how to start silver extracting business
what is the fixer solution
Silver is a very precious and important metal. recycling silver from waste
chemical is a profitable business.fixer hypo solution is the raw material of
silver extraction. all x-ray clinics, photographers have lot of waste fixer hypo
solution. because x-ray film and photography film has a thin coating of
silver. at the time of image formation, silver transfer from image portion of
films and comes to the foxing solution.repeating the same process again and
with the same solution, more silver dissolving in fixer solution. then due the
process the solution reaches the saturation level, and stop working.
this expired waste solution is the basic raw material for business of extracting
the concentration of silver in fixer solution varies because of process to
process and time to time. At the time of processing x-ray,photographic film,
the silver dissolve into the fixer solution from films and forms silver
thiosulphate complex ions. this is metal displacement process. in normaly
hypo solution contains up to 10gm/litr. you can estimate the concentration of
silver by using "silver estimation paper".
it is very simple , take a small silver estimation paper and dipped in the
solution. then the change is colur is compared with the color chart. you can
determine in gms/ltr within 5 seconds. the purchase price of raw material is
vary to place to place. but the average price is $1/litr. 1 liter of solution
contains 10 gms of silver=$9
that is =$8 profit in 1 liter processingfixer solution =$1
you can get 10gram of silver from this processing
with the current market price of silver $1000/kg =$10/10gm
4-Methods of extracting silver from fixer hypo solution.
>Take fixer solution
>Estimate gm/liter of fixer solution using silver estimation paper.
>Take 1 liter of solution and add approximate amount of sodium sulphate
(Na2S) and caustic soda (NaOH).
Due to common ion effect we can remove silver from it
>Using the proper proportion as per the upper estimation add proper amount
of sodium sulphide and caustic soda to all the solutio.
>we get a black residue at bottom due to reaction and the solution at the top
becomes yellow in colour. Filter the solution and retain the black residue.
Dry the residue using filter paper. Get it melted and molded. While melting
we can use borax/Na2CO3/CaCO3 etc.at last shiny silver is recovered from
black silver residue
>Make your own electrolysis machine.
>Use anode as carbon or graphite and cathode as stainless steel plate.
>Filling the waste solution to the machine and connect elecricity.
>Silver present in the solution starts depositing on cathode
>The machine should be operated till all the silver present in the solution gets
deposited on cathode plates as black flakes