# Maximum capacity of a solution of sodium thiosulfate for silver



## Ultrax (Jul 14, 2022)

Hi guys,
The maximum holding capacity of a thiosulfate solution (60 grams per liter) for gold is 4 milligrams per liter of the solution.
But the solubility of silver in thiosulfate is hundreds of times higher, but I don't have exact data.
Can anyone tell me the capacity of a solution of sodium thiosulfate for silver, depending on the concentration?
In other words, how much silver can a solution of sodium thiosulfate hold per unit volume?

Thanks for the help!


----------



## Lino1406 (Jul 14, 2022)

From literature silver thiosulphate is soluble in high sodium thiosulphate excess, up to 1.66% at 25C. Without sodium thiosulphate it is readily oxidized, hydrolysed


----------



## Ultrax (Jul 15, 2022)

Thank you


Lino1406 said:


> From literature silver thiosulphate is soluble in high sodium thiosulphate excess, up to 1.66% at 25C. Without sodium thiosulphate it is readily oxidized, hydrolysed


Thank you! So I can expect to hold approx 16 gr of Ag2S2O3 (or 5 gr of pure Ag) per liter in saturated solution? Maybe you have link to any scientific source like ISBN of the book,or DOI article to read about it in details?


----------



## Lino1406 (Jul 15, 2022)

Google silver thiosulphate solubility


----------



## Ultrax (Jul 15, 2022)

That's obvious, but scientific information directly from Google search isn't very reliable. And the quality of even scientific information has plummeted in recent years. Everyone is chasing the citation index, not scientific novelty or content. Many scientists even replicate errors from article to article. That's why I'm asking if anyone has had direct experience with ore silver thiosulphate dissolution or can point to a reliable data source. Thanks in any case.


----------



## AnotherMiner (Jul 16, 2022)

Here's a chart that shows silver chloride solubility in various solutions, including several concentrations and temperatures of thiosulfate. It probably doesn't answer your current question, but it might be handy some other time. 

Are you considering using sodium thiosulfate to leach a silver-bearing ore? If so, please describe the ore.


----------



## ION 47 (Jul 16, 2022)

I process silver containing photo solutions. On average, solutions from medical x-rays now contain 1.5-3 grams of metallic silver. Solutions from technical x-rays (radiographic method of flaw detection) contain 10 grams of metallic silver in 1 liter or more. What is the saturation limit of silver thiosulfate, I do not know, but when conducting certain analyzes of the silver content in waste containing silver bromide, chloride and iodide of silver, I was able to dissolve up to 20 grams of metallic silver in 1 liter of sodium thiosulfate solution (15-20% Na2S2O3).


----------



## Lino1406 (Jul 18, 2022)

A simpler choice is caustic soda solution which peels the silver as is


----------



## Ultrax (Jul 18, 2022)

AnotherMiner said:


> Here's a chart that shows silver chloride solubility in various solutions, including several concentrations and temperatures of thiosulfate. It probably doesn't answer your current question, but it might be handy some other time.
> 
> Are you considering using sodium thiosulfate to leach a silver-bearing ore? If so, please describe the ore.


Thank you! It will be useful


----------



## Ultrax (Jul 18, 2022)

Ultrax said:


> Are you considering using sodium thiosulfate to leach a silver-bearing ore? If so, please describe the ore.


I need to remove silver from the sulfide ore after 500C roasting (it contains more than 40% of silver, bismuth, and antimony) before further processing. The presence of silver in large quantity makes it VERY difficult to extract gold from the ore by chlorination. I lost more than 60% of my gold in the last experiment. Silver chloride also requires doubled chlorination stage to get the rest of the gold.
So I'm trying to avoid the additional step of ore processing to remove the silver chloride (with saturated NaCl or ammonia solutions).
Nitric acid is much more toxic than thiosulphate, so I'm trying to use thiosulphate to dissolve silver at the start point of processing.


----------



## Ultrax (Jul 18, 2022)

Lino1406 said:


> A simpler choice is caustic soda solution which peels the silver as is


Only in case, if you do not need to recover thiosulphate. It is very expensive reagent in large quantities.


----------



## Ultrax (Jul 18, 2022)

ION 47 said:


> I process silver containing photo solutions. On average, solutions from medical x-rays now contain 1.5-3 grams of metallic silver. Solutions from technical x-rays (radiographic method of flaw detection) contain 10 grams of metallic silver in 1 liter or more. What is the saturation limit of silver thiosulfate, I do not know, but when conducting certain analyzes of the silver content in waste containing silver bromide, chloride and iodide of silver, I was able to dissolve up to 20 grams of metallic silver in 1 liter of sodium thiosulfate solution (15-20% Na2S2O3).


Thanks!


----------

