I'm currently processing these lovely gals. Approximately 850 grams. But I'm afraid that my record keeping has failed me and it most likely closer to 1000. For the most part all the material is the same RAM IC chips, although I'm noticing that there are some small BGA chips mixed in not many but 3 or 4. I'm hoping this doesn't mess up anything. But I have ran them thru Hcl heated then with boiling water 5 to 6 times or more. Until the water rinsed pretty clear. Then I did the HCL, heated of course, and rinse thoroughly like the last time. I then tried to incinerate them with map and it works but not economically viable. I then tried pyrolyzation and that worked. In my electric furnace But it was too small and I had to much material. I then try to combination of pyrolyzation and incineration. But at my house it was too smoky and too stinky. So I found another place where I can just use a simple regular torch. Which was more economically viable. So I incinerated them. And now I'm trying to seive them thru a kitchen strainer thingy. I have no idea what the mesh size is. But I'm trying to crush and run them thru the strainer. Which is fastly becoming an arteries task. Grind with coffee grinder sift ground with mortar and pesto a little bit put it back in the coffee grinder and do it again! Does anyone have any helpful advice? I feel like I'm forgetting something on this post so there may be follow-up posts for the information I forgot to convey or ask. I'll attach photos as well.I just tested a new type of chips - SMALL BGA chips, like in newer RAM memory types (DDR2/DDR3), and the similar chips from motherboards and cards. They are all small, square or rectangle shaped, and all of them have a foil base with solder balls.
I soaked the chips in concentrated HCl and bring them to boil 3 times, the most of the tin dissolved. I incinerated the chips and washed with water. This time i used poorman's AR with KNO3. There was still some tin left so it took me some time to filter the solution with metastannic acid. I dropped the gold with SMB and washed the gold powder with hot water. I redissolved the gold again with poorman's AR to be sure that all of the contaminants are gone. I waited until AR was crystal clear and the contaminants like silver chloride and metastannic acid was settled at the bottom, then i carefully decanted the AR solution through the filter paper and dropped the gold with SMB again. I rinsed the gold powder with hot distiled water 3 times/3 times with hot HCl/3 times with hot distiled water. i dried the gold, measured it and here are my results...
View attachment 30335
Total weight of chips: 233.7g
Number of chips: 919pcs
Average weight of one chip: 0.25429815g
Gold recovered: 1.1g
Avg. gold per 1kg: 4.706889g
Avg. gold per one chip: 0.001196953g