To release the environmental pressure from the massive discharge of bauxite residue (red mud), a novel recycling method of red mud in steel making process was investigated through high-temperature experiments and thermodynamic analysis. The results showed that after the reduction roasting of the carbon-bearing red mud pellets at 1100–1200 °C for 12–20 min, the metallic pellets were obtained with the metallization ratio of ≥88%. Then, the separation of slag and iron achieved from the metallic pellets at 1550 °C, after composition adjustment targeting the primary crystal region of the 12CaO·7Al₂O₃ phase. After iron removal and composition adjustment, the smelting-separation slag had good smelting performance and desulfurization capability, which meets the demand of sulfurization flux in steel making process. The pig iron quality meets the requirements of the high-quality raw material for steel making. In virtue of the huge scale and output of steel industry, the large-scale consumption and zero-waste recycling method of red mud was proposed, which comprised of the carbon-bearing red mud pellets roasting in the rotary hearth furnace and smelting separation in the electric arc furnace after composition adjustment.

In the present study, it has been attempted an innovated application, i.e., electromagnetic interference shielding material, to reutilize copper smelter slag, aiming at an alternative high value added product. Notably, a proof-of-concept experiment with an addition of a 45 wt.% of copper slag alone to the cement matrix boost the shielding effectiveness (SE) to approximately 7–8 dB in the 500 MHz–1.5 GHz frequency range, highlights the incident electromagnetic wave has been weakened by approximately 60 pct. This phenomenon is attributed to the iron silicate, fayalite, and magnetite embedded in the sample mixture serve as magnetic and dielectric loss absorbent, deriving from the copper slag. Copper slag with low value application, shows its competitive economic and social advantages as candidate infill for electromagnetic interference shielding materials.

To characterize the splashing behavior under the impact of the top-blown gas jet in converter, in this paper a physical model is developed with the prototype of a 200 t converter in China. We captured the impact cavity morphology triggered by the top-blown gas jet of the oxygen lance, and found that the impact cavity shape gradually changed following the sequence of “disc” → “bowl” → “cone” with the increase in the gas flow, leading to the variation of the splashing modes. Moreover, the splashing inside and outside the converter was characterized quantitatively under the different top-blown gas jet conditions. The results showed that the splashing on the furnace inner wall concentrated at the region adjacent to the molten bath surface, implying severe flushing of the furnace lining of this region. The critical gas flow of splashing outside the converter is 32.3 Nm³·h⁻¹, corresponding to a gas flow of 39,000 Nm³·h⁻¹ in the prototype. In addition, the foaming slag can suppress the splashing during the smelting process. The statistics of the splashing flux provide a reference for maintaining the safety of the workers and the converter equipment.

Because of the acute toxicity of Cr(VI)-bearing substances, the pollution problem caused by chromite process residue has become a worldwide concern. In the view of relevant studies, the technologies based on the alkali treatment cannot fundamentally resolve the pollution problem, because the oxidation of Cr(III) to Cr(VI) is unavoidable during chromite decomposition. In contrast, the oxidation of Cr(III) to Cr(VI) can be controlled by the sulfuric acid treatment of chromite, and the Cr(VI) pollution can be eliminated from the original source of production. Many research studies focusing on the resolutions of the key obstacles hindering the development of the sulfuric acid treatment process have been carried out, and significant progress has been achieved. In this study, a clean hydrometallurgical process without the generation of hexavalent chromium is demonstrated. First, the chromite was decomposed and leached by sulfuric acid solution in the presence of an oxidant. Then, iron was hydrothermally removed from the acid solution as the precipitate of jarosite. Finally, chromium salts were obtained by adjusting the basicity of the solution, separation and drying. With the aim of realizing industrialization, future research emphasis on the development of the sulfuric acid treatment process is proposed in this study.