Abrasive Mill

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stoneware

Well-known member
Joined
Feb 3, 2020
Messages
431
Treadmill from landfill, propane tank for the drum.

The abrasive action on low grade gold plated junk will rub off then collected for further refining.

All thats left to do in mount the second roller, control module and find an inner tube to cut and stretch over the drum to give some traction.

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Are you using abrasive media in your tumbler or just letting junk work on itself?
Any boards that the big paper shredder could not handle were broken down, it's this shred that will do the work.

Lots of low grade pins that I would not otherwise bother with are going into the mill.

I figure a couple of hours in the mill then when it comes time to empty I'll discharge the load into a large plastic tub. Then rinse the barrel out with water.

A drop of dish soap to eliminate float, then screen out the chaff.

I anticipate some solder to also abrade free of the boards, a weak hot hcl should look after the tin - leaving me with what little silver maybe alloyed with the solder.

I'm working at installing the idler roller and control box this evening.

Have more gold plated junk from a box with a couple hundred insulin pumps a neighbor dropped off the other day and some more mother boards to strip. Before the mill goes into action.
 
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I like your ingenuity, let us all know how it works out. You may need to add some silica sand. Crushed will be more aggressive then beach sand.Good luck!
 
Let us know how it works out. You can add media, such as glass bottles after smashing on the ground, dry. My experience with metal on metal, especially soft metals, is that it will just agglomerate onto other particles, not really eroding off all the base metals. You may end up with a thicker deposition on certain pieces, but no real separation from base metals into individual PM particles. Glass or Silica is a relatively non reactive grinding media. In other words, it won't consume acids in the dissolution phase, like if steel balls were to be used.
 
The tank used is designed for liquid propane, the welded factory seam needs to be ground down a bit.

After the seam is smoothed out I'll cut a piece of the treadmill belting then use some spray on adhesive to hold it in place.

The center shell overlaps the end bells, you need to fill the gap inside the tank with silicon or similar filler otherwise some of your gold will find its way into the crevices.

Most treadmill motors, the pulley is threaded on. If you run the motor reversed chances are the pulley will come off.

The mill I'm using has a keyway with set screws.



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This is nice man! If you decide it works well enough to build an upgraded version (bigger and more power) I have a really nice 110/220 power supply with control knobs on it that controls the speed and torque of the motor. It's for sale but I would give you the deal. Anyways, I would love to see a video of this in full operation start to finish. I am really interested in yields. Keep thinking outside the box my friend.
 
Welds ground down, silicon has cured, belting inside to warm up making it more flexible - purchased Gorilla adhesive

Removed old paint and roughed up the surface for the adhesive.

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A bug on the first loaded run. there's about 60 pounds in the drum and the drive roller slips against the belting.
 
Cut an old bicycle inner tube into 2" long pieces, they're a bear to get stretched over the roller but managed to get three on before giving up.

On Monday when I have access to a metal lathe I'll turn a tapered cone that fits over the stub. This should make it much easier to roll the tube sections onto the roller.

Also added a blocker to keep the end of the drum from rubbing against the plastic pulley.

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Maybe try a long strip of bicycle tubing wrapped around, with contact cement to glue them on. It might be easier than trying to get the short sections over the hub.Wrap it like a golf club handle. IE, one piece of rubber on an angle so as not to overlap a lot, on the next spiral wrap.
 
Found a tube slightly larger in diameter than the first one, cut to length then ran some soapy water inside.

Nice tight fit.

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When the drive roller is new it has knurling on the center section to give it traction. Once worn it will slip against the belt.

Had the tubing on the drive roller had not been so thin would have welded dibbits onto the surface.

Another idea was to drill small holes then insert screws and let the heads grip the rubber coating on the drum.

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With the e-waste acquired yesterday and what I have on hand to process I'll likely have enough material for a small load.

No lift bar inside the drum so the ideal load would be 50% to meet this requirement I'll toss in some chaff from the first load.
 
I'm going to run this load five hours.

The blocker is doing a fine job of keeping the end of the drum from rubbing against the pulley.

I may have to add a metal surface to it to keep if from wearing.

 
I also have a ball mill, electric motor is going to be swapped out for a small gasoline engine.

Trailer mounted so I'm able to do my milling away from my neighbors, makes a lot of noise.

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One of the larger pieces tossed in with the shred, only the gold was removed, solder mask and copper untouched.

I did the damage to the end trying to feed it through the paper shredder.

copper.jpg
 
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