No but there are plenty space inside the traces on the PCB and since it is low amounts/concentration what ever precipitates will be very fine, probably too fine for most filters.
You have found a way that suits you and are happy with the results.
removing gold from copper?
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You have found a way that suits you and are happy with the results.
Our government has found that adding ludicrous amount of taxes on products that are legal but they don't like is an effective way of controlling the market.
Tobacco, Alcohol, gasoline and so on.
cejohnsonsr1
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Well you have my sympathy. I guess I really do understand after all. I hope you had a Merry Christmas and I wish you a Happy New Year.
cejohnsonsr1
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I didn’t use whole boards. I used closely trimmed fingers. If any metal can’t be detected by any means, it isn’t there.
BobK
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Prices and availability of what Americans would consider household chemicals vary widely in the world. In much of the EU there are several layers of taxes that most there are not even aware of. The VAT is just the most visible. Most of these taxes are designed to do as Yggdrasil says: control access through price.
Time for more coffee.
Time for more coffee.
cejohnsonsr1
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Yeah. When he put it in those terms I understood perfectly.
watchmaker
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The way to test this is to do a stannous test on the wash fluid when it is decanted from the
The way to prove or disprove this is to let the wash fluid settle after it is decanted from the foils. Reduce it and add it to aqua Regia then do a stannous test. If fine particles were present in the wash they would now be in solution.
Dunning-Kruger effect is especially dangerous in physical science like chemistry or metallurgy, those branches of science where it is quite easy to cause harm to both oneself and others. If someone doesn't understand why some thesis in science cannot be explained in 2-3 words or get a simple unambiguous answer to an incorrectly asked question, the only reasonable recommendation is to learn from scratch. But actually, those who like simple solutions don’t like complex advice.
goldsilverpro said:
I would make a small adjustment. Learn the basics of metallurgy and metal physics before reading the forum. Having at least basic knowledge about the physics of alloys will significantly help to separate the “possible” from the “impossible” in experiments.
Hello
Let me tell you my understanding and experience of dissolution of Au during the AP procedure:
CuCL2 and HCl will not dissolve Au but only Cu metal and other less noble metals like Zn,Fe,Al... by the following redoxreaction Cu2+ + Cu = 2Cu1+. This Cu1+ is existent in solution as a dark brown (CuCl2)- chlorocomlpex. Cu2+ in diluted HCl is a green chlorocomplex. So when you watch the reaction of gold covered copper in AP the brignt green solution becomes slowly dark brown. Now you have to add an oxidising agent in order to reoxidise all the Cu1+ into Cu2+ to continue the dissolution of copper. And dont forget adding additional HCl if necessary because the new formed Cu2+ ions need their corresponding chlorine anions. And especially be carefull when you add the peroxide because it should only oxidise the Cu1+ in the solution and not attack the noble metal Au. How to do this I recomend the following procedure:
Decant the brown solution into an other container (without any residue) and add slowly under stirring in small amounts the peroxide (ml wise for 3% or dropwise for 30% HP) until the solution is bright green again and not any more HP. An excess now would be able to attack Au (very much slower than Cu). If unfortunately Au is attackted, then Au ions are in the solution and can exist there as long as free HP is present. As soon as all HP is eaten up by the Cu1+ ions, than Au ions are no more stable in solution and will be reduced with a reducing reagent for Au (here mainly the metallic Cu) that means on the Cu surface (not in solution) there is again a redoxreaktion (cementation) between Au and Cu. Au ions and Cu metal are changing electrons forming Au metal and Cu ions.
So as soon as the solution has a little or strong brown color, there is no attack at gold.
Not soluble is not very very correct I should better say something like neglectible. Please take into account that a very small amount of Au is soluble in seawater (some micrograms per cubicmeter).
Let me tell you my understanding and experience of dissolution of Au during the AP procedure:
CuCL2 and HCl will not dissolve Au but only Cu metal and other less noble metals like Zn,Fe,Al... by the following redoxreaction Cu2+ + Cu = 2Cu1+. This Cu1+ is existent in solution as a dark brown (CuCl2)- chlorocomlpex. Cu2+ in diluted HCl is a green chlorocomplex. So when you watch the reaction of gold covered copper in AP the brignt green solution becomes slowly dark brown. Now you have to add an oxidising agent in order to reoxidise all the Cu1+ into Cu2+ to continue the dissolution of copper. And dont forget adding additional HCl if necessary because the new formed Cu2+ ions need their corresponding chlorine anions. And especially be carefull when you add the peroxide because it should only oxidise the Cu1+ in the solution and not attack the noble metal Au. How to do this I recomend the following procedure:
Decant the brown solution into an other container (without any residue) and add slowly under stirring in small amounts the peroxide (ml wise for 3% or dropwise for 30% HP) until the solution is bright green again and not any more HP. An excess now would be able to attack Au (very much slower than Cu). If unfortunately Au is attackted, then Au ions are in the solution and can exist there as long as free HP is present. As soon as all HP is eaten up by the Cu1+ ions, than Au ions are no more stable in solution and will be reduced with a reducing reagent for Au (here mainly the metallic Cu) that means on the Cu surface (not in solution) there is again a redoxreaktion (cementation) between Au and Cu. Au ions and Cu metal are changing electrons forming Au metal and Cu ions.
So as soon as the solution has a little or strong brown color, there is no attack at gold.
Not soluble is not very very correct I should better say something like neglectible. Please take into account that a very small amount of Au is soluble in seawater (some micrograms per cubicmeter).
Copper chloride significantly catalyzes the reaction of dissolving gold in chloride solutions.
Thanks for this remark. It helps me understanding, that sometimes during an AP procedure very small gold particles disappear after adding HP (in order to reoxidise Cu+ into Cu2+).
So in my opinion what happens? I insist in saying the mixture of CuCl2 and diluted HCl is not able to oxidise (dissolve) gold but it catalyses a possible oxidations reaktion of gold (oxidising reagents are for instance AR, HCl + H2O2, HCl + KClO3) that means the velocity of gold dilution is increased or something like this (it is a question of kinetik). This oxidation reaction of gold will happen, when you add more HP than necessary for the complete oxidation of Cu+ to Cu2+ and this excess of HP in the milieu of diluted HCl now will attack the gold as long as the HP excess is not eaten up by the new built Cu+.
HCl and Peroxide do indeed dissolve both Au,Pt and Pd.
That is why we do not recommend using Peroxide when using the so called AP etching.
We recommend using an air bubbler, for instance from an aquarium.
This is true, but 60 times slower than in aqua regia
