# Disolving silver



## mikeinkaty (Jan 6, 2013)

My 1st run with sterling had 2 or 3 tablespoons of pink gunk, kinda sandy in appearance, in the bottom after the disolve was finished. Was using nitric acid. Took a long time to filter that first run. Actually I filtered it twice. The next 3 runs were basically clear with no gunk at all. They sorta dropped through the filter like it wasn't there. What was the pink gunk? All the silver was from my cornflake jar that has been thoroughly mixed.

I did learn today that more surface area for the copper makes the silver drop faster. I had 4 copper pipes of different sizes with each about 2.5 " long all placed one within another. It dropped in half the time as the others.

my last 5 runs have each been with 10 ozt silver. My nitric usage is below what I anticipated. I am using a watchglass on top. THat bring up another question. I'm disolving using quart size Mason fruit jars. When I put a watchglass on top of them it seals out the air and the brown fumes (NO) can't form. When using a beaker, air can get in hence the brown NO fumes. Which is best? I'm thinking that air needs to get in to facilitate reflux??

By tomorrow night I should have about 50 ounces of powder drying. My 1st 2.5 liter of nitric is about half gone!

You know that first run was done in the shop with quite a bit of heat applied (~140-150 F). The rest were done outside with the temp about 45 degrees. The latter ones were a lot cleaner???

Mike


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## mikeinkaty (Jan 6, 2013)

Figured out what the pink stuff was. The heating/cooling cycles had caused some of the silver to percipitate out. The other batches that had no heat applied had silver nitrate crystals forming due to the cold temps. A little heat and more h20 caused it to go back into solution. I got 60 ounces digested and 30 ounces of powder now. Starting to nail down an assembly line for this.

I did see that the copper didn't drop all the silver in one batch. I came up short on one batch by about 20%. I now have more copper in that residue bottle and already about 1/2" has collected on the bottom. The other two batches dropped the expected amount.

Using a heat lamp to dry the powder. My hotplate is to busy.

Mike.


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## Anonymous (Jan 7, 2013)

By reading your post, I went outside here (it was around 45F degrees today) and I took one of my batches of Nitric/Peroxide solution and I put a Pyrex on the hot plate, added some water to the Pyrex dish, then I added one of my 1000 ml beakers to it, then I set the hotplate to 2 - 2-/12. It goes to setting no# 7.

The solution was blue when I started it a couple days ago, but when I added the heat to it, plus I added some more clean copper to it, after about an hour at most, the solution was more like ocean green, and not the blue from my other solution that I already have still sitting so I can add more to it.

After noticing how green the solution was, I took the beaker off the hotplate and I let it cool down. From there I placed it back in the drawer I have outside. The silver seemed to have all settled, except for a few floating blobs of silver.

My point?... Heating the solution may be quicker (still not sure due to my temp here and doing it outside), but I think that heating the solution rushes it and adds more impurities to it (copper).

I'm going to wash and dry my silver tomorrow and hopefully the solution isn't as bad as it looks. But I can say this much, when I added more copper and heat, it dropped more silver. I'm starting with 1 lb worth of keyboard mylars. I have plenty (about 50 lbs worth), but this is something still new to me. I already refined approximately 6 grams so far, and by the looks of what I have already from the second batch, I may very well end up with 15 grams from just 1 lb of keyboard mylars. I surely hope so. Then I'll know I'm doing something right, according to yield reports.


Kevin

*[EDIT]*
I have used the word copper in places when I meant to say silver, so I wanted to update/edit the areas in red so that I don't confuse anyone, because I got confused with my own post. I definitely have to double-check my postings before hitting "*Submit*".


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## mikeinkaty (Jan 8, 2013)

I think I either need to do less than 10 ozt of sterling at a time or increase my vessel size to something more than a quart jar. It seems like the silver drops better when the solution is dulited with h2o after the nitric reaction has stopped. Can someone elaborate on that? I'm using the prescribed amount of water and am starting with half the amount of nitric which I increase to the point where all reaction stops. Then I lean a long piece of sterling (like a fork) in the jar to make sure the nitric is exhausted. 

Rincing is a pain. Gotta work on that. I've been running the entire contents through a 4" Buchner funnel with a muslin cloth filter. then I set aside the silver slime and filter the solution again using a coffer filter. Once that's done I use a new filter paper (rincing the old one into the slime container) and then rince the slime with boiling water until the fluid runs clear. Then I dry the slime using a heat lamp.

Mike


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## butcher (Jan 8, 2013)

mikeinkaty, 
The gas escapes from solution (depending on conditions) whether you use a watch glass or not although the watch glass can somewhat help in refluxing, nitrogen monoxide NO is a clear gas, when it mixes with the oxygen in the air it can form the familiar brown gas nitrogen dioxide NO2, with the moisture in the air NO2 gas can form HNO3 nitric acid (or acid rain).
You are correct the cementing process works better from a dilute solution here H3O comes into play in the acid water.


2NO + O2 --> 2NO2
2NO2 + H2O --> HNO3 +HNO2
3 NO2 + H2O --> 2HNO3 + NO
4NO2 + 2H2O + O2 --> 4HNO3

Edited names I had nitrous on my brain :lol: 

testerman, 
The green solution when you concentrate can come from the free nitric acid in solution, when you are concentrating, you are also concentrating this free nitric acid in solution, this also explains the NO2 fumes you see evolving as the free nitric dissolves more copper and cements more silver from solution.

This will be especially true when using home made nitric acid, where the copper would form a blue copper sulfate mixed with copper nitrate giving the solution a green color, as long as copper nitrate is also in solution it will be colored green, until the nitric acid is distilled off, then the remaining copper sulfate will turn blue, once all of the nitric is gone from the solution. 

The green color can also come from palladium, a brown color Pd mixing with blue color of copper in the nitrate solution, giving a green color of nitrate solution.


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## mikeinkaty (Jan 8, 2013)

Thanks Butcher!

When I get finished I will pour all my gallon jugs of spent solution into a 5 gallon bucket and see if any more silver drops out. One of the gallon jugs dropped a whole lot more silver. To the 5 gallon bucket I'll add about 1 gallon h20. Once that finishes I'll strain into another 5 gallon bucket and then see if any copper will drop out of that. Will it drop out or adhere to the iron (steel?) and have to be scraped off?

This process does use a lot of copper. Fortunately I still have scads of it around.

Mike


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## mikeinkaty (Jan 9, 2013)

I have one batch of silver slime that is so fine that it goes right through 2 coffee filters and will not settle out to the bottom . I washed it several time with boiling water and carefully poured off the top as best I could. Keeping the pour-off in separate containers. I'm going to keep that batch separate and dry it out and melt it and see what happens. All the others would drop to the bottom in just a few minutes. ?????

With the stuff that settles out quickly I have taken to pouring boiling water in them about 3 times, stirring them, and pouring off the blue liquid through filters. After 3 or 4 washes the pour-off is colorless. I started doing this when my four 1500ml beakers arrived. Found them on eBay for $6 each.

I know there are chemical names for the stuff you pour off and for what is kept behind but dang if I can think what they are!


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## MysticColby (Jan 9, 2013)

for the ultra-fine silver that can't be filtered: you could add some nitric, heat until fully dissolved (shouldn't take much - colloidal silver is not a large amount), then cement with copper. the cemented silver should be more easily filterable.

for cementing copper with iron: I've had limited experience with this, but it seems to stick to the iron and need manual removal. not all of it, but a lot.


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## mikeinkaty (Jan 9, 2013)

I took two 4ozt bars over to a local PM buyer. One was poured from the batch that was extra fine slime and the other was from a normal grainy batch of slime. The XRF gun showed the same for each bar. Both measurements varied from 99 to 97 depending where on the bar the gun tested. The guy said that it was difficult to measure hand poured bars as opposed to commercial poured. He said the bars were showing some copper but he didn't say how much.

These first two bars didn't look ideal, having spots of borax glass showing and some rough areas. I used a glazed silica borax crucible for the pours. Would a graphite crucible do better? I'm presuming that graphic crucibles would not need to be glazed? Is that correct?

Mike


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## mikeinkaty (Jan 9, 2013)

Still not sure what the color of the spent solution means in my waste jugs. I have some blue solutions that aren't percipating any more silver and some that are. This is after the first pass of dropping the silver and decanting the fliuid into my waste jugs.

Does one ever need to add more nitric to start the percipitation again?

Basically I don't know how to tell if all the silver has dropped. Will stannous chloride help here?

Mike


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## Anonymous (Jan 9, 2013)

mikeinkaty said:


> I took two 4ozt bars over to a local PM buyer. One was poured from the batch that was extra fine slime and the other was from a normal grainy batch of slime. The XRF gun showed the same for each bar. Both measurements varied from 99 to 97 depending where on the bar the gun tested. The guy said that it was difficult to measure hand poured bars as opposed to commercial poured. He said the bars were showing some copper but he didn't say how much.
> 
> These first two bars didn't look ideal, having spots of borax glass showing and some rough areas. I used a glazed silica borax crucible for the pours. Would a graphite crucible do better? I'm presuming that graphic crucibles would not need to be glazed? Is that correct?
> 
> Mike


If I'm not mistaken, you don't ever want to melt in a graphite crucible. you pour into it to mold, but not use as a melting dish. I think I read somewhere here that it may crack or break, or if it did work, you might only get that one use out of it. Either way, don't use graphite as a melting dish.

As far as borax stains and spots on your silver, I learned a nice trick by trial and error. Here's how to easily remove the borax from the silver while melting and pouring.

I use a mapp torch for my melting.
Your melting dish should ALREADY be seasoned with borax. If not, do that first.

* Melt the silver until it turns to a liquid keep the torch close to it.

* Once the silver is fully liquified, tilt the torch sideways to the silver, as if it's pushing the silver from the side. Depending on your lighting conditions, you can see the borax sliding around the surface of the silver. What you must do is push the borax from over the silver to the outer edge of it and if you keep the torch there long enough, you'll see the borax burning away, or it's sticking to the dish. Either way, that's good.

* You must do the step outlined above by going around the whole silver that's melted to make sure no more borax is being lifted up by the force of the torch and flame. When all the borax is off the silver, you'll notice it because the silver will look just like mercury. 

I tried to make a button by letting the silver cool in the melting dish, then I could just pull it out. But what happened is the silver started turning almost black until it cooled down, then it had a frosted white look to it. That was the borax. That's when I reheated the dish and melted the silver back down to a liquid, and that's when I noticed a glaze of substance gliding around the surface of the silver. I suspected it was the borax, and that's when I put the torch to the side of the silver, pushing the borax to the other outer edge of the silver. From there I kept the torch where the borax went to and I could see it either drying up or sticking to the dish. I did that until no more borax would glide on the surface of the liquid silver. Then I simply poured the silver into a mold. I used a cast steel conical mold to pour my silver in.

Since I usually do my melting at night, where I have a light, it's easy to see the borax on the silver. I'm not sure if you can easily see it in the daytime.

Kevin


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## bigjohn (Jan 9, 2013)

The electric furnace uses a graphite crucible. But as far as I know its best to torch melt in a fused silica dish.


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## Anonymous (Jan 9, 2013)

bigjohn said:


> The electric furnace uses a graphite crucible. But as far as I know its best to torch melt in a fused silica dish.


You're correct. I forgot about the electric furnace.  

That may be why the graphite does work in those, because it's heat to the crucible and not direct flame.


Kevin


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## Anonymous (Jan 9, 2013)

mikeinkaty said:


> Still not sure what the color of the spent solution means in my waste jugs. I have some blue solutions that aren't percipating any more silver and some that are. This is after the first pass of dropping the silver and decanting the fliuid into my waste jugs.
> 
> Does one ever need to add more nitric to start the percipitation again?
> 
> ...


The color of the spent solution probably mean that you have copper in the solution (depending on the actual color). 

If you have some solution still dropping silver and some that isn't, I would say that the one that isn't dropping any more silver has been spent/depleted. It done its job. Drop a piece of silver shot or a piece of silver in it and if it doesn't dissolve, then it's done. If it does dissolve, then add some clean copper to it.

Once you filter, some of the silver will escape into the waste container you filter to. One way to deal with that is to let it settle overnight, then take a hose and siphon the liquid out instead of pouring/refiltering, leaving the residue on the bottom of the jar.

If you siphon it to just above the residue, you can add some distilled water, let it settle, then siphon the liquid out. From this point, especially if the water is clear, you can let the leftover water in the jar dry out on its own, or put some heat to it (hotplate on low). From there scrape out the substance and put it into a melting dish.

Kevin


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## mikeinkaty (Jan 9, 2013)

Thanks everyone!

I think one reason I've been getting very fine mud is that I haven't been adding h2o after the silver has disolved. That mud makes it difficult to clean up/filter. I have one batch here where I've added as much more h20 as called for during the disolve. This batch of dropped silver is more like curds of cottage cheese instead of very thin mud. Tomorrow I will be cleaning it up. Oh, the silver dropped much quicker and the quart jar is now more than half full of it. 

I have noticed that I can push the borax around in the crucible. One problem is that I have to much borax in the crucible. After my last cornflake melt I melted it and got most to pour out. I've only done 2 bars so far and the 2nd one looked better. The bottom half of it was perfect. Probably just take a while to get the technique down. Nice thing about silver is that you can remelt your mistakes.

It is nice to have people here that care to share their experience!

Mike


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## Anonymous (Jan 10, 2013)

mikeinkaty said:


> Thanks everyone!
> 
> I think one reason I've been getting very fine mud is that I haven't been adding h2o after the silver has disolved. That mud makes it difficult to clean up/filter. I have one batch here where I've added as much more h20 as called for during the disolve. This batch of dropped silver is more like curds of cottage cheese instead of very thin mud. Tomorrow I will be cleaning it up. Oh, the silver dropped much quicker and the quart jar is now more than half full of it.
> 
> ...


I'm so glad that you feel like you've been helped. It really does make me feel good and I'm sure the rest of the members here feel the same.

I, personally feel good that you must have tried the method/technique I mentioned about the borax. As you can see, you can burn the borax off your silver WHILE melting it. I'm still learning this refining stuff, but I am amazed at it and I love it. Be smart and be safe.


Kevin


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## mikeinkaty (Jan 10, 2013)

Found out that my 1st 2 bars ain't half bad! I went to Goodwill and bought a 2nd hand crock pot for $7 and made up a pickle solution with 1 liter of water and 100ml of Liquid-Fire. They came out lots better! I have a soft wire wheel and a polishing pad and compound for my grinder and after a couple of minutes each they looked like store bought! Da-- this is fun! By the way, most Goodwill stores have quite a bit of stuff a home refiner can use. Plus it's going to a good cause.

After finishing the bars I put my fuzed silica crucible in the crock pot. After 1 hour it was whistling clean! I have it in a flask now and tomorrow I will soak it for a while in distilled h20 then start it on a slow dry and bake. I have another as backup.

I boutght two of these crucilbles from Jewlerytooldepot: 
http://www.ebay.com/itm/220953808222?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

They are good and rugged! I really abused the 1st one and it has held up great. I cut most of my sterling with the torch, directly into the crucible.

I'm about 2/3rds through with converting the sterling into Silver powder. Anxious to add up all the batch weights.

Mike


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