Selenium toner : lifetime; safe disposal

[bernard_L]

I have some Dassonville T-55 toner made from scratch.
[yes, I know, I'll donate the remaining Se to a university chemistry dept; for now I have to cope with what I have]
Questions to chemists.

1. In other threads I read that dilute KSRT solutions have essentially "infinite" lifetime. Yet my dilute solution from 5 years ago is ineffective (fresh dilute solution is OK). Any idea what is the secret ingredient missing in T-55? Or maybe 5 years is beyond infinity when discussing photo product life?
2. I read that the active ingredient in Se toner is the selenite ion. It is also the most environmentally objectinable, more than elemental Se. Can I assume that "dead" toner has little or no selenite present, and can be disposed (with enough dilution)?

Thank you

 

[Vaughn]

I'll be interested in hearing from of our more chemical-knowledgable folks. Perhaps there is a simple way to create a stable selenium compound that would be safer to dipose of.

 

[Ian Grant]

I have some Dassonville T-55 toner made from scratch.
[yes, I know, I'll donate the remaining Se to a university chemistry dept; for now I have to cope with what I have]
Questions to chemists.

1. In other threads I read that dilute KSRT solutions have essentially "infinite" lifetime. Yet my dilute solution from 5 years ago is ineffective (fresh dilute solution is OK). Any idea what is the secret ingredient missing in T-55? Or maybe 5 years is beyond infinity when discussing photo product life?
2. I read that the active ingredient in Se toner is the selenite ion. It is also the most environmentally objectinable, more than elemental Se. Can I assume that "dead" toner has little or no selenite present, and can be disposed (with enough dilution)?

Thank you

Far more Selenium goes down the drains from people urinating after taking Selenium supplements

There's no secret ingredients it's just Selenium powder dissolved in Sodium Sulphite with Ammonium Chloride added after. It doesn't keep well after mixing KRST and similar use Thiosulphate instead.

Ian

 

[bernard_L]

Far more Selenium goes down the drains from people urinating after taking Selenium supplements

I had a similar thought. Politically incorrect. If I go to the nearby medium-sized river and slowly pour my toner from a bridge, it is right away below the environmental norm. And... (a little) Selenium is good for wildlife, too. Reminds me I need to take my Mercury dietary supplement.

It doesn't keep well after mixing KRST and similar use Thiosulphate instead.

I didn't quite get the meaning of your last sentence. You mean thiosulphate instead of sulfite? Do you have more insights into the KSRT Secret Formula?
[Edit] You are probably referring to this: https://www.photrio.com/forum/threa...ak-selenium-toner-formula.96284/#post-1278557

 

[bernard_L]

Far more Selenium goes down the drains from people urinating after taking Selenium supplements

Following up on that, just for fun. Daily recommended dose 50µg/day (see below) from natural foods or pills. I live in a community of approx 3000 people, and would bet I'm the only one using Se toner; in fact the only one doing wet B&W prints. Collectively my neighbors intake (and excrete?) 150mg/day of Se. Last time I prepared T55 Se toner was 5 years ago, using 6g of Se. In the course of those 1800 days, my neighbors excreted(?) 1800x150mg=270g of Se.

I bet now I receive a broadside of angry and politically correct comments. Just before you jump to your keyboards: I drive a car with a 1.2litre engine; and thanks to selective waste disposal, I contribute under 20litre/week to the garbage collection.

 

[Ian Grant]

I didn't quite get the meaning of your last sentence. You mean thiosulphate instead of sulfite? Do you have more insights into the KSRT Secret Formula?

There's nothing secret about the KRST formula, they just improved on the old Kodak T-55 toner which was sold commercially as Kodak Selenium Toner.

I meant they added Ammonium Thiosulphate alongside the Sulphite.

Ian

 

[Vaughn]

Selenium is a nasty chemical. It kills livestock, fish and birds. The line between needed levels of selenium and toxic levels is a narrow one. Found in the soil in various amounts, livestock die from eating the grass grown on soil containing high selenium levels, and human intervention in the movement of water can concentrate the selenium in the environment. Don't fear it, but respect it.

Filter feeders concentrate contaminates in the water. In Puget Sound, I suppose one should be able to get drugs and vitamins supplements galore by eating the shellfish. Prescribed (and street) drugs going thru the sewer system far exceed the amout of selenium!