Zinc Oxide

[green]

Dear people.

Got inspired to process catalytic converters.
and build a mobile burner.
the crucible i got still had about 10 kg, "what i was told",
zinc oxide from cyanide leaching sitting in it.
Knowing it is quite toxic i was hoping to melt/burn it off to recover pm values.
But after an hour of glowing/burning yellow it has not reduced much in volume.
On the forum i could not find any info on smelting/prosessing zinc oxide.
I did put some of the " zinc oxide" in sulfuric acid and that is bubbling away nicely.

Hoping to get some advice on possibility's to recover possible value's

 

[goldsilverpro]

The melting point of ZnO is almost 3300F.

 

[green]

Yes, you are right.
I was not sure when starting the burn if it was zinc, zinc oxide or even zinc sulfide.
So wile burning i just gave it a try and mixed up melting temp of zinc oxide and sulfide.
Zinc sulfide 2165 F is well with in the range of my temperature possibility's
But as can bee seen on the inside of the burner some yellow material was expelled from the crucible.
when cooled down this turned white.
Is my material likely, mainly zinc oxide?
If so are there any fluxes that will lower the melting temp of zinc oxide?
Will using sulferic acid as pre treatment get me closer to being able to smelt?
With the use of zinc shavings in the old days of cyanide leaching was the zinc always oxidated before smelting or did this happen over time.
my crucible might have been sitting for 20 years.
also i am wondering why this crucible was never finished?
Because the crucible was a little cracked or was there an other reason?

All questions and suggestions are welcome