Спонтанный спиновый магнетизм донорных электронов проводимости гибридизированных состояний кристалла, образованных системой примесных атомов 3d-элементов низкой концентрации (<1 at.%)

The given work is devoted to the experimental proof of existing the spontaneous spin polarization of the donor electron system of 3d-transition element impurity atoms of low concentration (<1 at.%) in a mercury selenide crystal. For this purpose there have been measured the dependences of the magnetization on the magnetic field strength. As a result of the analysis of the obtained dependences, there were extracted the impurity contributions, which are described by the magnetization curves typical of the ferromagnets, and by the magnetic parameters conforming to the spontaneous magnetism of the systems under study, which are unambiguously related to the donor conduction electrons of the outer d-shells of impurity atoms. By its nature, according to the developed theoretical concepts, the spontaneous spin polarization manifests itself in exchange interaction, taking place in hybridizing the electronic states of the impurity atom and the conduction band ones of the crystal.

Mercury Speciation in Natural and Mining-Related Systems

Mercury speciation and the composition of mercury phases in natural and mining-related environments is studied by the thermal release analysis combined with electrothermal atomic absorption spectroscopy (TA-ET-AAS), as well as scanning electron microscopy with energy-dispersive X-ray microanalysis (SEM-EDS). The analyses are applied to laboratory-made samples bearing mercury selenide and to field samples from sites known for relatively high natural or industrially induced Hg background. They are, namely, material from the dispersion train of the Ursk sulfide tailings (Ursk Village, Kemerovo region) and debris precipitated from snow sampled in the Kurai mercury zone (Aktash Village, Gorny Altai). The TA-ET-AAS method works well in discrimination and identification of Hg sulfide and Hg selenide provided that the samples contain sufficient amounts of both compounds, but the sum HgS + HgSe can be determined at any contents of the two compounds. The presence of both mercury sulfide and mercury selenide in the samples has been confirmed by SEM-EDS microanalysis. The temperature ranges for the mercury species (Hg2+; HgS+HgSe mixture; mercury bound with organic matter (Hg-OM), including CH3Hg+) are identical in the laboratory and field samples. Therefore, the suggested approach can ensure fast and reliable detection of Hg phases in rocks exposed to supergene alteration

Natural organic matter facilitates formation and microbial methylation of mercury selenide nanoparticles

Tiemannite nanoparticles available for microbial mercury methylation are formed during the co-precipitation of natural organic matter, divalent mercury and selenium.

Obtaining selenium concentrate from the slime of the sulfuric acid workshop of the Balkhash copper plant and extracting selenium from it into solution

The article presents the results of large-scale laboratory tests of obtaining selenium concentrate from the slime of the sulfuric acid workshop (hereinafter: slime) of the Balkhash copper smelting plant and the extraction of selenium from it into solution. This slime, in contrast to similar slime from non-ferrous metallurgy plants, significantly differs in chemical and material compositions, especially in the selenium content (4.6 - 12.5 wt.%). Involving it in the production sphere will increase the production of selenium by more than 20% from that obtained by the plant from copper electrolyte slime. The slime is washed with water to remove sulfuric acid, dried at 105 ° C. Selenium concentrate was obtained by sequential leaching of slime with solutions of sodium carbonate and nitric acid, selenium from the concentrate was leached with solutions of sodium sulfite (atmospheric pressure) and sodium hydroxide (high pressure, autoclave leaching). Slime, concentrate, cakes, precipitates isolated from solutions, and solutions were analyzed using modern devices of a new generation: An Optima-8300 inductively coupled plasma spectrometer, an Axios X-ray fluorescence spectrometer, an Optima 2000 atomic emission spectroscope, a D8 Advance diffractometer, a D8 Advance infrared spectrometer Avatar 370. From the slime containing, wt. %: 51.2 Pb, 12.5 Se, 3.21 Hg and other elements, a selenium concentrate was obtained with the composition, wt. %: 0.41 Pb, 59.16 Se, 15.4 Hg. The technological indicators for obtaining a concentrate are given, %: concentrate yield - 20.74, Pb recovery - 0.81, Se - 98.23, Hg - 99.50. According to XRD and IR spectroscopy, the concentrate contains elemental selenium and mercury selenide from 10 selenium substances contained in the slime (given in the article). The extraction of selenium from the concentrate into the solution was, %: sodium sulfite - 76.84, sodium hydroxide - 89.65. The pulp from opening the concentrate with sodium hydroxide solution was filtered very poorly. The filtrates contained a colloidal suspension, which could not be filtered off either under vacuum or centrifugation. Therefore, to determine the qualitative and material composition of the filtrates, salts were obtained by evaporating a certain and then neutralized volume to dryness. It was found that only elemental selenium is leached from the concentrate by solutions of both reagents, while mercury selenide remains in the cakes. Moreover, over time, elemental selenium partially precipitated again from selenium-containing sodium sulfite solutions; the salts contain only elemental selenium. An explanation is given for the transition of soluble selenium salts to its elemental state. Despite the higher recovery of selenium from the concentrate by leaching in autoclaves, taking into account the equipment, the complexity of its maintenance, filtration of the pulp and the chemical composition of the filtrate, it is preferable to use the method of leaching with sodium sulfite.