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Ted Mooney, P.E. RET
Pine Beach, NJ
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for Metal Finishing since 1989
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Recovering gold from plating drag-out by ion exchange or electrolytic. What resin is best?
An on-going discussion from 2000 to 2014 and beyond . . .
2000Q. The company I work for has recently set up its first gold plating line for wire. I am currently using strong base anion resin to reclaim any gold from my rinse water after my drag out rinse station. I use this successfully on my cyanide silver line. I have been told that this resin probably would not work for gold reclamation due to the chelators present in commercial gold baths. Is this true? Do I need to investigate some of the chelating resins? SBA resin is so cheap compared to the chelating resin, I would like to continue to use it, but if I'm losing gold it is obviously worth while spending the money for resin that works. I use electrolytic recovery in my drag out. The flow rate of the rinse water through the 8" x 48" cylinders does not exceed 2 GPM. Thanks in advance for any assistance.
Gerald D. Smith (Jerry)
- Bloomingdale New Jersey USA
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A. I would have it run into a large treatment tank and put a "Gold Bug" in that tank. This will electrolytically recover most of the gold and cost a lot less per troy oz recovered than the resins. I would follow up after the gold bug with the resin to remove the last traces of gold. The company that supplies your gold should be able to tell you if the chelators will cause a problem. Major resin companies like Rohm & Haas should be able to answer that question after they know the concentrations of all of the stuff in the rinse. James Watts- Navarre, Florida 2000 A. I don't think you need worry about this, if it's a cyanide gold. In that case all the Au is present as anionic complexes and hence isn't available to be chelated. I believe the chelators are added to keep the nickel, cobalt, or whatever(added to "hard golds" for hardness) in solution.  Dave Wichern Consultant - The Bronx, New York 2000 A. Hi Gerald , Why bother with the complexities of Ion exchange for recovery of precious metals , there are many fine "Plug-in" units available for electrolytic recovery from Drag-outs & even running rinses . If you want to persist with the ion exchange then call Resin Tech of Cherry Hill New Jersey , they are masters in using the right resins . regards  John Tenison - Woods - Victoria Australia 2000 A. Jerry, You should have no problem recovering gold using strong base anion resin. The only strong "chelator" in most gold baths is cyanide, unless you are using a sulfite system, or you have a acid gold chloride strike. The gold is in the form of a gold cyanide complex which exchanges quite nicely. And free cyanide comes out on the SBA resin as well. The problem you will have is that the gold cyanide won't be fully removed if you try to regenerate the resin. You are better off just sending it to a refiner to have it ashed for metal recovery when the resin is loaded.  Bill Vins microwave & cable assemblies - Mesa (what a place-a), Arizona 2000 |
2000
Thank You all for your responses. The bath is a neutral cyanide bath. I am extremely limited for space so a large holding tank is out of the question. This a wire plating line which has DI water dripping on the contacts on either side of each plating cell to prevent salt buildup, which insulates the wire from the contact. There are ten contact stations for the gold alone. The gold in this water is what I am trying to remove with the SBA resin. This rinse water does not pass through my drag out rinse station, it gets pumped through the resin, and then to cyanide destruct.
The drag out station pumps from a heated reservoir on the floor to the rinse cell and then drains back to the reservoir. I do have a Gold Bug operating successfully in the reservoir of the drag out station. The drag out is the first real rinse the wire sees after plating. I periodically bail out the reservoir, pass the water through the SBA resin, and send it to cyanide destruct, and refill the drag out with rinse water. After drag out there are two more rinses, the last being new DI water.
As there is a potential for significant gold in the water which bypasses the gold bug I will contact my gold bath vendor about the potential interference with IX. The Resin Tech lead is appreciated. I do not regenerate, the resin goes to refining after break through.
By the way, the first time I tried using a Gold Bug was on my silver cyanide line where I do not yet have a drag out (no room). I was attempting to use it in a flow through tank with very low concentrations of silver, and no significant dwell time. It did not work. That is where I first started using IX to reclaim my silver.
Gerald D. Smith (Jerry) [returning]- Bloomingdale New Jersey USA
Q. We have a dry lake bed with a large amount of water that holds precious metals in solution and wish the best way to recover same. Resin works good but expensive. Other suggestions are welcome. The lake is over 24 miles long and 500 feet deep, with water up to three feet from surface.
Marks Morrisonindustrial minerals - Windsor, Colorado
2001
Q. Sir,
We use ss 316 anodes to recover gold from drag-out of citrates and phosphates , where we put stainless steel sheets of 5*20 inches, one as anode and other as cathode. We have electrolyzed the solution under acidic and alkaline media , we noticed that these SS316 anodes getting dissolved but not ss cathode by this dissolution my recovery efficiency has become very poor and un wanted contaminants getting deposited.we use only demineralized water no halogenic ions. Platinised titanium anodes are costly and not last longing . So advise why this problem and suggest what type of anode material to be used. Thanks,
BY USING GRAPHITE ANODES GRAPHITE ANODES LOSING ITS BOND STRENGTH IN TURN CARBON IS COMING INTO SOLUTION , BY PUTTING PP BAG IS ALSO IS NOT SERVING THE PURPOSE, AND I CANNOT AFFORD FILTRATION IN THESE DRAGOUTS, AND EVEN I CANNOT GO FOR GOLD BUG. IS IT BECAUSE OF SIMILAR ANODE AND CATHODE MATERIAL OR IS IT ANYTHING RELATED WITH ELECTRODE POTENTIALS?
Panjala Mukesh
fashion jewelry mfgr.
Hyderabad, India
2002
A. I suspect that you are using too high a voltage when plating out the gold from your drag-out tank. I try to keep the voltage between 4-5 Volts on my gold recovery unit. We have used the same 316 SS anodes for our gold bath for many years with almost no deterioration. We always transfer our drag-out to a separate treatment tank for gold recovery. You should not have to adjust the drag-out solution to be able to plate out the gold. If you need faster recovery you need more surface area, not more voltage. You should be able to get the gold down to about 75 mg/L or less. To recover the last bit of gold, pump the solution through some resin. Finally, I do not see the significance of impurities in the deposit, it needs to be refined anyway correct?
Joel Tomasettiopticals - Petersburg, Virginia
2002
Q. Hello,
I'm working in a gold electroplating unit and we have a big problem of gold losses, as we have a final wash tank in which we wash the final workpiece after gold plating and we throw out this wash water in a trench.
I think there are many grams of gold in this water, so I want to know how can I extract gold from the water.
It is just simple demineralized water.
Thanks in advance.
- cairo, egypt
May 11, 2014
A. For a single tank and a small operation, ion exchange is one way to recover the gold. Any strong base resin in the chloride form will do this, but you must also find a refiner to complete the recovery.
There are also small electrowinners that are made especially for gold. These work best on a stagnant rinse before the final rinse and have the advantage of recovering the gold in metallic form, so it is easier to refine.
A web search should find these very quickly.
consultant - Cleveland Heights, Ohio
May 13, 2014
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