This is not a tutorial, but a video showing the gold recovered from 550g of mixed gold plated pins.
550g total of mixed gold plated pins are weighted and placed in a 2 litre flask.
The pins are covered with about a litre of CuCl2 solution.
Air is bubbled through the solution.
About a week later, as the solution becomes saturated with copper, insoluble, white CuCl precipitates out.
Not shown in this video, but the saturated solution is replaced with hydrochloric acid
which dissolves the white precipitate and the etching continues.
this cycle is repeated until there is nothing but gold foils left.
It took about a month for the full dissolution of the pins.
Foils collected in the filter were then dissolved in aqua regia, and gold was precipitated using ferrous sulphate.
the result from 550g of mixed gold plated pins
1.77g of gold which needs to be further refined.