Some problems in my first experience ( Dissolve silver in nitric acid )

[Palladium]

You said you had excess nitric in you solution when you went to cement it. The dark color is probably from copper contamination. This was before you tried to wash it with hcl of course! You're getting some good experience as what to do and what to not do though. Hcl will remove the iron, but not the copper. Hcl requires an oxidizer or elevated heat to attack the copper. Like Tropher said, iron and silver don't mix, you should have just melted it and run it in a cell. Sugar alone won't work for conversion. Use a hydroxide and convert it to silver oxide, don't add sugar, wash well with water, then nitric will dissolve it again. One way you could have cleaned it up was to add a small amount of nitric and water to the powder and heat it up. This would dissolve any copper or iron leaving the cemented powder fairly clean. You then take that wash water and put it back into a bucket with the next batch that needs cementing and any silver that was dissolved in the washing step would be recovered in the next batch.

 

[saadat68]

Thank you Palladium
I will review some topics in forum before start silver chloride convert
I don't have time for more mistake really

So problem was copper :?
Tonight I dissolved some powders again. They were a little residue from previous step
I couldn't find the weight of powders because they were wet but I tried add less acid that you school me
You said boil it 2 hour in high temperature and tonight I boiled it 3 hours!!! and still I have excess nitric
Also I have some undissolved powders that sound like nitric is less than powders.

Is it normal ? You don't have any fumes after 2 hour?
I don't want deal with excess nitric and copper again and lost my silver in third experience

I hope I added much acid that cause take 3 hours

 

[saadat68]

Last day I had excess nitric acid in my solution and today I add silver oxides to solution for consuming excess nitric and heat it for one hour again. I didn't see any red fume.

Does settling help to consume nitric acid?
Why there was nitric in my solution but after settling for one day not?

 

[saadat68]

I have excess nitric again
Why? I heated it for 4 hour
I had undissolve battries powder too

 

[Topher_osAUrus]

I have excess nitric again
Why? I heated it for 4 hour
I had undissolve battries powder too

You are assuming the solids are soluble in nitric. They must not be (assuming you had plenty of agitation so the material was in contact with fresh acid)

If this is the stuff that had some of it turn to chloride, there is your problem.
You can try and try and try but it will not go into solution. It needs converted first. Either to metal or oxide.

 

[saadat68]

Thanks
I converted them with naoh to oxide
Also I had some battries powders too
In previous experience I had same problem. Many times I saw water vapors but any red fumes
I think I must rotate solution more. Maybe powders don't contact to acid

 

[upcyclist]

I really don't have time to learning more. I must melt my silver this week and start my business and earn some money!

If you don't have time to learn, you don't have time for business.
At least a successful business.

Yes but in future
Now I must earn money because I rent my workshop and remains 5 month of my contract

I'm go back to this one--you'll have better luck if you perform those familiarization experiments now. Right now, you're working blind, then posting the results here and waiting for more help. Also, you're having problems describing what happens because you haven't taken the time to learn.

You will not magically figure out everything tomorrow and earn some money, then get to that magical "future" when you have time to learn. Learn now. Before you waste more of your time, and spend more time without income.

To put it another way (darn Upcyclist and his analogies), you're saying, "I don't have time to buy and feed chickens! I must have eggs to sell!"

 

[saadat68]

Thank you
I am in learning for one year
I accept I need more learn but I have own conditions.
Before I post here I search in forum and read some or read my notes and my topics several times or see videos in my computer
I am working in my workshop for 5 to 8 hour for just learning

 

[saadat68]

Hi, I have a question
Can I use this process for silver oxide batteries ?
- Crush and wash
- Mercury distillation
- Leach powders with dilute HCl to remove zinc and impurities
- Melt with some soda ash
- Run to silver cell and melt again

 

[Topher_osAUrus]

I am working in my workshop for 5 to 8 hour for just learning

You make it sound like learning is a chore. Maybe it's just me, but I love learning new things, and I would do it 18 hours a day if I could. Trying to do that extensive amount of edification has made it so I can refine decently, and if issues arise, I can alleviate them under my own accord.

As far as your recent question. Sure you can try to melt it, but I have a feeling you will be coming back shortly there after asking how to recover silver from solid slag.
Trying to melt impure metal can be a headache. Its best to recover and refine while in a powder form. It goes much faster. Try to master the standard practice before undertaking altered processes.

 

[Shark]

Try to master the standard practice before undertaking altered processes.

saadat68
I have been following this thread from the start along with the other related threads and I can not figure out why you avoid the tried and proven methods. You say you need to accomplish things quickly and yet you keep looking for new ways to do things before understanding your previous attempts. When I follow a process and something goes wrong I do not try another method. I will try it again and try to identify where my mistake was made. This way I can avoid it next time, and reduce the time it takes me to produce good results. By trying another method I often find that I create new problems that I don't understand and find that I am again wasting time.

All that wasted time testing new methods are fine so long as you have time. If you need to produce material to sell, don't experiment, follow the proven methods. The the time you save can be used to study other methods, giving you a better understanding of them when you get around to trying them.

 

[saadat68]

Thank you Shark and Topher
You right I am sorry
-------------
I tried to convert silver chlorid again now they are completely black and I will digest in nitric tomorrow
My cement was green. It had copper contamination. I wash them many but it doesn't clear so I wash with dilute nitric. The residue is clear now but not like a water. It is very very little green. My cement is gray
I wanted to melt cemented silver and sell 99% silver
But now I think it is better to make a silver cell and solve my problems this way (Excess nitric >> copper contamination >> need washing many )

 

[Shark]

If you wash silver cement with nitric acid will that not dissolve some of your silver also?

 

[Topher_osAUrus]

Couple things.

It is incredibly difficult to rinse silver cement. What I do, is stir it really well, and sit the vessel at an angle so the cement will pack up on one side of the beaker or bucket. Then I siphon off as much liquid as humanly possible. Before starting another rinse, I stir the cement up, or tap the vessel on the bottom multiple times (or both) to liberate more liquid trapped in the cement chunks. After that, I add more boiling hot water to it. Repeat and repeat until the rinse water passes the ammonia test (take a small sample of rinse water, add a small amount of ammonia, if it turns blue, it has copper ions in the rinse still)

Doing it this way has cut my washing cycles down exponentially. It should help you a great deal.

Secondly, a silver cell is a must. I know I wouldnt feel comfotable selling silver to clients when its purity is questionable (at best). You may have a 99% batch (if you are patient with the rinses, and lucky), but 97 to 98% is more par for the course. With a silver cell though, your product will consistently be 99%+, unless you let the electrolyte contamination climb too high, and run too high of a voltage. Also, it is much better (easier, cheaper, faster) to just sell silver crystals. Saves you time for melting, gas for melting, and the hassle of someone wanting 500g when you only have a kg bar. With crystals, you can sell $21 and 23 cents if you need to. Its a win win win win win.

Did I mention the anode slimes keep the PM values in your pocket and not the buyer? Because there is that, too.

 

[saadat68]

Shark
I saved residue for next batch

Topher
Thanks
I will use your advice for next washing. Selling crystals is harder than silver shots here but I will test

 

[saadat68]

Hi
Now I know why most of users in this forum hate silver chloride
I tried 4 times to convert silver chloride to silver oxide with NaOH but I couldn't
I don't know what is problem. I add NaOH and stir them for 20 min with hand then wash and filter and add nitric acid
When I added nitric I didn't saw any red fumes. I saw just white fumes. What is these fumes ?
It is not important to recovery these silvers because I lost 90 percent of my silvers but I want to know what is the problem. Why I didn't see any red fume in 4 times.
I could recovery 40 gram cemented silver from 400 gram silver!!!!!! I lost 360 gram in 3 experience

http://uupload.ir/files/gi1i_img_20171009_195308.jpg

 

[upcyclist]

Now I know why most of users in this forum hate silver chloride

I hear that, haha

I tried 4 times to convert silver chloride to silver oxide with NaOH but I couldn't
I don't know what is problem. I add NaOH and stir them for 20 min with hand then wash and filter and add nitric acid

A little more detail please. From your picture, it appears that at least some of the white silver chloride converted to black silver oxide. Did you rinse the AgCl to clean it up and raise the pH before adding the NaOH? After you added the hydroxide and got at least partial conversion, did you rinse that substance to remove the chlorides? If not, they're still in the mud, and as soon as you added the nitric acid, they converted your dissolving silver immediately to silver chloride again.

My formulas may be a bit off, but to at least show the fact that you need to get rid of the chlorides:

2AgCl + 2NaOH --> Ag₂O + 2NaCl + H₂O

If you get rid of the chlorides (salt), Ag2O + 2HNO3 -> 2AgNO3 + H2O

If you don't, you get Ag₂O + 2HNO₃ + 2NaCl --> 2AgNO₃ + 2NaCl + H₂O --> 2AgCl + 2NaNO₃ + H₂O

 

[Topher_osAUrus]

In your case saadat, I wouldnt have messed with lye and sugar. I would have went with dilute sulfuric and nails... It will eat up any iron powder mixed in the chloride and the nails convert the silver chloride to silver metal.

 

[saadat68]

Hi
I think I rinsed well but you right problem is rinse. I did mistake somewhere. I hate rinse and filtration
I added them to trash 2 days ago!!!
But I still have a little from filter paper and residue. I will try to convert them with iron method just for learning

Thanks

 

[saadat68]

I read this post in another topic from Lou

You speak of silver nitrate--it reduces itself to a black film of silver metal on your eyes, giving you ''black eye''. This is what happens when you get dust of luna salts in your eyes, or even when you melt it.

I can't clean cemented silver. I washed them many with boiling water but still there is a little contamination. Residue is a little green that seems it is copper nitrate.
I decide make a silver cell and get pure silver this way and always melt cemented silvers with a little contamination

Is it dangerous ? :shock: I will wash them but If cemented silver has some copper nitrate and silver nitrate can it hurt me ?