Abstract

In this study, a process was designated to recover gold from bismuth and tin containing wastes obtained after the electroform process that was used in the jewellery manufacturing. Waste, which was sieved to a certain size, was leached by aqua regia in the initial stage of the experiments. Optimal conditions for aqua regia leaching were considered to be as follows; room temperature, solid/ liquid ratio of 1:10, 5 min of leaching duration, and 600 rpm of stirring rate. Dissolution efficiency of gold by leaching was 99.38%. In the second stage, gold in solution was recovered by chemical precipitation using NaH2SO3. Optimal precipitation conditions were determined as; the use of NaH2SO3 as 5 times of the stoichiometry, by the stirring at 600 rpm for 30 min at 80 C and the precipitation efficiency were calculated as 99.73%. Gold precipitates were melted to produce gold bullion.

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