Determining the contaminant.

[Lou]

Check out Belart.


We have a couple that are about 3' in diameter that work nice.

 

[4metals]

As Lou said Belart makes nice tabletop buchner funnels, but they are available with a perforated plate and a Fritware porous plate. Make sure you get the perforated plate. That is the plate with the drilled holes. The fritware porous plate does not have visible holes and as they age and you get sloppy, the pores get clogged and are tough (if even possible) to clean out.

You can choose either plate fixed (welded in) or removable. I have always had good luck with a welded in plate but some refiners swear by the removable plates as well, so it is a personal preference.

Belart claims the removable plates are for precious metals recovery but if you are accumulating values that have gone through your filter media (or under the edge of your filter media) you need to work on your technique.

The holes in the perforated plates are available in two sizes. If you choose the larger hole size you may need to back your filter paper with cloth sheet material to prevent the vacuum from blowing a hole in your paper (if filtering hot this is a bigger issue).

https://www.belart.com/buchner-table-top-funnels.html

Another nice tool if you are using a tabletop buchner is a vacuum plate. It is basically a rigid piece of polypro that covers the top of the funnel and is sealed with a gasket. In the center is a fitting to connect to a suction hose which allows you to pull a vacuum on the filter and put the hose in the liquid you want to filter. The suction will pull the liquid through the hose and into the funnel and you will not have to lift and pour. iShor makes one of these systems but they are super simple and easy to make your own for substantially less money.

https://www.ishor.com/shor-buchner-vacuum-plates-and-gaskets

 

[Topher_osAUrus]

I hope justin sees this reply.
Brilliant stuff.
He was just talking about something identical to the polypropylene cap and hose design recently on another thread.

 

[Justincase]

I hope justin sees this reply.
Brilliant stuff.
He was just talking about something identical to the polypropylene cap and hose design recently on another thread.

Yes that is perfect.
I have bid on tabletop buchner funnels but had not thought about simply using a plate and four threaded bars to form a vacuum.
Much thanks.

 

[autumnwillow]

The 300$ 26cm inside diameter is similar to a 240mm 130$ Buchner funnel?
I guess I'll stick with the funnel type first not unless we process heavier lots. Silver can wait. Heh. I'll go buy the 36" when our lot sizes increases. Hopefully the 240mm will speed things up. Thanks for the advice guys!

Sent from my SM-G920F using Tapatalk

 

[autumnwillow]

Would a #4 filter paper for silver chloride and silver powder filtration then a #5 for any gold solution/precipitate filtration suffice?

Sent from my SM-G920F using Tapatalk

 

[Tndavid]

Would a #4 filter paper for silver chloride and silver powder filtration then a #5 for any gold solution/precipitate filtration suffice?

Sent from my SM-G920F using Tapatalk

I think I've seen that combo used willow. But then again if the solution is still not Crystal clear there will still be contaminates. I'm still poor as far as equipment goes and still use coffee filters. Yea I know guys. But anyways I filter until the contaminates fill the pores in the filter paper and then I'll continue filtering until my AuCl is clear. Even with coffee filters via a lot of filtering you can still get a really pure product. The clarity of your solution will tell you a whole lot.

 

[autumnwillow]

Just noticed that silver chlorides bypasses a #1 filter. Proceeding with a #4 filter will not be good. I think a #5 will be enough for aucl. We used to use a #42 and a #2. This #1 whatman filter is the worse filter that I have used. Very slow, clogs easily and some precipitate bypasses the filter.

Sent from my SM-G920F using Tapatalk

 

[anachronism]

A number 1 to filter solutions with silver chloride in is fine if used correctly. It certainly won't block the filters, in fact I use these filters for volumes of silver chloride precipitated from silver nitrate using HCl. The only think I have found that blocks a number 1 filter is fines from ashed carbon.

I agree that sometimes I have had to filter twice though, often using the same original filter.

 

[autumnwillow]

Is there a way to keep the agcl precipitate above 25 micron size? Perhaps using a different precipitant? Temperature control? Diluting the solution further or vice versa?

Sent from my SM-G920F using Tapatalk