Problem AgNO3 + NaOH

[kasutatudarvuti]

Dear Sir' s

I have tried to find solution for my problem from this site but as much I have searched it seems I cant find it.

Maybe someone have been in same problem.

I had about 1,5 kg AgNO3 in solid state. I read that UV lam convert it to Ag but something went wrong. Solution was in water and whet I mixed it two days it become slurry and all Ag NO3 was as one solution purple gray.
After that I take NaOH and added it with water to try convert it with sugar method but only I get is black solution, adding water it become dark yellow.

What Can I do to resolve this mess. As I know zinc dos not help me here.

I add a picture of solution I have.

 

[kasutatudarvuti]

A picture of solution (mess)

 

[Topher_osAUrus]

You mean AgNO3 or AgCl?

 

[kasutatudarvuti]

You mean AgNO3 or AgCl?

AgNO3 was wroted on the canister but all liquid was dried out so only what was left was sediment purple/gray.


Thanks for reply

Ain

 

[butcher]

You state you had 1,5 kg AgNO3 in solid state (silver nitrate crystals)dissolved in water, and you have read that UV lamp could convert it to silver metal, but something went wrong after two days the solution went purple gray a reaction but still in solution.

If it was silver ions which converted to silver metal it would form a precipitant or powder. from your description there was no precipitant, which means the silver did not convert to atoms of silver, or they could be in colloidal form, or even the reactions could be something else.

How do you know what you had in the beginning was in fact silver nitrate?, was solution clear when dissolved in water, or was there a color to the solution (from some other metals)?
If it did even have silver and nitrates or what ever it could have been.

Now you added sodium hydroxide which lowered the pH, and got another reaction, you got a black solution of some metal hydroxide in solution which turned yellow with water.
From your descriptions there was no precipitant, I suspect this was not just silver nitrate you had in the beginning, so if you do not know what your dealing with, you cannot get the same expected result you would get with a known reaction of silver ions with UV light or NaOH.

so what it looks like we first need to figure out what was the material to begin with was it silver nitrate or just about anything else, did it in fact even contain any silver, and if so how much or what else was involved what other salts of acids or metals???

Lets say there was pure silver nitrate salts (purple gray) the purple and (black) gray (black mixed with with salts of silver . The reduced silver purple or black would not have dissolved in the water, water could not take an electron from the silver to put it in solution.
Adding some nitric would put the purple or black powder into solution.

We need more details, to the puzzle, it sounds like we have lots of pieces of missing information.

 

[geedigity]

Could you take a couple drops of the black solution and add a few drops of water and then a few drops of hydrochloric acid? If the solution reacts to form silver chloride (white precipitate), then possibly you did have silver nitrate. Not sure how much NaOH you added, but you would need enough drops of HCl to neutralize the NaOH in your sample test.

You could also place a few drops of the black solution onto a copper bar to see if the silver cements out of the solution.

 

[g_axelsson]

Could you take a couple drops of the black solution and add a few drops of water and then a few drops of hydrochloric acid? If the solution reacts to form silver chloride (white precipitate), then possibly you did have silver nitrate. Not sure how much NaOH you added, but you would need enough drops of HCl to neutralize the NaOH in your sample test.

You could also place a few drops of the black solution onto a copper bar to see if the silver cements out of the solution.

You don't need to worry about neutralizing the sodium hydroxide, if there is an excess of NaOH then there is no silver nitrate left in solution. If there is AgNO₃ in solution then there isn't any NaOH. So just add a few drops of HCl and it will work as a test for silver, lead or mercury in solution.

AgNO₃ + NaOH -> AgOH + NaNO₃
and
2 AgOH -> Ag₂O + H₂O

Göran

 

[geedigity]

Thank you, I wasn't quite sure how that reaction would go with NaOH and AgNO3.

 

[lazersteve]

For anyone with AgNO3 in the solid form wants to avoid a mess like this here is a quick method to recover the Ag as a metal.

Dissolve the AgNO3 in room temperature water. Make sure all of the nitrate dissolves ( no solids remain).

Add HCl with stirring to form AgCl appearing instantly as a white curd like solid that settles very fast. Add HCl slowly with stirring between additions until new addition of HCl no longer forms AgCl.

Allow to settle and pour off the bulk of the liquid.

Cover the AgCl with twice it's volume of fresh water. Use a glass or heavy plastic container that has at least 3x the volume extra space in head room above the water level.

Follow the standard process for converting AgCl with lye and table sugar dissolved in water.

If your feedstock AgNO3 and reagents are pure, the resulting Ag will be 100% purity. The whole process will only take about 15-30 minutes.

Steve

PS: If you want to grow Ag crystals from AgNO3 simply build a small silver cell to grow the Ag electrolytically from the crystals mixed with water and a touch of nitric acid. This method will produce Ag metal directly, but will take considerablly longer to complete. One advantage of this method is that the leftover liquid will contain nitric acid from the AgNO3 that can be used to dissolve more base metals and or Ag.

 

[samuel-a]

Dry or damp AgNO3 crystals can be slowly heated and then melted.
The heat will decompose is to Silver metal O2 and NO2 gas.

Requires good ventilation though.

 

[kasutatudarvuti]

Hi for everyone!

Thank you who give so fast reply.

I was not able reply to you so fast, as I moved to other location.
I tried to use your recommended option to get my silver out of the solution. I added HCl to my solution as mentioned on posts. Only thing I got is brown sediment on the bottom of bottle. Do I need to clean it with other chemical? As I understand if it is silver it must be white, maybe sugar give this additional color.

Thanks in advance
Ain

 

[g_axelsson]

Silver chloride is a white solid when pure. It turns purple when exposed to light.
It can have other colors if it isn't pure and in this case the color looks more like iron hydroxide (rust) than silver chloride. If you have any silver there it doesn't look very pure.

What is the pH of the solution?

Do you have anything left of the starting material, the "silver nitrate". Any pictures?

Pure silver nitrate should look like sugar, no color and makes beautiful water clear crystals when a solution dries up. In solution it is clear as water.

Göran

 

[joseph1990]

Hi for everyone!

Thank you who give so fast reply.

I was not able reply to you so fast, as I moved to other location.
I tried to use your recommended option to get my silver out of the solution. I added HCl to my solution as mentioned on posts. Only thing I got is brown sediment on the bottom of bottle. Do I need to clean it with other chemical? As I understand if it is silver it must be white, maybe sugar give this additional color.

Thanks in advance
Ain

You literally had solid silver nitrate around 1.5 kilograms and now from looking at your pictures are dealing with less than 30 grams. So hypothetically speaking if it were to be 99% pure silver nitrate that would equate to 952 grams. Since maybe it's possible you have a very impure silver nitrate let us say you have a 10% pure solution this would equate to 94.5 grams of silver. I believe you made a mistake at some point where you dumped some dissolved silver because the photo clearly shows you have less than 30 grams of silver.....this would equate to about a 3% pure solution of agno3 you have now. Some big happened and hope you could get it back, I know it sucks losing some metal

 

[kasutatudarvuti]

Hi Joseph,

thank you for reply.

This picture is only sample what I made to find out reaction.

As I mentioned before. I received canisters with yellow solution an bottom of canister was withe sediment like cottage cheese. I took only sediment and tried to change it to silver with UV light but as I stirred it all solution become gray and it was like slurry solution after what I tried lye sugar method but all solution become dark brown. Now I added HCl and this reaction was result of it.

Regards
Ain

Hi for everyone!

Thank you who give so fast reply.

I was not able reply to you so fast, as I moved to other location.
I tried to use your recommended option to get my silver out of the solution. I added HCl to my solution as mentioned on posts. Only thing I got is brown sediment on the bottom of bottle. Do I need to clean it with other chemical? As I understand if it is silver it must be white, maybe sugar give this additional color.

Thanks in advance
Ain

You literally had solid silver nitrate around 1.5 kilograms and now from looking at your pictures are dealing with less than 30 grams. So hypothetically speaking if it were to be 99% pure silver nitrate that would equate to 952 grams. Since maybe it's possible you have a very impure silver nitrate let us say you have a 10% pure solution this would equate to 94.5 grams of silver. I believe you made a mistake at some point where you dumped some dissolved silver because the photo clearly shows you have less than 30 grams of silver.....this would equate to about a 3% pure solution of agno3 you have now. Some big happened and hope you could get it back, I know it sucks losing some metal

 

[kasutatudarvuti]

Thanks Göran for yor reply.

Yes, silver chloride should be clear white as it was before I did this mess. These canisters were in trashbags and when this white sediment bottom of canister become purple awter I put UV light to it.

If there was Iron hydroxide, then why adding HCl to brown sediment (on picture) did not react with it?

Regards
Ain

Silver chloride is a white solid when pure. It turns purple when exposed to light.
It can have other colors if it isn't pure and in this case the color looks more like iron hydroxide (rust) than silver chloride. If you have any silver there it doesn't look very pure.

What is the pH of the solution?

Do you have anything left of the starting material, the "silver nitrate". Any pictures?

Pure silver nitrate should look like sugar, no color and makes beautiful water clear crystals when a solution dries up. In solution it is clear as water.

Göran

 

[g_axelsson]

Thanks Göran for yor reply.

Yes, silver chloride should be clear white as it was before I did this mess. These canisters were in trashbags and when this white sediment bottom of canister become purple awter I put UV light to it.

If there was Iron hydroxide, then why adding HCl to brown sediment (on picture) did not react with it?

Regards
Ain

Maybe there was enough lye in the sediment so it never got to acidic pH. That's why I asked about it.

Yellow solution with a paste in the bottom doesn't sound like silver nitrate. Was it plastic, glass or metal containers?

Göran

 

[kasutatudarvuti]

Dear Görabn

Canisters were plastic and liquid was similar as NaOH in liquid state as well odor, only color was yellow.

Canisters were marked silver leftovers and one of them was AgNO3, this last one was dried out of liquid but with still moisted purple gray sediment.


Regards
Ain

Thanks Göran for yor reply.

Yes, silver chloride should be clear white as it was before I did this mess. These canisters were in trashbags and when this white sediment bottom of canister become purple awter I put UV light to it.

If there was Iron hydroxide, then why adding HCl to brown sediment (on picture) did not react with it?

Regards
Ain

Maybe there was enough lye in the sediment so it never got to acidic pH. That's why I asked about it.

Yellow solution with a paste in the bottom doesn't sound like silver nitrate. Was it plastic, glass or metal containers?

Göran

 

[joseph1990]

Hi Joseph,

thank you for reply.

This picture is only sample what I made to find out reaction.

As I mentioned before. I received canisters with yellow solution an bottom of canister was withe sediment like cottage cheese. I took only sediment and tried to change it to silver with UV light but as I stirred it all solution become gray and it was like slurry solution after what I tried lye sugar method but all solution become dark brown. Now I added HCl and this reaction was result of it.

Regards
Ain

Hi for everyone!

Thank you who give so fast reply.

I was not able reply to you so fast, as I moved to other location.
I tried to use your recommended option to get my silver out of the solution. I added HCl to my solution as mentioned on posts. Only thing I got is brown sediment on the bottom of bottle. Do I need to clean it with other chemical? As I understand if it is silver it must be white, maybe sugar give this additional color.

Thanks in advance
Ain

You literally had solid silver nitrate around 1.5 kilograms and now from looking at your pictures are dealing with less than 30 grams. So hypothetically speaking if it were to be 99% pure silver nitrate that would equate to 952 grams. Since maybe it's possible you have a very impure silver nitrate let us say you have a 10% pure solution this would equate to 94.5 grams of silver. I believe you made a mistake at some point where you dumped some dissolved silver because the photo clearly shows you have less than 30 grams of silver.....this would equate to about a 3% pure solution of agno3 you have now. Some big happened and hope you could get it back, I know it sucks losing some metal

ok well that changes the dynamic. Now buy some copper rods from ebay preferably one that can reach 75% of container you will be using. Mix the agno3 in the container then do electrolysis....the process is done once the solution turns fully blue. This is the most simple method I can think of right now and it's always better to avoid chemicals. The drawback is you will be doing this for a couple of hours, make sure the copper has a high surface area. You may get copper contamination but the refiner can deal with this issue.

 

[FrugalRefiner]

Now buy some copper rods from ebay preferably one that can reach 75% of container you will be using. Mix the agno3 in the container then do electrolysis

Since you didn't mention adding any electrical current, what you've described is called cementation, or a replacement reaction. That may seem nit picky, but if he searches for electrolysis, he not going to find the right information. If he searches for cementation he will. There can be different names for a process, but using the most common will help members more when you're giving advice.

the process is done once the solution turns fully blue.

Can you quantify that for me? Fully blue? :?

The reaction is done when no more silver cements out.

Dave

 

[Topher_osAUrus]

Can you quantify that for me? Fully blue? :?

The reaction is done when no more silver cements out.

Dave

As Dave brought up, precision can be paramount.
Simple addition of salted water or muriatic will tell you when all silver has been reduced.

I'd be curious to see the original "silver nitrate"
If it had white cottage cheese looking curds on the bottom, that's pretty suspect..

The yellow solution could be too, but I suppose it comes down to "how yellow is this yellow"