Thiourea leaching gold and silver from the printed circuit boards of waste mobile phones

The present communication deals with the leaching of gold and silver from the printed circuit boards (PCBs) of waste mobile phones using an effective and less hazardous system, i.e., a thiourea leaching process as an alternative to the conventional and toxic cyanide leaching of gold. The influence of particle size, thiourea and Fe3+ concentrations and temperature on the leaching of gold and silver from waste mobile phones was investigated. Gold extraction was found to be enhanced in a PCBs particle size of 100 mesh with the solutions containing 24 g/L thiourea and Fe3+ concentration of 0.6% under the room temperature. In this case, about 90% of gold and 50% of silver were leached by the reaction of 2 h. The obtained data will be useful for the development of processes for the recycling of gold and silver from the PCBs of waste mobile phones.

► Thiourea is a selective and less hazardous agent as an alternative to the conventional and toxic cyanide.
► The agent was applied to leach gold and silver from PCBs of waste mobile phones.
► The influence of the particle size, thiourea and Fe3+ concentrations and temperature was investigated.
► In the best condition, about 90% of gold and only 50% of silver were leached with a contact time of 2 h.
► The thiourea leaching would be an alternative and low-toxic methodology for gold extraction from PCBs of waste mobile phones.