Undiluted selenium toner precipiate

Yes, just what the title says, precipitate in undiluted KRST. It is dark gray and has made a thin layer at the bottom of the bottle. The bottle was stored in much less than ideal conditions. Ok, that's a euphemism for temperatures ranging from about 0°C to 40°C or thereabouts... could be lower and/or higher. I've seen blackish precipitate in diluted toner, but have never heard of it in stock toner. I guess I can filter it and see if it's still potent, but the question is, has anyone experienced this before? Is it elemental selenium? What caused it?

Just as fixer can throw down elemental sulfur so can selenium from some of its compounds. Both elements are in the same column of the periodic table and have similar chemistries. Elemental selenium is grey in appearance although there is also a red allotrope. Both forms are insoluble in water, You will see this happen not only for the toner concentrate but also for its dilute solutions. Unless the amount of precipitate is large the activity of the toner should not be seriously effected.

Gerald C Koch said:

You will see this happen not only for the toner concentrate but also for its dilute solutions. Unless the amount of precipitate is large the activity of the toner should not be seriously effected.

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Gerald

When returning used toner (K-RST) to its' container I will funnel it with a screen to get rid of this goop.... Am I altering the toner in a bad way or should I just live with it?

Bruce Osgood said:

Gerald

When returning used toner (K-RST) to its' container I will funnel it with a screen to get rid of this goop.... Am I altering the toner in a bad way or should I just live with it?

Click to expand...

The activity of the diluted toner may be a bit less unless the amount of precipitate is large. Any selenium filtered out should be taken to a toxic waste facility. It is particularly toxic to fish and should not be put down the drain.

Thank you Gerald.