Extensive, continuous mining has depleted most tungsten deposits, leaving vast quantities of tailings that now represent a potential lean-grade hematite resource. The isothermal reduction kinetics of beneficiated tungsten mine tailings using boiler-grade coal as a reductant were investigated in the temperature range of 1273-1373 K. Reduction experiments demonstrated that both temperature and holding time strongly influence the extent of reduction, with a maximum fractional conversion (alpha) of 0.854 achieved after 60 min at 1373 K. XRD and SEM analyses confirmed sequential phase transformations from hematite to magnetite, w & uuml;stite, and ultimately metallic iron, with crack formation and spherical iron particles observed on the briquette surfaces. Kinetic modeling indicated a mixed-control mechanism: the contracting geometry (CG3) model predominated in the initial stages, while diffusion (D1) governed the later stages. The apparent activation energies were calculated to be 52.18 kJ/mol (CG3 stage) and 65.81 kJ/mol (D1 stage), indicating a higher energy demand for diffusion through the product layer. The findings provide the intrinsic mechanism for the reduction behaviour of beneficiated tungsten mine tailings-coal composite briquettes and demonstrate the potential of utilizing industrial boiler coal as a reductant in solid-state ironmaking.
In the context of the global energy transition, a crucial technological pathway is proposed that uses bamboo scraps (ZX) and bituminous coal (YM) as feedstocks, enhancing energy conversion efficiency through micro-carbonisation. This study systematically explores the potential for producing metallurgical synthesis gas (MSG) through micro-carbonisation under different ratios and temperature conditions. Using various characterisation techniques, including thermogravimetric analysis, gas chromatography, Fourier Transform Infrared (FTIR) and Scanning Electron Microscope (SEM), the gas release behaviour, structural evolution of solid products and energy characteristics during the micro-carbonisation process are revealed. The results indicate that the generation of MSG occurs in three stages: CO-dominated release, generation of CH4 and CnHm and significant H2 production, with no distinct boundaries between these stages and overlap occurring. Under ZX: YM = 7:3 and 500 degrees C, the MSG achieved a maximum cumulative instantaneous lower heating value (LHV) of 144.9 MJ & centerdot;m-3, with H2 and CO as the major gas components. The temperature and raw material ratio significantly influence the gas composition, heating value and carbon content of the solid products. This study provides a theoretical foundation and process optimisation strategies for the synergistic energy utilisation of bamboo-based biomass and YM, providing a proof-of-concept basis and process insights for potential scale-up.
This study systematically evaluates the effects of slurry formulation, specifically the solid-liquid ratio (SLR) and sodium carboxymethyl cellulose (CMC) binder concentration, on the characteristics of spray-dried mold powder granules. Slurry viscosity increased from 0.14 to 0.38 Pa & centerdot;s as the solid loading rose from 44.44 to 54.55 wt.%, accompanied by a more negative zeta (180.85 mV). This promoted the formation of larger, hollow granules with reduced packing density (decreasing from 0.57 to 0.48 g & centerdot;cm(-3)) and lower compressive strength. Conversely, increasing CMC content from 1.00 to 3.00 wt.% increased both slurry viscosity and granule size, resulting in denser particles and raising packing density from 0.45 to 0.59 g & centerdot;cm(-3). A synergistic optimum identified at 50.00 wt.% solids loading with 2.00 wt.% CMC, which collectively improved particle sphericity, size uniformity. The optimized particle characteristics of this formulation are expected to ensure efficient utilization, particularly in high-speed continuous casting applications.
This study developed an indicator prediction model for steel processes adapting to dynamic operating condition deviations. By combining just-in-time learning, ensemble learning techniques, and target similarity extraction, the model improves prediction accuracy and robustness. Validated on industrial rolling and sintering data, the model achieves up to 18% improvement over traditional models. Utilizing multi-dimensional parameters, the 6% error margin hit rates for yield and tensile strength reached 86% and 99% in rolling data, while the Al 2 O 3 hit rate reached 96% in sintering. Notably, for boundary samples (top/bottom 25% quantiles), the model achieved a 56% relative improvement in hit rate. Furthermore, the model significantly enhances prediction robustness under dynamic operating deviations, reducing the accuracy fluctuation across time segments from 12% to 5%.
Interstitial-free (IF) steel is extensively used in many fields because of its brilliant formability and timelessness properties. However, inclusions formed in steel affects these properties to a great extent. To reduce the influence of inclusions on steel quality, an industrial produced IF steel from a steel mill was taken as the research object of this study. A comprehensive assessment of the whole process of IF steel production was conducted, revealing excessive inclusions in both tundish and slab during IF steel production. This was identified tundish as the critical bottleneck limiting the cleanliness. Hence, a systematic investigation was conducted through physical simulation, numerical simulations, and industrial trials to optimise the tundish configuration. Physical simulation results indicated when the immersion depth of long nozzle was 50 mm, the relative distance between the weir and dam was 50 mm, the distance from the weir to the centre of the long nozzle was 400 mm, and the metallurgical effect of the tundish was the best. Simultaneously, numerical simulation results demonstrated that the stagnation time of molten steel in the tundish was extended after implementing the optimised scheme, and low-temperature zone ratio at the working interface was reduced from 14.74% to 9.65%, effectively promoting the flotation and removal of inclusions. Finally, the industrial test results showed that the total oxygen content in the tundish was reduced from 4.11 & times; 10-5 to 3.5 & times; 10-5, and the number density and average size of Al2O3 and TiN inclusions were reduced with optimisation scheme. This study improves the cleanliness of IF steel in steel mills and provides reference for other steel mills to improve the quality of steel grades.
