Electrorefining in Aqueous Chloride Media for Recovering Tin From Waste Materials

Kékesi, Tamás

doi:10.12776/ams.v19i3.161

Cited by 7 publications

(3 citation statements)

References 5 publications

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“…Electrorefining was successfully used to extract metals from many types of waste (Kekesi, 2013; López and Alguacil, 2015; López et al, 2018). It is cheaper than thermal methods, more selective, and environmentally friendly.…”

Section: Introductionmentioning

confidence: 99%

Tin and silver recovery from wave soldering dross

García‐Díaz

López

2018

Waste Manag Res

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This work proposes a method for the recovery of tin and silver from wave soldering dross produced during the manufacture of printed circuit boards. Samples of wave soldering dross were first subjected to carbothermic reduction to obtain an ingot containing the above metals plus other elements. This ingot was then subjected to electrorefining at different densities of electrical current, electrolyte flow rate, and cathode-anode separation distance, to determine the optimum conditions for recovering pure tin. Under such conditions, 82 wt% of the tin in the ingot was recovered at a purity of 99.94%. After subjecting ingots to continuous electrorefining under optimum conditions for 845 h, the slime collected at the anode was removed for the recovery of silver. This slime was subjected to thin-layer leaching with concentrated nitric acid. The leachate produced was subjected to copper-cementation; the silver adhering to the copper rod was collected by washing. This process recovered 92% of the silver in the wave soldering dross ingot at a purity of >99.6%. Some 99% of the copper entering the leachate from the copper rod during cementation was recovered by liquid-liquid extraction with 40% LIX84 (dissolved in EXXOL D100). This method could provide a rapid, inexpensive means of recovering pure tin and silver from wave soldering dross.

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Section: Introductionmentioning

confidence: 99%

Tin and silver recovery from wave soldering dross

García‐Díaz

López

2018

Waste Manag Res

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“…The amount of the metallic phase strongly depends on the conditions of anodic dissolution. At high anodic potentials, associated with high anodic current densities, dissolution results in the generation of Sn(IV) species which may in turn react with the metallic particles of the thick slime layer [3,4]:…”

Section: Introductionmentioning

confidence: 99%

Leaching Behavior of the Anode Slime Generated by the Electrorefining of Sn-Ag-Cu Alloys

Harangi¹,

Nagy²,

Kékesi³

2015

The Publications of the MultiScience - XXIX. MicroCAD International Scientific Conference

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The waste material produced in lead-free wave soldering is melted, skimmed and cast into anodes. Anode slime, the by-product of electrorefining in hydrochloric solutions is collected and the basically undissolved silver and copper constituents are removed by selective leaching. The first step is the elimination of metallic tin using HCl of high concentration and temperature, followed by the leaching of the nobler metallic components in HNO 3 under similar conditions. Kinetic study on the leaching behavior of the raw anode slime in both media has shown the optimum conditions. The metallic tin content of the anode slime can be dissolved virtually completely in 10 M HCl at the highest possible temperature of 85 o C, however it takes about 3 hours. On the other hand, silver can be o quickly dissolved in about 15 minutes by applying approx. 50% HNO 3 at 90 C. Combination of the two steps in this order can result in an efficient recycling of the slime by producing relatively pure SnCl 2 and AgNO 3 solutions, respectively. The tin content can be recycled conveniently to the tin electrolysis and the silver containing solution can be used for recovering silver by electrowinning or precipitation.

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“…(crude Sn anode)을 만든 다음 이를 전해정련하여 순도 99.9 % 이상의 고순도 주석을 생산하고 있다 [10][11][12][13] . 주석의 전해정련기술 14) 은 이미 상용화된 기술로서 산성 또는 알 칼리 전해액을 사용하여 낮은 전류밀도에서 행해진다.…”

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Electrochemical Behavior of Tin and Silver during the Electrorecycling of Pb-free Solder (Sn-Ag-Cu) Waste

Kim¹,

Lee²,

Kim³

et al. 2022

Resour. Recycl.

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We investigated the electrochemical behavior of Sn (93.0 %)-Ag (4.06 %)-Cu (0.89 %) during electrolysis of Pb-free solder waste to recover tin and silver. A thin strip of the solder waste produced by high-temperature melting and casting was used as a working electrode to perform electrochemical analysis. During anodic polarization, the current peak of an active region decreased with an increase in the concentration of sulfuric acid used as an electrolyte. This resulted in the electro-dissolution of the working electrode in the electrolyte (1.0 molL -1 sulfuric acid) for a constant current study. The study revealed that the thickening of an anode slime layer at the working surface continuously increased the electrode potential of the working electrode. At 10 mAcm -2 , the dissolution reaction continued for 25 h. By contrast, at 50 mAcm -2 , a sharp increase in the electrode potential stopped the dissolution in 2.5 h. During dissolution, silver enrichment in the anode slime reached 94.3% in the 1 molL -1 sulfuric acid electrolyte containing a 0.3 molL -1 chlorine ion, which was 12.7% higher than that without chlorine

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Electrorefining in Aqueous Chloride Media for Recovering Tin From Waste Materials

Cited by 7 publications

References 5 publications

Tin and silver recovery from wave soldering dross

Tin and silver recovery from wave soldering dross

Leaching Behavior of the Anode Slime Generated by the Electrorefining of Sn-Ag-Cu Alloys

Electrochemical Behavior of Tin and Silver during the Electrorecycling of Pb-free Solder (Sn-Ag-Cu) Waste

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