Expansion of the fields of application of molybdenum and its compounds of high purity requires the study of their various purification methods. The paper considers low-temperature chlorination of technical molybdenum dioxide, purification of the gas mixture from impurities in the filter system, condensation and dissolution of purified molybdenum oxychloride compounds in water. On filters made of tableted sodium chloride, gaseous molybdenum dioxide is purified from aluminum, iron, chromium and nickel with the formation of low-volatile compounds. The capture of silicon by this filter was not detected. Purification of tungsten on filters of granular molybdenum oxide practically does not occur. Purified molybdenum oxychloride compounds are desublimated in the form of compact and fluffy products with an underestimated chlorine content relative to the stoichiometric composition of molybdenum dioxide. Compact molybdenum oxychloride compounds dissolve in distilled water with little or no precipitation. When dissolving fluffy compounds of molybdenum, a tangible precipitate is formed, into which a significant part of the impurities passes.

Investigations of the synthesis of multicomponent coatings and their subsequent application to metal substrates to increase the wear resistance of materials is relevant for industry. Nickel compounds obtained from oxidized magnesia-iron nickel ores with a desorption rate of more than 94% were used to create Ni-MoO₃-WO₃ electroplating. Such composite samples formed from an aqueous alcohol solution reduced the content of sodium and ammonium chlorides. The annealing and dehydration of samples at a temperature of 725 °C in an air atmosphere made it possible to achieve the highest level of crystallinity. In this case, an isomorphic substitution of W atoms by Mo occurs, which is confirmed by electron paramagnetic resonance (EPR) spectroscopy studies. The invariance of the shape of the EPR spectrum with a sequential increase in microwave radiation power revealed the stability of the bonds between the particles. The surface morphology of Ni-MoO₃-WO₃ films deposited on an Al substrate is smooth and has low roughness. In this case, an increased degree of wear resistance has been achieved. Thus, a recipe for the formation of an electroplating with stable bonds between the components and increased wear resistance was obtained.

The study of the processes of low-temperature synthesis of one-dimensional particles, which are the basis for two- and three-dimensional structures, is relevant for materials science. The modified metal-stimulated electrochemical etching method made it possible to synthesize silicon nanowires with an average thickness of about 292.6 nm. Scanning electron microscopy has shown the formation of nanowires, flower-like structures, and clusters of matter after the deposition of zinc oxide on the porous surface. The hexagonal structure of ZnO crystallites was determined by X-ray diffraction spectroscopy. Studies of the initial sample by electron paramagnetic resonance (EPR) spectroscopy revealed a narrow signal in the center of the spectrum. The subtraction of the EPR spectra with a sequential increase in microwave power up to 8 mW shows the absence of saturation of the signal. This indicates an almost free flow of charges through the surface nanostructures under the influence of an external field. Heat treatment in an air atmosphere at 300 °C caused a significant increase in the intensity of the EPR spectrum. This led to an increase in the intensity of charge transfer through paramagnetic centers.

Selective Ni(II) recovery from polymetallic sulfate leachates is challenging because of competition from accompanying metal ions, particularly Mg(II). This study systematically evaluated selective Ni(II) recovery using commercial chelating ion-exchange resins and assessed their adsorption performance and regeneration behavior in the context of their integration into a conceptual flowsheet for oxidized nickel ore processing. The ore was characterized by XRF, XRD, and SEM–EDS, while Seplite LSC 495 (bispicolylamine) and Seplite LSC 773 (iminodiacetate) were evaluated using selectivity tests, kinetic and equilibrium studies, FTIR spectroscopy, and adsorption–desorption experiments. Both resins exhibited high selectivity for Ni(II) over Co(II) and Mg(II). Under the optimized conditions, Seplite LSC 773 achieved 99.36 ± 0.08% Ni(II) recovery from the model solution and 98.59 ± 0.36% from the actual leach solution, whereas Seplite LSC 495 achieved 94.62 ± 0.21% and 94.23 ± 0.21%, respectively. The equilibrium data exhibited a Giles S-type profile without reaching a distinct saturation plateau within the investigated concentration range, and the Freundlich model provided the most appropriate description of the data, consistent with adsorption on energetically heterogeneous binding sites. FTIR spectral changes indicated the involvement of the chelating functional groups in Ni(II) binding. Among the regeneration conditions investigated, 20 wt.% H₂SO₄ provided the highest Ni(II) desorption efficiency; however, desorption remained limited to approximately 42%, indicating that regeneration remains a major constraint on practical application. The experimental findings were incorporated into a conceptual flowsheet integrating sulfuric acid leaching, selective Ni recovery, subsequent Co separation, and MgSO₄·7H₂O production. Further work should focus on optimizing regeneration, extending cyclic testing, evaluating continuous-flow operation, and validating the integrated process at the pilot scale.