查看更多>>摘要：The leaching of zinc from zinc oxide dust was investigated in choline chloride-urea deep eutectic solvent (ChClurea DES) with the addition of nitrilotriacetic acid (NTA). The effect of important parameters on leaching process, such as leaching temperature, leaching time, liquid/solid ratio and NTA concentration was investigated and the optimization was done using surface response methodology (RSM) based on central composite design (CCD). The optimum condition for leaching of zinc from zinc oxide dust was identified to be a leaching temperature of 79.0 degrees C, a leaching time of 35.4 h, a liquid/solid ratio of 12.1 and an NTA concentration of 0.07 mol/ L. A maximum of 87.9% of zinc was recovered under the optimum experimental conditions. The leaching process is controlled by diffusion and the corresponding activation energy is 26.2 kJ/mol. The resultant leaching solution was directly used for the electrodeposition of zinc, and pure zinc deposit is obtained.
查看更多>>摘要：This study aims to investigate the potential of mechanical-electrical dewatering (EDW) on the recovery of process water from tailings slurry of Miduk copper mine. The EDW experiments were carried out using three voltage levels, including 50, 70 and 90 V, and the mechanical pressures of 3 and 6 bar for 120 min. The moisture content and the pH values of the filtered tailings were determined at the end of the process. Moreover, the electrical resistivity and the electric energy consumption were calculated. To investigate the energy efficiency of the recovered/removed water, four indices were calculated including, water removal (WR), additional water removal (AWR), specific energy (SE) and normalised specific energy (NSE). Mechanical filtration extracted 63% and 71% of the process water at 3 and 6 bar, respectively. Also, EDW experiments recovered 8-31% more additional water. A higher rate was achieved for the process water by applying more voltage while increasing energy consumption. The EC and pH values of the recovered water were in a suitable range of the process water for Miduk copper mine. The average moisture content of filtered tailings reduced to 3.7-12.7% and indicated an ascending trend from anode to cathode sides. Although the pH values of the filtered tailings in the anode side decreased to the point of zero charge, the reverse electro-osmosis process did not significantly affect the potential of EDW. Due to the joined impact of moisture variation, temperature and hydrolysis process, the interpretation of electrical resistivity was complex. Overall, the least amount of energy consumption for removing the additional process water was achieved by applying a voltage level of 70 V. However, a combination of a mechanical pressure of 3 bar and a voltage of 90 V recovered up to 92% of water by the optimal values of SE and NSE indices.
查看更多>>摘要：Developed economies such as the USA and European Union (EU) have classified antimony as a critical raw material. China leads the global antimony production (67% on an average from 2015 to 2019) followed by Russia and Tajikistan. Antimony has been applied in the industry (plastics, etc.) and new/emerging technologies (cell panels, infrared, etc.) where antimony trioxide (Sb2O3) is its most produced and used compound. With technological advances, recent trends indicate a growing demand for this metal; however, with the on-going production rate, antimony is anticipated to become one of the scarcest metals by 2050. Several minerals of antimony exist; nevertheless, stibnite (Sb2S3) is the primary mineral. Extractive metallurgical routes such as pyro and hydro-metallurgy have found industrial applications for stibnite processing; however, bio-hydrometallurgy is slowly gaining momentum. In this piece of review, the world-wide scenario of antimony production, recent market trends along with the common and current research advances related to applications of antimony in emerging technologies is presented. Comprehensive details along with the recent advances related to stibnite processing through the aforementioned extractive metallurgy routes, their technological improvements and antimony purification/recovery methods from leach solutions are also discussed. Furthermore, the future perspectives in terms of research and industrial needs are discussed and summarized.
查看更多>>摘要：The selective separation of scheelite from fluorite is difficult because of their similar surface properties. In this study, diethylenetriaminepentaacetic acid (DTPA) was used as a novel depressant for the efficient removal of fluorite from scheelite, and its depression effect and mechanism were systematically investigated by conducting micro-flotation experiments and a series of surface analyses. The micro-flotation experiments showed that the floatability of fluorite was significantly reduced by DTPA, whereas that of scheelite was minimally affected. Zeta potential measurements revealed that DTPA selectively adsorbed on fluorite surface and decreased the zeta potentials, whereas the zeta potentials of scheelite were negligibly influenced by DTPA. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy further proved that the interaction between DTPA and the fluorite surface was chemisorption, and in the adsorption configuration, the carboxyl groups of DTPA chelated with Ca sites on the fluorite surface. Additionally, an electrical analysis showed that electrostatic attraction facilitated the adsorption of DTPA on the fluorite surface. The adsorption of DTPA on fluorite surface could strongly inhibit the further adsorption of NaOL on fluorite surface, and therefore significantly depressed the floatability of fluorite. In contrast, the interaction between DTPA and scheelite was very weak and was impeded by steric hindrance caused by WO42-and electrostatic repulsion. Therefore, DTPA has the potential to act as a depressant for the effective separation of scheelite from fluorite.
NSTL
Elsevier