silver cementing disaster??

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Woolf

Well-known member
Joined
Oct 24, 2010
Messages
92
my first attempt cementing silver i thought i did well one.. while watching others videos and reading others reactions i believed i did good... how ever i am being told now not to use urea so im doing a second test... first let me explain the steps of my first experiment

i took 70% nitric mixed it 50/50 with bottled water

placed inside of beaker

placed 925 sterling inside

stirred around until majority was dissolved

urea until no more reaction took place

filtered

then placed copper tube inside...

i saw the reaction it looks correct... im assumeing i let it dry then melt..


now my second attemptim told not to use urea but so far its not anywherenear the same... i start off the same 50/50

but this time im using more silver and more acid.... so i place all the silver in my beaker and only put half th acid in to stat so i can watch the reaction.... the first amountclearly did not dissolve everything so i pour in the rest of the acid stir until all is dissolved but this time im getting a sea green color or a milky green color... i left the acid alone.. had to run errons for a few minutes maybe 30-45 came back and theres a solid white color at the bottom... it was chunky like cottage cheese? when i stired this it bubbled a little so i applied heat to the beaker and saw a small reaction i continued applying heat and stiring i left the acid alone for some time now and when i try to filter this white creamy substance is very thick and wont filter with out my pump... any idea what this is?
 
i just finished filtering the milky substance its starting to harden like wax but still remains the while milky color.,..
 
Woolf said:
i just finished filtering the milky substance its starting to harden like wax but still remains the while milky color.,..
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sounds like you had some tin mixed in your sterling did you test every piece?
did you incinerate to burn off oils, wax and other uglies?
Tin and nitric equals what you experienced ,hard to filler.
If it was silver chloride only then it would be easy to filter .

This is good to experience the effect of tin ,for I faced this demon many times before.Now I avoid him like the plague .

good learning
 
i took 70% nitric mixed it 50/50 with bottled water
Click to expand...

I see no reason to use urea in a silver cementation. Copper will quickly consume any remaining free nitric.

Confirm your bottled water is RO purified or distilled and without added flavor enhancing salts, avoid natural spring water. And skip the urea it is unnecessary and may be the source of your troubles.
 
well this is why im experimenting =) im jusmt trying to learn reactions.. so can i filter out the remaining white cream and still cement the silver out?
 
Yeap, you need distilled water for your 50/50, otherwise ag will precipitate, i made that same mistake. :roll:
If you neutralized all the nitric with urea, I don't think you'll get a reaction.
I would filter, add a bit of nitric & try cementing; hope you didn't drop all the silver that was in solution.

Just my 2 centavos, too! 8)

Phil
 
if its looks like a snow in your solution, its AgCl. try to expose to a daylight or UV gas charge...if it turns greyish - its silver chloride,filter it and keep for another processing(you used water with consisting Cl- ions)
if its like a gel, its metastannic acid , you can expose it on UV, there will be no change of colour

filter it and cement silver using copper

you can add a little bit of nitric (finer mesh precipitated and costs more copper, but a little bit clearer)
 
i just went out and bought distilled water the cream looks greyish after filtered and a little dry its like clay or something... im going to put copper inside and see if theres any reaction
 
alright cementing worked all done now i just need to let it sit over night and dry/melt =D
 
this was earlier on in the morning... im just now finishingalmost 12 hours after... and im going to let it sit over night with copper inside
 
Woolf said:
alright cementing worked all done now i just need to let it sit over night and dry/melt =D
Click to expand...
I read no mention of rinsing. Surely you know you must rinse it well?
Rinse until there is no color in the rinse solution. Tap water will serve perfectly well. If you have a Buchner funnel, once the color is gone, get the silver in the Buchner, tamp it down hard, and rinse with water to collect any loose silver that clings to the sides. You can then force dry the cemented silver by placing in an evaporating dish and heating slowly. Don't be surprised to see traces of nitric being expelled as it dries.

Harold
 
yes i filter many times even after the water was clear i continued to rinse the silver just to double check im going to let it dry by sitting out i have alot of 5toz bars im considering refining ( 925 bars ) thank you everyone for the help =))
 
These is from notes that I have saved from the different posts:
"It takes about 38 ml of nitric acid to dissolve 1 troy oz. of silver.
& It takes about 79.3 ml of nitric acid to dissolve 1 troy ounce of copper."

Do some math & calculate how much you should need.
Remember to add the nitric to the water, & in increments, 'til all reaction stops, so you don't over use nitric.

And remember, its 50/50.

Take care!

Phil
 
hmm im doing a a pretty big batch this time... so far it has taken all day and still not done dissolving the silver... but this time im noticing black powder on the bottom of my beaker?? any one know what this is?

i do not have a heating tray or anything and its very cold outside =(

im assuming thats why its taking very long
 

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