Papers by Keyword: Electrowinning

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Authors: Bi Xia Wang, Xin Zhe Lan, Yong Hui Song, Ying Sheng Li
Abstract: The electrowinning method for treating high copper cyanide solution was investigated by thermodynamics analysis and experiment. The influences of copper concentration, solution temperature, electrolysis time, current density and flow rate on copper recovery and current efficiency was studied in detail and the suitable operation parameters were chosen. Copper electrowinning from the industrial barren solution with copper concentration of 12.40g/L was performed under the condition of current density of 75 mA/cm2, flow rate of 30mL/min and 50°C for 8 hours. An alloy with copper concentration of 99.87% was obtained at the cathode with total energy consumption 2938KWh/t. The used electrolysis solution added with some fresh cyanide sodium solution can be recycled to leaching process.
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Authors: Chinmaya Kumar Sarangi, Ayonbala Baral, Jayasmita Panigrahi, Kali Sanjay, Tondepu Subbaiah, Barada Kanta Mishra
Abstract: Studies based on electrocrystallization of antimony were carried out to evaluate the effects of current density and antimony concentration in the electrolytic bath on cathodic current efficiency, energy consumption, and quality of the deposits during electrowinning of antimony from Sb2O3-HCl and Sb2S3-NaOH systems. In acidic bath, current efficiency for electrodeposition of antimony increases with the increase in current density till 150 A/m2, beyond which it follows a trend of gradual diminution. On varying antimony concentration in the bath, current efficiency was found to improve significantly and the optimum antimony concentration in Sb2O3-HCl system was evaluated to be about 60 g/L. In alkaline bath, current efficiency was observed to be maximum at 50 A/m2 and further, with the increase in current density it progressively decreases. However, energy consumption for electrowinning of antimony in both of the baths gradually increases with the increase in current density. At a current density less than 150 A/m2, alkaline bath was found to be more current efficient in comparison to the acidic bath. Crystallographic studies by XRD, imaging by optical microscopic technique and morphological studies by SEM were also carried out to differentiate antimony deposits obtained from acidic and alkaline baths.
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Authors: Yong Ming Zhang, Peng Zhi Xiang, Ying Bo Mao
Abstract: This paper use the copper content of copper-rich solution is 49.43g/L for electrolyte, and it effecting factors of the quality of electric copper electrodeposition are studied. The results show that under the these conditions of the electrodeposition current density is 180A/m2, and time of electrodeposition is 1.5h, concentration of NH4+ in electrolyte is less than 2g/L, thiourea is 40 g/t and Henkel glue is 40 g/t, the cathode copper which have less impurity content and Cu+Ag≥99.95% could be obtained.
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Authors: D.S. van Vuuren, Eugene Swanepoel
Abstract:

In the Kroll and Hunter processes to produce titanium from TiCl4, magnesium and sodium are used respectively as reducing agents. These processes are slow and very energy intensive and consequently much work was done over the years to improve the economics of producing these metals. In this regard, more success has been achieved with improving the economics of magnesium electrowinning than with alkali metal electrowinning. Magnesium electrowinning cells generally have electrodes with a planar shape and alkali metal electrolysis cells have electrodes with a cylindrical shape. Furthermore, recent advances in magnesium electrolysis allowed the introduction of bipolar electrodes, whereas such electrodes have not been introduced in alkali metal electrowinning cells. It is conceptually possible to replicate the advances in the construction of magnesium electrowinning cells to improve sodium or other alkali metal electrowinning cells. However, there are underlying fundamental reasons why it would be difficult to do so.In this paper the technologies for magnesium and alkali metal electrowinning cells are briefly reviewed. The reasons why it would be difficult to copy the improvements made in magnesium electrowinning technology to alkali metal electrowinning technology are then explained in terms of the implications of the underlying chemical and physical properties of the chemicals involved in the processes.

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Authors: A. Da Camara, Joaquín Lira-Olivares, Soo Wohn Lee, H.D. Park, Y.S. Park
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Authors: Jia Chao Jiang, Cui Xiang Guo, You Cai Zhao
Abstract: . In this paper, a novel hydrometallurgical process for zinc powder production in alkaline solution at industrial scale was reported. The production procedure was developed and discussed, and the characteristics of the zinc powder products, including mineral phases, chemical composition, surface morphology, apparent density and specific surface area were investigated. It is found that the chemical composition of the products have completely reached the need of the National Standard GB/T 6890-2000. Although the outward apperance is always in powdery form, the zinc powder products are composed of dendritic deposits from a microscopic viewpoint, which is important in applications such as cementation, paints and extraction of gold and silver etc. where high specific surface areas are needed. Compared with the acidic-air pulverization process for zinc powder production, about 10-20% energy can be saved by the alkaline process.
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