Tantalum in a strip cell

[DNIndustry]

Hey guys.
I am building a stripping cell. I am trying a little something different .
Rather than flat, I thought id let gravity help.
I picked up a 3ft (ballpark) 3"OD glass flange made by Buchi.
I was going to place the items to be striped at the top.
At the bottom I was going to use a PVC floor drain with glass microfiber filter at the bottom (I believe the cellouse ones would burn) with a ball valve & vaccum attachment (it needed) to drain and filter simultaniously.

Now structurally I had 2 Ideas...
I have a lead plug I made. While puring it I trimmed the ends of the corrosion resistant milspec cable. I was going to place the anode below the drain/filter. as to keep it cleaner yet still get conductivty. The basket is a bit different. I got a high grade SS mesh & Pointed stand offs. I placed it inside at the very top of a plastic/rubber cavity. It resembles one of those ball on a string toys....(does that make sense?) The pins would be enough to fill it to the end where I would use a nylon mesh just big enough for them not to fall out. The Idea is the current has to be passed through pins. the walls are inert as it the retaining mesh.


My questions are have anyone used tantalum as the Cathode or Anode. It is the best in corrosion but would it degrade from current?

Has any one tried using a small plastic pump to recirculate in a down ward motion. The filter would clean the acid prior to entering the pump.?

Any ideas as to the recommended current density and voltage. The cylinders ID is 87mm & 36in <- (dont have my tables)?


Ill try to post some imgs this morning. Please any advise would be helpful.

 

[Lou]

It's rather hard to give recommendations when I don't know what current density, the voltage, the distance between anode/cathode, whether or not it is agitated, or exact bath concentrations.

Using a pump is a common thing to do for electrolytic baths, reactions, even heat flow applications. Just make sure your pump's diaphragm (although you can use a peristaltic pump too) is resistant to your electrolyte at high temperature.

If I were you, I would stay away from tantalum and other valve metals save titanium. Ta is needlessly expensive and a real bear to fabricate while Ti is cheap, machinable, and can almost always substitute...

Heck, it's just a stripping cell, why not use what everyone else uses? They seem to be getting a long fine!

Titanium is really good for plating sponge gold.


Lou

 

[DNIndustry]

I thought I described it...
A glass flange 36"L x 2.75"ID. anode and cathode are on opposing ends.
Both arecircular about 2.5" diameter. The plated parts may extend in 4-6"
Its for a sulfuric cell. : ) : )
Pics would help.
Im trying to eliminate the need for dilluting. Keeping everything self contained. The built in separation grate has a filter to hold the gold powder all together after draining out.
The pump question was to keep the liquid/pwder flowing downward to the filter so settling is less time.

 

[butcher]

would ion exchange membrane work better with bag? how about making material into dore anodes?

 

[Anonymous]

(From an electrical standpoint, I do not think a tall skinny column would be good for a sulfuric stripping cell because the current and nearly all of the ions would work on(at) the surface area of the face closest to the cathode.(Only or primarily)


Jim

 

[NobleMetalsRecovery]

Just to let you know, I offer Tantalum wire on eBay for $3.00 a foot. I have experimented with it from time to time over the years.

I seem to recall that it forms an oxide coating, which keeps it from being dissolved in Aqua Regia.

I think it's a nice item to have on hand for experimental purposes. If you want some please PM me.

 

[DNIndustry]

I actually ordered some samples of Ion Exchange media from DOW.
Dowex21. I forget the specifics. I was looking for Purolite a500c & amberjet 4400 I believe...

 

[butcher]

look into crucibles , coors pourous membrane cups, even clay flower pots might work, and maybe think large flat circles, more surface area,and greater cathode current

 

[qst42know]

Red clay pots get their color from iron oxide. They are also not fully vitrified.

Wouldn't iron oxide cause chemical problems?

 

[butcher]

not sure but have heard of them being used.