EFFECT OF COMPOSITION ON ELECTROLEACHING OF ALLOY OBTAINED FROM USED
PCB MELTING PROCESS IN SULFURIC ACID SOLUTIONS
ABSTRACT
Min-seuk Kima,b*, Jae-chun Leea,b, and Jeong-soo Sohna,b
a
Resources Recycling, Korea University of Science and Technology, Daejeon 34132, Korea
b
Mineral Resources Research Division, Korea Institute of Geoscience and Mineral Resource (KIGAM),
Daejeon 34132, Korea
Alloy mass containing precious metals was produced by melting of used printed circuit boards. For the
development of recovery process of precious metals from the alloy, an electroleaching of the alloy was
conducted in sulfuric acid solutions. Based on linear polarization study of main alloy components, such as
copper, tin, and iron, tin was found as a key role component for an anode slime formation, resulting in a
precious metal enrichment in the slime. An average composition of the alloy was 85.6 % of copper, 5.92 %
of tin, 1.91 % of nickel, 2.74 % of iron, and etc.. The precious metal content was 0.87 %. During the
constant current electroleaching at 10 mA/cm2 and 40 oC in 1 mol/L H2SO4 solution, the alloy components
were distributed to the three phases: anode slime, electrolyte, and cathodic deposit. 67 % of copper was
predominantly distributed to the cathodic deposit, while 94 % of tin to the anode slime and 96 % of iron
and 99 % of nickel to the electrolyte. The precious metals were concentrated in the anode slime and the
component ratio was 4.34 %; the enrichment ratio of precious metals in anode slime to anode is 5:1 and it
makes following hydrometallurgical processes for separation and purification easy to handle.
KEYWORDS
Electroleaching, Alloy, Used PCB, Precious metals