulting when large sized drops were used. In these runs, a considerable amount of neodymium was apparently removed by carbide formation with the container wall prior to the extraction with silver

A Report on the Seminar on Demand for Farm Products

This report includes papers presented and discussed at a seminar on demand for farm products, The seminar was sponsored by the Center for Agricultural Adjustment of the Division of Agriculture, Iowa State College, The seminar met for two hours per week for three months during the spring quarter. The seminar was organized to include about 60 members formally designated by the committee. These seminar members, as well as a formal discussant for each topic, evaluated the presentation at each session.https://lib.dr.iastate.edu/card_reports/1001/thumbnail.jp

Equilibrium distribution studies of dysprosium nitrate-erbium nitrate-nitric acid-tributyl phosphate systems

'!be equilibrium distribution of dysprosium nitrate, erbium nitrate, and nitric acid between water and tributyl phosphate was studied in this research. Separate equilibrium data were obtained for the distribution of dysprosium nitrate-nitric acid, erbium nitrate-nitric acid, and dysprosium nitrate-erbium nitrate-nitric acid mixtures. The equilibrium data were obtained by making single stage extractions from aqueous feed solutions using commercial grade tributyl phosphate. Equilibrium distribution of solutes was determined by analysis of each phase from the single stage extractions.</p