Does copper only knock out gold or does it also knock out silver?

[ólom]

Ok - I just took a closer look at the traces on these boards - this time I enlarged the pics for a better look - They are clearly not silver &/or palladium - clearly tin & because of their age (VERY OLD) maybe even tin/lead

The tin (&/or tin/lead) was applied by a wave soldering method (molten solder applied to the traces)

This is clearly evident in that with a close up (enlarged) look at them they (the traces) are raised up & rounded over - so they are not even really plated - evident by the molten solder applied to them

Even the traces that are flat(er) are clearly tin (these traces are likely plated) --- the dead give away is the fact that many of the traces have "breaks" in them where the tin has etched/corroded away &/or etching/corroding on the edges of the traces over MANY years of exposer to normal atmospheric conditions --- silver &/or palladium would NOT do this

Tin plating &/or wave soldering was VERY COMMON with OLD circuit boards

There is no need to test these boards (for silver &/or palladium) any further --- they are VERY clearly tinned

Kurt

Thank you for checking!

 

[ólom]

Nitric acid can passivate the surface of iron or steel... for a while. Then the reaction can take off and accelerate. Make sure there is plenty of extra room in the vessel.

Dave

I don't know how long it will take, but blue indicate Copper not Silver.
Silver Nitrate is colorless.

I don't know how long it will take, but blue indicate Copper not Silver.
Silver Nitrate is colorless.

How to speed up the process so that the gold does not dissolve, maybe add a little hydrochloric acid?

 

[Yggdrasil]

How to speed up the process so that the gold does not dissolve, maybe add a little hydrochloric acid?

If you add HCl to Nitric you will have AR and Gold go into solution

 

[ólom]

If you add HCl to Nitric you will have AR and Gold go into solution

even if a little?

 

[Yggdrasil]

Yes of course.

 

[ólom]

Yes of course.

Thanks for the answer!

 

[stoneware]

Thanks for the answer!

Don't forget city water has chlorine in it, using tap water is not recommended for most of the chemistry involed with refining precious metals..

 

[ólom]

Don't forget city water has chlorine in it, using tap water is not recommended for most of the chemistry involed with refining precious metals..

Thank you for telling me this!

 

[ólom]

Don't forget city water has chlorine in it, using tap water is not recommended for most of the chemistry involed with refining precious metals..

Does the gold dissolve in it, and if so, how do you get it out?

 

[Yggdrasil]

Does the gold dissolve in it, and if so, how do you get it out?

The problem with Chlorine in the water is mostly an issue when treating Silver with Nitric.

 

[FrugalRefiner]

Don't forget city water has chlorine in it, using tap water is not recommended for most of the chemistry involed with refining precious metals..

Does the gold dissolve in it, and if so, how do you get it out?

Chlorine in city tap water alone will not dissolve any appreciable amount of gold. An oxidizer would be needed to oxidize the gold so it could complex with the chlorine. In gold refining, it is fine to use tap water for diluting AR, washing precipitated gold, etc.

As Yggdrasil said, the chlorine in tap water is mostly a problem when refining silver, as it will combine with dissolved silver to form insoluble silver chloride.

Dave

 

[ólom]

Thank you for your answers!

 

[ólom]

Olom, great attitude!
When this book was written, the environment was not a big issue yet.
By now, most of humanity has learned not to poop in your own water well. Some parts of the world are still catching up.

Most sustances are only harmfull at certain concentrations, others can accumulate over time in your body or in nature and cause serious damage that way.

It usually comes down to emission limits. So much micro gram of a substance per cubic meter of expelled air. Or total amount per hour.

No economic way to measure that for the small guy.

Prevention is the biggest factor. No need to scrub fumes if they are not created
(in large quantities). So either slow reactions in semi closed vessels with low emissions or big and fast reactions which will require huge scrubbing systems.

So don't create a lot of fumes, and if you do, don't let them escape to open air without scrubbing them first. Have the fume hood there to get the traces of gasses and unintentional releases or accidents vented away from you.

But very good to hear you are aware of this and you want to limit the gases expelled.

If I connect a pipe to the hood and lead the gas into water, is the solution to the problem of not getting outside?

 

[Yggdrasil]

If I connect a pipe to the hood and lead the gas into water, is the solution to the problem of not getting outside?

You need retention time in contact with water. For that you need either depth (which needs pressure) or a coloumn with large wetted surface which don’t need much pressure but need a flow/suction.

 

[ólom]

You need retention time in contact with water. For that you need either depth (which needs pressure) or a coloumn with large wetted surface which don’t need much pressure but need a flow/suction.

Thanks for the answer!

 

[ólom]

You need retention time in contact with water. For that you need either depth (which needs pressure) or a coloumn with large wetted surface which don’t need much pressure but need a flow/suction.

I could ask you to put it another way because I don't understand that way.

 

[butcher]

bubbles of gases can go through or pass through a solution so fast they do not combine with the water solution to form the resulting acid, or to scrub the gases passing through the water.

The smaller the bubbles are, the more surface area of the gas bubble has to come into contact with the water, and the longer the gas bubbles are held in the solution (retention time) (or made to pass through a maze holding it in solution longer), the more the water and the gas will combine chemically to form the acid or complete the chemical reaction before all the gas passes through the water.

 

[ólom]

bubbles of gases can go through or pass through a solution so fast they do not combine with the water solution to form the resulting acid, or to scrub the gases passing through the water.

The smaller the bubbles are, the more surface area of the gas bubble has to come into contact with the water, and the longer the gas bubbles are held in the solution (retention time) (or made to pass through a maze holding it in solution longer), the more the water and the gas will combine chemically to form the acid or complete the chemical reaction before all the gas passes through the water.

Thank you very much! That makes sense.

 

[ólom]

Can you recommend something simple to prevent these gases from escaping?

 

[Yggdrasil]

Can you recommend something simple to prevent these gases from escaping?

Search the forum for "making your own fume hoods", it is all there, many threads.