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Selective leaching of silver from selected semiconductor waste

Meng, L. K. and Sadikin, Aziatul Niza and Othman, Norasikin and Kamarudin, Khairul Sozana Nor and Mat, Hanapi (2004) Selective leaching of silver from selected semiconductor waste. In: 18th. Symposium of Malaysia Chemical Engineers (SOMChe), 2004, 13 - 14 Dec. 2004, UTP, Perak, Malaysia.



Depletion of natural resources is becoming a serious issue in recent decades. This situation gives an arising interest to recover recyclable resources from industrial waste. Semiconductor waste that contains high concentration of precious metals may be treated as potential sources of precious metals if economic extraction is available. Characterization of the waste sample in this study has shown lucrative silver content of 5.35% by mass with co-presence of aluminium, copper, calcium and ferum. The potential of thiosulfate solution in selective leaching of silver from this selected waste was investigated. Thiosulfate leaching of silver follows a combination of reaction paths that include direct leaching, indirect leaching and catalytic leaching. At selected leaching conditions, nearly 90% of silver is leached and high selectivity is achieved. Silver leaching efficiency is influence by concentration of thiosulfate, L: S ratio, A: T ration and temperature. Varying initial pH of the leaching agent did not result in a marked different in silver leaching efficiency. However, an alkaline medium is preferred to avoid or minimize decomposition of thiosulfate, loss of ammonia, formation of sulfide ions that enhance precipitation, and dissolution of undesired metals. Thiosulfate solution exhibited a high selectivity of silver over other metals.

Item Type:Conference or Workshop Item (Paper)
Uncontrolled Keywords:Leaching, semiconductor, silver, thiosulfate solution
Subjects:T Technology > T Technology (General)
Divisions:Chemical and Natural Resources Engineering (Formerly known)
ID Code:6019
Deposited By: Norhani Jusoh
Deposited On:29 Jul 2008 06:58
Last Modified:01 Jun 2010 15:37

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