home.gif search3.gif vendbutton.GIF sheets.gif listervsbutton.gif compicon2.gif

printech, January, 2001
Re: silver magnet


New Message Reply About this list Date view Thread view Subject view Author view

From:Gary Jones(gjonesprinting@aol.com)
Date:Mon, 22 Jan 2001 15:51:38 EST


Sherry: Thanks for the fax of the silver magnet. Essentially it is an electrodepositon unit where the silver is plated onto the cathode (+) and the cathode is sent to the refiner for processing. I am not sure why the entire cathode needs to be sent to the refiner, because with the other units I have seen, the printer just knocks the silver off the cathode and the cathode is reused. >From the fax it is not clear if the cathode rotates while it is recovering the silver. With the other units I have seen, the cathode rotates in the solution while it is recovering the silver. While this is not necessarily bad, but the turbulence created by the turning cathode will increase the amount of silver recovered and care needs to be taken with the electric current to minimize sulfide buildup. You can cook the solution and cause a mess. It is also not clear as to how you know when you are done recovering silver with the unit. With other units I have seen, there is either a set time for recovery or a meter on the cathode measuring resistance. The other major question is how efficient is the unit at actually recovering silver and how much is left in solution when it is discharged? Will the printer be able to meet their local limits? This may have to be a site specific test. How long does it take to plate the silver? While you are plating, you can't be developing film so when does the plating occur and will it interfere in productivity? You may also want to check with the hazardous waste folks to see if this would be considered treatment of a hazardous waste under the state regs. This could be tricky as EPA does not consider continuous inline silver recovery treatment, but batch recovery can be considered treatment since it is not hard piped. However, since this unit is placed in the processor tank, you could argue it is done on a continuous basis since the fix can be "reused" after silver recovery. These are my initial thoughts. I would be interested in what answers are to my questions.



New Message Reply About this list Date view Thread view Subject view Author view