The process experts are concerned in tellurium due to its various physical and chemical properties. The copper anode slime is the main industrial source of tellurium, after processing of that tellurium becomes marketable product and can be sold both in elemental form and tellurium-containing middling. Physical and chemical properties of the tellurium-containing middling of Kazakhmys Smelting LLP produced in 2018 have been studied in this paper. The following methods have been applied during the study: particle size distribution, X-ray phase, X-ray fluorescence and scanning electron probe microscopy. It was found that material is mainly represented by the large pieces of 0.2 mm in size, with moisture content of 15.57 %, bulk density of 0.8 g/cm3 without tapping and 0.88 g/cm3 with tapping, the angle friction - 33°. The elemental composition of the material was determined by X-ray fluorescence method as follows, wt. %: Cu – 33.327; Te – 21.863; Se – 0.766, O – 35.116; S – 5.045. X-ray phase analysis showed that material is mainly in the amorphous state, the following phases had been identified: Cu2.5SO4(OH)3·2H2O, Cu3(SO4)(OH)4, CuSO4(H2O)3. Tellurium-containing phases could not be detected due to strong amorphism. Hydrosulfate forms of copper in the form of flakes have been found on the surface of the middlings by electron probe microscopy. EDS analysis of individual areas showed that patina also contains small amounts of chlorine, selenium and up to 25 % tellurium, in addition to such elements as copper, sulfur and oxygen. Small amounts of sulfur, chromium, selenium and up to 45 % of oxygen has been found in the open area of material, that is specific for its oxidation.
Only a few works have been devoted to thermodynamic studies of the lead-tin system by methods including the volatile components evaporation process. When the binary system is separated into metals by distillation, the volatile component is removed from the alloy and the low-volatile component accumulates in the bottom products, that is, there are alloy composition changes over the entire concentration range. It is necessary to know the boundaries position of the melt and vapor coexistence fields on the state diagram, especially for solutions beneficiated with non-volatile metal to assess the quality of the vapor phase by the content of the low-volatile component. In this regard, the study has been completed with the purpose to clarify the values of the thermodynamic functions of the formation and evaporation of lead-tin melts required to calculate the boundaries of the liquid and vapor coexistence fields on the state diagram that enables us to judge the amount of a low-volatile component in the vapor phase under equilibrium conditions. The thermodynamic activity of lead was calculated, as well as the numerical integration of the Gibbs-Duhem equation using the substitution proposed by Darken is the thermodynamic activity and pressure of saturated tin vapor Based on the values of the saturated lead vapor pressure, determined by the boiling point method (isothermal version) for alloys predominantly of the lead edge of the phase diagram. The thermodynamic constants thus obtained will add to the base of physicochemical data and will be used to calculate the boundaries of the vapor-liquid equilibrium fields on the phase diagram, allowing to determine the possibility and completeness of the distillation separation of metals.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.