Yangshuai Qiu,Zhenfei Mao,Kangkang Sun,Lingyan Zhang,Yupeng Qian,Tao Lei,Wenbo Liang,Yaxin An
Flotation is one of the most used methods to upgrade natural graphite resources. However, the efficiency is usually decreased due to the entrainment of undesirable fine gangue minerals. In this work, the impact of different factors such as particle size, pulp density, and flotation reagent on the entrainment of mica and quartz in a flake graphite flotation was studied. The single gangue mineral flotation results showed increased gangue entrainment when reducing the particle size of gangue minerals and increasing the pulp density. Moreover, the flotation of artificial mixtures indicated enhanced entrainment of mica and quartz in the presence of graphite particles. The collector and frother also strongly affect gangue entrainment by modifying the structure and stability of the froth. Kerosene, which has a prominent deforming feature, can reduce gangue entrainment more effectively than diesel.Keywords:entrainment;froth flotation;quartz;mica;flake graphite
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.
Foam flotation is a promising technique for recovering nanoparticles from their highly diluted suspensions. In this work, a novel S type internal was developed to intensify the foam flotation of CuO nanoparticles (357.6 nm in average particle size) from their suspension of 6.2 × 10 −2 mmol/L. By enhancing foam drainage, the S type internal increased the enrichment ratio of CuO nanoparticles by 139.3 ± 12.5 % without significantly affecting their recovery percentage. Under the optimal conditions of Cetyl trimethyl ammonium bromide (CTAB) concentration 0.45 mmol/L, superficial airflow rate 2.6 mm/s, and volumetric feed rate 1.0 mL/min, the enrichment ratio and recovery percentage of CuO nanoparticles reached 81.6 ± 4.1 and 95.4 ± 4.9 %, respectively, using the foam flotation column with the S type internal. Furthermore, about 95 % CTAB could be recycled by recovering CTAB from the foamate and the residual solution. The recovered CuO nanoparticles were associated with CTAB molecules, so they had better dispersity and dispersion stability than the starting CuO nanoparticles. Therefore, they would have good reusability.
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