Hammer Mill vs Granulator

What is the difference between a hammer mill and a granulator. I can find granulators all over the place (ebay) used and at a decent price, but everything that i see scrappers using is a hammer mill (youtube) which are 10k+ and can only be found over seas?



I am looking to turn pcb into a powder in order to do copper recovery from PCB's

Thanks
Mike

I think you need to establish exactly what you want to do with the PC boards to decide what you need to use to grind them up. Are you going to "grind" the boards and all the electronic "stuff" on the boards into a powder so you can separate the metals by washing, with the heavies settling out? Kinda like panning gold?

Or are you just breaking the stuff down so you can get a chemical process going on all the metals in the mix? Which might mean quite a bit coarser grind? (and less costly grinder)

There will be a tradeoff here, as the finer the material is ground, the quicker the chemical reactions will take place. But the cost of finer grinding may start to interfere with the economics of the process.

Also, you probably are looking for the higher value metals from the mix, such as gold, silver, etc, that is found in small amounts in e-scrap. It can outweigh the copper in value.

I am doing a bit of blue sky talking here, as I have not done either type of process but understand some of the physics behind them.

If you are looking to do the chemical recovery work, you need to pop over to the "gold refining forum" to ask some questions. But be warned: they are a crusty bunch over there and don't take the sillier newbie questions very well!! I'm sure there are lots of people over there who have done or are doing exactly what you describe.

We have a few people who refine e-scrap who visit this site from time to time...maybe they will chime in.

Good luck,
Jon.

Originally Posted by sawmilleng

I think you need to establish exactly what you want to do with the PC boards to decide what you need to use to grind them up. Are you going to "grind" the boards and all the electronic "stuff" on the boards into a powder so you can separate the metals by washing, with the heavies settling out? Kinda like panning gold?

Or are you just breaking the stuff down so you can get a chemical process going on all the metals in the mix? Which might mean quite a bit coarser grind? (and less costly grinder)

There will be a tradeoff here, as the finer the material is ground, the quicker the chemical reactions will take place. But the cost of finer grinding may start to interfere with the economics of the process.

Also, you probably are looking for the higher value metals from the mix, such as gold, silver, etc, that is found in small amounts in e-scrap. It can outweigh the copper in value.

I am doing a bit of blue sky talking here, as I have not done either type of process but understand some of the physics behind them.

If you are looking to do the chemical recovery work, you need to pop over to the "gold refining forum" to ask some questions. But be warned: they are a crusty bunch over there and don't take the sillier newbie questions very well!! I'm sure there are lots of people over there who have done or are doing exactly what you describe.

We have a few people who refine e-scrap who visit this site from time to time...maybe they will chime in.

Good luck,
Jon.

I am looking to get them as fine as possible and use water methods.

Now i am planning to remove all the chips from the board first, then incinerate those and run them with a water process so i would just be grinding up the bare PCB for the copper the gold and such should be in all the chips.

Another food for thought, do you know how well the fiberglass of the pcb bonds to the copper? In the video posted below they use a granulator to chop up copper wire, and then separate the shield from the copper based on a shaker table due to the weight difference. This works because the copper has no bond with the shield and when it gets to the shaker table it is 2 pieces. If the fiberglass bonds to the copper, it wont be 2 different pieces and be unable for the table to separate The higher the bond with the fiberglass the smaller finer the pcb needs to be ground to get them to separate.

Thanks for the responses guys
Mike

Mike,

I think you may have to do some experimenting. PC boards are made from lots of different things, not just fiberglass, and the bonding of the copper to the PC board has just as many different glues. You might be looking at a couple of processes to get the boards down to a small size: hammermill hogging for the first pass and then putting through a ball mill to get the stuff down to a powder.

How well the copper will separate is a good question. More reason to do the experimenting. The ball milling copper separation may work better dry, wet, or hot...to break glue bonds---more experimentation.

If you are looking to do this on any sort of scale, then discussion with the purchaser is in order. A percentage of waste (in this case, circuit board material) in the copper feedstock to, say, a smelter, may not be an issue for the purchaser.

I've been critical of the wire granulating because of the same questions. Smaller wires don't have any reason to fall free of the insulation that surrounds it. A lot of the granulating vendors don't talk much about copper recovery %'s and contamination of the recovered copper with unwanted wire insulation. Press them a little by trying to write a separation guarantee into the purchase agreement and watch them squeal like pigs!!

This would be a waste of time to float out Cu from PCBs. It is laminated in the fiberglass with resins. You must free the Cu from the resins first with heat. After that just melt it and form Cu alloy bars.

The only reason to grind with a HM would be to mix it well to get a good sample to send to a refiner. This seems like spending $100.00 bills to find dimes.

Eric

Originally Posted by spinroch

I wonder what the EPA & the DEC would have to say about grinding up circuit boards.....

They would say you are good to go as long as you have the required permits and permissions and/or you can afford the fines.

Whats the bad actor in grinding up circuit boards? As long as the process is not releasing deleterious products to the air, water or land. Burning the electronics removed from the boards is more likely to cause rectal hemmorages down at the epa.

All I can see in the process of grinding up boards is maybe dust issues or water disposal issues when separating the copper. But not enough to cause anyone to cut short their donut stops before taking the handcuffs to badass environmental bandits...

Jon.

Originally Posted by spinroch

I wonder what the EPA & the DEC would have to say about grinding up circuit boards.....

I'm concerned with the "water methods".

What do you do with all the water when you're finished?

Water is a precious commodity, your recirculate and reuse.

Hamme rmill wins hands down as it can do more than one product. The downside is that they require a lot of horse power.

http://www.scrapmetalforum.com/off-t...l-cyclone.html

I think you may be looking for a set up like this?

with a shaker table.