Silver Recovery From My Used Filters And Rags
As a photographer, I use a lot of silver-based materials in my work. This includes both silver nitrate filters and silver-impregnated rags that I use to clean my equipment. Over time, these materials become saturated with silver and need to be disposed of properly to prevent environmental contamination. However, I have recently discovered a method for recovering the silver from these used filters and rags, reducing waste and saving money in the process.
Collecting Used Filters And Rags
First, I have been diligent about collecting all of my used filters and rags in a separate container. This ensures that none of the silver is lost or mixed with other waste materials. I have also been careful to avoid contaminating the filters and rags with chemicals or other substances that could impact the silver recovery process.
Silver Recovery Process
Once I have collected a sufficient amount of used filters and rags, I begin the silver recovery process. I start by cutting up the filters and rags into small pieces to increase surface area and aid in the extraction of silver. I then place the pieces into a container with a solution of nitric acid and water.
After allowing the filters and rags to soak in the solution for several hours, the silver reacts with the nitric acid to form silver nitrate. I then filter out the remaining material to isolate the silver nitrate solution. I add a reducing agent, such as copper, to the solution to precipitate out the silver as a solid.
Benefits of Silver Recovery
By recovering the silver from my used filters and rags, I am able to reuse the material in future projects or sell it for a profit. This reduces waste and prevents harmful chemicals from entering the environment. Additionally, silver is a valuable metal that can be reused in a variety of industries, making it a sustainable and eco-friendly option for disposal.
Conclusion
Recovering silver from my used filters and rags has been a rewarding process that not only helps the environment but also saves me money in the long run. By taking the time to collect and properly extract the silver from these materials, I am able to reduce waste and contribute to a more sustainable photography practice. I encourage other photographers to consider silver recovery as a viable option for disposal of their used silver-based materials.
To achieve a 100% conversion to silver metal a constant temperature of 85 to 95 C must be maintained during the whole process.
Place the beaker in a water bath, together with a thermometer. Add NaOH in small doses while stirring vigorously. A very exothermic reaction occurs, but it'll not be enough to maintain the optimal temperature during the whole process, therefore a gentle heating underneath the water bath is necessary to keep the temperature correct for the remaining part of this process.
I always place the beaker in a clamp on a metal lab stand in such a way it's hanging a bit above the bottom of the water bath, allowing the water to flow free under and around the beaker; thus avoiding any spots becoming too hot. The water helps dispersing the heat when the NaOH and especially later when the sugar is added; important to avoid caramelization of some sugar types.
Adding NaOH as a near saturated aqueous solution calms down the violent reaction quite a lot, and keeping a constant temperature of 85 to 95 C, as well as later adding sugar dissolved in water, all reduces the total reaction time of this process.
Beware of the delayed reaction when adding the sugar. After the first dose of sugar solution, stir and wait until it start reacting, then continue to stir and add more in small doses to avoid overflow/boil over.
Both while adding NaOH, and later while adding sugar, temperature increases will occur so the external heat source must be adjusted accordingly.
Pretty cool way to recover the silver
Would cloudy ammonia work ?
Very cool 😊
Hi Mike, So now you have a candy factory with your refining – great job! The bottle of ACE ammonia that I have is called "Janitorial Strength Formula". The label says 10% ammonium hydroxide. This process is another 'tool' in the tool box of refining methods! Thanks for educating us – again! Have a great day! Jim
Rags to riches! 😂
I found the best way to tame the reaction when adding the sugar is to dilute it into a syrup. I've done both the fructose (corn syrup) and sucrose (table sugar) and found sucrose to be both cheaper and easier to do. I'll make a basic 2:1 sugar/water syrup and heat it to warm. Drizzle it in as I stir and no boil-overs. It boils but it's WAY easier to control any sudden flare-ups.
Oh…and for rinsing I prefer using boiling water. Add in twice as much as the current volume (ie if you have 500ml in the beaker add in 1L) and stir well. Start to add in HCl slowly to help neutralise the NaOH. It'll bubble and fizz so watch out. It'll also start to lighten up in colour. Stir well and check ph. When it gets close to 7 stir more and then let it settle. You'll be shocked at how much more quickly it settles and clarifies. Then I just pour it all through the filter…no decanting. Catch everything and rinse the filter with more boiling water. Nice and clean and uses WAY less water.
You use syrup? Is that an inverted sugar syrup? that contains about half Fructose. Fructose already caramelizes at 106C from the back of my head. Maybe use sugars that caramelizes at higher temp. Glucose or Sucrose. Haha try to clean a pan you made craramel in… that's terrible to rinse out.
A nice recovery! I'd wondered if you'd go after the silver. I understand you wanted to weigh the metallic silver now but otherwise it might be easier to keep a jar of silver chloride and turn it metallic when you've accumulated a bunch.