# Methods of Silver Chloride Conversion



## goldsilverpro (Jan 26, 2014)

This pdf contains the most definitive article on silver chloride conversion that I've seen. It's from an IPMI refining seminar that I attended in 1981. I could find no copyright notice anywhere in the book.

It's probably too big (33M) for downloading on the forum. I put it on Dropbox and you can download it from there with this link.
https://www.dropbox.com/s/zqlgydt1e4d6dh4/Silver%20Chloride%201.pdf

I screwed up somewhere in the scanning to pdf conversion and the pages need rotated. I'll fix it sooner or later. In the meantime, if you use Adobe Reader to view the pdf, click on View/Rotate View/Clockwise. Probably all the pdf readers have something similar.
EDIT: I fixed the rotation. The new link above works fine.

You're welcome!


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## necromancer (Jan 26, 2014)

thank you GSP !!


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## bmgold2 (Jan 26, 2014)

goldsilverpro said:


> I screwed up somewhere in the scanning to pdf conversion and the pages need rotated. I'll fix it sooner or later. In the meantime, if you use Adobe Reader to view the pdf, click on View/Rotate View/Clockwise. Probably all the pdf readers has something similar.
> 
> You're welcome!



GSP, I did a little editing and rotated the pages for you but don't have a place to upload the file. PM me with an Email and I'll send it to you if you want. Cut the size down to around 14.2 MB also (just how it ended up)


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## butcher (Jan 26, 2014)

My ole neck is sore but it was a darn good read.


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## 4metals (Jan 26, 2014)

1981, Wasn't that in Rhode Island? I was there as well. That's where I first got into using Sodium Borohydride called Venmet solution made by Morton Thiokol (in the pre O ring days)

Amazing that you remembered that talk, the IPMI had only had a few seminars before that one. Now they're into the high 30 something.


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## nh6886 (Jan 27, 2014)

Thank you for sharing that is a great read.


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## Lou (Jan 27, 2014)

Venmet is the best at silver chloride!!

30 seconds and then you're off to melting.


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## goldsilverpro (Jan 27, 2014)

4metals,

The 5th annual IPMI conference was held in Providence in 1981. Also, in San Diego that same year, they had the Symposium on Recovery, Reclamation, and Refining of Precious Metals. That's the one I attended and have a book from. I also have the book from the 1981 R.I. conference that has the borohydride article in it.


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## Westerngs (Jan 27, 2014)

Rhode Island was 1984. (edit - 1984 Rhode Island was the Analytical Seminar)

I have a similar article to this one written by Alchemy, a long defunct (I believe) refiner in Texas if I remember correctly. It was very good as well. I will look for it in the next few days, but all my books are currently in boxes in my garage. I can't even remember what book or proceedings it was in.


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## 4metals (Jan 27, 2014)

If you do enough silver chloride, Venmet is the way to go, it kills two birds with one stone. I doubt it economical or even available to the small scale refiner.


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## Lou (Jan 27, 2014)

Dow is pretty selective on who they do business with, but it's certainly economical. 

Thing with Venmet is that there's the right way, and the wrong way. Took me a while to figure out the conditions to get things to always filter quick.


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## goldsilverpro (Jan 27, 2014)

Here's the sodium borohydride article from IPMI's Precious Metals 1981. The book was in a flood and the scans aren't great.


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## 4metals (Jan 27, 2014)

The VenMet has a range of pH that makes it happy. I have found that 2 - 2.5 works well on silver chloride. Depending on the level of rinsing you have done, or conversely how much nitric remain, your caustic pretreatment usage can be minimal or not.


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## sharkhook (Jan 27, 2014)

Thanks. I haven't worked with silver, but I have been saving it up for later.


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## Palladium (Jan 27, 2014)

On the formate reduction you post about 4metals i read the patents from Kodak, god knows i won't question you, but it mentioned dilution before the sodium hydroxide step and it also list a different ph prior to the formate reduction. I know you have your reasons for your recipe, but could you elaborate any or go into the finer details?


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## 4metals (Jan 27, 2014)

Which patent from Kodak are you referring to? Is it possible that the source of their silver is a silver halide film emulsion?


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## Palladium (Jan 27, 2014)

4metals said:


> Which patent from Kodak are you referring to? Is it possible that the source of their silver is a silver halide film emulsion?



My bad i should have added more. I think i did read somewhere that sodium formate could be used for chloride conversion some how, not sure, but my questions where about the process you posted for a formate reduction of silver from a sterling silver nitrate solution.
http://goldrefiningforum.com/~goldrefi/phpBB3/viewtopic.php?f=50&t=1275#p39590


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## goldenchild (Jan 28, 2014)

So is there any way to get ahold of sodium borohydride? Or is this only available commercially?


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## Lou (Jan 28, 2014)

It can be made in various ways, but it is a watched chemical of concern due to possible illicit diversion.


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## FrugalRefiner (Jan 28, 2014)

goldenchild said:


> So is there any way to get ahold of sodium borohydride? Or is this only available commercially?


Grainger lists it. I don't know what hoops you might have to jump through.

Dave


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## butcher (Jan 28, 2014)

Jumping through those hoops would probably be easier than making it, or getting what you would need to make it.

http://www1.eere.energy.gov/hydrogenandfuelcells/pdfs/review_chemical_processes.pdf


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## goldenchild (Jan 28, 2014)

Lou said:


> It can be made in various ways, but it is a watched chemical of concern due to possible illicit diversion.



It's a shame that this along with many of the other things we use in this field are restricted because of shmucks that use them for illicit purposes.


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## Lou (Jan 28, 2014)

Just this field?

I believe the core truth of the matter transcends any politics. Simply, it's that a minority of humans are selfish and/or irresponsible and in this world only for their own ends, and most likely, are psychopathic individuals. They consider themselves entitled--entitled to take others' lives at a theater, entitled to drain aquifers and move on in the name of profit, entitled to pollute our shared biosphere, entitled to force their belief system down others' throats, and so on in any evil conceivable. They can't just live and let live, so here we are.

Hence gun control, the war on drugs, certain ridiculous traffic laws, _occasionally_ absurd but necessary regulations (their necessity justified in precedent by the aforementioned set of reprobates). 

Every time you're stymied in doing what you want to do in good faith, with honest intentions and with personal responsibility, harming no one else, you have those hopeless souls to thank, those who would gladly and knowingly profit from others' misfortune and care not a whit about the consequences of their actions. These are the thieves that have robbed an honest man of his rights throughout human history. 

These persons and their unchecked, reckless ambition are why we have government and must always have one: to protect some of them from themselves and us from all of them. It's an imperfect system, with some consequences that are unforeseen and perhaps unavoidable, but we're imperfect creatures. The irresponsible are why the responsible are regulated; the more responsibility required of an entity (i.e. for handling certain chemicals, being a surgeon, building bridges etc.), the more severe the regulation--as it should be. 

Quoting someone far, far more intelligent than I:

“If men were angels, no government would be necessary. If angels were to govern men, neither external nor internal controls on government would be necessary. In framing a government which is to be administered by men over men, the great difficulty lies in this: you must first enable the government to control the governed; and in the next place oblige it to control itself. A dependence on the people is, no doubt, the primary control on the government; but experience has taught mankind the necessity of auxiliary precautions.”

― James Madison, The Federalist Papers 

I agree, it's a shame that some people are just so very bad, or so terribly stupid with their own lives and others'. So it is that a few ruin it for all, but that's just the way it is. 

What a pity, borohydride is a great solution to difficult waste streams. When I set up our account, I had to be very, very clear (and provide references) of what I was using it, such is the concern with diversion.


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## FrugalRefiner (Jan 28, 2014)

I'd like to nominate Lou for the next presidential election!

Dave

Unfortunately, I know he is far to wise to take the job.


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## Tub Buster (Feb 3, 2014)

*OCR'ed and formatted. Enjoy!*


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## goldsilverpro (Feb 3, 2014)

Tub Buster said:


> *OCR'ed and formatted. Enjoy!*


Great job! You put a lot of work on it. Is that from the scan I did? What is the best OCR program? I have a new ABBYY but haven't used it much.


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## Tub Buster (Feb 4, 2014)

goldsilverpro said:


> [>>Is that from the scan I did?


Yes



> What is the best OCR program? I have a new ABBYY but haven't used it much.


I use a 15-year old copy of "Textbridge".

I've been looking at ways to separate silver from solder using sodium chloride salt. This led me to read an 1880 paper by T. Sterry Hunt, "The Hydrometallurgy of Copper, and its Separation from the Precious Metals". His main concern is extraction of copper from ore, but as a sort of afterthought he mentions a way to separate silver from the copper and other base metals. 

The solubility of AgCl in pure water at room temperature is 0.0019g / L. This is derived from the CRC Handbook, which uses other units. So that's about 2 mg. / L.

Hunt noticed that the solubility of AgCl is an aqueous solution of NaCl is about 1 gram per liter. Here's a short excerpt:



> As regards the solubility of chloride of silver in solutions of chloride of sodium, Vogel found that one liter of a saturated solution, at ordinary temperatures, held dissolved 0.950 grams of chloride of silver, while according to Hahn, a liter at 19.6* C. holds 1.269 grams. Becquerel found at ordinary temperatures for a similar solution 0.800 grams to the liter. 100 parts of water, saturated at 100* C., hold 26.61 parts, and at 15.6* C., 26.34 parts of chloride of sodium, the densities of the solutions being respecitvely 1206.93 and 1204.03. Hence, one liter of a saturated solution at 15.6* C. holds 316 grams of common salt, 1000 parts of which solution under these conditions dissolve, according to Hahn, at 15.6* C., 3.0 parts of chloride of silver; while, according to the observations of Vogel and Becquerel...


Yadayada -- that's how they cited authorities way back when.

So what he suggests is that you take that freed up gram of AgCl and sequester it with iodine. The solubility of AgI in pure water is 0.00003g / L. or about 30 mcg / L. So now another gram becomes available, and it is taken out, pretty soon it's all AgI. Then you reduce with steel or zinc (I've forgotten which).

Some time ago, GRF member Solar Plasma posted a German text of this subject. Some interesting stuff in there, including a bit about silver and iodine. I've done a rough translation which I'll post. Bear in mind I speak not one word of German, but I have my trusty chemist's dictionary to fill in where Google translate falters.

If anyone can improve the translation, please do so.


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## Tub Buster (Feb 8, 2014)

goldsilverpro said:


> What is the best OCR program? I have a new ABBYY but haven't used it much.


Further thoughts on OCR. 

I don't usually write about something until I've had a chance to think it over. So at this point, I can add some comments. They are off-topic, but this message thread is moribund, so it shouldn't matter.

Two of the main uses for OCR are republishing of old documents and translation. As an example, University Microfilms has a database of millions of documents, but they would need to be retrieved and OCRed before the information in them could be used in other publications. A second example is U.S. Government records, especially those processed by the National Technical Information Service http://www.ntis.gov. Many of these consist of the page image, with embedded OCR, so you can copy text by highlighting the text in the original image. The ones I've seen use a program called iText from http://www.Iowagie.com for that. The military has a large document database at http://www.dtic.mil that may be of interest to people dealing with surplus.

In these cases, selection of a good text processing program is important if you want to prepare a presentable document quickly. Most everyone has Microsoft Word, but that program requires plug-ins, for which one must pay, to produce anything useful. There is a plug-in for producing PDF documents. There is another one for writing equations. There are plug-ins for the different languages. If you are collaborating with others, they need to buy the plug-ins as well. For composing original material, MS Word still shines, but for editing OCRed stuff, there are better choices.

OpenOffice Writer is a free text processor, downloadable from http://www.OpenOffice.org. If will do equations, languages, and PDF publishing. You can tell it to automatically generate bookmarks (the hyperlinks that appear in a navigation panel to the left of a PDF document). So this is a good place to start for publishing.

For translation, the role of OCR is to pull the words off the paper or the image file and to get them into machine-readable format. Then the translation software, which must be obtained separately, can process the text and produce approximate translations, which need to be reviewed and edited so that they make sense. Sometimes commercial translation software includes OCR.

Two publicly-available translators are http://babelfish.altavista.com and http://translate.google.com. As far as commercial programs, I have no recommendations. Perhaps someone else can comment on that.

It is essential that the OCR program be able to recognize the characters in the source language. This is one of the main differences between the various software products. For people on a limited budget, you can utilize http://www.free-OCR.com. Just upload a scanned page image, select a language, and the OCRed page will be displayed where you can copy it and paste into the document you are composing. It will process dozens of languages, but only one page at a time.

There is one other component required if you want to be a Master of the Universe with regard to information retrieval, and that is a document retrieval service. Such services locate the article you want, no matter how obscure, no matter what language. They deal with any copyright issues and then mail you a copy of the article, for a very reasonable price. The info retrieval services I'm aware of are MEDLINE (Google it) and Infotrieve, run by Canada's National Science Library (they accept orders from Americans and other nationalities). They are at http://cisti-icist.nrc-cnrc.gc.ca or 1-800-668-1222.

Want a challenge? Shop here: http://www.rudmet.ru/catalog/


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## isma_123gold (Oct 10, 2022)

Hello, sorry to resurrect this old thread but does anyone have the other sections of the "Symposium on Recovery, Reclamation and Refining of Precious Metals" (1981) from IPMI apart from the silver chloride one?

Thanks, 
- Ismael


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## Lou (Oct 11, 2022)

I do but it's in hard cover copy.

Usually IPMI will mail them out for a small fee to members.


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## isma_123gold (Oct 11, 2022)

Thanks Lou. The only problem is that I am not in the US at the moment.


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