# AgCl conversion fail



## Bluebloomer (Oct 5, 2017)

I tried to convert my silver chloride with lye and sugar. The moment the AgCl turned black, I let it rest for a couple of minutes, then added granulated cane sugar, and a little syrup made from glucose and sugar.

The result was a pitch black liquid with lots of small flakes. After adding hot water, I let it rest, decanted the water and added new water, but the liquid stays black and now I have this 3 cm layer of black precipitant.

I am doing something wrong, that's obvious. Did I add too much lye, or did I use the wrong and or too much sugar ?

I now understand normal granulated sugar, even in a watery solution will do the trick, and have to add it slowly, things I will do from now on. But what is this black fluffy precipitant, and how is it created ?


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## Lino1406 (Oct 5, 2017)

Need to give it a stirring and more time


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## Bluebloomer (Oct 7, 2017)

Thank you for that reply. I will use a stirring device in the future.

Could you or anybody else explain the thick black layer of precipitant ?

Is this a half conversion, or failed conversion, or a by product of too much NaOh / Sugar ?


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## snoman701 (Oct 7, 2017)

I really like sulfuric method myself. Add acid, stir with a piece of steel that has the end taped with electrical tape (just to protect glassware)


Sent from my iPhone using Tapatalk


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## Lino1406 (Oct 7, 2017)

Black layer = silver oxide, received in the absence of sugar. Can be melted directly


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## Ravn (Oct 8, 2017)

Hi

Your problem is properly due to use of the wrong type of sugar. 
You have to use a reducing sugar like e.g. glucose or fructose, cane sugar also called Sucrose is unfortunately not a reducing sugar.

https://www.masterorganicchemistry.com/2017/09/12/reducing-sugars/


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## Lino1406 (Oct 8, 2017)

Compliments Ravn for noticing. Sometimes things look so obvious that we do not notice them


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## danieldavies (Oct 8, 2017)

i use cane sugar. try heating the solution and silver oxide. you should start to see a mirror forming on the beaker, take off the heat when this happens and add more sugar slowly.


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## Bluebloomer (Oct 8, 2017)

Thank you all for the replies, you guys have been a great help!

I filtered the black stuff and will set it aside to dry. Can it still be converted to elemental silver and how ?

Normaly I use glucose sugar, but since it's pretty expensive here, I tought I try this brown cane sugar once.
Lesson learned... :lol: 

Never tried the sulphuric acid method, and for us in the Netherlands the ban on some chemicals have been in place, so the only H2SO4 I can still buy is I believe 94% but it's a draincleaner.

Nitric acid, H2SO4, KNO3 and even 30% H2O2, are now all banned unless you have a license to buy it.

Precious metal recycling has gotten a lot more difficult now..


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## FrugalRefiner (Oct 8, 2017)

Bluebloomer said:


> Never tried the sulphuric acid method, and for us in the Netherlands the ban on some chemicals have been in place, so the only H2SO4 I can still buy is I believe 94% but it's a draincleaner.


Try checking at auto parts suppliers and places that sell car and motorcycle batteries. They may carry the acid used in those lead acid batteries. It's usually somewhere around 30% sulfuric. Since you only need to use around 10% acid in the silver chloride conversion process, it serves well and won't have any of the additives found in some drain cleaners.

Dave


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## rickbb (Oct 9, 2017)

Ravn said:


> Hi
> 
> Your problem is properly due to use of the wrong type of sugar.
> You have to use a reducing sugar like e.g. glucose or fructose, cane sugar also called Sucrose is unfortunately not a reducing sugar.
> ...



Here in the US we have a product in the cooking section of the food stores called Kayro syrup, it's a fructose and works well for this.


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## geedigity (Oct 9, 2017)

Regular old fashioned pancake syrup also works well.


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## Ravn (Oct 10, 2017)

Pancake Syrup contains Glucose and or Fructose.

The cheapest sugar to use would properly be; inverted sugar syrup 
https://en.wikipedia.org/wiki/Inverted_sugar_syrup


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## lazersteve (Oct 11, 2017)

I use regular table sugar dissolved in hot water on a daily basis to convert AgCl with great success. I have converted batches from a few grams to several pounds like this.

I never heat the reaction as it self heats when the lye pellets are added. 

Stirring is essential.

Make sure there is no white/purple solids present before adding any of the sugar water solution. Additional lye and stirring accomplishes this.

Your problem is likely a very dirty feedstock of AgCl or incomplete rinsing of the AgCl.

Steve


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## 4metals (Oct 11, 2017)

Normally the refiners I deal with accumulate silver chlorides in 5 gallon pails so i developed a program to determine the quantity of 50% liquid caustic and karo syrup needed based on the depth in a 5 gallon pail. 

But here on the forum, quantities are often less so the attached spreadsheet can be used for smaller quantities. This uses karo or corn syrup and 50% w/w liquid caustic. Both of these are often stocked by refiners encountering silver chlorides often. You can make 50% liquid caustic by adding sodium hydroxide powder or pellets to an equal weight of water. This produces a thick liquid but if it stays over 50º F it remains in solution. 

View attachment formulas for chloride conversion 4 liter beaker.xlsx


This is a locked spreadsheet so the only figure you can add is the volume in milliliters of the settled silver chlorides. The program will tell you the weight of the other ingredients to add.


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## lazersteve (Oct 11, 2017)

Thanks for the spreadsheet Rick. 

I never measure any of my reagents when converting silver chloride, instead I observe the reaction and look for key endpoints that indicate i have added enough of each reagent. I save my AgCl until I have several pounds and convert in 5 gallon pails as well, but if I have the need to get a silver weight from particular test, then i will convert smaller amounts in beakers. The reaction is so fast and easy, that you can quickly go from AgCl to Ag in a matter of a 1/2 hour of less for smaller volumes. 

With proper attention to techniques (hot water rinses, feed stock grouping, end point observation, and post reaction rinsing) this method produces an excellent product that routinely shoots 100%+ on xrf. The resulting Ag cement is also very easy to handle and settles quickly.

If you r resulting Ag is not gray green in color and is slow to settle, you likely did not follow proper protocol in preparing the AgCl or did not run each step to completion.

All in all the lye sugar method of converting AgCl to Ag is one of my favorite reactions to run. It's quick, simple, uses common household ingredients, and requires little setup time or equipment. 

Steve


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