Sciencemadness Discussion Board

Extract Silver From X-RAY Film

Waffles SS - 7-2-2012 at 22:19
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There are several ways to extract silver from other compounds and materials. Most people who are interested in extracting silver are interested in extracting it from used camera film and X-ray film, as well as from waste chemicals used in processing films. If you are looking for a home-based business that has high profit potential, as well as one that will help reduce chemical and physical waste that is buried in landfills, then consider setting up a silver extraction business.

Instructions

Extract Silver

1- Buy or build an electrolysis machine. This machine will help you to extract silver from your waste chemicals. You can find electrolysis machines in science supply stores, or you can make your own using a 12-volt charger and a rubber tub.

2-Find waste products to extract silver from. You can contact hospitals and imaging companies or place an ad in the local newspaper to collect used film rolls, X-rays and waste photographic chemicals. (Hypo and fixers both contain silver.) You can expect to generate about 0.254 grams of pure silver from each roll of 24-exposure film.

3-Set up your electrolysis station. If you have an electrolysis machine, you will fill the machine with a caustic solution and turn the machine on. If you are working with your homemade electrolysis machine, you will want to place hot water and your caustic solution into your rubber tub, place the charger plates in the solution and turn on the charger.

4-Prep your waste materials for electrolysis. If you are working with waste chemicals, you can just pour them into the electrolysis tank. However, if you are working with films, you will need to burn them before dumping their ashes in the tank.

5-Complete the process of electrolysis. You will dump your prepped waste materials into the electrolysis tank and allow the silver to be leached out by the chemical reactions created by the caustic solution and the electrical current. As the process progresses, you will notice silver flakes developing on the charger plates. This process can take anywhere from 30 minutes to several hours, depending on the voltage and caustic solution you are using. Don’t leave your electrolysis machine unattended during this process until you are familiar with how long it takes for the process to complete.

6-Collect your silver. Turn off the charger and remove the plates from the tank. Scrape the silver flakes from the charger plates onto a paper towel. Then use tweezers to move the silver flakes into a glass jar.

http://www.ehow.com/how_4501375_extract-silver.html
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[img]http://www.paladix.cz/img.php?ido=11281[/img]
http://www.paladix.cz/clanek.php?aid=10304&sid=1&hle...



Somebody know better or easier way for this purpose?
using KMNO4 ?Na2Cr2O7


crazyboy - 7-2-2012 at 23:59

I have extracted silver from X-ray film successfully, however, I am going from memory there may be a few flaws in my procedure.

X-ray films were placed in a plastic five gallon bucket, standard unscented bleach free of surfactants and dyes was added to the bucket. The films were agitated and washed with the bleach until they were transparent. The films were removed and the suspension was allowed to settle, it was filtered to yield a sludge of AgCl. The AgCl sludge was washed with cold water and dissolved in Nitric acid, then it was precipitated with copper. This can be further refined by electrolytic means.

This procedure should also work with HCl, though I have not tried it and I do not know what concentration would be ideal.

unionised - 8-2-2012 at 01:33

AgCl does not dissolve in HNO3. If it did the classic test for chlorides wouldn't work.

Intergalactic_Captain - 8-2-2012 at 02:04

http://www.sciencemadness.org/talk/viewthread.php?tid=18549

About halfway down is a phoducumentary of EXACTLY what you're looking for

Waffles SS - 8-2-2012 at 12:04
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Whats interesting! Congrats Plante1999.

I was under impression that silver only dissolves on dilute HNO3 acting on it. Now, a complete home method to process silver mylar keyboards!

But I prefer x-rays scrap.. these are much richer in Ag!

Hope this wont be off topic, but since you people are talking about dissolving silver from keyboard, it would be nice to talk also about other scrap sources of Ag here..

Acetate/protein bearing silver particles (like on x-ray sheets..black parts) and other photographic scrap, can be process in another way (still oxidizing, but alkaline way).

The yield could go up to 5g Ag/m^2 x-ray.

Ive found that other Ag scrap, like X-ray can easily be processed with home bleach (2% bleach is just fine), it is very easy to do..

The gelatinous material used in photographic emulsions consists primarily of proteins which under the action of the alkaline bleach are hydrolyzed slowly crumbling and releasing silver dispersed therein. So the silver can be attacked by the hypochlorite:

4 Ag + 2 ClO- + H2O -----> 2AgCl + Ag2O + 2OH-

You could easily reduce then AgCl/Ag2O with hot NaOH/sugar solution. The mud containing non-hydrolised matter , Ag, AgCl and Ag2O is reduced by NaOH/sugar because beyond it will hydrolise all the organic remnants from bleach step, in hot alkaline-reducing media, all AgCl is converted in Ag2O which oxidizes sugar to CO2, formic and levulinic acid (you can see acid smell during this step, even though solution is alkaline) and gets reduced back to elemental Ag..


Get a shallow plastic or glass container and dilute 2% NaOCl bleach with water (3:2).



Put in cut squares of your x-ray scrap:


Bleach will eat x-ray film very fast, leaving transparent celluloid behind..


After done, spray it with water on the shallow dish, to bring down stuck AgCl..



Treated films.. It tooks about 10 mins to make about 4 foils (that were cut in smaller squares to fit in the dish..)



Plasticware dish with AgCl








Carefully decant (it may take a day):


And reduce with hot NaOH/sucrose:


Unfortunatelly I dont have photo of the actual process, but is very simple.. The colour of mixed solution quickly turns light brown, dark brown then grey/black.. Will try to make a video next time I put my hands on more x-ray films...

Filtering (neutralize it with mild acid BEFORE you filter, since hot NaOH solution will eat your filter paper. I learned this through bad way)..


Save the filter paper used to filter Ag. It is impregnated and could be processed later along with other silver scraps with dilute HNO3 (or Plante1999 proposal of acetic/H2O2 )

Ag powder from previous runs:



There are of course patents of process.. e.g.
http://www.freepatentsonline.com/3960550.pdf
though this is a bit different and harder to do at home.. But gives ideas on how to melt/purify your silver..
http://www.sciencemadness.org/talk/viewthread.php?tid=18549&...


Why we should use 2% Sodium hypochlorite solution?Why we cant use stronger solution of it?(commercial bleach contain sodium hydroxide)

AirCowPeaCock - 8-2-2012 at 12:37

I have Hi-Lex (I think thats the brand) bleach, ~5.25% NaClO ~94.75% water

[Edited on 2-8-2012 by AirCowPeaCock]

Waffles SS - 9-2-2012 at 23:23

What ratio of NaOH/sucrose is needed for reduction step?

Solomon - 27-6-2013 at 17:53

On page 74 in the golden book of chemistry experiments (copyright 1960), it says that more than 150 tons of silver are used each year in making film for the movies.