A Study on the Enrichment Behavior of Precious Metals on Anode Slime during Electroleaching of Copper-based Alloys in Sulfuric Acid Solutions

Min-seuk Kim; Hyunsik Park

doi:10.7844/kirr.2026.35.4.43

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2026 Vol.35, Issue 4 Preview Page Next Page

A Study on the Enrichment Behavior of Precious Metals on Anode Slime during Electroleaching of Copper-based Alloys in Sulfuric Acid Solutions 동 기반 합금의 황산용액 전해침출 시 양극슬라임으로의 귀금속 농축거동 연구

31 August 2026. pp. 43-55

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Abstract

Precious metal enrichment of anode slime formed during the electroleaching of Cu–Sn–Fe–Ag–Au alloys was investigated to simulate gold and silver gathering from waste Cu–containing PCBs. Anodic potential sweep experiments in 1 mol/L sulfuric acid showed that the anodic currents of copper and iron increase with increasing temperature, whereas that of tin decreases. Under constant–current electroleaching conditions (1 mol/L sulfuric acid solution, 60 °C, and 25 mA/cm² applied current density), the Cu–16.8Sn–0.3Au–0.8Ag alloy produced an anode slime composed of 68.18 % Sn, 24.17 % Cu, 5.04 % Ag, 0.78 % Au, and 1.46 % O. The precious metals were predominantly concentrated in the anode slime, resulting in an enrichment ratio of approximately 440 % relative to the raw alloy. Replacing tin with iron did not alter the precious metal distributions in the slime; however, the reduced slime formation increased the enrichment ratio. When the tin content was reduced from 16.8 % to 6.6 % with a corresponding increase in iron content, the anode slime yield decreased from 21.2 % to 11.7 %, and the precious metal enrichment ratio increased to approximately 800 %.

Keywords

Cu alloy

precious metal

electroleaching

anode slime

enrichment ratio

본 연구에서는 폐 PCB 함유 금과 은을 Cu로 건식 포집한 경우를 모사한 Cu–Sn–Fe–Ag–Au 합금의 전해침출 시 양극슬라임으로의 귀금속 농축율을 조사하였다. 1 mol/L 황산용액에서 합금 성분금속의 전극전위를 높일때 구리와 철은 용액 온도가 높아짐에 따라 산화전류가 증가한 반면, 주석은 반대의 경향을 보였다. Cu–16.8Sn–0.3Au–0.8Ag 조성의 합금을 사용하여 1 mol/L 황산용액, 60 ℃, 인가전류 25 mA/cm²의 조건에서 정전류 전해침출을 실시한 결과 Sn 68.18 %, Cu 24.17 %, Ag 5.04 %, Au 0.78 %, O 1.46 % 조성의 양극슬라임을 얻었으며, 귀금속은 모두 양극슬라임으로 분배되었고 원시료 대비 귀금속 농축율은 약 440 %로 계산되었다. 합금 내 주석 함량을 낮추고 이를 철로 대체했을때 양극슬라임으로의 귀금속 분배율은 차이가 없었으나 생성되는 양극슬라임량이 줄어들면서 상대적으로 농축율은 높아졌다. 주석의 함량을 16.8 %에서 6.6 %로 낮추고 철의 함량을 높인 경우 용해된 합금량 대비 양극슬라임 생성량은 21.2 %에서 11.7 %로 낮아졌고 이에따라 귀금속 농축율은 약 800 %로 높아졌다.

키워드

구리 합금

귀금속

전해침출

양극슬라임

농축율

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Information

Publisher :The Korean Institute of Resources Recycling
Publisher(Ko) :한국자원리싸이클링학회
Journal Title :Resources Recycling
Journal Title(Ko) :자원리싸이클링
Volume : 35
No :4
Pages :43-55
Received Date : 2025-10-15
Revised Date : 2026-07-14
Accepted Date : 2026-07-24
DOI :https://doi.org/10.7844/kirr.2026.35.4.43

Resources Recycling ISSN:2765-3439(Print) 2765-3447(Online) 자원리싸이클링

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