I used Sreetips (youtube) metod and converted 2 silver chloride batches to silver and no problem before but today something went wrong. I made silver chloride from ca 2 kg of silver, added ca 1.5kg lye and used a mixer, but did not get the black color (temp was 55C), only dark grey. I immediately added sugar and stirred by hand, but no reaction so I added more and more sugar. Ended up using 1.5kg of sugar but still no reaction, only some smoke and ca 70C temp. Then I took a sample and heated it on the stove to ca 110C but still no reaction. Then I took another sample and added more lye (after the sugar was already in) and heated that one too, but still no reaction. Now they have cooled down and look like dark brown mud. Please help me to recover the silver from this batch.
Silver lye and sugar, but no reaction
- Thread starter erling66
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A few more details: I used up all the nitric acid when I dissolved the silver and I washed the silver chloride very well until the washing water was totally colorless. The only difference from previous batches was that it was colder where I did the process, 0 C vs 5C. and this batch was larger 2kg AG vs 1.5kg. And now I have this mud that did not separate. So what can I do? remove the sugar in some way, heat it up and add more lye? I guess the process of converting chloride to oxide did not go well. Or maybe add iron to start a process? I hope someone with knowledge can help me.
Martijn
Well-known member
I cant help you much here. Hope someone else can.
Rinse sugar and lye out and start over?
Once you convert the AgNO3 to AgCl, HNO3 is created again, which does not matter, as you've washed the AgCl.
So n.a. If all nitric was used up or not.
Rinse sugar and lye out and start over?
Once you convert the AgNO3 to AgCl, HNO3 is created again, which does not matter, as you've washed the AgCl.
So n.a. If all nitric was used up or not.
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- Jan 14, 2021
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You probably have the silver...but the reaction went too slow.
How you know that your final profuct is not silver?
How you know that your final profuct is not silver?
In my previous batches, the silver separated from the liquid and settled at the bottom as fine sand. This time nothing separated, everything is just like a thick mud.
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Did you try to filter few mL and see if you have Silver or Ag2O? Solution is basic?
No lead for sure.
I will try to take a small sample and wash it several times with hot water to try to remove the sugar. Then heat it up and add some more lye so see if it will react and go black. If so, I will add sugar again.
Never go to the next step until you are sure you have completed previous one. Conversion of AgCl to Ag2O often require heating and depending on the particle size could be very slow. Water content could also play significant role in conversion time - from my practice less water = quicker conversion.
I would filter bit of the suspension (about 50 ml), rinse it and try adding more lye with heating and stirring. If this cause darkening of the precipitate - you did not converted all to the Ag. Continue to the point when you cannot see any white specks and suspension do not darken more. If the suspension do not darken at all with addition of lye, you are probably done and you have converted all to silver previously.
It does not need that much sugar for complete conversion.
Heat the sample of previously treated suspension to at least 85-90°C, get the beaker with suspension of Ag/Ag2O off the hotplate and stick thermometer in. When you equilibrate the temperature, add small ammount of sugar. This reaction is highly exothermic = it will heat up significantly => you will see temperature rise after addition of sugar.
If you do not see temperature rise, no reduction is happening = no Ag2O is present in suspension.
I would filter bit of the suspension (about 50 ml), rinse it and try adding more lye with heating and stirring. If this cause darkening of the precipitate - you did not converted all to the Ag. Continue to the point when you cannot see any white specks and suspension do not darken more. If the suspension do not darken at all with addition of lye, you are probably done and you have converted all to silver previously.
It does not need that much sugar for complete conversion.
Heat the sample of previously treated suspension to at least 85-90°C, get the beaker with suspension of Ag/Ag2O off the hotplate and stick thermometer in. When you equilibrate the temperature, add small ammount of sugar. This reaction is highly exothermic = it will heat up significantly => you will see temperature rise after addition of sugar.
If you do not see temperature rise, no reduction is happening = no Ag2O is present in suspension.
Thanks guys for help. Here is what I did. First tried to melt a small sample, Very difficult, had to stir and and the silver was covered in some black liquid that became like glass. I broke it off and the silver look good. I guess the black stuff was sugar so I rinsed the whole batch many times with hot water. Then I heated the AgCL/Ag20 with very little water and added lye. It reacted at once, I added lye until it started to separate. Then I added liquid hot sugar and got a violent reaction, I had a large drum so it did not boil over. After it quiet down, the silver had separated nicely from the liquid. So now I am back on track and will clean the silver several times, dry it and try to melt it and see. I will post a photo of the ingot when it is ready.
When you have difficulty with this reaction, always use basic flux (soda, lye etc.) when melting the silver. In case there is unconverted AgCl, this will help you to convert it thermochemically back to metallic Ag.
This reaction is relatively slow. Also when you see white smoke arising from the melt, be cautios. AgCl vaporize relatively easily, and it isn´t healthy at all
Not to mention you lose your values to the air.Stay safe
