When In Doubt, Cement It Out _cementation_

[Rreyes097]

Oh yeah. One more question. Are you using an air stone? Or just straight air coming out of the tube?

 

[Rreyes097]

I constructed this today. Thanks so much for the blueprints to create this! The build was fairly easy. And I used 1.25" PVC. Any advice or critiques on how to improve it are welcome.

So I was thrift shopping at the goodwill looking for glassware because all my fancy lab glass has broke over time and I'm too poor to buy more fancy glass. So I look for pyrex and what not.... So I came across this! And although it's not glass it seems to suit my needs perfectly! It's a iced tea or flavored water, or whatever you want to call it pitcher thingy. it is a bit smaller then my original build. But what I like about it is that it's clear! You can see what's going on while it bubbles away. In the middle of it there is a clear tube with holes all the way thru it. That screws on and off. Plus it being a pitcher, it's shaped to pour which the first container was NOT. Maybe there's too many holes but at least it looks like this bubbles will get all over the copper since I simply ran the air line down to the bottom of the tube containing the copper.

 

[goldshark]

You may want to put it in a containment vessel, in the event a heat reaction breaks it.

 

[Rreyes097]

You may want to put it in a containment vessel, in the event a heat reaction breaks it.

Oh like have it sitting in a container? Just in case it breaks or heats up and possibly melt? Well I do. It just was moved so people can see it.

 

[madscientistatlarge]

So I was thrift shopping at the goodwill looking for glassware because all my fancy lab glass has broke over time and I'm too poor to buy more fancy glass. So I look for pyrex and what not.... So I came across this! And although it's not glass it seems to suit my needs perfectly! It's a iced tea or flavored water, or whatever you want to call it pitcher thingy. it is a bit smaller then my original build. But what I like about it is that it's clear! You can see what's going on while it bubbles away. In the middle of it there is a clear tube with holes all the way thru it. That screws on and off. Plus it being a pitcher, it's shaped to pour which the first container was NOT. Maybe there's too many holes but at least it looks like this bubbles will get all over the copper since I simply ran the air line down to the bottom of the tube containing the copper.

You should check out the prices at aliexpress.us. It is buyer beware (thuogh you can usually get your' $$ back). I'd avoid the very cheapest sellers and personally don't use sellers that have been using it for less than 2 years, and I prefer longer term users. Also try to look for factories or vendors who specialize in what you are looking for, many sellers have a real hodge podge of items and don't know any of them.

Look for sellers who have Borosillicate labware, the generic non trade mark name for "pyrex". And yes, always use some secondary containment in case a vessel cracks/shatters (all solutions used for this are very nasty at room temp and terrifyingly toxic/corrosive when heated). If you get anything hot enough to melt borosilicate you have other major problems, even if you melt ordinary sodalime glass your' at very high temps and your' solution has boiled dry (above 1300 Deg F!) and you may have already started a fire. Major down side is it will take a month or so to get your' package depending on what country you are in, in the US it's usually about a month. If you have any doubt ask the seller if it's borrosillicate. I also look for sellers with a high feedback score, ignore any less than 90%, above 95% is better.

I've had to have testubes reshipped as the first ones were plastic, styrene I think, despite the add saying "glass". Many resellers just copy other peoples listings, propagating errors widely. I always test the glass by applying a lighter flame to one edge for a bit (5-10 seconds). Borrosillicate handles this, sodalime cracks fairly quickly (do be careful as it might shatter, tough gloves would be a good idea, as well as doing it over the sink etc. in case it shatters, use eye protection as well). Courtesy when dealing with vendors is essential, Asians tend to disrespect those who don't show proper courtesy, when messaging always thank them etc. (good practice in any culture).

 

[Rreyes097]

So I'm in doubt so I'm attempting to cement it out. I had an AR solution which I put the ends of ribbons and some other stuff like small pieces of circuit board that have gold plating. But when testing with stannis nothing was coming up even though I seen that the gold was dissolved. Not knowing exactly what the problem was whether it was tin or something else that may be stopping my stannous test from showing that there was indeed gold in the solution like I seen it dissolve. What makes a stannis test not work? Like what I mean is what in the solution could block the stanous test from coming up positive? So I put some pieces of copper pipe into the solution hoping just to cement it out but the nitric acid keeps dissolving the copper and I put probably 20 g of copper in it? That's an approximation though. This should be more than enough copper to use up the nitric that was in there, which was not a lot. Cement out after the nitrate was spent.

 

[Martijn]

You've answered your own question: too much nitric. Keep adding copper.
Next time dissolve it the right way.

Edited for spelling

 

[Rreyes097]

You've answered your own question: too much nitric. Keep adding copper.
Next time dissolve it the right way.

Edited for spelling

Dissolve what exactly the right way? I'm not following you.

 

[cejohnsonsr1]

Dissolve what exactly the right way? I'm not following you.

Only add enough nitric to dissolve the gold. Incremental dosing. But even before you get to AR, you need to recover the gold by separating it from whatever it’s bound to. Usually copper. For that you use AP.

 

[Rreyes097]

Only add enough nitric to dissolve the gold. Incremental dosing. But even before you get to AR, you need to recover the gold by separating it from whatever it’s bound to. Usually copper. For that you use AP.

I did add the nitric incrementaly. But maybe it didn't react right away and so I may have added too thinking it wasn't enough?

 

[Yggdrasil]

So I'm in doubt so I'm attempting to cement it out. I had an AR solution which I put the ends of ribbons and some other stuff like small pieces of circuit board that have gold plating. But when testing with stannis nothing was coming up even though I seen that the gold was dissolved. Not knowing exactly what the problem was whether it was tin or something else that may be stopping my stannous test from showing that there was indeed gold in the solution like I seen it dissolve. What makes a stannis test not work? Like what I mean is what in the solution could block the stanous test from coming up positive? So I put some pieces of copper pipe into the solution hoping just to cement it out but the nitric acid keeps dissolving the copper and I put probably 20 g of copper in it? That's an approximation though. This should be more than enough copper to use up the nitric that was in there, which was not a lot. Cement out after the nitrate was spent.

As Martijn say, you have too much Nitric so before the Gold will stay out of solution, you need to overcome the Nitric.
(We know that there are too much Nitric because the Copper gets eaten away)
On the other hand there may not be Gold in there at all.

cejohnsonsr1 is also correct. Removing the golden color of the end of the ribbons do not necessarily dissolve the Gold permanently.
It may just relocate it to another piece of undissolved base metal,
and that is why we take away the base metals completely or dissolve all the metals present.

Stannous sometimes react just in a flash if there are too much oxidizer, how did you test with Stannous?

 

[Rreyes097]

As Martijn say, you have too much Nitric so before the Gold will stay out of solution, you need to overcome the Nitric.
(We know that there are too much Nitric because the Copper gets eaten away)
On the other hand there may not be Gold in there at all.

cejohnsonsr1 is also correct. Removing the golden color of the end of the ribbons do not necessarily dissolve the Gold permanently.
It may just relocate it to another piece of undissolved base metal,
and that is why we take away the base metals completely or dissolve all the metals present.

Stannous sometimes react just in a flash if there are too much oxidizer, how did you test with Stannous?

Qtip
And I'm not disagreeing that there is too much nitric. Because there obviously is. I was just saying that the method of delivery of said nitric was incremental.

 

[Yggdrasil]

Qtip
And I'm not disagreeing that there is too much nitric. Because there obviously is. I was just saying that the method of delivery of said nitric was incremental.

How much of said cables was used, and were they totally dissolved?
Have you tried a Stannous after the copper was dissolved in the solution?
Are there any trace of black mud in the bottom?

 

[Martijn]

With that much copper in solution, a stannous test will be too brown to show traces of purple.
What was the amount of used nitric and cable ends and other material?

For that 20 grams of copper that dissolved, you had at least about 80ml of free nitric in the AR. If you were dissolving only gold, that would would have been enough for 8o grams of gold..
With your beaker holding 600ml, you can add about as much cable ends to recover 5 grams of gold. And i think that's on the very optimistic side of things.
So to have at least 80 ml of nitric too much in there is overshooting it a bit too fast, yes.
What was the temperature of the first AR bath?

 

[Wonka]

How acidic does the solution need to be for this process to work? And can I guess it would have to be an acid that can readily dissolve copper. So I would have to put more AR in to solution?

 

[Yggdrasil]

How acidic does the solution need to be for this process to work? And can I guess it would have to be an acid that can readily dissolve copper. So I would have to put more AR in to solution?

pH lower than 4 but best in the 1-2 range.
Just use HCl no need to be able to dissolve Copper.

Have you read the thread https://goldrefiningforum.com/threads/when-in-doubt-cement-it-out.30236/

 

[gulottamichael58]

Thanks. The jar, and everything else in the rig is plastic. The only metal is the copper used to cement the values.

If you're using pennies, be aware that they are not pure copper. Those minted before 1982 are 95% copper and 5% zinc. From 1983 on, they're 97.5% zinc with a copper plating. The zinc will cement out most metals, so pennies will cement out more than just gold.

Dave

I think the pre 1982 pennies are 5% tin, not zinc. Minor detail, but still good to know. I realize that I am writing this almost 2 years later, but I just began to read this thread. Good information here. Waste management can become overwhelming if you don't keep up with it.

 

[FrugalRefiner]

Well, we're both partially right. Thanks for catching my error.

1864 - 1942 and 1947 - 1962 were 95% copper, 5% tin and zinc
1963 - 1982 were 95% copper, 5% zinc
1983 to current, 97.5% zinc, 2.5% copper

Dave

 

[gulottamichael58]

Well, we're both partially right. Thanks for catching my error.

1864 - 1942 and 1947 - 1962 were 95% copper, 5% tin and zinc
1963 - 1982 were 95% copper, 5% zinc
1983 to current, 97.5% zinc, 2.5% copper

Dave

Hi Dave, thanks for the clarifying detail. I didn't know that they changed the content in 1963- 1982. I knew about the change in 1982 to mostly, zinc. But I didn't know that they removed the tin in 1963. Interesting.

 

[Ag and Au]

Hi Dave (and others).... In keeping with the title of this thread, do you consider copper to be a "selective precipitant" with respect to selectively dropping out only those five (5) metals below it on the reactivity chart?