# What is wrong with my zinc process?



## mda20 (Jun 15, 2013)

Hi dear members. 

I have read some posts about silver recovery from fixer using zinc powder. I did a try but did not get a good result. Here is my process:
I added 10gm of zinc to 5 lts of fixer (silver concentration is about 2gm/lts). I used a HDPE container.The solution changed to grey color. 2 days passed but no progress. I expect that solid material will settle down but nothing happened. I thought I have to do something. So I took two samples of the solution:
First sample: 40ml of vinegar (Acidity %6) has been added to 450ml of the solution.
Second sample: 550ml of tap water has been added to 450ml of the solution. 

Two days passed but no progress. What is wrong with my process?

Best Regards,
mda20


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## MysticColby (Jun 17, 2013)

what is the purpose for adding vinegar and tap water?
how do you know there is 10 grams of silver in the solution? (5L x 2g/L = 10g)
I assume the zinc settles to the bottom - do you stir it occasionally? This wouldn't explain the lack of silver, but would speed up recovery.


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## mda20 (Jun 18, 2013)

Thank you *MysticColby* for your reply.



MysticColby said:


> what is the purpose for adding vinegar and tap water?


Because there was no precipitate, I thought I have to do some change in the pH of the solution. So I added vinegar and water.




MysticColby said:


> how do you know there is 10 grams of silver in the solution? (5L x 2g/L = 10g)


I used estimate paper.



MysticColby said:


> do you stir it occasionally? This wouldn't explain the lack of silver, but would speed up recovery.


No, I never stir it. I just added the zinc and waited or result.

Regards,
mda20


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## Westerngs (Jun 23, 2013)

At this point, my first step would be to decide if there is any silver in solution.

The easiest way is to a take a very shiny penny - A brand new one is best - and submerge it in the fixer solution for a minute or two. If there is silver in the fixer, it will cement out on the surface of the penny. 

A very clean piece of copper strip will also work nicely. Clean the copper strip by removing all surface oxidation with a scotch pad or with fine sandpaper.

If there is is still silver in solution continue with small zinc additions, until copper test is negative. Stirring the solution after adding zinc will speed up cementation process.

Once there is no silver in solution, filter silver out.


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## mda20 (Jun 25, 2013)

Thank you Dear *Westerngs* for response,

I have tested the solution by a piece of copper. It have given a negative result.

2 weeks passed so far but no progress, no precipitate.

what should be done?

Regards


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## goldsilverpro (Jun 25, 2013)

mda20 said:


> Thank you Dear *Westerngs* for response,
> 
> I have tested the solution by a piece of copper. It have given a negative result.
> 
> ...


According to this, there was no silver in the solution to start with.


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## Westerngs (Jun 25, 2013)

I agree with GSP, there is now no silver in solution and maybe there never was.

In my experience, the silver estimating papers are not very good, I never liked them and much preferred the penny or copper test.

If you believe there was silver at one time, filter the fixer. If there was silver, it will now be in the sludge. If there is no sludge, there never was any silver. Of course, any sludge you get will not be pure silver. Smelt it and see if you get a silver bead.


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## mda20 (Jun 26, 2013)

Thank you dear Chris
Thank you Westerngs

I will repeat the process with a new solution. 

Regards,


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## mda20 (Jun 26, 2013)

Here is my new try.
- 1 lt of fixer
- Silver concentration is 3gm/lt
- 3 gm of zinc has been added.
- The solution has been shaken well.

I am wiating for the result.

Please see the pics.

Regards


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## nh6886 (Jul 16, 2013)

Mda20,

How did this work? 
Did your precipitate settle down?
I don't use the zinc method but with the method I use until all the the silver is converted it is very slow to settle. The material that does settle is very light and next to impossible to decant, even siphoning is problematic. However once the conversion is complete the bulk of the powder settles quickly and decants easily.

I didn't see here where you tested the silver content of the fix before you added the zinc?
I would suggest using Manuel's copper wire test, it works perfect for me. I use it not only as a starting point but to know when to stop.
I also don't see where you corrected the PH of your fix to "5" before adding the zinc? 
There are lots of fixes out there a friend of mine has medical x-ray fix from an automatic processor that has a PH of approximately 10
Mine is industrial radiographic fix and is slightly acidic. 
The point is I think you need to know and control the PH for the zinc to work in a predictable way.
Of course you need to know if you have silver to start with and how much you should be expecting in order to know if any is missing.

I am not by any means an expert so take this as my best attempt at helping. By reading and rereading the great instructions here and asking lots of questions I have recovered a couple of pounds of very nice silver so don't give up! If its in there you will win if you don't quit.

All the Best
John


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## mda20 (Jul 16, 2013)

Hi John,

Thank you for your post. 



> How did this work? Did your precipitate settle down?


 Yes, but after about 2 weeks.



> Of course you need to know if you have silver to start with and how much you should be expecting in order to know if any is missing.


 I usually use estimate paper to measure the silver content.

This is the first time I use zinc. Although many members here say it is the best way to recover silver from fixer,I did not get a good result. It is very slow. May be there is something wrong.

Regards


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## nh6886 (Jul 17, 2013)

Mda20,

I wish I had some information on how I made the zinc work. I do not.

Did you check the PH of your fix? I think this may be where I went wrong. 

Here is what I would try in order to get some good help here.

1. Measure the silver content with the copper wire test (even if its just to verify your estimating paper)
2. Check and adjust PH to 5
3. Add excess zinc (20% extra it's easy to remove later)
4. Heat solution to about 120*F
5. Settle, decant/siphon
6. Rinse with very hot water and leave a little on the last rinse
7. Add small amounts of HCl until no bubbling results
8. Rinse and dry
9. Weigh silver powder

Report this information back here. If there is silver missing the folks who can help you find it are here.

GSP, Manuel, Westerngs, or anyone else who might be willing to chime in. If the Fixer is Ammonium Thiosulphate based rather than Sodium Thiosulfate does the zinc work differently?

All the Best,
John


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## mda20 (Jul 22, 2013)

Thank you John,

There is a simple method, just adding zinc and washing the sludge with karo syrup. I tried that way as I mentioned in previous post but I failed. I think there is something wrong.


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## vitalclues (Aug 5, 2013)

How do I check and adjust the PH of the fixer to 5? Is the Zinc method more reliable than sodium sulphide method. Pls let me know step-wise from ph checking on how to get it well done. Thanks! One love!!


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## vitalclues (Aug 5, 2013)

How do I check the Ph?
How do I adjust the ph to 5?
What is the use of the vinegar?
How can I step by step get it done?
Is the Zinc method preferred to Sodium sulphide method?


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## Juan Manuel Arcos Frank (Aug 8, 2013)

Dear mda20:

I have read carefully all your posts so I tell you the following:

First of all,Did you add some diluted sulphuric acid solution(5% in weight) at the same time that you added zinc powder?I have not seen it in all your posts,so this could be the mistake.Add the acid solution to the fixer,stir well then add zinc powder.

This process works well in acidic pH(below 4).If you have problems with this process then try to use my sodium sulphide process.

Keep us posted about your progress.

Kindest regards.

Manuel


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## mda20 (Aug 9, 2013)

Welcome back dear Manuel and thank you for your reply.

I never added sulphuric acid. But how much acid I have to add per gm of silver in fixer?

Regards,
mda


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## nh6886 (Aug 9, 2013)

Mda20, Vitalclues,

Search Juan Manuel Arcos Frank's posts. There are many great teachers here on the forum but the instructional work Manuel posted on this subject is fantastic and is "exactly" what I use. 
I do not use the zinc process for the fix I have. I tried it again last weekend with the same results I have achieved every time before. Disappointing but one day I will work through this.
The Other method Manuel explains works every time! This is also covered in Hoke's book in the silver section. The conversion of the Ag2S with KNO3 that Manuel shares is better than anything else I have tried. I couldn't be happier with it and the silver I'm refining is very satisfying. If you use the Sodium Sulfide method please be very clear on the potential hazards. They are easy to control but only if you understand the process before you start.

All that being said there are some very real risks to both methods and I would strongly advise you to read Hoke's book and the all the safety warnings here on the forum. 
Download the MSDS for every chemical you plan to use. If you have trouble finding any of them let me know I would be glad to send you any you need. As you probably know, the MSDS will tell you what you need to know in order to safely handle the chemical it represents but can't cover all the things you might do with it. 

If you come up with a plan and post it here, there are many people that will help you look it over. For what it's worth I would be more than happy to do so as well. Anyone who can help you is going to expect you to do some home work first though and I would include myself in that. Do the research here, ask questions about what you can't find or understand, then develop a plan. I'm a planner (procrastinator) I spent a long time (over a year) trying different experiments before I refined any silver from fix. In that time I never used more than 50ml of fix in a single experiment. 

The result of what I have learned here on the forum is that I can go from fix to very pure silver consistently. The fact that I am getting ready to ship about forty ounces of silver to trade for rounds is a nice bonus.

Vitalclues Welcome to the forum.

All the Best,
John


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## mda20 (Aug 9, 2013)

Thank you John for your post and your help.

Manuel posts are very useful. He has told many processes to recover silver from fixer. Zinc process is one of them. I think this method is the best but I could not do it properly. Zinc process is easier than sodium sulphide process which need a long melting process as Manuel explained.

If you think I am wrong please let me know.

Regards,
mda


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## vitalclues (Aug 10, 2013)

Thanks a lot Mda20 but let me state my what I did step wise yet got nothing:
Firstly,I tested the Fixe(by dipping copper wire into it) to be sure it contains silver and it was very evident it does.
Secondly,I checked the ph of the solution which was about 7 and adjusted it to 5 by adding vinegar.
Thirdly,I added Zinc dust,stirred occationally and allowed to settle,then decant.
What I could only recover was the Zince dust without Silver.
Please,what could've been my error(s) and please once more,can u step wise tell me what to do cos I seem confused.
Although I got something when I used the Sodium sulphide method but it wasn't great.
Can I also use Zinc method for Bleach,Developer and hypo?
Please help me on a step by step method including purification so I can stop wasting my chemicals and solution.
Whoever can help,I'll be greatful.
Please just be patient with my ignorance cos I really want to learn more.
Thanks a million! [email protected]


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## vitalclues (Aug 10, 2013)

Both the Zinc and Sodium sulphide methods seems to be giving me hell. Pls can you re-post step by step what u've been doing to achieve the desired result.
Be patient with my ignorance please.
Thanks!
[email protected]


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## vitalclues (Aug 10, 2013)

How do I prepare a 10% sulphuric acid solution?
In correcting the PH to 5 or below is Sulphuric acid prefared to Vinegar?
How can I generate my own fixer and bleach?
Please bear with my ignorance.
Thanks a million


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## vitalclues (Aug 10, 2013)

How do I prepare a 10% or 20% sulphuric
acid solution?
In correcting the PH to 5 or below
is Sulphuric acid prefared to
Vinegar?
How can I generate my own fixer
and bleach?
Please bear with my ignorance.
Thanks a million
[email protected]


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## vitalclues (Aug 10, 2013)

Mda20,pls how do I get or measure 5% weight of sulphuric acid?
Please bear with my ignorance


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## butcher (Aug 10, 2013)

Remember never pour water into concentrated acid, you can end up with a steam explosion of acid.
Pour the acid into water.
http://www.nclark.net/Solution_Preparation.pdf


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## rickbb (Aug 10, 2013)

Kinda funny seeing that PDF from Carolina Bio Supply, I can almost hit their building with a rock from my house. :lol:


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## nh6886 (Aug 11, 2013)

Vitalclues,

Please make no mistake we all start out with ignorance, that's why most of us are here to start with. I found this forum trying to figure out why the process I saw on utube didn't work. 
Those who come here to share their wealth of knowledge have my true gratitude. Because I have been given so much here I would really like to help you. However I seem be falling short. The information you seek is all here. I gave you the name to search and Manuel answered back in this same thread. Click on his name, go to "profile", on the profile page click on search user's posts, when that opens search the word fixer. 
I know you want that material now but I'm afraid that its going to take some work on your part to make that happen chemically. 
You might also consider buying GSP's refining book, there is a link in his signature line.
There are also ways to plate the silver out. You can buy one of these units and start right away but that's not something I've done.

As for your developer there should be no silver in that solution.

Be safe,

John


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