- Joined
- Apr 17, 2014
- Messages
- 63
I would like to hear opinions from other member on zinc burning off issue. As all probably know, it melts at 420 degrees and boils at 907 c. We use 30KW induction machine when smelting karat gold bars and we cook the molten metal around 1200 c for fifteen minutes before taking a pin sample and pouring off to ingot.At this temperature zinc must be evaporating from the molten metal and carried up the stack.However as it goes up it must be cooling down too and probably becomes zinc deposit in the stack or bag house. We still detect around 4-6 percent zinc in the pin sample. I have never seen complete eliminating the zinc from karat gold bar.
1. how come zinc does not completely evaporate based on its boiling temperature and our operating temperature.?
2. the refinery we recently started to work with indicates about 0.5% more melt loss on out well melted bars. it was never an issue with other refineries we worked with. they say it is due to excess zinc in the bar.?
3. we could increase the meting temperature of our machine to 1400c but that would really push the limits of out induction melter which we prefer not to do so.
any opinions?
1. how come zinc does not completely evaporate based on its boiling temperature and our operating temperature.?
2. the refinery we recently started to work with indicates about 0.5% more melt loss on out well melted bars. it was never an issue with other refineries we worked with. they say it is due to excess zinc in the bar.?
3. we could increase the meting temperature of our machine to 1400c but that would really push the limits of out induction melter which we prefer not to do so.
any opinions?