The Study of Carbon Materials in the Pyrometallurgy Method to Recovery of Silver Metal from Computer Circuit Board Scraps

Document Type : Research Article

Authors

1 Department of Chemistry, Amirkabir University of Technology, Tehran, I.R. IRAN

2 Department of Chemistry, Semnan University, Semnan, I.R. IRAN

Abstract

In this paper, the recycling of silver metal from computer circuit board scraps was investigated by the pyrometallurgy method. In this method, firstly, the computer circuit board scraps were mechanically crushed by a jaw crusher and then were pulverized according to the vibratory of the disc mill machine. In the next step, the sample was melted by charging material. The choice of charging materials for the production of low slag and the formation of the lead-gold-silver alloy was very important, and among the charge materials, carbon materials due to ash and the effect of various oxides of its elements on the efficiency of extraction and production of slag were investigated. In this study, various carbon materials such as gas coke, iron melting metallurgy coke, semi-coke, coal, and charcoal were studied.
As a result, the semi-coke was selected for higher fixed carbon (84.87%) and ash (8.97%) and also less aluminum oxide (11.87 %) in the ash, then the amount of its optimum value was 6 g. Also in this study, charcoal because of high ash (14.20 %) and tin oxide in its ash (3.54 %) has the lowest extraction efficiency (65%) and the highest amount of slag (45%). In the next stage, the lead-gold-silver alloy was separated from the slag phase on the basis of a large difference in the mass volume of the slag phase. Then the silver metal was separated from the gold by the parting process. Finally, the silver was extracted by the process of cementation. In this method, extraction efficiency was reported to be 94%.

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References

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