# Copper?



## ssharktu17 (Mar 30, 2022)

Where do you get it? I was thinking of just buying some scrap wire and melting it into a bar? But is the wire even pure? Copper ingots seem ridiculously expensive to purchase for this purpose of cementing.


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## galenrog (Mar 31, 2022)

I use scrap copper buss bars from electrical panels. Others use copper pipe, although I like having all exposed area visible and accessible to be lightly brushed.

Scrap is easy to find.

Time for more coffee.


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## ssharktu17 (Mar 31, 2022)

galenrog said:


> I use scrap copper buss bars from electrical panels. Others use copper pipe, although I like having all



Hmm I couldn’t even find busbar anywhere near spot price. And aren’t pipes alloyed?


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## nickvc (Mar 31, 2022)

Copper pipes are fine to use just open them out flat so they are easy to clean off, as cementation is a recovery process if alloyed it shouldn’t make much difference .


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## Martijn (Mar 31, 2022)

Copper pipe and electrical wire is pure red copper. 
Keep brass and soldered couplings out. Only use clean red copper. You only want less reactive metal than copper in your cement. 
Go to a scrapyard and buy some if they can sell ot to a private person. It will be as expensive or more expensive than spotprice to buy from them. 

I just scrap whatever i can and occasionally help friends out with electrical work, masonry, carpentry, plastering and plumbing in their home. And ask if i can get the 'valuable' leftovers to fill my scrap bins. 

Lately i just use the cathode plates from the copper sulfate cell for cementing silver. Or silver plated copper connection blocks from high voltage switch gear go in the stockpot. 

The CuNO3 from cementing silver gets distilled with H2SO4 for HNO3 and CuSO4 to reuse. Full circle recycling.


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## ssharktu17 (Mar 31, 2022)

Martijn said:


> Copper pipe and electrical wire is pure red copper.
> Keep brass and soldered couplings out. Only use clean red copper. You only want less reactive metal than copper in your cement.
> Go to a scrapyard and buy some if they can sell ot to a private person. It will be as expensive or more expensive than spotprice to buy from them.
> 
> ...


Ok thats definitely reassuring! If I use copper wire do I need to melt it first into a bar? what is the issue with brass?


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## cosmetal (Mar 31, 2022)

ssharktu17 said:


> Ok thats definitely reassuring! If I use copper wire do I need to melt it first into a bar? what is the issue with brass?


_*what is the issue with brass?*_

The zinc (Zn) in brass.


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## ssharktu17 (Mar 31, 2022)

cosmetal said:


> The zinc (Zn) in brass,


ok guess thats one of the reasons we cant use pennies lol Zinc will go into the cement? So alloyed copper doesnt usually have zinc or other contaminates to worry about.


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## cosmetal (Mar 31, 2022)

ssharktu17 said:


> ok guess thats one of the reasons we cant use pennies lol Zinc will go into the cement? So alloyed copper doesnt usually have zinc or other contaminates to worry about.


Ton of info regarding Cu on this site:

Copper Development Association


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## Martijn (Mar 31, 2022)

ssharktu17 said:


> ok guess thats one of the reasons we cant use pennies lol Zinc will go into the cement? So alloyed copper doesnt usually have zinc or other contaminates to worry about.


No, zinc is way down in the reactivity series.





Reactivity series - Wikipedia







en.wikipedia.org




And:








When In Doubt, Cement It Out


When In Doubt, Cement It Out This is advice I often give to new members who find they've created a bit of a mess, and they're wondering how to recover their values (gold, silver, PGMs, etc.). Perhaps they've followed a process they've seen on YouTube that left out some important details...




goldrefiningforum.com


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## FrugalRefiner (Mar 31, 2022)

Martijn said:


> No, zinc is way down in the reactivity series.


Actually, it's way up in the reactivity series. Metals that are high on the series, like zinc) are highly reactive. Metals that are low, like gold, are low in reactivity. While I've seen some charts that are reversed, most follow that idea.

Dave


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## ssharktu17 (Mar 31, 2022)

FrugalRefiner said:


> Actually, it's way up in the reactivity series. Metals that are high on the series, like zinc) are highly reactive. Metals that are low, like gold, are low in reactivity. While I've seen some charts that are reversed, most follow that idea.
> 
> Dave


But zinc will be left in the insoluble silver cement? Seems like zinc chloride is highly soluble. Almost like you could just use zinc instead of copper.


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## FrugalRefiner (Mar 31, 2022)

It's not that zinc will be left in the insoluble silver cement. It's that zinc will displace everything below it in the reactivity series, including chromium, iron, cadmium, cobalt, nickel, tin, lead, antimony, bismuth, and copper, if they are present in your solution. So, all those metals will be in your silver cement.

Dave


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## ssharktu17 (Mar 31, 2022)

FrugalRefiner said:


> It's not that zinc will be left in the insoluble silver cement. It's that zinc will displace everything below it in the reactivity series, including chromium, iron, cadmium, cobalt, nickel, tin, lead, antimony, bismuth, and copper, if they are present in your solution. So, all those metals will be in your silver cement.
> 
> Dave


Ok so if I use copper then how can zinc contaminate it wouldn't it just be left in solution?


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## galenrog (Mar 31, 2022)

When precipitating values from solution, a refiner wants the cleanest precipitate possible. Of common, inexpensive metals, coppers place in what is called the “reactivity series” makes it the most practical, and the most frugal. 

Also, why the fixation on zinc? I do not understand. 

Time for more coffee.


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## ssharktu17 (Mar 31, 2022)

galenrog said:


> When precipitating values from solution, a refiner wants the cleanest precipitate possible. Of common, inexpensive metals, coppers place in what is called the “reactivity series” makes it the most practical, and the most frugal.
> 
> Also, why the fixation on zinc? I do not understand.
> 
> Time for more coffee.


Well I was curious about using copper scrap and the possible alloys. Zinc was mentioned above. I actually just bought a lot of copper wire one eBay which was surprisingly cheap About $3 pound considering the shipping weight/price being included.


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## orvi (Mar 31, 2022)

Copper in wires is as pure as you can get. Any contaminants in copper drastically decrease conductivity, that is why is wire copper always at least 99,5% pure. Use clean copper, do not think any other metal like brass. It will ruin your day 

Wire is impractical to use for cementation, as small pieces can fall to the cemented metal and contamine it. Also the precipitate is more easily locked between wires. And wire is light - you need to use a lot of it. Bigger bar or plate is much more practical. Also copper pipe as nickvc mentioned, opened up and hanged in solution.


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## ssharktu17 (Mar 31, 2022)

orvi said:


> Copper in wires is as pure as you can get. Any contaminants in copper drastically decrease conductivity, that is why is wire copper always at least 99,5% pure. Use clean copper, do not think any other metal like brass. It will ruin your day
> 
> Wire is impractical to use for cementation, as small pieces can fall to the cemented metal and contamine it. Also the precipitate is more easily locked between wires. And wire is light - you need to use a lot of it. Bigger bar or plate is much more practical. Also copper pipe as nickvc mentioned, opened up and hanged in solution.


Thanks, So I need to melt this wire into an ingot then I will be fine?


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## Martijn (Mar 31, 2022)

FrugalRefiner said:


> Actually, it's way up in the reactivity series. Metals that are high on the series, like zinc) are highly reactive. Metals that are low, like gold, are low in reactivity. While I've seen some charts that are reversed, most follow that idea.
> 
> Dave


Thanks. I always mix that up. I guess it's because the least reactive metals are the 'purest' so 'high' on my list compared to the 'inferior' reactive ones...  sorry


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## goldshark (Apr 1, 2022)

Another good source for scrap copper is a high end sheet metal shop. I used to install copper standing seem roofs and got a lot of scraps from cutting hips and valleys. I think the problem may be that it is usually 16 oz. per square foot material, so may be a little too thin for refining purposes. If you were doing small batches, it may work fine. Lots of surface area. They will sell to the scrap yards at a reduced price, so the scrap yard can make a buck.Can somebody answer what the preferred thickness of plates should be?


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## orvi (Apr 1, 2022)

goldshark said:


> Another good source for scrap copper is a high end sheet metal shop. I used to install copper standing seem roofs and got a lot of scraps from cutting hips and valleys. I think the problem may be that it is usually 16 oz. per square foot material, so may be a little too thin for refining purposes. If you were doing small batches, it may work fine. Lots of surface area. They will sell to the scrap yards at a reduced price, so the scrap yard can make a buck.Can somebody answer what the preferred thickness of plates should be?


Thick enough that you are sure it wont eat through it. For me thicker = better. You could then use the bar more than once. In tough times, I also used copper sheet, like 0,8 mm thick, but it was pretty annoying because of quick dissolution. At least 1-2 mm if it should be usable. Also you can use various very thick wires (like 5+ mm) and hang these straight in solution - not twisted or "spiraled". 
Idea is, that nothing from the metal used for cementation will fall down (or lock solids in between) as the material is eaten by cementation process.


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## kurtak (Apr 1, 2022)

ssharktu17 said:


> Thanks, So I need to melt this wire into an ingot then I will be fine?


Yes - you want to melt/ pour that wire to an ingot or bar as that wire will cause problem - as Orvi pointed out



orvi said:


> Wire is impractical to use for cementation, as small pieces can fall to the cemented metal and contamine it. Also the precipitate is more easily locked between wires.



Kurt


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## Martijn (Apr 1, 2022)

If you only have thin plates, use new copper for silver cementing and pull it out when it becomes too thin. 
Then use them for the stockpot. 
A solid cone shape of copper pointing down would last the longest i think.


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## dpgold (May 30, 2022)

FrugalRefiner said:


> It's not that zinc will be left in the insoluble silver cement. It's that zinc will displace everything below it in the reactivity series, including chromium, iron, cadmium, cobalt, nickel, tin, lead, antimony, bismuth, and copper, if they are present in your solution. So, all those metals will be in your silver cement.
> 
> Dave


Hi, since this is one of the best description of what happens according to the reactivity series I would like to ask you if I understood it correctly. Any element on the reactivity series will displace every other element below, so in order to collect or separate them I could start with the higher one on the list which will cement out (precipitate) all the others below. But if I want to take out of solution only one let's say copper I would cement it out with the next one above (lead). That way I could selectively collect them if they are worth it?


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## FrugalRefiner (May 30, 2022)

In theory, that's correct, but in practice, it's not quite that simple.

One factor is that the solid metal being used to cement the dissolved metal must be soluble in the solution. So, even though silver is above gold, you can't use it to cement gold from a chloride solution because silver is not soluble in a chloride solution.

There must also be a significant difference in electromotive force between the two metals. Copper works well because there is a significant difference between it and the precious metals below it in the series.

Then there are some metals that are just resistant to cementation.

Dave


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