At 700 ☌, the volatilization rate of antimony sulfide and lead sulfide is 0.455 g/cm²/min and 0.009 g/cm²/min, respectively. The volatilization ratio and purity of antimony trisulfide at different temperatures and holding times were also investigated. The volatilization rate of pure sulfide at 20 Pa was measured by self-made vacuum weighing equipment. The enrichment of antimony sulfide from jamesonite was systematically studied. Jamesonite is an important mineral for the preparation of antimony sulfide, which can be decomposed into different metal sulfides under vacuum. SEM and XRD techniques indicated that the cathodic products deposited on the titanium electrode have excellent cleanliness and purity. The EIS results demonstrated that the reduction process of In3+ is subject to a diffusion-controlled step when pH = 2.5 and the applied potential was −0.5 V. The mechanism of indium at potential steps of −0.3 to −0.6 V was close to diffusion-controlled instantaneous nucleation with a diffusion coefficient of 7.31 × 10−9 cm2 s−1. The nucleation mechanism of indium electrodeposition was analyzed by chronoamperometry. The average charge transfer coefficient a of In3+ was calculated to be 0.116 from the relationship between the cathodic peak potential and the half-peak potential, and the H+ discharge occurred at a higher negative potential of In3+. The cyclic voltammetry results showed that the electrodeposition process is irreversible.
Cyclic voltammetry (CV), chronoamperometry (CA), and alternating current impedance (EIS) techniques were used to investigate the reduction reaction of In3+ and the electrocrystallization mechanism of indium in the indium sulfate system. In this work, the electrochemical behavior of In3+ was investigated by using different electrochemical methods in electrolytes containing sodium and indium sulfate.
Indium is a crucial material and is widely used in high-tech industries, and electrodeposition is an efficient method to recover rare metal resources. The proposed HTP-ZC process has the potential to stably, cleanly and efficiently produce high-purity lead and ultrapure lead. This approach, with huge industrialization potential, pushes the direct yield of the product to 90% and effectively removes trace impurities with low boiling points, such as As, Cd and Zn, in refined lead. Removal efficiencies of 99.96% for As, 99.98% for Zn, and approximately 100% for Cd were achieved. The HTP-ZC results indicate that As, Cd and Zn are condensed as residues and removed in the condensation stage. To cope with this, a novel high-temperature pyrolysis-zone condensation (HTP-ZC) vacuum purification process is proposed for further As separation. In contrast to the removal efficiencies of Zn and Cd by LTVD, the removal efficiency of As impurities is only 4%. Correspondingly, the contents of Zn and Cd impurities decreased from 4 ppmw and 1 ppmw to 0.006 ppmw and 0.01 ppmw, respectively. Detailed analysis of the initial and purified lead was performed by glow discharge mass spectrometry (GDMS) to reveal that Cd and Zn were evaporated as volatiles and were removed from the refined lead in a crucible. In this paper, the low-boiling point trace impurities As, Zn and Cd in refined lead are removed by low-temperature vacuum distillation (LTVD). Environmentally friendly vacuum distillation has been employed to purify refined lead (99.996%), aiming to separate low-boiling point trace impurities of As, Zn and Cd in refined lead and to provide a foundation for the preparation of high-purity lead (5N) and ultrapure lead (6N).
0 kommentar(er)
