# Droppins Silver with Copper



## MR.ED (Apr 5, 2011)

I have been dropping Silver from Silver Nitrate using 100% copper tubes and have been finding some intersting finding

1ST... When copper starts to drop from solution it is a nice light brown color but 2 - 3 hours later or so the cement color that is forming on the copper tubes are turning into a blackish color on the copper rods. 

Is this DARK color silver cement just as good as quality as the nice light brown silver cement??


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## Irons (Apr 5, 2011)

what is your source for the Silver Nitrate? 

Is your cementing container exposed to bright light?


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## Oz (Apr 5, 2011)

There is something wrong with your silver nitrate if you are getting a brown or black cement on copper.


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## MR.ED (Apr 5, 2011)

I know i have pure Silver nitrate and its not the glass container that are the problem. I have done the silver cementing for the last 50 times. I always start with Nitrate that comes from .925 sterling. Then i take that silver nitrate and use copper tubes to cement the silver out. The first 2 hours of cementing i get nice light brown silver into solution droping out. But it seems around 3 - 4 hours the copper tubes start getting a black fluffy residue that has the same texture as the light brown stuff but it is black in color.

So is this black stuff silver or a lower form of silver.


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## Oz (Apr 5, 2011)

Silver nitrate solutions cement silver onto copper as a light grey – silver gray colored material. I have never seen it as a brown or black. Even high PGM content still just gives a darker grey cement silver.

If you are sure it was sterling silver then I would have to question your copper tubes, is this plumbing pipe? Did you filter your silver nitrate until it was translucent before cementation was started?

If it is clean copper and you only digested sterling silver in nitric, I would have to say you got some contaminated sterling. If you filtered before cementation then what you are getting as cement is less reactive than copper electromotively. Most things less reactive than copper in nitric have value, many greater than silver. It just does not seem plausible for there to be that much present in sterling. What was the source of this sterling?

Something is wrong here.


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## MR.ED (Apr 5, 2011)

Thanks OZ you are right i am dropping Light grey silver but then the Grey turns to black collored silver 2 - 3 hours into the cement process. The grey turns black later in the proecess.
Im using the 8 foot long plumbing copper tubes then i cut the up and drop my silver with them. I do filter the silver nitrate. i do this in a low light environment area. I also put the silver nitrate into a large 4000 ml glass to cement the silver. I also use distilled water. What i am thinking is as soon as the good silver has dropped and the silver nitrate is just about saturated with the is that the silver that comes of the copper tubes is polutted with something.

Need help. Is the copper good copper to use. Or is something else going on


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## Oz (Apr 5, 2011)

Your copper is fine as to purity.

Does your “light grey silver” change color after it has been cemented and sets on the bottom of your beaker? Or is it that the color of the cement being formed on your copper starts having a darker color as it is produced after the first couple of hours?


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## stihl88 (Apr 5, 2011)

What does "Droppins" mean in your thread title, did you mean Dropping?


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## metatp (Apr 5, 2011)

Mr.Ed,

I have had a "black" cement type color before, but only when I was dissolving silver with some material like tungsten present as well. The solution would be transparent, but it appeared to be dropping more than silver when copper was added. I use copper piping all the time. I think the other material (salts) were getting dragged down with the silver. When I added HCL to the filter cemented silver, it dissolved the black (actually a dark blue or purple) stuff and I was left with the grey silver. I decided to re-process that silver again, and everything was fine after that.

Hope this help,
Tom


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## Harold_V (Apr 6, 2011)

A black deposit that comes down after silver is often one of the platinum group metals. If your solution prior to the black forming has a green tint, and slowly turns blue, you may have something of value present. It might help to know the source of the silver. If it has been used for inquartation, there's more than a good chance you have platinum group metals involved. 

Harold


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## MR.ED (Apr 6, 2011)

Hey Guys, Thanks for your responses. 

The material i use for my Silver nitrate is always .925 sterling.
i process using 70% nitric with distilled water.
The solution im left with is a bluish green Silver nitrate.
I then dilute the silver nitrate with distilled water about 50% (Add to existing silver Nitrate) 
I then filter the solution into a 4000ml glass beaker.
I put the copper tubing into solution right away. (I mean i dont wait until the Nitic acid is used up, I guess this takes a day)
Then i add copper tubing from Lowes (hardware store) Copper tubing in solution would be about a total of 24 inches of 3/4 tubing.
The tubing starts to cement nice grey color cement.
After about 3 - 4 hours the cement that is on the copper tubes is like a dark purple, black cement.
This dark purple, black cement will slowing cement and cause the silver nitrate solution to turn the Dark plue color.
But the longer i leave the copper tubes in solution the more dark purple, Black color cement i get.
I get the dark purple cement every time i do this procedure. My work area is sterile and also use sterling silver from Holloware, flatawre ect.
I usually now monitore the cement until i start seeing the dark purple/black cement start to form and then i stop the procedure. The problem is that when i stop the procedure early i get less silver.
If i do capture all the cement both grey and dark purple color can i use the HCL to clean rinse my cement so i can get that dark purple / black colr out of my grey silver..
Is my process ok
Please leave feedback. I have done this 50 - 60 times with the same result


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## Oz (Apr 6, 2011)

MR.ED,

If you had gotten these results once I would be inclined to think you had PGM in your silver. But if you have had this result 50-60 times something else is up.

Are you perhaps making your own nitric with sulfuric acid and a nitrate? My thought is that you may have some free sulfuric in your electrolyte that is sulfating your silver black.


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## Harold_V (Apr 6, 2011)

Based on your comments, I'm inclined to think that you should add a few drops of nitric to your solution. I get the idea you are consuming anything that may have been free. When pure copper is used and there's free nitric present, it's common for the copper to be clean and bright when the cementation process has ended. 

Just a few drops makes a big difference. It's worth a try, although I sure wouldn't discount Oz's thoughts. 

Harold


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## samuel-a (Apr 6, 2011)

MR.ED

does your final cement steps looks like that?






The copper had black deposit on in that i separated and will test later, but most likely it's just copper....

In any case, all metals lower on then silver (on the EMS) can be separated easily in silver nitrate cell.


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## MR.ED (Apr 7, 2011)

Het Sam, great picture . that is exactly what happens to mt silver cement. Please let me know what you find out and great pic :lol:


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## samuel-a (Apr 8, 2011)

MR.ED

The final black cement turned out to be mostly Cu and Ag with slight presence of Pd.


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## MR.ED (Apr 9, 2011)

hey sam, thats what i thought it was. so there is a point when the solution will become to saturated with silver cement that coppe3r will form and stert to cement. I see people leave the copper in the silver nitrate for hours and they have nomention of the copper starts to drop too. That is not good if you want the purrer silver. 

Samt do you let your silver nitrate sit over night to help evaporate the nitric acid that is used when you break down the sterling or ect...?


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## samuel-a (Apr 9, 2011)

MR.ED

Either you do not fully understand the nitric leach mechanism or i didn't understand your questions properly. (no offense)

First: definition of saturation at our point of view. (no. 1)

Copper will not cement on silver, no matter how much powder is in there, the silver however, can redissolve back at elevated temperatures only to re-cement on the copper slab, this is why i cement mostly at room temp' 

As much as copper cementing on copper, i know of no such phenomena, but haven't researched that subject in-depth.
I think that is highly possible that some copper is detaching with cemented material and is lucked by the powder, therefore not dissolved by the already saturated copper nitrate solution.

In general, achieving pure silver of cementing process is highly unlikely and will mostly result in powder that is about 99% Ag with the rest being copper.
Proper water wash with plenty of water will eliminate most of the copper nitrate solution left over, but will not remove any elemental copper.

If you should choose not to further refine the silver via electrowinning process (results in 99.99% Ag), I'd suggest you incinerate the dry silver powder after washed well with water and perform a dilute HCL boil (dilute 32% HCL with 2-3 part of water) followed by several water washes and then melting, though i can't tell what will be the final purity and can only assume it will be at around 99.5-99.9%

I'm leaching inquarted gold with dilute 50/50 nitric solution and usually boil it for 1 hour or so and the move to filtering and silver cementing.


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## MR.ED (Apr 10, 2011)

Thanks Samuel.
HERE IS MY COMPLETE PROCESS..
Temp is 60 degree, Working inside workshop (real clean)
I use lab grade glassware and Funnel.
I use 50/50 nitric 70% lab grade and Distilled h20.
I use sterling in solution.
I boil sterling until disolved in solution (Blue/green colored liquid)
Let cool for 2 hours down to room temp.
I then ad 50% distilled water to dilute the nitric acid.
I then add Copper tubes bought from harware store (I hope is 99% cu)
In 2 - 3 hours nice greyish cement color but the 3rd hour shows dark purple/black color.
I stop process when i see the dark purple/Black color shows.
I then rinse solution well with hot water and the dry and melt.
I will add the HCL rinse that i was not doing before.
How long do you usuall keep the copper in solution (Hours)


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## samuel-a (Apr 10, 2011)

MR.ED

There is no need to further dilute the solution before cementing.
It will only raise the volume of your waste solution without adding any value to the process.

Remember Harold's advice, add a little nitric before cementing the silver.

When i cement with copper, i usually just leave it overnight to ensure PGM's are also cementing, Then again, i'm not worried about purity since the silver circulates back to the next inquartation. 

I think i haven't been very clear in my previous post, the dilute HCL boil comes after the incineration.
When done correctly, the incineration will turn any copper powder to CuO (and for that matter, most of other base metal will turn to their oxides) which readily dissolves in HCL. 
Oxidizing flame is best suited for this incineration in my opinion, as it will also oxidize Pd if present.

Here is a picture of the same batch (from the previous post) after being washed several times with water, boiled twice with dilute HCL (without incineration) and then again washed with water, then dried.
You can notice clearly the reddish color indicating still copper in there, i broke one 'rock' open (at the bottom) for you to see the color difference between the silver inside to the outer contaminated shell.
This to show you that without incineration, it is highly unlikely to eliminate all of the copper without harming the Silver. 






I don't know your purity demands, but at this point, it is not a fine silver product in my opinion.
As HTP said, either re-process silver powder with nitric or move on to electrowinning your silver.
Although Electrowinning will require you to commit silver to the electrolyte, i believe you will benefit at the long run by producing much superior product.

Sam


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## lazersteve (Apr 10, 2011)

Be sure you have thoroughly removed all of the silver nitrate solution that may have been trapped in the silver cement before adding any HCl or you will end up with AgCl mixed in with your silver. A vacuum filter set up works good for this task.

Dilute HCl will dissolve finely divided copper powder and tiny Cu pieces without any difficulty. It requires lots of stirring and a little patience, but it works.

The resulting silver can them be boiled in water and then rinsed with water in the vacuum filter until the water runs clear. If you are real particular about getting the copper out you can test a sample of the rinse water with a drop or two of ammonia hydroxide, any hint of blue means copper is still in the silver. 

For highest purity you must melt and run through the silver cell.

Steve


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## Profikiskery (Feb 23, 2015)

Dug up this post trying to find answers. The same thing just happened to me. 

I dissolved a 7oz. sterling ladle with nitric using 340 ml of nitric. When the silver/copper nitrate was ready for cementing a I dropped the copper into the solution. For the first 2-4 hours the cement was a light gray I was familiar with and all seemed well. Went to bed and after about 12 hours the solution seemed half full of good cement. I stirred well and let it sit for at least 12 more hours. I decanted the solution and filtered well with hot distilled water. 

Once the cement was cleaned...i.e. dripping clear water, I placed the cement into a hot plate to dry it and noticed it was very dark. I thought maybe it was the moisture and would lighten up when I dried it. It did not. 

I went ahead not being sure and melted it into shot for electrolysis. When melting in the crucible I got a good silver puddle but noticed floating on the top were a few more contaminates than I was used to seeing at the top of the puddle. I went ahead and poured into shot all of the cement to see what the outcome would be. 

My shot is covered in copper. More than I am used to. Usually at this point I can see some "traces" of copper on my shot...but this time it seems to have a good coating. It seemed not to bead as normal and my shot was more "stringy" and copper coated. 

I can't imagine there was too much nitric left over as my copper tubing was left pretty much intact. Attached is the pictures of my results. Should I go ahead and refine through electrolysis?


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## Lou (Feb 23, 2015)

I would suggest it takes a trip to the cell. With a Thum cell, you can just add the material in, stick in an inert electrode (like gold plated copper  ) and harvest away the fine stuff!

Plenty of instructions. Palladium (Ralph) has an excellent little hobby-sized cell he describes.

Lou


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## Palladium (Feb 23, 2015)

Are you checking your solution with salt or hcl to make sure the cementing process is complete ?


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## Lou (Feb 23, 2015)

Quite appropriate question!

You should always (and periodically) pull out a sample and test qualitatively with salt solution. 1 mL nitrate liquor diluted to 10 mL. This is a batch wise process. 

Personally, I don't like adding copper.

I precipitate as chloride, and go from there with iron.


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## Profikiskery (Feb 25, 2015)

I saw Lou's post and ran it through the cell and seems to be doing great. 

Palladum I did not. When I saw your post I read some more about it. I wasn't aware but am now and appreciate the advise. However, its been 24 hours give or take and I might have some dust on the bottom of the jar on the edges, but not even enough to cover the bottom. So I think I got most of it. I burned everything with a torch before it was dissolved but the ladle was in pretty rough shape prior to. I'm wondering if that may be why....I should have taken a picture of the cement but it looked about as dark as what was posted above.

If it happens again I'll dig some more into it. The flakes in the cell sure are pretty....I just love to watch!!

Thanks guys
Craig


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## artart47 (Feb 25, 2015)

Hi!
Have you tested your HCl rinse with SnCl? Should let you know if there are PGMs present.

Hope that helps!
artart47


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## Bjc3 (Sep 9, 2015)

I had small bits of copper wire in my silver cement and when I turned it into shot it is contaminated with copper is it okay to put in the anode bed if the silver cell or do I need to reprocesse it and is there a way to clean the ceramic crucible from contaminates or just bye new ones thanks


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## Palladium (Sep 9, 2015)

Just run it through the cell.

Buy new ones. Use the old one for melting your cemented silver and the new one for the crystals if you melt them. Then when that one gets trashy just demote it one step down the line.


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## Bjc3 (Sep 9, 2015)

Thanks you very much so the copper wont grow crystals in the cell and I am sorry if these questions have been answered already thanks again


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