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Abstract
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High purity of silver is one of the many important factors in material science and industrial such as electronics industry and preparation of silver nitrate for the photographic industry. In silver electrorefining method an impure silver metal is employing as anode. After electrolysis purified silver crystals are deposited onto the cathode surface in an electrolytic cell. However, in this process silver ions are required as supporting electrolyte typically silver nitrate, which may be contain an increased concentration of impurities from previously dissolved anodes. In this work, Electrodeposition of high pure silver crystals by electrorefining method investigated. The surface morphology and crystal structure of the electrorifined silvers were characterized by SEM, EDX and XRD respectively. The effective parameters and optimization of electrorefining process such as current density (5-50 mA/cm2), concentration of electrolyte (0.1-2.0 M) and cathode material are evaluated. In this process, we used of impure silver as anode and stainless steel or graphite as a cathode and AgNO3 and HNO3 as supporting electrolyte. The high pure silver crystals, according to the X-Ray diffraction pattern (XRD) obtained at the aqueous solution of Ag+ with concentration of 0.5 M and 0.25 M nitric acid with the 20 mA/Cm2 current density and during of 60 min (Fig.1).
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