Gold chloride

[Palladium]

If I wanted to make a true 1% gold chloride solution for analytical testing purposes what would be the best way? I know this is 1 gram of gold dissolved in 100ml, but if I use nitric and hcl it wouldn’t be a true solution for analytical purposes would it? If you added extra gold to consume the nitric then you would not be able to calculate the exact weight would you? I guess you could evaporate the excess nitric off? Am i making any sense? Hummm……

 

[Geo]

what makes gold chloride "gold chloride"? gold in liquid form suspended in chlorine solution.if it were just gold and chlorine it would be perfect.you could use 1 grain of powdered gold and dissolve with hcl/cl and then evaporate down to the desired volume without use of nitric acid.i suppose if you could rid the solution of free nitric without discoloration or adding more gold or another reagent it would be perfect gold chloride but every time i evaporate AR i get a color change.

 

[Harold_V]

every time i evaporate AR i get a color change.

Of course you do. You're concentrating the content when you evaporate. You can expect color to range from pale yellow through deep red/brown. Dilute it and the color returns, according to the degree of dilution.

Harold

 

[Palladium]

I've thought about hcl/cl but i don't have a cl generator right now. If i use hcl/bleach it will leave sodium present. I guess i could use hcl/h2o2 and it would be easier to expell than nitric acid would.

 

[Geo]

you can generate chlorine gas the same way as making nitric with the pickle jug.use a glass jar and put a plastic tube in the lid tightly and the other end you do like AP, melt the end together and make some holes.place this end in the reaction chamber with the hcl and gold.in the glass jar place several trychlor tablets from pool supply and add some hcl and screw the lid on.chlorine gas will be generated and forced through the reaction chamber with the hcl and gold.ive never done this but have put some thought into how it could be done.with some practice and hands on im sure someone could get it to work.i may try it myself at some point but ive been so busy trying to reclaim all the PM's from the material i posted when i first joined the forum.(yep,it was that much)

 

[Palladium]

I had totally forgot that Geo thanks. I been planning on making one for quiet some time now, but like you said " never enough time " lol

Yeah the TCCA method is unbeatable. If you don't feel like shelling out the cash for a Kipps, a standard 600ml erlenmeyer flask with dropping funnel and outlet tube affixed works just wonderful. If you go with this method, powder the TCCA moderately finely (shoot for coarse sand) and mix with a small amount of distilled water. A stirrer would make this even more friendly, but even without it is a very steady stream of quite clean Cl2 gas. The premixing of water is quite important; otherwise the HCl will tend to clump a portion of the unused TCCA up, making it useless. I think that 1 mol of TCCA (230g) and 1 mole of 31% HCl (~120ml) will generate 3mol of Cl2 gas.

 

[SilverNitrate]

I made a bromide solution once, KBr added in a goldAR in concentration will make a violet-red crystals that can be collected. the crystals are dry and not hydroscopic like gold chloride. I didn't do the analytics but take a gram of the crystals and decompose under heat to get the weight of the gold and you'll find out the precentage of gold in the gold-bromide crystals. the gold bromide will fully dissolve in water.

 

[qst42know]

Would it be possible make gold chloride electrolytically with no additives other than high purity HCL?

 

[Harold_V]

Would it be possible make gold chloride electrolytically with no additives other than high purity HCL?

Yes. It's done when making electrolyte for Wohlwill cells. I am not familiar with the process, however.

Harold

 

[Dr. Poe]

I've got two ways to tell:
#1
Gold will dissolve in a mixture of bromine liquid and water (use distilled). Don't heat it, just add a cap and shake well.
The product is AuBr3 -xH2O a simple compound (not complex).
#2
Separate your electroplating cell electrodes by placing the cathode in a porous ceramic tube that's filled with HCl and a graphite rod. Fill the rest of the cell with concentrated HCl. Make gold your anode. Apply dc current of 2.45 volts or slightly higher.
0.85 volts will work for this cell, but is too slow. 1.68 volts and 0.77 volts equals 2.45. the 0.77 is to overcome build up passivity and the 1.68 from electromotive force tendency of gold to reduce. Since the AuCl3 is simplex it migrates to the cathode, except the cathode is unreachable so it remains in solution as HAuCl4.
I got the impression that you might be trying to make "Bluing" for rifles and pistols. It's a good idea as bluing is terribly expensive. Dr. Poe

 

[Oz]

Would it be possible make gold chloride electrolytically with no additives other than high purity HCL?

You can make gold chloride as pure as the HCl and Gold you start with by simply placing your “pure” gold in HCl and bubbling air into the solution. The finer the grain of your gold, the faster the process is.

 

[Geo]

hey.this may be a use for the oxygen concentrator.wouldnt bubbling pure oxygen through hcl and gold solids make pure AuCl? i have a question on this.if your contamination in refined gold happens from mixing chemicals during the refining process couldnt you dissolve the refined gold powder in this fashion to make .9999 gold as long as you dont add contamination when precipitating?

 

[Oz]

There is no need for pure oxygen. It sounds like you would just be using a fancy way to double refine gold Geo.

 

[kadriver]

Yeah the TCCA method is unbeatable. If you don't feel like shelling out the cash for a Kipps, a standard 600ml erlenmeyer flask with dropping funnel and outlet tube affixed works just wonderful. If you go with this method, powder the TCCA moderately finely (shoot for coarse sand) and mix with a small amount of distilled water. A stirrer would make this even more friendly, but even without it is a very steady stream of quite clean Cl2 gas. The premixing of water is quite important; otherwise the HCl will tend to clump a portion of the unused TCCA up, making it useless. I think that 1 mol of TCCA (230g) and 1 mole of 31% HCl (~120ml) will generate 3mol of Cl2 gas.

Palladium:

I have been searching the forum for a simple chlorine gas generator and this is the best description I have found.

Is TCCA an acronym for Trichloroisocyanuric acid? Or does it mean something else?

From your description above it looks like you are putting the TCCA into a flask with a side arm and adding some distilled water to form a slurry mixture.

Then dropping HCl via a tightly sealed dropping funnel into the flask containing the TCCA slurry.

I'm thinking a clamp to ensure a tight fit between the funnel and flask would be ideal for this setup.

A length of clear poly plastic tubing (from the hardware store) with one end connected to the side arm of the flask, and the other sealed shut, then multiple perforations added (small holes) to dispense the Cl2 gas into the target solution.

With this setup, one could regulate the amount of acid flow to the slurry, and thereby regulate the amount of chlorine gas generated quite nicely.

I have a stir plate to keep the slurry agitated during the operation of the chlorine gas generator. Also have a ducted acid chemical fume hood on the way.

I have no experience with controlled chlorine gas generation - only experience with HCL/Cl leaching of PGM catalytic converter material.

I am preparing for precipitating ammonia soluable brick red (NH4)2PdCl6 Ammonium hexachloropalladate(II) using chlorine gas from a chlorine gas generator setup as described above.

Any input would be greatly appreciated.

Thank you - kadriver