Xingyuan Wang,Jiamin Qi,Hengxi Zhu,Jiancheng Wang,Heping Zeng,Bin Li,Si Yan
The aluminum industry is facing severe economic and environmental problems due to increasing carbon emissions and growing stockpiles of red mud (RM). RM is a strongly alkaline, high-emission solid waste from the alumina industry with potential for CO 2 sequestration. However, the effectiveness of RM carbon sequestration is poor, and the mechanism behind it is not well understood. In this study, the effect of microwave and tube furnace activation of RM on CO 2 sequestration in alumina was first investigated at different temperatures. The result showed that the CO 2 sequestration capacity of unmodified RM (URM) was only 14.35 mg/g at ambient temperature and pressure, and the CO 2 sequestration capacity could be increased to 52.89 mg/g after high-temperature activation and modification. Besides, high-temperature activation and modification will effectively improve the carbon sequestration capacity of RM. The carbonized RM was characterized by FT-IR, SEM, XRD , laser particle size, TG-DSC, and pH measurements. In addition, the mechanism of RM capturing CO 2 was also proposed, which shows that CO 2 was finally sequestered in the RM as CaCO 3 . The change in particle size distribution and the mineral phase in the RM indicated that high-temperature activation modification positively affects the application of RM to the sequestration of CO 2 . This study can provide a promising technology for the low-carbon and green development of the aluminum industry, as well as achieving the waste treatment and utilization objective.
Xiaowei Chen,Zhengjie Chen,Yonghang Zhang,Xiuhua Chen,Ruizhe Wang,Dandan Wu,Wenhui Ma
Spent carbon cathode is a kind of solid waste produced by the electrolytic aluminum industry, and it poses a high environmental risk. However, it also contains valuable graphite resources that can be recycled and used as raw materials in industry. In this work, we aimed to enhance the efficient recovery of graphite by introducing ultrasonic waves into the flotation process. Particle size test, inductively coupled plasma (ICP), BET surface area, and other analytical techniques confirmed that ultrasound could promote particle dispersion, clean the surface of minerals, increase the porosity of the graphite surface, and thus strengthen the flotation performance. The results showed that after ultrasonic treatment for 30 min, the recovery rate of graphite increased from 86.22% to 96.24%, the fixed carbon content of tailings decreased from 26.99% to 9.68%, and the fixed carbon content (84.95%) was close to that of conventional flotation (85.32%). Compared with the traditional purification method, this strategy reduces the follow-up cleaning steps of tailings, simplifies the process, reduces the use of chemicals, and features strong market competitiveness and green environmental protection advantages. Additionally, the process is simple and low-cost and can be applied to the recycling of other waste graphite, with potential industrial application prospects.
危险品化学品经营许可证（带存储）