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electrowinning of gold from anode slimes sciencedirect

Decopperizing the anode slimes retains much of the metallic gold, but also promotes the incorporation of gold in the structure of silver-rich selenide species. A greater fraction of the gold is converted to (Ag,Au) 2 Se or Ag 3 AuSe 2 when high-Se and high-Ag anode slimes are decopperized at elevated temperatures and pressures.

The average concentration of gold in the anode slimes is about 40 ppm and the total amount of anode slimes produced annually in the world are almost 55,000 t ... ion exchange, electrowinning, and ...

The separation of gold by electrowinning was achieved from the thiourea-H 2 SO 4 solutions (Juarez and Dutra 2000). ... A Review on the Recovery of Noble Metals from Anode Slimes Article

possesses considerable resources of tellurium both in its gold bearing minerals and in the copper anode slimes. Recovery and purification of this tellurium indeed is a promising business in a near future. This thesis work focuses on a single stage of every tellurium processing line; electrowinning. Electrowinning is an important stage

Anode slimes resulting from the electrorefining of Cu, Pb, Sn, and Zn contain noble metals, such as Au, Ag, and platinum group metals. Pretreatments have been employed to enrich the noble metals ...

Copper Anode Slime Recovery. Anode slime is a byproduct from copper or lead electro-refining process. The copper/lead anode slime usually contain As, Sb, Bi and precious metals like gold and silver. Smelter of anode slime is most likely divided into two groups by the two different recovery processes based on its property and treatment capacity ...

Electrowinning is a process used to recover metals (eg. gold and silver) from concentrated solutions by applying a voltage across electrodes immersed in a concentrated solution. The positive terminal from the rectifier is connected to the anode where the oxidation reactions occur and electrons are generated.

Electrolytic refining utilizes anodes comprised of impure metal. When the current is passed through the solution, the anode is corroded into the solution, causing the metal cation to migrate over to be re-plated onto the cathode. In electrowinning, on the other hand, the metal is already dissolved into solution hence the anode is inert.

Electrowinning is defined as the cathodic deposition of metal, in this example copper, from a copper bearing solution by the passage of an electric current current using an insoluble anode.. For copper the electrowinning reaction reaction is: CuSO4 + H2O ⇒ Cu + ½O2 + H2SO4. The overall reaction is the combination of two electrochemical half reactions.

An electrowinning process using air agitation in an acid electrolyte is described for the recovery of gold at 25 °C from anode slimes of the Wohlwill electrorefming cell. The degree of purification of gold improved from 93.4% to over 99%. The rate of gold dissolution is estimated to be 2.2 g A −1 per h at 80 mA cm −2 and 3 V. The ...

Leaching of gold in the anode slimes is affected by some elements such as silver, copper, iron, and selenium. The anode slime was first washed with 4 M sulphuric acid to remove all the copper. Sulphuric acid was then added to anode slime in a 1:10 (solid to liquid) phase ratio and the mixture heated on a hotplate in the presence of oxygen while

The gold, silver, and metals of the platinum group are insoluble in the sulphate electrolyte, and drop to the bottom of the cells as slimes when the anodes are dissolved. The electrolyte is copper sulphate and contains 3 per cent, of copper as sulphate, and from 3 to 4 per cent, of free sulphuric acid.

An electrowinning process using air agitation in an acid electrolyte is described for the recovery of gold at 25 °C from anode slimes of the Wohlwill electrorefming cell. The degree of purification of gold improved from 93.4% to over 99%. The rate of gold dissolution is estimated to be 2.2 g A −1 per h at 80 mA cm −2 and 3 V.

The gold slimes recovered from the spent silver anodes are melted into impure gold anodes for further refining into pure gold, while the spent silver anodes (typically 15-20% of the original anode weight) are re-melted into fresh anodes to start the electrorefining process anew.

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