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"Silver extraction from waste hypo/fixer solution"
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Q. I need to extract silver just for a school project, so a thin strip will be sufficient. Can you please answer my queries:
-what concentration of sodium thiosulphate [affil. link to info/product on Amazon] to be used
-what voltage must be used
-anode and cathode, etc.
I need a minimal amount and the simplest procedure will suffice.
p.s. if there are any alternatives, please suggest.
- ahmedabad, gujarat
June 21, 2010
Q. HEARD ABOUT SILVER REFINING FROM HYPO/FIXER, BY PRODUCT OF X-RAY DEVELOPING PROCESS CAN GIVE PUREST SILVER, IS THAT TRUE? IF YES, HOW CAN WE KNOW THE PERCENTAGE OF SILVER IN GRM/LTR? WHAT ARE THE VARIOUS METHOD OF REFINING THE EXTRACTED SILVER? IS IT AFFORDABLE?ANTONY JOSEPH
HOBBYIST - ERNAKULAM, KERALA, INDIA
July 1, 2010
Q. Hi Sir.....
I am Rajesh
Recently I had started silver recovery unit I want to know what is the process for color bleach in manual method.
That is I heard one manual method. In color bleach some chemicals will be mixed after mixing that chemical all silver content will come come down and waste water will come up.
I have to know what is the chemical is used to extract silver like this.
Product designer - Andhra Pradesh, India
August 28, 2010
Q. I like to know which chemicals are used to extract silver from sodium thiosulphate. Is it possible to extract it from sodium hydroxide & sodium sulfide?vikram doke
student - thane,maharastra,india
September 9, 2010
I WANT TO START A BUSINESS OF "SILVER RECOVER FROM PHOTOGRAPHY PLATE" .
PLEASE GIVE ME PROCESS OF REMOVING SILVER FROM PHOTOGRAPHY PLATE
STUDENT - delhi,new delhi,india
December 20, 2010
A. I read about the topic of recovering silver from fixer. I have knowledge since I was working before in the refining of precious metal. All of the answers I read are right but the only way to purify the silver is the electrolysis but as what mr! (I forgot the name) said is also right. But always be careful when somebody is doing experimental procedure! Good luck to all of you guys.erick tagacay
Supervisor (refinery of precious metal) - UAE
March 4, 2011
Q. I want to know what are the equipments required for electrolysis method for silver extraction for anode, cathode, what tank is best? And can I recover 100% silver from this method.how much current have to use in electrolysis method? I know the chemical process also, so which one is best?pradeep meher
March 7, 2011
You say you know the chemical method, and you can see that hundreds of other readers got here first, looking for that information that you can offer. So please describe the chemical method that you know. Then maybe people can compare it to the electrolysis method for you.
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
April 28, 2011
I have searched for advice on recovering silver from spent film fixer. I mostly found questions on this site with no answers. This is what I deducted. Both developer and fixer start out clear. The developer turns muddy but the fixer stays relatively clear. Both are very alkaline. The developer is waste. The fixer needs to be pH adjusted to about neutral using sulphuric acid (battery acid). The reaction was very weak in the alkaline solution. I used OOOO fine steel wool and immediately saw a chemical reaction. The solution turned milky white and a dark precipitate dropped. In a different container, I used powdered zinc. The reaction was much stronger. I have photos, but don't know how to post them here.
Now for volume processing, I plan on adjusting the pH then 1st precipitating with the steel wool, then decanting into a container with powdered zinc for a second round of precipitation.
Theoretically, I can purify the silver in the steel wool tank by exploiting melting points of silver vs. iron. Theoretically, I can purify the silver in the zinc tank by re-dissolving the melted metal nugget in nitric acid, precipitate the silver with table salt, wash with distilled water and bring to a boil. The silver chloride should remain as a precipitate while the zinc should go back into solution.
I need to investigate stripping film for silver recovery next. The oxalic acid post was interesting.
- Sussex, New Jersey, USA
Ed. note: Attach the photos in email to
May 2, 2011
Q. I know how to extract silver from waste fixer chemically but the process is somewhat difficult. I use the following chemicals sodium sulfide, caustic soda sodium nitrate borax soda ash this process finally I get the black powder which is to be melted at high temperature.
Is there any other method to extract pure silver chemically without melting the powder. I want the method to extract silver without melting chemically.
buyer - Bangalore, Karnataka, India
May 12, 2011
Seriously?? I'm a chemistry instructor and am amazed at the number of repetitive questions... Do they not teach chemistry where they are? My intro to chemistry students could do a better job at thinking about this than all the postings...hats off to the gentleman that is trying to get you guys to post answers. I love the "get rich quick mentality" of tell me how to extract silver at home so I can get money for doing nothing...Take a few chemistry classes...Donna Talbot
- Missouri USA
May 21, 2011
A. I thick Ted is right on the money on the amount of silver in fixer solution; most of the film now that is used is known as rare earth film. Very low in silver content, even the green film has a low amount. You cannot recover near the amount on a 1000 lb. of rare earth that you could on the older film.
I have bought and sold tons of film and even tried the processing route without any success. A lot of the Techs at the hospitals will lead you to think you can really do well at their hospital; don't get too excited though, it is a tough business to compete in. It is like trying to outdo the big boys that have all the knowledge, equipment, and resources. If a person can find used X-ray units that are in good condition and are of the size for the application and you maintain a monthly check you might have a chance of making a little money for the time and effort, but do not be disappointed when you find out you are working for pennies.
I have been down this road before. To all who try may I wish you the best of luck.
- Ruidoso, New Mexico
June 2, 2011
Q. Respected sir,
Now I want to extract silver from fixer solution and x ray films.
To date I use sodium sulfide, sodium hydroxide, borax for fixer solution but I got black metal with impurity of Pb sisa) according to goldsmith and it is breakable in nature.
Please give me proper instruction (step by step) for fixer solution and x-ray films.
MBA student - Jaipur, Rajasthan, INDIA
August 22, 2011
Q. Dear sir: once burned x-ray films and having the ash, what's the next step to obtain silver by electrolysis?Eduardo Francis
Medicine student. - Caracas. Venezuela.
September 1, 2011
A. I have read many forums and thousands of threads but this one is amazing! Hundreds of questions. A few answers that are succinct and to the point.
The chemical solution:
Better question: What chemical(s) do I add to a KNOWN solution to recover silver (of unknown purity).
Example: Recovery of silver from silver chloride...
The chemical reaction of Sodium Hydroxide with Silver Chloride results in a KNOWN combination of compounds; sodium chloride, silver with hydrogen and oxygen.
NaOH + AgCl --> NACl + Ag + H + O
In photography, Sodium Thiosulfate (Na2S2O3) combines with silver bromide (AgBr) to create a complex compound...
[Ag(S2O3)2] with three spare electrons + Br with one spare electrons. These are ionic compounds.
From what I have seen, the recovery is done with proprietary chemicals.
Electro-chemistry is MORE fun than chemistry!
The answer was given above in the thread. Using a power supply with a graphite anode and stainless steel cathode, it is possible to electro-win or plate the silver out of solution onto the stainless steel plate (electrode).
How much voltage?
How much current?
"Recovery And Refining Of Precious Metals"
by C.W. Ammen
from Abe Books
The voltage required and the current required depends on all of the above.
Depending on the quality of the solution, you will get silver in the form of crystals or "sludge". The sludge and/or crystals can be melted into impure silver.
The book, "Recovery and Refining of Precious Metals", by C. W. Ammen is one of many recommended publications on the subject.
Less noble metals... Copper, Iron (nails) will precipitate silver from photographic fixer. (it's actually electro-chemical without a power supply)
It has been an impossible thread! The answers were impossible! The answer IS possible with a knowledge of chemistry and the willingness to apply chemistry AND electrochemistry to find the answers to the above questions.
What are the economics of silver recovery?
The answer is impossible without knowing what the costs and revenues are. Where in the WORLD are you? What does labor cost in India vs the US? Certain people have replied with knowledge and experience that say it is not economical. Controlling efficiency and cost while maximizing the revenue side while noting the price of silver today will affect economics.
Good luck!Chuck Merritt
- Cochise, Arizona, USA
September 2, 2011
Q. I am planning to start silver extraction business part time from waste photographic hypo solution. I am Photographer. I shall be very thankful if you please answer some of my questions.
1. Various chemical methods employed to extract silver on small scale. Its exact procedures?
2. Electro-Chemical method (Through Electrolysis) Its feasibility?
3. Procurement of plant and machinery
In nutshell I want to know the details of easy and profitable practical method for the extraction of Silver from waste Hypo fixer solution. Please guide accordingly. I shall be very thankful to you
photo studio - Sangli, Maharasatra, India
September 19, 2011
A. In answer to the chemical solution for recovery of silver from Sodium Thiosulphate:
SODIUM sulfide is added to the solution of sodium thiosulphate [affil. link to info/product on Amazon]. The reaction is:
Ag2S2O3, 2Na2S2O2+Na2S = Ag2S+3Na2S2O3
The silver is precipitated as silver sulfide. The silver sulfide settles to the bottom of the container in which the reaction occurs.
Silver sulfide can be purchased or produced for use.
If lead is in the solution, then the FIRST step is to precipitate the lead with sodium carbonate (washing soda) [affil. link to info/product on Amazon] and remove the lead. Otherwise, the lead will be precipitated with the silver.
- Cochise, Arizona, USA
December 6, 2011
Q. Dear Sir,
Kindly provide me the exact detail of two things, which is required to separate silver from fixture, mentioned below:
1. Which 3 chemicals is used to separate the silver from fixture.
2. How much the quantity of chemicals to be mixed in fixture. and which chemical should be used first and what the next step.
Desperately waiting for the reply
- Hyderabad, A.P, INDIA
January 12, 2012
A. Hello. Everyone who wants to know about the extraction of the silver from waste fixer.
SO MANY QUESTIONS TO ANSWER:
1) CHEMICAL PROCESS
ADD 1/4 KG CAUSTIC SODA TO APPROX. 100 LITERS OF FIXER, STIR IT WELL, AND THEN ADD 1 KG OF SODIUM sulfide TO IT AND STIR IT WELL, AND LEAVE IT FOR 2 TO 3 HOURS ....SALT WILL GO DOWN TO BOTTOM REMOVE ABOVE WATER CAREFULLY .....MAKE SURE SALT GETS DRY BEFORE MELTING.
BORAX WILL BE USED FOR MELTING SALT TO GET PURE SILVER
2)MOST PEOPLE ARE ASKING ABOUT EXTRACTING SILVER FROM X-RAYS
FOR THIS YOU NEED LOTS OF PERMISSIONS FROM GOVT FOR EX: -POLLUTION LICENSE ETC ... HEADACHE
TO THE NEWCOMERS MY SINCERE ADVICE IS DON'T BUY CHEMICALS WITHOUT PROPER KNOWLEDGE ... THAT WILL GIVE HELL LOT OF HEADACHES TO YOUR BANK BALANCE ....
SOMEONE ASKED HOW MANY GRAMS WILL YIELD FROM 1 KG X-RAYS
HERE IS THE ANSWER
1) CHEST 3 GRAMS MAX PER KG
2) ORTHO 9 GRAMS MAX PER KG
3) MIX 6 GRAMS PER KG
THANKS TO ONE 'N' ALL
- HYDERABAD, India
January 19, 2012
Dear Rajesh, Thanks a lot.Moin
- Chittagong, Bangladesh
January 4, 2013
Q. Sir, can anyone help me in recovering the silver from the QSS lab bleach and stabilizer? And which chemicals are used for the precipitation and for the melting?Kasturi Surendra
- Kurnool, AP, INDIA
September 17, 2013
I'm Rathod from Bangalore, actually sir I'm planing for setup silver extraction machine and I'm new for this kind of business so I need help from you sir , means whether I can do or not, is it profitable or what and do I get the raw materials in Bangalore.
- Bangalore, India
September 29, 2013
Q. Dear sir, good morning, I'm Rajesh from India; I want to know which chemicals are used in silver extraction from x-ray fixer ? What is approximate amount of these chemicals in 100 ltr? How to complete this process method? Thanks sirRajesh Kumar
- Kota, India
April 28, 2014
Q. For silver recovery from x-ray fixer what should add sodium sulphate/sodium sulfide? Please guide me.ramanamurthy. d .v
- kakinada, A.P, INDIA
October 6, 2014
A. SILVER FROM FIXERS:
PROBABLY THE BEST WAY IS TO HANG COPPER SHEET/WIRES/SCRAP IN FIXER. SILVER METAL FALLS DOWN TO BOTTOM. FOR TESTING WHETHER THERE IS SILVER, JUST DIP A COPPER WIRE. THE REST ARE ALL EXPENSIVE WAYS FOR MOST PEOPLE
NE SPINELS & OXIDES - Rajkot,India
April 4, 2015 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread
Q. I am a wet plate and Daguerreotype photographer. I use a 1% cyanide solution as a fixer when making tintypes. After fixing several plates the bath gets exhausted; it no longer clears the photographic plate as it is saturated with silver. I have tried using this solution with a fine silver anode and a copper or brass cathode. I get a durable silver coating, but after a minute or two I get a yellow scum that needs to be polished off the plate. Is this a half-decent way of getting a .5 mil coating? I would love to reuse this bath both to reduce any haz waste and reclaim some silver. One more thing, the silver is from silver nitrate in water, soaked into a colloidal matrix. There is a minute amount of cadmium in the colloid, roughly .05 g per litre
The cath/anode are 5" apart, I am feeding it 2 volts at .2 A
- Illinois USA
June 3, 2015
Q. I have done the metal replacement method to recover the silver out of spent fixer. I used a copper tube and just left it sit in the fixer for a few days and now I have the black sludge. How do I refine this? I have looked and looked but have not found what to do with it.Ken Johnson
- Mapelton, North Dakota, USA
November 9, 2015
Hello and welcome.
l have gone through the maximum questions posted over there and found that so many people are aware to the extracting of silver from solutions but not revealing their methods; but a very few philanthropic personalities have answered nicely.
I salute & thank all of them who are Best Guide for ...seeking help.
- Shimla HP. India.
July 15, 2016
A. SILVER FROM PHOTOGRAPHIC SOLUTIONS
Various people are trying to recover pure silver by various methods. I feel the quantity involved for most is too small to get it in to any complex processes / costly equipments, which will make is less economical / viable.
Simplest processes are metal replacement. i.e., less noble metals dissolves in solution precipitating more noble. Say, copper, iron, etc. will precipitate silver from its solutions.
Copper (sheets / turnings or iron turnings, iron wool used for paint polishing (do not try iron wool used for cookware cleaning; it contains other metals). Manufacturers sell 000 to 0000 grade at about Rs 130/kg (USD 1.95/kg ). For your purpose use only pure Iron wool, Iron wool 0000 grade has highest surface area. Thin metal turnings will have more surface area.
HIGHER THE SURFACE AREA, FASTER IS YOUR RATE OF RECOVERY
In a simple set up you take 20 liter waste solution in a plastic bucket / HDPE drum, Take Scraped copper rod /thick; scrape piece, thin sheet turnings are wrapped around with synthetic thread. Alternatively use a iron rod and wrap iron wool around it. Put it in non woven bag /polyester/nylon bag, put this bag in waste solution. You will get most of silver with sulfur/sulfides and some other metals as a black sludge in the bag. It takes 12 to 24 HOURS.
For faster cycle you can hang a graphite electrode on other side of the bag. It should not touch (Say about 2-3 inches apart). Use discarded car battery with at least 3-4 cell working or 29-25 ampere DC rectifier; connect negative to graphite and positive to center rod/scrape of copper / iron.
Little stirring / vibration will help collect all silver sludge at the bottom and becomes more efficient,
You can use bright sanded copper strip to check if any more silver is left behind in solution. In few seconds it turns black if you have 500 mg/ltr or more. If it takes more than 5 mins to turn slightly brown-black it is close to 20-30 mg/ltr.
KINDLY NOTE IN MOST COUNTRIES IT IS NOT ALLOWED TO DUMP ANY SILVER over 5 mg/ton IN DISSOLVED FORM. It's a very toxic heavy metal. KINDLY REMEMBER.
To above dried sludge add, say, 1 kg sludge + 250 gram soda ash + 50 gram borax + 200 gm Sodium nitrate. Fire it in a graphite crucible slowly to 1150 °C. vibrate few times, you should get pure white silver of 99%+
*BORAX is used to lower meting temperature of glass phase of sludge impurities
*Sodium nitrate is used to avoid evolution of toxic SO2 gas
EXTREMELY IMPORTANT: when using Sodium nitrate, as gelatine from the waste soln. Makes highly explosive combination. Melt smaller quantities to start with, very slowly raise temp, from 600-900 °C.
*Clay / ceramic crucible are not suitable as soda ash, borax, etc. will melt the furnace.
NE Spinels & Oxides - Rajkot, India
December 17, 2016
Q. I work for a company that manufactures fire suppression for commercial airlines. Part of that process is x-raying the bottles for cracks in the welds.
We use a CPAC ARU-1200 which is a silver recovery electrolysis system to minimize the amount of silver or heavy metals that drains into our industrial waste line. After spending some time figuring out what this system did and its process, I am stating to recover what I think is some type of silver building up on the Cathode (which is made of stainless steel).
What do think the purity is if it silver? Does it need further refinement?
Thank you so much. I really appreciate all of your hard work and effort in making this a website that anyone can use to educate oneself for a better end result.
- Simi Valley California USA
A. Hi Dave. I expect that this would be silver suitable for shipping to a refiner. But guessing isn't a good way forward. I would suggest having a sample of the x-ray effluent analyzed before treatment so you know how much silver was actually in it, and have the recovered silver weighed and analyzed so you know what percentage you recovered. With these two numbers you have some measure of what you are accomplishing, whether you re operating efficiently, and whether it's even worth the effort; without those numbers, you really don't know much. Good luck.
Ted Mooney, P.E. RET
Aloha -- an idea worth spreading
finishing.com - Pine Beach, New Jersey
December 18, 2016
A. If the deposit is very white and hard, it could be as high as 97-98% pure. If it's black, smelly, and loosely adherent, it could be as low as 80-85% pure. It never is pure from those electrolytic units. The impurity is sulfur. The brittle silver is broken off of the stainless steel drum by tapping it with a hammer.
It is purified in a gas crucible furnace. Some borax is added to the silver along with several lengths of rebar (long enough to protrude from the top of the crucible, so they can easily be removed). Some of the iron from the rebar combines with the sulfur in the silver and this iron sulfide goes into the borax slag which floats on top of the molten silver.
When the reaction is complete (in an hour, or so), the rebar is removed and the molten slag and silver is poured into a large cast iron rectangular or cone shaped mold. When cool, it is dumped out of the mold and the slag is broken away from the silver. If done right, the silver can be 99.9% pure, or better.
- Nevada, Missouri, USA
April 13, 2018
Q. Dear sir
I just heard about this business. I just want to know what are the companies sell this used hypo/fixer.
- Punjab Sialkot Pakistan
A. Hi Malik. We are now in the digital age so I suspect there are ever declining sources for this silver-bearing photographic fixer solution, but you could check with local hospitals and x-ray laboratories.
Ted Mooney, P.E. RET
Aloha -- an idea worth spreading
finishing.com - Pine Beach, New Jersey
August 27, 2018
A. There must be a sufficient amount of silver to be recovered before attempting to recover it from the material because the cost of equipment needed must be justified.
There is no way to condense the entire subject in brief post.
some posts ask how much silver can be recovered from an Xray film. It depends on how large a surface the film has, how much of exposed area on it ( whites, transparent parts of it mean total absence of silver in those areas of exposed surface where hypo just removed it from film.
Others ask about recovering the silver that is in the hypo.
Yet others ask for stripping the image on the material and recovering silver from emulsion.
Each has its own process and yes, if there is enough yield projected then you can proceed with your project.
The fixer solution can be treated for recovering silver in recovery machine by electrolysis.
Film and paper can be stripped off and the gel remaining can be returned to recovery machine.
We also use special bucket type of recovery equipment that will recover silver but will take very long time for it because gravity fed cans work drop by drop.
Recovery machines will treat 7 to 20 gallons in about 17 hours.
Master Technician - Los angeles California USA
December 16, 2018
Q. Dear sir I just came across this very interesting and mind blowing business. I am a graduate of Chemical engineering; please I want to know everything that has to do with extraction of silver from waste. I want to also know various waste from which silver can be extracted. I am very much interested. Thanks
- Kubwa, FCT Abuja, Nigeria