TUMBLER CELL

[goldsilverpro]

Your black powder needs further refined in AR or HCL/Cl before melting.

I totally agree. It's so much easier to dissolve when in powder form.

 

[glorycloud]

OK, help me out here. How great an improvement in his gold quality will he see
when re-dissolving and re-refining as you suggest? Is it because he is processing pins?
Just an approximate estimate would be helpful or a more detaiked explanation as to
what that second process will eliminate potentially.

Many thanks!!

 

[qst42know]

Traces of lead if present would have reported to the bottom and perhaps other compounds. Stripping is a recovery process not a refining process.

 

[goldsilverpro]

How great an improvement in his gold quality will he see
when re-dissolving and re-refining as you suggest? Is it because he is processing pins?
Just an approximate estimate would be helpful or a more detaiked explanation as to
what that second process will eliminate potentially.

In order for gold to be reused for most new products, it must be first refined to a minimum of 99.95% purity. If it's not at least that purity, it is not pure or Fine gold. This has been the accepted minimum standard in the industry for many years. When companies make new gold products, they want to start with (and, in most cases, MUST start with) pure gold. Therefore, if it is less than that purity, it MUST be refined by someone. Refining costs money. Either you refine it to at least that purity or receive less money when you sell it.

When gold is pure, the buyer knows what he is getting. He knows that there are not impurities in it that would create problems when new products are made. For some uses, gold plating salts, e.g., the gold must start at 99.99% pure.

I feel safe in saying that the black powdered gold coming out of the sulfuric cell is NEVER that minimum purity of 99.95%, no matter what you are running. It's not even close and melting won't help the purity much. Purity is a go/no-go thing. It either is or it isn't. If it isn't, it must be refined. Even if the purity is 99.90%, it will have to be refined by someone before it can enter back in to the marketplace.

qst42know is right. Sulfuric stripping is a recovery process and not a refining (purification) process.

After I had the black powder, I could dissolve it in AR and refine it easily to 99.95% in, say, 2 hours. It's so simple at that stage that one would be foolish not to do it.

 

[glorycloud]

Great - thanks for the reply. This is somewhat like having to wash the gold folis when
they are removed from the finger cards in lieu of just melting them w/o going through
the washing process prior to dissolving in HCL / Clorox.

I haven't used a cell but I understand now.

Thanks!

 

[firewalker]

17.4 grams of black powder after all the processing,

I guess I should have been more descriptive. I used the word black cause I was thinking about the powder in the cell when I posted. I did state "after all the processing", I guess I should have been specific in that I finished processing the power by washing with water(4 times), hcl(3 times), and ammonia(1) time and finished by using A/C and dropping with SMB.

After all is said, I still have 17.4 grams of powder LOL

 

[qst42know]

If it is all gold you will still have 17.4g after AR or HCL/Cl. If it is not you will have a 17.4g of not quite pure gold.

You won't know for sure until you finish the job.

Edit

A/C = HCL/CL Sorry I missed that.

 

[Gold Trail]

What is the voltage and amperage when you run 1/2 pound? Have you experimented with higher amperage to decrease the time. You have quite a bit of solution and I don't think you would have problems with the solution overheating. Of course, you don't want to overheat the cables.

GSP, this question is reguarding a regular cell, i just made mine today, and used it heavily for a while, mostly testing this and that. after a while, i concentraed on CPU lids.

i noticed the acid got HOT and the more i ran, the worse things got. my cable between the aligator clipd were sizzling, ect
cell specs:
HIGH concentrate sulfuric... (i used Clobber from the plumbing supply house, not avail to just anyone)
6/12 vdc 6 amp charger set on 12 vdc @ 6 amp
Lead anode / cathode
the hotter it got the slower things went, is it possible i have saturated the acid? (i really didnt do that much) is the high heat normal?
what can be done to not get the acid so hot? i assume its not good?
the acid was so hot that i splashed some on my arm and it imeadiatly blistered (generally you can splash sulphuric on ya and can run to the sink and get it off with out serious injury)
any comments?

thanks in advance for your insight Ryan






L

 

[butcher]

if wires burn amperage is high, current and voltage cause wattage, and wattage is heat, I dont run a sulfuric cell, but I will venture to say the metal content is high in solution almost shorting out your power supply.

here is a trick for a cheap but very good regulator, I use in electrorefinning, and other things. add a light bulb in series with your cell, example the positive wire from power supply to the light bulb then a wire from other side of light bulb terminal to the anode of your cell, the light bulb acts as a variable resistance, and control the amperage your cell will pull from power supply, the wattage of the light bulb will determine maximum current through it, it also acts as an indicator as to condition of your cell (or circuit), if cell is a short the lamp lights full brightness, if very little current in cell the bulb is dim,
this is an old trouble shooting tool to find shorted circuits or protect equiptment if there is a short,
heck fix one up to fit the fuse box of yer truck for next time yer troublshooting those shorted out horse trailer lights.

 

[Gold Trail]

interesting, yet simple approach , worth a shot

its been 3 hours since i ran the cell and the dish is still warm...

ryan

 

[goldsilverpro]

In most electrolytic systems, you are limited to so many amps per unit volume, before overheating or other problems occur.

How large is your tank? How many amps are you running?

In the large 50 gal tank I ran, I pulled 250 amps - 5 amps/gallon. That increased the solution temperature to about 110F max, after running all day, a figure I was comfortable with. You are obviously running much higher than that.

 

[Gold Trail]

GSP, my tank hold about a 1/2 gallon, and runs between 6 and 8 amps,

i will tune in down to half of that or less, which would put me within your figures.

I only guess that overheating this acid is not good, and will shorten the life of it?

Thanks again, ryan

 

[golddie]

Hi Folks
This is a project I am interested in very much
I have e-mailed the company for the machine and they said that they don't sell it in the way you see it in the picture that we have it here in this forum
So I would have to modify it
If anyone have the details to help me out please post it here.

Also I see that Gold Trail is having problems
I guess you are doing this in a different way

I would really like to have a cell like this that will work
Thanks

 

[Palladium]

Everything you need to know is pretty much listed in this thread some where. The website shows video's that might help. It's explains everything in detail.

http://www.nulltime.com/zincplating/site_map.html

 

[Palladium]

If you want bigger try barrel plating. http://www.singletoncorp.com/portable_barrels.html

 

[goldsilverpro]

golddie,

Just remember that electrical contact has to be made to every gold plated portion. Solid metal parts, like pins, work well. It wouldn't work on fingers for 2 reasons (1) You won't make contact to every finger. (2) The circuit board material will be attacked by the sulfuric.

 

[SapunovDmitry]

BTW What about the contact (anode) material? Will it be attacked by sulfuric?
And how can one make a constant contact to the pins without current disrupting from time to time? One should use a spring?

 

[goldsilverpro]

SapunovDmitry,

I used to use non-coated bare racks, made of 1/4" brass square stock, with carbon steel (not stainless) piano wire spring contacts, to hold the parts I was stripping (old side braze CPU packages). Neither brass nor steel was attacked after several hundred cycles. The only things I know of that are attacked by the sulfuric, when they are made the anode, are Au, Ag, Pd, Ni (slightly), and Co (slightly). In another forum, finishing.com, I, just today, posted a method of using this to strip gold from aluminum, without attacking the aluminum.

I have had problems with stainless and Ni or Co superalloys. The nickel in non-magnetic stainless may be attacked. Once, I used a magnetic stainless beaker as the cathode and it developed holes at the solution level. Therefore, it may also eat chromium. If too much Ni or Co builds up in the solution, it will stop stripping gold.

At the solution level, you could experience slight etching on a rack or wire due to the moisture and/or oxygen in the air, especially in high humidity. Concentrated sulfuric is a common lab desiccant and will absorb water from the air. Therefore, if you don't stir occasionally, the top layer of solution will be more dilute. At some concentration, the absorption will stop. In my experience, after using the same solution daily for at least 2 years, the total amount of water absorbed doesn't effect the selective stripping of the gold.

To prevent attack on most metals, don't dilute the acid too much and don't let it get too hot. On another forum, a guy experimented with battery acid (35% H2SO4). Although the gold still formed a powder, the copper under the gold dissolved very rapidly. At some concentration, the Cu, or other base metals, will start dissolving - the concentration is probably different for each metal. I really don't know what these threshold levels are. To avoid a problem, I wouldn't add more than 10% water to the concentrated H2SO4 (I usually only add 5% water - a little water will make it strip faster). I prefer the temperature to not be over about 43C (110F).

The original patent, 2185858, was for stripping Au, Ag, or Pd from Zn, Cu, brass or bronze. It was not for Au recovery, but for removing faulty plating, without damage to the substrate, so that the parts could be replated with fresh gold.
http://www.google.com/patents?id=L3FVAAAAEBAJ&printsec=abstract&zoom=4&source=gbs_overview_r&cad=0#v=onepage&q=&f=false

If you are stripping pins in a standard tumbling plating barrel (see the Singleton Corp. link that Palladium gave above - the one I owned was a Singleton and was nearly identical to the one in the photo - they're expensive), using a dangler, button, or rod contact, only about 1/3 of the pins make contact at any given time. No problem. Eventually, all will make contact and all will be stripped. When plating in one of these barrels, they only apply 1/3 as much current as they would if the same amount of parts were on a rack. Therefore, to get the same plating thickness, they triple the time. The same logic would apply to barrel stripping as opposed to rack stripping.

Chris

 

[Palladium]

When plating in one of these barrels, they only apply 1/3 as much current as they would if the same amount of parts were on a rack. Therefore, to get the same plating thickness, they triple the time. The same logic would apply to barrel stripping as opposed to rack stripping.

Chris

That just makes so much sense. You can run 3 times the volume, while only drawing 1/3 amperage needed. Just adjust your time intervals. This means your rectifier is not constantly overloaded or at max draw time. This would also lead to lower acid temperatures wouldn't it ?

Chris, Did you notice that will the Barrel plating process that you overall gold consumption for say 100,000 pieces or some large volume would run higher than when plated on a rack all at the same time. I'm figuring that will barrel plating their is just a little more uneven plating thickness on some parts more than others. It would only make sense in large volumes though. But then again i think that's the purpose of barrel plating.

 

[goldsilverpro]

Ralph,

That just makes so much sense. You can run 3 times the volume, while only drawing 1/3 amperage needed. Just adjust your time intervals. This means your rectifier is not constantly overloaded or at max draw time. This would also lead to lower acid temperatures wouldn't it ?

Actually, it has nothing to do with overloading the rectifier. Let's assume you have a certain type of gold plating bath that provides the best plating at a current density of 10 amps/square foot (asf) of surface area on the parts. Let's say that the total surface area of all the parts you are running in a load add up to 1 square foot and, at 10 asf, to get the gold thickness you want, it would take 15 minutes. If you ran them on a rack, you would simply adjust the current to 10 amps and remove the rack after 15 minutes. However, in a plating barrel, it is well known in the plating industry that, in general, only 1/3 of the parts make contact at any given time. Therefore, if you were to apply 10 amps, the parts in contact would have a current density (CD) of 30 asf, which would surely burn the parts. To counteract this, you only apply 3.33 amps and triple the time to 45 minutes.

I am speaking of averages. Depending on such variables as the shape of the part, the 1/3 thing could be a little off. It might be 25% or 40%. After running several batches of the same parts, the astute operator will make adjustments to the amperage and the time. However, the total number of amp-minutes (amps x time) will remain the same.

Chris, Did you notice that will the Barrel plating process that you overall gold consumption for say 100,000 pieces or some large volume would run higher than when plated on a rack all at the same time. I'm figuring that will barrel plating their is just a little more uneven plating thickness on some parts more than others. It would only make sense in large volumes though. But then again i think that's the purpose of barrel plating.

Except for the plating efficiency of the particular gold bath (which is a constant for a particular type of bath - assuming the bath is up to par), the gold consumption is only related to amps x time = amp-minutes. In the example above, on a rack, the gold consumption would be directly related to 10 x 15 = 150 amp-minutes. In a barrel, it would be related to 3.33 x 45 = 150 amp-minutes. Same number of amp-minutes. Therefore, in each case, the same theoretical amount of gold consumption.

In a barrel, the plating would be a little more uniform than on a rack. On a rack, e.g., the parts on the perimeter of the rack would receive more current than those in the center of the rack. In a barrel, everything constantly changes position and every part ends up receiving about the same average amount of current over a period of time.

If a valence 1 gold bath operates at 100 efficiency (which it never really does), it will deposit .122 grams of gold for each amp-minute. For the example above, it will deposit 18.37 grams of gold in 150 amp-minutes, whether the parts are plated on a rack or in a barrel (theoretically, at least). It's all amps and time (Coulomb's Law). When stripping, it's the same thing in reverse, although the efficiency may vary more in practice. Amps and time.

The main purpose of barrel plating is to eliminate the labor that would be required to rack or wire the parts. The same with stripping.

Your friend, Chris