Ural Institute of Metals

Abstract Manganese dioxide is a material that is more and more used in its particular form, for many industrial applications such as chemical catalysis or for batteries. Thus, workers can be exposed to this particulate chemical. It is known that overexposure to manganese leads to a brain disease called manganism. However, manganese is also known to impact the pulmonary function, which is important as pulmonary exposure is of prime importance for workers. We thus investigated the effects of manganese dioxide on macrophages, i.e. the scavenger cells that take particulates in charge in our bodies. To this purpose, we used a combination of proteomic and targeted approaches, in order to obtain a wide view of the cellular responses to manganese dioxide. We also used a repeated exposure mode, in order to better mimic occupational exposure. Our results point out the fact that manganese oxide nanoparticles are rather toxic for macrophages and induce mitochondrial dysfunction, oxidative stress and a pro-inflammatory response. Environmental significance Manganese dioxide is more and more used in batteries, so that workers in batteries factories are exposed to this metallic oxide. As always for particulate materials, macrophages are the first line of defense of the organism. We thus investigated the effects of manganese dioxide on macrophages, using a repeated exposure scheme to mimic occupational exposure, and the effects were documented by a combination of proteomic and targeted approaches. The functional effects include mitochondrial dysfunction, oxidative stress and inflammation.

In this study, a comprehensive method for processing lithium-ion battery electrode material is proposed, based on the selective cuprum leaching using an NH4HCO3 liquor followed by its sorption using the ion-exchange resin Purolite S930 Plus. Certain optimal conditions for ammoniacal leaching ensure cuprum recovery at approximately 90%. Loading tests demonstrated a high static sorption capacity of the resin—125.4 mg g–1, while dynamic experiments and elution using H2SO4 showed the possibility of efficient cuprum recovery and resin regeneration. Additional analyses using IR and XPS spectroscopy confirmed the formation of stable coordination bonds between cuprum ions and the functional groups of the resin. The obtained results indicate the promise of the proposed technology for the industrial processing of spent lithium-ion batteries to recover valuable metals.

Corson (Cu-Ni-Si) alloys were unidirectionally solidified via the Mizuta method under air or water cooling. To replicate the microstructure of a Corson alloy during solidification, phase-field (PF) simulations were performed, and the numerical results were compared with the experimental findings. The comparison between the air- and water-cooling conditions revealed that the primary dendrite trunks were thinner, and the secondary dendrites were longer and more developed under air-cooling conditions. These results were consistent with the experimental observations. Furthermore, the secondary dendrite arm spacings were evaluated via PF simulations, and the calculated results were consistent with the experimental observations. The interface energy and its anisotropy adopted in the present PF simulations were reasonable for the Corson alloy when compared with the values reported in other studies.

The higher share of unfluxed pellets in blast furnace burden determines the increase of sinter basicity (CaO/SiO2) up to 1.7‒2.2 units. Study of the microstructure formation peculiarities of such sinters is an urgent challenge. Recently, the mining enterprises have been increasing the iron content in the concentrate and use concentrate grades with iron content of 68‒70% in sintering. In this regard, it is interesting to study the microstructure of sinters with high iron content and the influence of mineral composition of the binder on the sinter strength. The schemes of formation of mineral composition of sinter with low basicity and high SiO2 content and with high basicity and low SiO2 content are given. The role of hedenbergite, ferrites and alumoferrites in the formation of the melt and the formation of the sinter structure is shown. It has been established that the structure of sinter with a basicity of 1.8 units and iron content of 57.1% consists of phases of partially oxidized magnetite, calcium monosilicate and glass of variable composition. In 1.8 basicity sinter with iron content of 59.4% the structure consists of phases of magnetite, calcium ferrite and glass of variable composition. The large amount of glass and pores in the binder does not allow the sinter hardening to be fully realized. The increase in strength is achieved by increasing the basicity of the sinter up to 2.1 units. The crystal structure of ferritic binder is needleshaped, which provides high strength of sinter. The amount of glass is reduced and it fills the gaps between the crystals of ferrite isolated from ore grains.

By the previous studies it was established that the character of solid fuel distribution throughout the bed height considerably effects the sintering machines productivity and the sinter quality. The purpose of the study was assessment of solid fuel distribution in the agglomerated burden throughout the height of bed at sintering machine. Sinter mix samples were taken from three sections of the bed: 150 mm - top part, 150 mm - middle part and 170 mm - bottom part at the sintering machines of NLMK. After screening the samples, particle size distribution was determined, as well as carbon content throughout the bed height and in the particles of different sizes. It was found that all solid fuel, irrespective of the size, gets balled into sinter mix granules, fine fuel (fraction -0.63 mm) was almost evenly distributed over the granules of different sizes, while coarse fuel (+3 mm) is mainly picked up by large granules. Solid fuel of -3 mm +0.63 mm fraction is mostly balled into 3-5 mm granules. Such nature of solid fuel distribution in the granules of the pelletized mix results in suboptimal distribution of fuel throughout the bed height at sintering machines No. 1, 2, despite satisfactory size segregation of the mix: it changes from low content in the top part to a higher content at the bottom of the bed. At sintering machines No. 3, 4 where there was no size segregation of the mix, fuel distribution throughout the bed height changes from optimal to non-optimal (low content in the top part). To optimize solid fuel distribution throughout the bed height with both good and poor segregation of the mix, it is necessary to reduce the content of 0-0.5 mm particles fraction in coke breeze.

A process of manufacturing of rolled sheets from a new high-strength wear-resistant weldable steel H500 MAGSTRONG® with wear resistance, strength and impact toughness parameters at negative temperatures not inferior to those of the best world counterparts is described. Transmission electron microscopy is used to study the structure of a sheet with a thickness of 12 mm formed as a result of hot rolling and quenching.

The results of an experimental study of the electrical resistivity of liquid gadolinium at temperatures from 2000 to 4250 K at elevated pressure are presented. Samples of gadolinium (93.0% pure) in the form of plates 80-µm thick were heated by a single current pulse, for a time of about 5–10 µs. Gadolinium plates were placed between two silica-glass plates to preserve the original shape, reduce vaporization, and create some pressure above atmospheric. Electrical resistivity is measured using a high-speed oscilloscope (excluding thermal expansion of gadolinium).