Zinc Rain?

[DrP]

There is a furnace that gets some use near me for incinerating stuff. I would reckon, from what I know about furnaces, that it probably burns from about 800 to 1200 C (maybe higher) depending what's in it, whether it is closed or not, how full it is and stuff. It has quite a high metal chimney.

 

OK - on the out side of the furnace, sometimes, metal spheres form about 0.5 to 1.5 mm in diameter. They stick to the side of the metal furnace.

 

I was wondering what these could be and the only thing I could come up with was that it could be from metal contaminants in the furnace. It would need to be a common metal with a boiling point lower than 1200 C. I think that maybe some zinc (BP - 900C ish). I am thinking that any zinc in there gets vaporised, sent up the chimney with the smoke, condenses pretty quickly and falls back down and sticks to the side of the furnace as these metal spheres. The only other thing I can think of is that maybe the outside of the furnace may have been treated with a zinc rich metal primer paint.... and at high enough temperatures the zinc could melt out of the paint layer and coalesce into these little balls which solidify when it cools.

 

So - which is it? Zinc rain or zinc leachage from the coating. If it was rain from the chimney smoke then maybe the balls would be more splatted? Some are a little squashed, but some are near perfect balls. I don't think it comes from the coating because of the formations are in streaks running down from top to bottom... as if it has rained down, but I could be wrong.

 

Thoughts?

 

 

[Sensei]

metal spheres form about 0.5 to 1.5 mm in diameter.

 

Collect them, melt, squash to have thin sheet/wire, and use in electrolysis of water.

If it's Zinc, Zn(OH)₂ / ZnO should be made, which should be visible as white fluffy substance in the water.

After adding acetic acid, and making zinc acetate, solution will be immediately perfectly transparent (unlike aluminium acetate).

 

Zinc oxide is widely used in paints.

https://en.wikipedia.org/wiki/Zinc_oxide

Edited June 28, 2017 by Sensei

[DrP]

I thought Aluminium first off... maybe from a drinks can, but the boiling point of aluminium is 2470 C. I don't think the furnace gets that hot. I will try the test you mentioned though. Thanks.

[TheRadiochemist]

Zinc forms quite a few oxides and hydroxides under these described conditions, and nearly all of them are toxic.

[John Cuthber]

Zinc forms quite a few oxides and hydroxides under these described conditions, and nearly all of them are toxic.

Zinc is also an essential trace element.

If the post had said "taste the mixture" you might have had a better point.

 

The furnace isn't that different from a zinc smelting furnace so it's possible that the zinc is being made, but in smelting, you need to be careful to quench the gases or the zinc is oxidised back to oxides.

Certainly, zinc burns if heated in air so I can't see how it would survive the process.