Previous investigations into the hydrometallurgical recovery of Au from WPCBs and other secondary sources have focused on the use of cyanide lixiviants for the leaching step , . However, due to the environmental and human health risks associated with cyanide toxicity, there has been a great deal of research on the replacement of cyanide with alternative lixiviants such as thiosulfate, thiourea, and halides , , . Among them are iodide lixiviants which are known to be recyclable, non-toxic, and highly efficient Au leaching lixiviants.