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Possibilities for controlling heavy metal sulfides in scale from geothermal brines

Description: Heavy metal sulfides form a substantial part of the scale solids depositing from high-temperature, high-saline geothermal brines. An assessment has been made of the prospects for controlling this deposition by chemical modification of the brine. An outline is given of the types of reactions influencing sulfide precipitation. It is suggested that two factors affecting sulfide solubility and that are amenable to chemical modification of the brine are oxidation state and pH. A partial oxidation process can be used to convert aqueous sulfide species to free sulfur, a process favored by thermodynamics and kinetics. Some oxidizing agents are suggested for this purpose. A discussion is given of the possibilities of precipitating other solid phases after extensive oxidation. It is concluded on the basis of the available data that this possibility exists, but that uncertainties in reaction kinetics, unavailable data, and solution complexity make an exact analysis difficult. The usefulness of a field evaluation of chemical modification processes is indicated. (auth)
Date: January 19, 1976
Creator: Jackson, D. D. & Hill, J. H.
Partner: UNT Libraries Government Documents Department

Bremsstrahlung-Induced K Fluorescence

Description: Bremsstrahlung radiation can be used to excite nearly monoenergetic x rays in secondary targets, which are then used to study the energy response of radiation detectors if the intensity and purity are known. A method is suggested for calculating the spectral intensity of the secondary target radiation, including K-fluorescent x rays, and the bremsstrahlung and characteristic line radiation scattered from the target. Coherent and incoherent scatter are included in the calculation. To test the theory, bremsstrahlung radiation from an x-ray unit operating in the 100- to 300-kV potential range was used to excite K-fluorescent radiation in secondary targets that range in atomic number from 29 to 90. The primary and secondary spectra were measured with NaI, silicon, and germanium detectors. The measured primary spectral intensities were used as input to the secondary spectral intensity calculation. Calculated secondary spectra were within 20 percent agreement with measurement. Optimization of the secondary target intensity and purity is discussed as a function of target thickness, potential, and selective filtration.
Date: September 1, 1976
Creator: Storm, Ellery
Partner: UNT Libraries Government Documents Department

Neutron scattering studies of solid electrolytes

Description: The role which neutron scattering can play in determining the nature of the disorder and the conducting mechanism in the solid electrolytes is discussed. First, some of the general formalism for elastic and inelastic neutron scattering is reviewed, and the quantities which can be measured are pointed out. Then the application of neutron scattering to the studies of three different problems is examined; the anion disorder in the fluorite system, the dynamical behavior in beta-alumina, and the cation diffusion in ..cap alpha..AgI are discussed. 8 figures. (RWR)
Date: January 1, 1976
Creator: Shapiro, S. M.
Partner: UNT Libraries Government Documents Department

Structural and magnetic transitions in BaMnF/sub 4/

Description: Neutron scattering studies have been undertaken to probe the structural and magnetic transitions in BaMnF/sub 4/ occurring at T/sub c/ = 247 +- 0.5K and T/sub N/ approximately 26K respectively. Below T/sub c/ superlattice reflections are observed at incommensurate positions along the (zeta/sup 1///sub 2//sup 1///sub 2/) and (zeta00) directions of the base centered orthorhombic (A2/sub 1/am) Brillouin zone. The new reflections appear at q/sub 1/ = (+-0.392, +-0.5, +-0.5), q/sub 2/ = (+-0.216, 0, 0) and q/sub 3/ = 3(+-0.176, +-0.5, +-0.5) which bear the relationship q/sub 2/ = 2q/sub 1/ and q/sub 3/ = 3q/sub 1/. Above T/sub c/ critical scattering is observed only at the q/sub 1/ positions implying the existence of a primary order parameter with the wave vector Q/sub 1/ and either harmonics or secondary distortions with wave vectors q/sub 2/ and q/sub 3/. Below T/sub N/ magnetic superlattice peaks (q/sub 0//sup M/) were observed characteristic of the antiferromagnetic structure of the isostructural compounds BaNiF/sub 4/ and BaFeF/sub 4/. Two sets of satellite peaks q/sub 1//sup M/ and q/sub 2//sup M/ analogous to the nuclear satellites were also found. The magnon dispersion curves were measured and near neighbor exchange constants determined.
Date: January 1, 1976
Creator: Shapiro, S M; Cowley, R A; Cox, D E; Eibschutz, M & Guggenheim, H J
Partner: UNT Libraries Government Documents Department

Chemical Engineering Division thermochemical studies annual report, July 1975--June 1976. [MgUO/sub 4/; CaUO/sub 4/; BaUO/sub 4/; beta-LiAl]

Description: Standard enthalpies of formation at 298.15 K, ..delta..H/sup 0//sub f/(298 K), are reported for MgUO/sub 4/, CaUO/sub 4/, BaUO/sub 4/, VF/sub 3/, and PrF/sub 3/ based on solution and fluorine bomb calorimetric measurements. High-temperature enthalpy increments have been determined for MgUO/sub 4/ by drop calorimetry. Preliminary work on ..gamma..-UO/sub 3/ and ..beta..-LiAl is described.
Date: January 1, 1976
Creator: O' Hare, P A. G.; Johnson, G K; Ader, M; Hubbard, W N; Fredrickson, D R et al.
Partner: UNT Libraries Government Documents Department

Potentiometric determination of sulfate with EDTA and the cupric-selective electrode

Description: Sulfate was indirectly determined by precipitating sulfate as BaSO/sub 4/ and then dissolving BaSO/sub 4/ in excess ammoniacal EDTA. The excess EDTA was titrated potentiometrically with La/sup 3 +/. A cupric-selective electrode was used to detect the end point. About 10/sup -3/M SO/sub 4//sup 2 -/ was determined in 3M HCl solutions of metal oxides with a relative standard deviation of 3.5 percent and a bias of +4 percent.
Date: November 1, 1976
Creator: Baumann, E. W.
Partner: UNT Libraries Government Documents Department

Structural studies of the BaPb/sub 1-x/Bi/sub x/O/sub 3/ system

Description: Superconductivity has recently been observed in the BaPb/sub 1-x/Bi/sub x/O/sub 3/ system for x between 0.05 and 0.3, the highest transition temperature being around 13/sup 0/K. Structural studies have been carried out at 25/sup 0/C by means of x-ray Guinier techniques and profile refinement of neutron powder data. BaPbO/sub 3/ is orthorhombic, space group Ibmm, and has a distorted perovskite-type structure in which the Pb atoms occupy one set of equivalent positions with the surrounding oxygen octahedra tilted roughly 8/sup 0/ about a pseudo-cubic (110) axis. BaBiO/sub 3/ has a basically similar structure, but in this case the Bi atoms are situated on two sets of octahedral sites, and there is an additional shift in the position of the oxygen atoms of about 0.1A from one set of sites towards the other, consistent with ordering of Bi/sup 3 +/ and Bi/sup 5 +/. The resulting symmetry is monoclinic, space group I2/m. The superconducting region is characterized by a tetragonal structure at 25/sup 0/C, space group I4/mcm, similar to that of the low temperature form of SrTiO/sub 3/. In BaPb/sub 0/./sub 7/Bi/sub 0/./sub 3/O/sub 3/, the oxygen octahedra are tilted roughly 8/sup 0/ about the (001) axis. For x between 0.4 and 0.75, orthorhombic symmetry is once again observed.
Date: January 1, 1976
Creator: Cox, D E & Sleight, A W
Partner: UNT Libraries Government Documents Department