Where the
world gathers for metal finishing
Q&As since 1989


-----

How can we get a homogeneous zinc pot?

2006

Daer All:

How can we get a homogeneous zinc pot for CG lines which contains Zn (density 7.14) Al (density 2.7) Pb (11.3), is the stripe motion on roll with 60 cm diameter and 150 cm wide enough for that? and what is the available agitation and How?

Best Regards,

Salah Salman
- Cairo, Egypt

---

2006

Sir:

Solubility of lead in zinc is:

At 820 F 1.20%

At 830 F 1.30%

At 840 F 1.40%

At 850 F 1.50%

Lead just thrown into the zinc melts and passes through the dross layer. Once under the dross layer it takes months for the lead to dissolve in the zinc. There are several lead/zinc alloying devices that can cause the lead to fully dissolve (depending on temperature). Once the lead is dissolved in the zinc it will come out of the zinc and be returned to under the dross layer if the temperature of the zinc is reduced.

Aluminum is usually added to the zinc via 5% or 10% (aluminum in zinc) "brightener bar." These brightener bars must be added below the zinc surface or the aluminum will be at a higher concentration on the surface and may cause "floating dross." There is an aluminum/zinc alloying device which allows pure aluminum to be rapidly alloyed into zinc. Lengthwise uniform mixing and dissolving of these two alloying metals can be a problem in some lines.

Regards,

Dr. Thomas H. Cook
Galvanizing Consultant - Hot Springs, South Dakota, USA