Chain impact mill

[kjavanb123]

Update,

I have promised and planned to test the efficecy of my chain mill to process boards using gravity separation.

Since there is no shredder in the lab as of yet, I manually sheered the board into smaller pieces to feed to chain mill,


It went pretty fast, here is the result.


I use two different sieves, one to separate the very fine powder, and other the coarse pieces, and the oversize part which was minimal.

Using my homemade blue bowl, I separated the non-metalics fine from the metalic fine powder,


Here is the clean up of fine powder, after ferrous pieces were manually removed,


Here is the ferrous fine powder which was removed,


More in next post

 

[kjavanb123]

The following is the "coarse" pieces cleaned up, and separated into ferrous and non-ferrous parts,

Non-ferrous


Ferrous


First I added dilute hydrochloric acid to dissolve any lead, tin, aluminum etc, as it can seen, reaction is taking place as is evident by the bubbles on surface.


In previous experiment which I depopulated and smelted components of identical circuit board, there was no gold recovered, but I recovered 2.9 grams of silver.

During cleaning up process of non-ferrous fine powders, I did not notice any gold bond wires, only grayish powder which seemed to be the heaviests.

I will update this as I try to recover silver from concentrates recovered from milling and gravity separation, to see how close it will be to silver recovered using lead smelting.

 

[kjavanb123]

Ok somewhat interesting result so far. I was able to hand pan the hcl solution which still reacting with non-ferrous fine, and see the lovely yellow band of heavies.

I let the fine powder to react with hcl till tommorow so I can neutralize solution then dissolve the remain in nitric acid.



Tommorow if time permit, I will recover silver and report my finding.

Although seeing gold in this process tells me that for whatever reason I could not cupel it right with my last identical sample.

Best
KJ

 

[kjavanb123]

Hi all,

I have another 20 lbs or so of cut bare boards to run in the chain mill.

So far recovery percents for minus 100 medh and plus mesh 100 to minus mesh 40 in two different batches were as following,

Batch 1:
Percent of pulverized boards that pass mesh 100 screen is 87.56%
Percent of pulverized boards that is bigger than mesl 100 but passes through mesh 40 screen is 12.43%

Batch 2:
Passing mesh 100 is 91.36%
Passing mesh 40 but stay on mesh 100 is 8.63%

I can only think of size of cut boards has to do with smaller output size. For this design mill with 5mm holes, the bigger chunk of boards the smaller the pulverized output size will be.

Also in local lab supply market I found a supplier who is paying $17 per kg of pulverized copper, which is really good.

More updates soon.

Best regards
KJ

 

[kjavanb123]

All,

Recovery and melting copper from my leftover bare boards partially completed. Here are 6 kg copper ingots. There is another 6 kg of copper which waiting to process boards.

Used salt and lemon to polish the surface.







So far recovery percentage has been 19% of weight of bare circuit boards.

Thanks and best regards
Kj