Industrial silver

[Chaos]

Hey all,

I have recently acquired a very large amount of silver~
Though I'm not sure of it's purity...
I've been reading the Hoke manual (on page 70 so far) and trying to research online material~
Currently, studying a lot of different things and find myself spread thin...
So...the silver in question was used in an old factory for maintaining heat throughout a system~
Some of it is in pellet form and some of it is in block form~
I have done several tests (but no acid yet...nitric will be delivered Wednesday)
Tests results= Not magnetic, does not spark (used grinder), excellent heat conduction, electrical conduction, mailable, dull gray color (not sterling), blocks made a ringing sound when struck with a small tool~
I also took a torch to the pellets and block (had aluminum pellets beside to compare)
Results= Aluminum melted into a blob almost immediately, silver pellets took longer...no blob, but clumpy (heated on 1/8 steel plate and plate melted in area where silver was grouped...not the case with aluminum...factor of heat conduction)
Silver block= Never would melt (50 LB block dissipates heat well), cutting with bandsaw worked (but, difficult...very dense), cutting with grinder (thin metal blade) also worked...but quickly eroded the blade...never any sparks~

I guess the next step is to see if samples dissolve in nitric acid?
Tried to get a purity test from e-bay to verify this info:
To determine the purity of the silver, you can buy a test kit with different types of acid. When a type of acid is applied to the bars, it sits there for a min or so and then starts to change color. If the acid turns blue, it is 85% silver and the more grey it turns the higher silver content of the bar, and when you get one that is clear silver, you have .999 silver.
But, the guy selling the kits told me his just tested for silver period...not the purity of silver~
Can anyone provide a link to a silver purity test kit?
What is the best way to cut a huge block of the stuff?
Also, any expert feedback would be great

 

[qst42know]

Do you have any more information on what this material was used for?

Many things will conduct heat and cost far less than silver, seems a strange choice of material.

 

[AlanInMo]

Hey all,

I have recently acquired a very large amount of silver~
Though I'm not sure of it's purity...
Tried to get a purity test from e-bay to verify this info:

But, the guy selling the kits told me his just tested for silver period...not the purity of silver~
Can anyone provide a link to a silver purity test kit?

These are the color reactions displayed by my kit (using a test stone and one acid)..

Ag
925 Ag = Dark red
800 Ag = Brown
500 Ag = Green

You can get the packaged deal (including platinum test) cheaper than on Ebay... On Sale for now..

--> http://www.scales-n-tools.com/index.php?main_page=product_info&cPath=9&products_id=32

 

[qst42know]

If you have nitric acid on the way buy some potassium dichromate. To make Schwerter's solution.

http://en.wikipedia.org/wiki/Potassium_dichromate

 

[teclu]

If you have HNO3 70%, you can dissolve a sample -for example 100 grams of silver alloy- in HNO3 50/50, then cement silver on copper, wash and dry well this powder and compare the mass with the first sample...


teclu

 

[LeftyTheBandit]

Hoke says:

How SILVER REACTS
First remove any surface coat, such as lacquer, and to each article apply a drop of nitric acid. Let it remain for thirty seconds or so, then rinse it off and see if the surface of the metal was attacked. You will find that nitric acid reacts with silver, even the highest grade, turning dark and making a gray spot on the metal.

Fine silver, when dissolved in nitric acid, gives a colorless solution that darkens after exposure to light. Sterling silver and coin silver show some green color, the green being due to the copper with which they are alloyed.

To confirm silver, place a fresh drop of nitric acid on a clean surface, let it react for a half minute, then with the point of a penknife drop in a single small grain of table salt. A white substance will appear—silver chloride—of a cheesy consistency. This is characteristic
of silver.

THE FLAME TEST
If you can turn the flame of an air-gas or oxygen-gas blowpipe on a piece of suspected metal, you can, within a few seconds, obtain an excellent idea of its nature. Nickel, chromium, brass, and most other base metals promptly turn black. Most base metals will melt, forming oxides of characteristic color and form. White gold alloys will melt promptly in the oxy-gas flame; more slowly in air-gas. Or, if the flame is removed before actual melting occurs, a definite darkening is visible. This is also true of sterling silver. Fine silver when molten absorbs oxygen, and on cooling expells it with violent spitting and "crabbing". This tendency is less conspicuous with sterling and coin silver.

These tests will tell you if you are dealing with silver.

 

[Chaos]

Do you have any more information on what this material was used for?

Many things will conduct heat and cost far less than silver, seems a strange choice of material.

True, it would seems like a strange choice today...but, not back in the 1930's when this manufacturing environment was originally created~

What do you know of that most closely mimics silver (heat conduction, weight, general appearance, etc) but, would cost far less?

Thanks man

 

[lazersteve]

I would dissolve a small sample in 35% nitric and add a few drops of HCl to the resulting solution. If you get a white curd like precipitate when the acid is added, you have silver.

Once you know it's silver then proceed to testing with Silver Testing Solution.

Steve

 

[goldsilverpro]

Do as Steve/Hoke said. Until you test with nitric, every other test you made doesn't amount to a hill of beans. All those tests are "maybe" tests. The nitric/chloride is a very sensitive "yes or no" test. If the answer is "yes", send some to me and I'll assay it.

 

[qst42know]

True, it would seems like a strange choice today...but, not back in the 1930's when this manufacturing environment was originally created~
What do you know of that most closely mimics silver (heat conduction, weight, general appearance, etc) but, would cost far less?
Thanks man

Seems a strange choice even in the 1930s, In the 30s silver was money. How much weight did you say you had?

Hope for you it is silver but still I can think of a couple of substitutes.

Monel, and Nickel silver, for the short list. Both are very conductive and far more corrosion resistant.

http://en.wikipedia.org/wiki/Monel

http://en.wikipedia.org/wiki/German_silver

If those pellets are from a plating environment be careful you don't have a bunch of cadmium. I would avoid melting or grinding any more until your testing is done.

http://en.wikipedia.org/wiki/Cadmium

 

[Harold_V]

Seems a strange choice even in the 1930s, In the 30s silver was money.

Correct. And lots of money, in fact. The dollar was struck with the official valuation of silver being $1.29/ounce. At that point in time, $5 would buy four large sacks of groceries.

I would have serious doubts about the material being silver, although I might see some value in having it silver plated. Key here is to determine if the material is silver, and if so, whether it's plated or solid.

Harold

 

[Chaos]

Thanks for your replies...
I have some nitric coming next Wednesday and I'll do further testing~
Based on the new info, I am less hopeful about my find :-(
But, we'll see...


Quick question: The nitric I've got ordered is 68%...how do I dilute that for testing purposes and would it be a different factor for actually processing scrap?

CHAOS