Gold Separation of Computer Circuit Board scraps (CCBs) By Sodium Metabisulphite as a Precipitant

Abstract

In the electronic and telecommunication industries, gold has been applied for sinyal strength than other metals such as copper. Gold recovered on electronic scraps namely computer circuit main board, printed circuit board, handphone printed circuit board. Based on characterization results, computer circuit board scraps (CCBs) contains gold and other metals such as copper, lead, alumunium, ferous, nickel, zinc, and silver. It is essential to separate the precious metal of CCBs. Generally, gold separation has been done by cyanide and amalgamation methods. Separation by these methods produce a high gold‘s purity (>80%) and it can be done in a simple way. Yet, mercury and cyanide are very toxic for living things, causes death for them. In this research, gold separation of computer circuit boards (CCBs) has been done by leaching and precipitation methods. In general, recovery gold of electronic scraps has been done by pyrometallurgy and hydrometallurgy methods The method was applied in gold separation processes from modificated methods already existence. This paper reports a promosing method to separate gold of CCBs. Aqua regia and HNO3 solutions lwere used in the leaching processes, and sodium metabisulphite (Na2S2O5) was applied in the precipitation process. Silver, Copper, ferous, alumunium, lead etc. are relatively instable ions and dissolved in HNO3, but gold is stable as a solid residue in HNO3 solution. Gold separation of solid residue by leaching with aqua regia. Gold formed a brown solid with the amount precipitated is 0.089g in the 5g CCBs samples was treated, also gold found high purity 98.9% .