SIlver nitrate not cementing with copper

[cmethowusa]

I just ran about 3 oz of sterling scrap in 300 ml of 60% nitric acid. I ran the dissolved solution through a filter to take out the solids. I've used up about a foot of half inch copper tubing and still have no precipitate just a very dark blue solution. Please help

 

[Oz]

You used about 2 1/2 times too much nitric. It will take a good bit of copper to eat through it. The best thing would be if you had some more silver you could dissolve instead of wasting your copper and nitric.

 

[cmethowusa]

I've got more scrap. Will try what you suggest. Thanks OZ.

 

[cmethowusa]

OZ; I've never used the sodium chloride method. Would you recommend it over the copper?

 

[Oz]

It depends on if you want silver metal or the silver chloride your salt will give you. Some sterling silver scrap has lead from soldering that will go into nitric and form a lead chloride solid with salt as well. With cementing on copper you will not get a lead precipitate.

If your 300ml was 70% nitric mixed 50/50 with distilled water it would dissolve 8 ¾ Troy ounces of silver under moderate heat. Since yours is 60% and you have put extra copper in it will dissolve less. If you have the scrap, keep adding until no more dissolves with moderate heat. Once cool you will want to filter your solution before cementing on copper. You may have formed some silver nitrate crystals as your solution cools, but they dissolve easily with water.