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Antimony Extraction from Stibnite Ore Using Alkaline Hydrometallurgical Method
, M.Sc. Thesis Sharif University of Technology ; Yoozbashizadeh, Hossein (Supervisor)
Abstract
In this research, antimony extraction by hydrometallurgical method has been investigated using an alkaline medium. Stibnite ore, as a source of antimony was leached in alkali potassium hydroxide solution. Furthermore, related kinetic equations and process factors were also studied. It was determined that optimum conditions occure when the concentration of KOH is 0.5 mol /L, the solid to liquid ratio is 100 g/L, the reaction temperature is 25 °C, and the process is performed in 115 minutes. It was found that diffusion through the ash layer controls the reaction kinetics during the first 60 minutes. Finally, for the first time, the effect of different parameters on antimony electrowinning was...
Iron Removal from Copper Electrowinning Procces
, M.Sc. Thesis Sharif University of Technology ; Askari, Masood (Supervisor)
Abstract
Iron is a common impurity in copper minerals. The presence of iron in hydrometallurgical copper PLS causes continuous reactions between Fe(II) and Fe(III) ions. In order to improve energy efficiency and product quality iron removal shall be done. In this study separation of iron from Sarcheshme copper leaching liquor containing 6 g/L Fe, was conducted by solvent extraction using D2EHPA in kerosene. Chloric acid solution was used to strip the loaded iron from organic phase. Results of extraction experiments designed by taguchi method showed 92.49% iron recovery and 2.44% copper extraction under optimum condition. Using same method for stripping experiments, it was found that variation of time...
Nickel Recovery From Copper Bleed Solution
, M.Sc. Thesis Sharif University of Technology ; Yoozbashizadeh, Hossein (Supervisor)
Abstract
In copper electrorefining process, to control Nickel and other impurities concentration and avoiding copper cathode contamination, a certain volume of electrolyte is withdrawn continuously from the circulation system and replaced by fresh electrolyte. The spent electrolyte includes valuable elements such as Nickel, Copper, Iron and also great value of sulfuric acid which is worthwhile to be recycled. Solvent Displacement Crystallization (SDC) method is suitable for this purpose because it retains significant amount of acid and have low energy consumption. The present work studies the using of SDC method to recover Nickel and other impurities from Sarcheshme Copper bleed solution and...
Effect of anode compositions on the current efficiency of zinc electrowinning
, Article Proceedings - European Metallurgical Conference, EMC 2011 ; Volume 2 , 2011 , Pages 387-396 ; 9783940276377 (ISBN) ; Rashchi, F ; Vahidi, E ; Emami, M ; Khoshnevisan, A ; Sharif University of Technology
Abstract
The main goals in zinc electrowinning process are decreasing of power consumption and increasing of current efficiency. The purpose of this research was to investigate effect of different alloy compositions used in production of lead-based anodes on the zinc electrowinning process. The anode compositions prepared and examined in this study were binary alloys Pb - (0.5 and 2 %) Ag and quaternary alloys Pb - 0.5 % Ag - 1 % Ca - 2 % Sn, Pb - 0.5 % Ag - 1 % Ca - 1 % Sn - 1 % Sb and Pb - 0.5 % Ag - 1 % Ca - 1 % Sn - 1 % Bi. The electrowinning experiments were conducted using a laboratory-scale apparatus, at a plating time of 4 hours, a current density of 500 to 1000 A/m2, industrial zinc sulfate...
Study on electrowinning of cobalt by cyclic voltammetry technique
, Article Iranian Journal of Materials Science and Engineering ; Volume 7, Issue 2 , 2010 , Pages 45-48 ; 17350808 (ISSN) ; Yoozbashizadeh, H ; Sharif University of Technology
2010
Abstract
Nowadays cobalt is mostly produced through the electrowinning process of sulfate solutions. Regarding to the competition between the precipitation of cobalt ions and evolution of hydrogen gas on the cathode surface during the reduction process in a sulfate bath, investigation on the mechanism of metal precipitation is of great importance. In the present work, study on the kinetics of cobalt electrowinning and the mechanism of the involved reactions have been carried out. The obtained results, confirm the mechanism of cobalt precipitation by depletion of hydroxides. The effects of temperature and scan rate parameters were studied on electrowinning of cobalt by cyclic voltammetry technique....
Effect of a synthesized pulsed electrodeposited Tin/pbo2-ruo2nanocomposite on zinc electrowinning
, Article Industrial and Engineering Chemistry Research ; Volume 60, Issue 31 , 2021 , Pages 11737-11748 ; 08885885 (ISSN) ; Rashchi, F ; Ghalekhani, M ; Dolati, A ; Razi Astaraei, F ; Sharif University of Technology
American Chemical Society
2021
Abstract
Nowadays, there is a growing interest in synthesizing electrodes used in zinc electrowinning, increasing active surface area, decreasing specific energy consumption, and the oxygen evolution reaction (OER) overpotential. In this study, modified nanocomposite anodes were synthesized by applying pulsed and constant direct current electrodeposition to improve the catalytic activity of the electrodes toward the oxygen evolution reaction (OER) and reduce energy consumption in zinc electrowinning. By decreasing particle size, the active surface area of PbO2-RuO2 nano-mixed composite electrode was 2.88 and 14.22 times greater than PbO2-RuO2 microcomposite and pure PbO2 electrodes, respectively....