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Stainless-steel slag was used to prepare glass-ceramics, which could solidify chromium (Cr) in the slag. The migration and distribution state of chromium in the slag during the preparation of the glass-ceramics have a great influence on the chromium fixation ability of the glass-ceramics. In this paper, the effects of Al2O3 content in the glass-ceramics on the migration and distribution of chromium during the nucleation and crystallization steps, and on the chromium fixation effect of the glass-ceramics were systematically studied. The results show that in the nucleation stage, with the increase of Al2O3 content, the number of chromium spinel (Cr-spinel) nanocrystals formed in the glass first increases and then decreases, and Cr in the glass phase gradually migrates to Cr-spinel nanocrystals. TEM and XPS analyses show that during crystallization, part of Cr in Cr-spinel diffuses into diopside lattice, and the other part of Cr still exists in Cr-spinel wrapped by diopside. Cr in the glass phase also diffuses and migrates into the diopside lattice with the formation of diopside crystals. The optimal Al2O3 content is 11.8wt.%, which results in 97.94wt.% of the total Cr being fixed in the diopside crystalline phase. The ability of chromium fixation is very high giving a very low Cr leaching concentration of 0.004mg/l. The research results provide theoretical and technical support for increased chromium fixation and realizing harmless and high-value utilization of stainless-steel slag.

BACKGROUND In recent years, the study of rare polymetallic ore tends to be increasingly detailed. As one of the important research methods, electron probe quantitative analysis has made great progress in trace element measurement. During analysis, in addition to increasing the beam size and time to reduce the detection limit, more attention should be paid to removing the interference from other elements, especially the main elements. During the routine testing of rare polymetallic samples, Si, Ta, W interfere with each other. Such interference affects the analytical results of trace elements, and is not easily detected due to its low content, thus affecting the accuracy of the final conclusion. OBJECTIVES To determine the interference relationship among Si, Ta and W under different analytical conditions. METHODS Taking SiO2, metal Ta and W of SPI as the research object, each element was analyzed under different conditions by electron probe microanalyzer. RESULTS In the analysis of silicate, TAP-Kα is used for Si, and LIF-Lα is recommended for Ta and W. In the analysis of niobium tantalum ore, it is suggested to use PET-Kα, PET-Mα and TAP-Mβ for Si, Ta and W, respectively; since 100% Ta will produce about 0.1% Si, therefore, the results are more accurate with the interference correction of Ta on Si. CONCLUSIONS It is important to understand the spectral peak stripping method and the principle of element interference and spectral peak overlap, adjusting the parameters according to the actual situation to ensure the accuracy of data.

China has undergone rapid urbanization and internal migration in the past few years, and its up-to-date gridded population datasets are essential for various applications. Existing datasets for China, however, suffer from either outdatedness or failure to incorporate data from the latest Seventh National Population Census of China, conducted in 2020. In this study, we develop a novel population downscaling approach that leverages stacking ensemble learning and big geospatial data to produce up-to-date population grids at a 100 m resolution for China using seventh census data at both county and town levels. The proposed approach employs stacking ensemble learning to integrate the strengths of random forest, XGBoost, and LightGBM through fusing their predictions in a training mechanism, and it delineates the inhabited areas from big geospatial data to enhance the gridded population estimation. Experimental results demonstrate that the proposed approach exhibits the best-fit performance compared to individual base models. Meanwhile, the out-of-sample town-level test set indicates that the estimated gridded population dataset (R2=0.8936) is more accurate than existing WorldPop (R2=0.7427) and LandScan (R2=0.7165) products for China in 2020. Furthermore, with the inhabited area enhancement, the spatial distribution of population grids is intuitively more reasonable than the two existing products. Hence, the proposed population downscaling approach provides a valuable option for producing gridded population datasets. The estimated 100 m gridded population dataset of China holds great significance for future applications, and it is publicly available at https://doi.org/10.6084/m9.figshare.24916140.v1 (Chen et al., 2024b). [ABSTRACT FROM AUTHOR]

In order to investigate the influence of the deflector layout on the performance of mine-used main fan diffuser, the RNG k-ε turbulence model was applied to numerical simulation of the internal flow fields under three inlet velocity conditions with and without deflector. The influence of the central angle and starting angle of the deflector on the performance of the diffuser was investigated. The results show that for the diffuser without deflector, a serious flow accumulation phenomenon exists inside the flow field, which restricts the performance improvement of the diffuser; when the center angle of the deflector is small, the larger the starting angle of its installation is, the higher the diffusion efficiency of the diffuser under the three inlet velocities considered, however the secondary flow due to the uneven pressure on the upper and lower sides of the deflector head appears at some starting angles, which results in an increase in flow losses. As the center angle of the deflector increases, the flow accumulation inside the diffuser improves gradually, and the secondary flow also gradually weakens. When the center angle reaches 60°, the diffusion efficiency is the highest.