My DIY Filter press overall design

[PickyPlans]

Here is a design I created for a customer to filter cyanide leaching solutions from ores. It achieves a filtration rate of about 1–1.5 liters per minute using just a large piece of filter paper. While I no longer have the unit, I can guide you in building one if needed. It’s also effective for filtering metal hydroxide waste.

The main body is made from a 35 cm diameter steel pipe, internally coated with polyamide paint for protection. One end of the pipe is welded to a flange, which is secured with a hydraulic jack. I had the flange lid custom-cut and machined with circular grooves (2 mm deep and 6 mm wide) to collect filtrate from the entire surface area of the filter paper. The filtrate is then directed to a collection side, where a simple welded tap allows for easy drainage.
The system operates using compressed air, which is directed to the top of the chamber. This pressure forces the dirty solution through the filter paper, allowing the filtrate to pass through while the solid residues accumulate as a filter cake. Once filtration is complete, the solids can be easily removed.

 

[4metals]

This is a simple yet effective low cost design to the refiners dreaded slow drip filtration. I can see this being quite useful for filtering metal hydroxides from a classic destruct waste treatment process without breaking the bank.

 

[PickyPlans]

This is a simple yet effective low cost design to the refiners dreaded slow drip filtration. I can see this being quite useful for filtering metal hydroxides from a classic destruct waste treatment process without breaking the bank.

Thanks for taking into the account

 

[4metals]

I was thinking about the material you made the press out of,

The main body is made from a 35 cm diameter steel pipe, internally coated with polyamide paint for protection.

and I wonder if it could be made of schedule 120 PVC pipe. schedule 120 PVC is rated to 300 PSI and all fittings, including flanges, are available as well. Obviously welding would be the best way to build it but I am considering the corrosion resistance of PVC to make the press also a viable option to filter jewelers sweeps which are notoriously difficult to filter. The PVC would stand up to the acidity and the schedule 120 would stand up to the pressure. With sweeps you could drain the pregnant aqua regia and fill the press back up with water to rinse the cake both quickly and efficiently. Just a thought I had while driving, one day I may get over thinking about refining!

 

[Shark]

.......one day I may get over thinking about refining!

Let's hope not. Slow down maybe, but don't stop.

 

[PickyPlans]

I was thinking about the material you made the press out of,

and I wonder if it could be made of schedule 120 PVC pipe. schedule 120 PVC is rated to 300 PSI and all fittings, including flanges, are available as well. Obviously welding would be the best way to build it but I am considering the corrosion resistance of PVC to make the press also a viable option to filter jewelers sweeps which are notoriously difficult to filter. The PVC would stand up to the acidity and the schedule 120 would stand up to the pressure. With sweeps you could drain the pregnant aqua regia and fill the press back up with water to rinse the cake both quickly and efficiently. Just a thought I had while driving, one day I may get over thinking about refining!

PVC is a good choice, and you provided some great details. However, I’ve come across a Teflon version used in a gold cyanidation plant. The chamber was made of 5 cm thick Teflon with a 30 cm diameter, and both the top and bottom were sealed using O-rings placed in machined circular grooves. The entire system was secured with star-shaped screw and nut placements, similar to lab-scale autoclaves. This design eliminates the need for welding or flanges and effectively filters pregnant solution from jeweler’s sweeps.
I usually get all those ideas and plans while I'm trying to sleep. Kinda in the same situation...
Take care, my friend...

 

[haveagojoe]

I was thinking about the material you made the press out of,

and I wonder if it could be made of schedule 120 PVC pipe. schedule 120 PVC is rated to 300 PSI and all fittings, including flanges, are available as well. Obviously welding would be the best way to build it but I am considering the corrosion resistance of PVC to make the press also a viable option to filter jewelers sweeps which are notoriously difficult to filter. The PVC would stand up to the acidity and the schedule 120 would stand up to the pressure. With sweeps you could drain the pregnant aqua regia and fill the press back up with water to rinse the cake both quickly and efficiently. Just a thought I had while driving, one day I may get over thinking about refining!

I was thinking something similar, wondering how to make a smaller, lower pressure tabletop version for hobbyists like myself, using a hand operated air pump such as a bicycle pump. I don't think it would need very high pressure, just enough to speed up filtration a bit.

ABS pipe might be another option, since it can be easily bonded with Solvent Weld. However it isn't rated for pressure.

Transparent acrylic pipe might also work and can also be solvent bonded.

The car jack @PickyPlans uses to secure the filter plate is a really great idea, but it might not be so effective in a plastic version. Perhaps a bolted flange would work instead, although undoing bolts would make it take longer to change the filter. Plastic pipe could be threaded to fit a flange, or for limited pressure solvent bonding would probably be ok.

Overall I think the idea of using positive pressure instead of a vacuum is very interesting to consider, since vacuum pumps are so expensive and are directly subjected to chemical vapors.