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topic 49295

How to reduce bottom dross in hot dip galvanizing line?

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July 10, 2008

We are facing a bottom dross generation problem in the continuous hot dip galvanizing pot. The furnace is all vertical type annealing furnace. We are maintaining a pot temperature in the range of 455 Deg. C.

Pl. suggest how to reduce the bottom dross generation ?
What parameters should kept to reduce/eliminate the dross generation.

Rajesh Rajput
employee - Pune, India

July 12, 2008

See dross generation is basically because of the iron particles.What you can do best is check on daily basis that your bath is free from any iron structure that has slipped into the zinc while Galvanizing.You should also check the iron content of the water before flux and after pickling and if possible get it changed as fast as you can and last but not the least your flux solution.See any loose iron particle that goes inside the kettle will create dross.You should always Dross at regular intervals because it will create more dross.

- Kolkata, India

July 15, 2008

What type of continuous hot dip galvanizing do you do?
I suggest you respond to the following:
1)Describe your kettle furnace design, I suspect that it is not proper. High dross production is often coming from the kettle itself.
2)Describe you drossing methods. A "clam" does not work well.
3)At what temperature do you dross?
4)Are you "wet" or "dry" kettle?
5)What is your dross production relative to production? (e.g. dross/production times 100%)
6)How much dross (in cm) is at the kettle bottom 24 hours after you dross?

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

"Faults in Hot-Dip Galvanizing"
by Dietrich Horstmann
from Abe Books
info on Amazon

"Handbook of Hot Dip Galvanization"
by Maass & Peissker
from Abe Books
info on Amazon

March 4, 2009

dear sir,

we have a top heated ceramic kettle (2500 mm x 2500 mm x 700 m) for fasteners galvanizing. we face excessive dross i.e.3% of total production.
i) how to minimise the problem?
ii) Is it up to the mark?
iii) what is the gross zinc consumption in fasteners galvanizing?


somen ganguly
galvanizing employee - Mumbai, Maharashtra, India

March 18, 2010

keep Al in the bath more than 0.16%

Ed vd Outenaar
- beverwijk, Netherlands

August 25, 2010

Please we are a galvanization company; our products are malleable cast Iron Fittings.
How can I minimize the consumption of zinc and lessen the Dross and Ash?

Bet Regards

Nagy Aslan
- Cairo, Egypt

December 17, 2010 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread

my self Mukesh Goyal I am presently working in a steel company.
my question is:
bottom dross -: our line speed 146 mpm zinc pot capacity 85 ton. monthly bottom dross 18% is very high please give suggestion to minimize the dross percentage

Mukesh Goyal
employee - Mumbai, Maharasta, India

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