Process of Extraction of Gallium from Technological Solutions with the Use of Ion Exchange Resins

Metallurgist - D-403 weakly basic anion exchange resin is used for the sorption extraction of gallium in the form of hydroxo complexes from alkaline aluminate solutions. The thermodynamic...     

Rare Earth Metal Extraction from Apatite Ores

Metallurgist - Rare earth metals (REM) after sulfuric acid treatment of apatite ore are partly (15–20%) transferred into extraction phosphoric acid (EPA) solution. Solvent extraction of REM...     

Kinetics and Mechanisms of Dolime Dissolution in Steelmaking Slag

Metallurgical and Materials Transactions B - The kinetics of dolime dissolution containing 20 and 50 pct of magnesium oxide in steelmaking slags has been studied in a high-temperature...     

The mutagenic action of the dust of natural zeolites and chrysotile asbestos

The cell chemiluminescence method was used to demonstrate the ability of asbest and zeolite dusts from 8 deposits of the USSR to induce generation of free oxygen radicals in the phagocytosing cells suspension. It has been found that asbest and zeolite (0.01 and 0.05 mg/ml) increase levels of cells with chromosome aberrations in human cell cultures. The cytogenetic effect of asbest was inhibited by superoxide dismutase (50 mg/ml). The damaging effect of zeolite was decreased by the pharmacological drug bemithyl (0.007-0.07 mM) and completely eliminated by catalase (20 mg/ml). The results obtained indicate that mutagenic effect of dust particles of asbest and zeolite is mediated by oxygen radicals.     

Sorption recovery of gallium and aluminum from alkaline solutions on an AN-31 anion exchanger

Sorption of aluminum and gallium in the form of hydroxo complexes on a weakly basic AN-31 anion exchanger at 298 K from model solutions is investigated. Based on the experimental data, the forms of ions sorbed by the solid phase of the anion exchanger are determined. Sorption of pentahydroxy aluminate and pentahydroxy gallate ions occurs in the Stern–Helmholtz layer. Apparent constants and Gibbs energies of ion-exchange reactions are calculated. The values of the total exchange capacity of gallate ions of 55–58 g/kg in static conditions determine the use of an AN-31 anion ex change resin during the concentration of gallium ions from alkali aluminate solutions.     

Surface properties of ZnS and AC powder electroluminescent phosphors

Abstract— Phosphor surface properties play an important role in luminescent and processing performance. We studied the distribution of surface active absorption centers (DAC) of ZnS powders and ZnS:Cu electroluminescent phosphors with changes in synthesis and processing conditions. Photometric measurements of the colorimetric indicator adsorption from water solutions demonstrated that in the process of ZnS milling, increasing numbers of active centers are accompanied by the transformation of strong‐acidic centers into weaker ones while moderately basic centers are changed into weaker bases. For the case of phosphor powders, the total number of active centers is inversely related to the intensity of photoluminescence and electroluminescence. This may be explained by considering these centers to be sites of non‐emissive recombinations. Samples with different copper content that distinguished surface centers were studied. It was further found that electron‐beam irradiation causes the formation of strong‐acidic and strong‐basic centers on phosphor surfaces. The DAC acid‐base indicator technique is a useful tool to investigate interfacial processes and surfactant efficiency during phosphor‐based device fabrication.     

Sorption of gallium from the alkali solutions based on anionites

The sorption of gallium from alkali solutions on various weakly and strongly basic anionites is studied in dynamic conditions, and the breakthrough dynamic exchange capacity and complete exchange dynamic capacity are investigated. The D-403 selective anionite is selected. The sorption isotherm of gallate ions on the D-403 weakly basic anionites is described by the Langmuir equation modified for the ionexchange equilibrium and the thermodynamic parameters of the sorption are determined. The method of evaluating the form of situating gallium in the alkali sodium solution is suggested. The sorption ability series of the anions on the surface of the solid phase of the D-403 anionite is presented.