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What causes the concentration of gold to drop although tank is idle?

2007

Hi every one,
I'm a chemical supplier of chemical..One of our customer encounters problem which lowering the concentration of gold even bath is in idle..
We target the concentration to 9 g/L.
Here are the activities that we had before again checking the concentration and idle the bath.
1. Dummy plating two times using a FR2 CCL.
2. Load 2 racks of actual products.
3. Get Sample for hull cell testing..
All of this activities can lessen only about 1 g (max)
but the result of concentration became 5 g/L. after idling for 5 days.
We correlate the results of gold conc. using 2 AAS ⇦ this on eBay or Amazon [affil links] instruments and the result is the same..
In this case what other factors which will results of lowering the gold concentration.
Thanks,

Rolan,

Rolan Ropal
sales & service Engineer - Philippines

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I would be very slow to accuse anyone of theft but very quick to admit the temptation. If you deal in gold, you must use analysis methods and tracking methods that track the total gold.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2007

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2007

That was my thought. Someone is removing liquid and replacing it with water.
To make sure, stir the tank and reanalyze. Consider adding a locked cover to the tank.
You might want to put a recording camera on that area. They are only a couple hundred dollars and the input is recorded on a computer with a time date on it.

James Watts
- Navarre, Florida

James has the best solution with the locked cover suggestion. Some years back I caught workers plating up jewelry, so we had to install the locked cover. We also had to monitor and record data from our amp hour meter for each shift and loads plated. It's also possible that someone is plating up a coupon in gold when nobody is watching. It is much easier to smuggle out a flat plated part, than say a quart of plating solution, also much easier to sell the gold in plated form. You want to also make sure you change your filter on a regular basis, and make sure carbon filters are not over - used. I used to change the filter cartridge one time per month and run a carbon tube for 2 hours, once per month. Save all your filters for reclamation. Good Luck!

Mark Baker
process engineer - Syracuse, New York
2007

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2007

You did not mention if the tank was heated or not. If you are heating with steam or hot water it is possible that pinholes can form in the heating coils and when the heat is turned off, gold solution gets sucked into the coils.

Theft is most likely, but check your heating coils.

Pat Mentone
St Paul, Minnesota

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2007

Hi,
It is a simple case of stealing.
I had an experience of an operator plating out and building up gold on duplicate keys for his house.Please remember you can give a nickel over coat to cover up. He will only be caught if god is not happy with what he is doing!.
This way even the sophisticated security could not find it out.
Regards

T.K. Mohan
plating process supplier - Mumbai, India

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That was a very clever trick!, T.K.! If that plater focused as hard on doing good plating for customers he might be a terrific plater. I hope that trick is not food for thought :-)

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2007

If we consider there is no stealing happen, what other factor that can affect decreasing of gold concentration?

Joy de Luna
- Philippines
2007

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Joy,
I don't know if your inquiry is related to the first one in this letter. First completely rule out stealing by installing a locked cover. Only the plating of shift supervisor should have the keys. The tank should only be opened when you have to plate gold. Check to see if the tank and filter system are free of any small leaks. Samples should be drawn with the tank heated to operating temp, and the filter running. Duplicate samples should be run on the AA. As mentioned previously, be sure tank heater is free of any pinholes. Be sure tank is in good shape - no deep gouges where organics can thrive. I have seen where a certain chain of organics will accept gold deposition. That is all I can suggest at this time. Good Luck!

Mark Baker
process engineer - Syracuse, New York
2007

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2007

Hi Joy,

If stealing doesn't happen, how about unreported chemical spillage and water was used as replenishment to bring back to the original volume. With precious metal involved, you really need to define a strict control. You probably need to do more frequent analysis, one before the start of the shift and another one at the end of the shift (after the last load. You can now determine the quantity of gold consumed for the whole shift's operation and you can relate this with the theoretical gold consumption based on total plated area and average thickness. the variance should not be too big. Good Luck.

Germie Maravilla
- Philippines

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On one occasion I found the "stolen" gold solution in the extract duct. Someone had over filled the tank.
On the other hand...
I have seen the key trick and also the practice of not adding a whole unit of GPC. A gramme "saved" at each addition soon adds up !

Geoff Smith
Hampshire, England
2007

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Hi to All,

Thank you very much for the good info given to us regarding this concern. We'd done many corrective actions in this gold variance issue and we'd seen our efforts when the variance was too little.

Germie and Mark have a good point. We do not consider the water used as a replenishment to bring back to original level, the heating coil and the filter cartridge. We try to check this concerns and do necessary action.

My mistake. I opened this letter number again only today. Not knowing there are other good info to be consider. But is not too late to correct and do corrective actions.

Joy de Luna
- Philippines  
March 2, 2009