EDTA is used in certain food products to prevent fats and oils from becoming rancid. It does this by chelating certain metal ions which catalyze the oxidation which causes the rancidity. -----Original Message----- From: pure-silver-bounce@xxxxxxxxxxxxx [mailto:pure-silver-bounce@xxxxxxxxxxxxx] On Behalf Of Richard Knoppow Sent: Thursday, March 17, 2005 7:27 PM To: pure-silver@xxxxxxxxxxxxx Subject: [pure-silver] Re: Pyro in a Jobo Processor ----- Original Message -----=20 From: "John Black" <jblack@xxxxxxxxx> To: <pure-silver@xxxxxxxxxxxxx> Sent: Thursday, March 17, 2005 12:14 PM Subject: [pure-silver] Re: Pyro in a Jobo Processor > >> >> Rollo Pyro uses EDTA-Na4, I believe, to sequester rotary >> oxidation. >> > > Hmmm... I've got to look this property up. I really don't > think EDTA can > sequester non-metallic series elements, there must be a=20 > different mechanism > involved. > > Now where did I put my Haist... > > JB > My understanding is that EDTA holds metallic salts like=20 Magnesium carbonate in suspension. Parhaps it has some=20 effect on oxidation products of developers also. Sodium=20 sulfite preferentially absorbs oxygen to prevent is=20 oxidising the developing agents. Sulfite has several=20 functions in developer but this is a principal one. Rotary processors use rather small amounts of developer=20 in thin layers, a condition guranteed to cause aerial=20 oxidation. Pyro developers appear to be particularly=20 vulnerable to aerial oxidation although they are also=20 supposed to be fairly good about not causing aerial fog. It=20 seems to me that Pyro developers are just not a good choice=20 for drum type processors. --- Richard Knoppow Los Angeles, CA, USA dickburk@xxxxxxxxxxxxx=20 =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D To unsubscribe from this list, go to www.freelists.org and logon to your account (the same e-mail address and password you set-up when you subscribed,) and unsubscribe from there. ============================================================================================================= To unsubscribe from this list, go to www.freelists.org and logon to your account (the same e-mail address and password you set-up when you subscribed,) and unsubscribe from there.