Did you ever try to estimate the amount of gold that can be extracted from half a pound of electronic waste? Around one gold bead and imagine the effort you will have to put in it. The value of gold you abstract will be far less than the hard work and equipment you will for the process. Still, if you wish to do this, you will have to start by dumping all the waste in a ball mill for crushing. Next, set all the junk on fire and sift the ashes. The junk and slatted trash will thus be removed from the powder. 

 

 

 

You can not remove the iron bits by moving a magnet over the remaining powder. The lead can be removed by boiling the mixture at 1700 degrees, Then remains, copper that can be removed by giving the mixture a water and acid wash along with electrocution. Post this, you will have to add some more acid and melt it with flux and litharge. The mixture that the experimenter took here was a mixture of waste computer parts that mostly consisted of motherboards and other such stuff. 

 

Post the ball mill and incineration, the sifted stuff is of main use. The man here was able to abstract 4 milligrams of gold from a 150 grams sample. The gold is never in the ashes; acid has a tendency to stick with heavy metallic particles.  You can get rid of all kind of oils with the help of dish soap. The mixture will also contain other precious metals like silver, palladium, etc. but you will have to use a few other techniques to sort those out. The black thing that you will notice is actually copper (cupric oxide) that can either be melted or washed with hydrochloric acid. The gold is usually carried by small chips that use very fine wires of gold for making a connection between silicon located in integrated circuits and external wires.

 

You can see the complete process at https://youtu.be/ee_lmZIAwek.