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How to reduce bottom dross in hot dip galvanizing line?

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<- Ed. note: Please describe your situation rather than posting in the abstract What? Huh?

Q. How to reduce drosser in dip hot galvanized zinc?

Rawdah Muhammed
- Cairo
August 31, 2022

Closely related historical posts, oldest first ...

Q. 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 10, 2008

"Hot Dip Galvanizing of Steel Structures"
by Kuklik & Kudlacek
from Abe Books

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A. Hey,
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

? Sir:
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

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

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Q. 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 4, 2009

A. keep Al in the bath more than 0.16%

Ed vd Outenaar
- beverwijk, Netherlands

Q. 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?

Best Regards

Nagy Aslan
- Cairo, Egypt
August 25, 2010

Q. 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
December 17, 2010

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