# Silver refining to 999 fine



## erling66 (Dec 31, 2021)

Is it possible to refine silver scrap to minimum 999 pure silver without using a silver cell as the final step in the refining process?


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## kurtak (Dec 31, 2021)

You can use the salt/lye/sugar method & hit three 9 even four 9

Kurt


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## erling66 (Dec 31, 2021)

kurtak said:


> You can use the salt/lye/sugar method & hit three 9 even four 9
> 
> Kurt


Thank you for info. So i guess using copper to cement out the silver will not produce 999+ pure silver (without a silver cell) and I will try the salt/lye/sugar method. It will be my first attempt to purify silver.


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## kurtak (Dec 31, 2021)

erling66 said:


> Thank you for info. So i guess using copper to cement out the silver will not produce 999+ pure silver (without a silver cell)



correct 



erling66 said:


> and I will try the salt/lye/sugar method. It will be my first attempt to purify silver.



Make sure you FULLY understand this process before you start in - you are dealing with chemical reactions here so are going to have "foaming" --- you don't want to end up with a boil/foam over

Kurt


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## erling66 (Jan 3, 2022)

I have started to dissolve silver with nitric, but is there a best nitric water ratio? 1/1? or maybe a 1 part nitric to 2 parts water will be better with less risk of a boil over? I started at 8 to 1 and add nitric every time the reaction stops.


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## orvi (Jan 3, 2022)

erling66 said:


> I have started to dissolve silver with nitric, but is there a best nitric water ratio? 1/1? or maybe a 1 part nitric to 2 parts water will be better with less risk of a boil over? I started at 8 to 1 and add nitric every time the reaction stops.


Many people go with 30-35% nitric, or 1:1 ratio. Use larger beaker than you need. If it foam, it wont make it through the edge  best is not to cross 50-60% of the vessel volume.

Rough estimate is cca 35-45 ml of conc. nitric for ozt of silver. To roughly know how much space you need. Depends on conditions, contaminants in silver and also temperature.

Start with less than 1/3 of this estimated ammount, slowly heat the mixture and observe. If it start to foam and reaction get more vigorous, put it out of heat and let it cool a bit. Silver is relatively gentle, it does not runaway so easy as copper, but caution is needed. More finely divided/more surface area, more likely it will react violently.

When reaction start to die down, slowly take it to the higher temperature. Finally to boiling. Observe the fumes comming out. Cover the vessel with watchglass or round bottomed flask filled with water. If no more yellow/brown/red fumes of NO2 are present after some time boiling, the nitric is spent.

You can then decant the silver nitrate bearing liquid to another container and start with fresh nitric - this is faster than boiling large ammount of very dilute acid to eat last bit of metal. Or you can continue boiling and adding nitric in small increments till the metal dissolve completely.

Work in the fumehood or outside, wear gloves (silver nitrate irritate and stain the skin), stay safe


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## orvi (Jan 3, 2022)

Silver chloride to Silver


Hello, I would like to change silver chloride to silver metal. I know that we can add it in caustic soda and then with dextrose obtain the silver powder. However, i would like to know if there is a way to disolve it in ammonia for example and then make the silver powder precipitate. My main...




goldrefiningforum.com





Once I written my procedure for lye/sugar method. This is how I do it, procedures vary from person to person, in terms of setup, hydroxide ammount and water ammount. It is a dangerous process, so be careful. Wear good gloves, goggles or better face shield, labcoat/old clothes all over arms and body, and work in fume hood with protective shield - reaction could spatter boiling hydroxide to you, instant burns, very painful, drop to your eye and you could be blind in second.

If you aim on 999 fine, washing should be excellent. Use ammonia solution to test rinsing water for copper - main contaminant. If you see the blue colour, even the slightest hint, rinse again.
If you will be dealing with larger quantity of silver on regular base, electrolytic cell is the best option - try to avoid AgCl formation if it is possible. It is much more painful to recover Ag from it, than it is from AgNO3 (copper cementing--->silver cell).

Sreetips on his YT channel has great videos also on this method, I recommend watching them. He also have a video of a runaway reaction - good to see and learn a lesson from it.


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## cejohnsonsr1 (Jan 3, 2022)

I don’t really think it matters which chemical process you use to recover and refine your silver as purity is concerned. The only real difference between the processes mentioned are the number of steps involved and the precipitant used. Either way you wind up at the same place, with the same mud, at about 99-995 fine after 1run. Personally, I prefer to cement on copper because it’s less expensive and less time consuming. If you really want to get to 999-9995 fine in a small scale home operation then you really need to run your mud through an electrolytic silver cell. Whether or not you have enough silver to justify the time and expense to get that kind of purity is entirely up to you.


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## erling66 (Jan 4, 2022)

I finished disolving 2 kg of 830/900 silver scrap. I used ca 2.2l 70% nitric acid and 4 liter of distilled water in a stainless steel beaker. But when the liquid cooled down, it started to form Crystals. I guess there are about one liter of them in the beaker now. Can anyone tell me what happened? Do the crystals contain silver nitrate? Or can I start to precipitate out the silver nitrate using copper?


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## FrugalRefiner (Jan 4, 2022)

erling66 said:


> I finished disolving 2 kg of 830/900 silver scrap. I used ca 2.2l 70% nitric acid and 4 liter of distilled water in a stainless steel beaker. But when the liquid cooled down, it started to form Crystals. I guess there are about one liter of them in the beaker now. Can anyone tell me what happened? Do the crystals contain silver nitrate?


Sure. Warm solutions can usually hold more salts (like AgNO3, Cu(NO3)2, etc.) in solution than cold solutions. When your solution cooled, some of the salts precipitated out. I would assume the crystalized salts might contain a combination of silver nitrate and copper nitrate, even if the copper nitrate is only trapped in the silver nitrate crystals.


erling66 said:


> Or can I start to precipitate out the silver nitrate using copper?


Add water to the solution till the salts (crystals) are dissolved. Then cement on copper.

Dave


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## erling66 (Jan 4, 2022)

FrugalRefiner said:


> Sure. Warm solutions can usually hold more salts (like AgNO3, Cu(NO3)2, etc.) in solution than cold solutions. When your solution cooled, some of the salts precipitated out. I would assume the crystalized salts might contain a combination of silver nitrate and copper nitrate, even if the copper nitrate is only trapped in the silver nitrate crystals.
> 
> Add water to the solution till the salts (crystals) are dissolved. Then cement on copper.
> 
> Dave


Thank you for answer, I started to worry since it is my first try. But can I add tap water or do I need distilled water?


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## galenrog (Jan 4, 2022)

Municipal tap water nearly always has chlorine or other chlorides added as disinfectants. If you add chlorinated water to your electrolyte, it will form silver chloride. 

Well water can also contain chlorides, and a host of other contaminates. 

I have both municipal and well water available to me. Would I use either in this situation? No. 

Time for more coffee.


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## FrugalRefiner (Jan 4, 2022)

I agree with Galenrog. I only use distilled water for my silver cell.

Dave


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## 4metals (Jan 4, 2022)

I have successfully concerted silver chloride into 3 nines silver and also to 4 nines silver (but that requires an exceptional quantity of rinsing). When it comes down to refining in quantity, the silver electrolytic cell will be the most cost effective approach. 
When you consider that all of the silver needs to be dissolved in acid and dropped as a chloride before you begin the reduction process, you realize that 100% of your metal needs to be dissolved in acid and that acid is single use. When you refine sterling the nitric acid goes much further as the electrolytic process constantly “recycles” the nitric at the cathode to dissolve more Silver from the anode. 
And the waste is much less as well. Lots of rinsing with the Silver chloride reduction process. 
This may not be an issue when you are talking a few hundred ounces a few times a year, but for a steady flow of Silver to refine, think about a cell.


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