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topic 13337

How to reduce dross generation in galvanizing?

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A discussion started in 2003 but continuing through 2019


Q. Regarding to the question of dross forming, how to minimize the dross forming? Does the temperature of the zinc bath influence the dross formation? Or should we put some additive element like aluminium to minimize?

Catherine Sim Li Ling
- Kuching, Sarawak, Malaysia


A. Temperature has influence on dross forming (the higher the more iron loss), but with normal galvanizing temperatures (around 450 °C) there is hardly any difference. At a temperature 490-520 °C your kettle is in danger (high iron loss. Aluminium makes zinc more fluid, influences the structure of the alloy layer, reduces zinc-ash forming and gives a better color and gloss of galvanized material. Biggest influence on dross forming is carry over of dissolved iron from pickling via rinse and flux. Finally I have to tell you the whole process is too complicated to explain everything via Maybe you need a galvanizing course.

Dolf van den Berg
Dolf van den Berg
- Leusden, The Netherlands

August 3, 2009

Q. How to minimize dross formation?

Sami Allen
- Saudi Arabia

August 21, 2009

Hi, Cousin Sami. Mr. Van den Berg has invested a bit of his time answering that question. In the interest of not running the thread in silly circles, and to show thankfulness for his effort, please try your best to express your question in terms of what has already been said -- and include the details of your own situation rather than continuing in the abstract. Thanks!


Ted Mooney, Teds signature
Ted Mooney, P.E. - Pine Beach, New Jersey
Striving to live Aloha

2006 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread

Q. Which of the parameters responsible for dross generation and how to reduce top and bottom dross? actually I'm doing thesis on reduction of dross generation. So I want to know the parameter on which the dross generation depends and also how to reduce the dross generation ? please give the response as soon as possible.

Bharat Kumar Lautre


Please write the Title of your project, & faculty you belong to. In research you have to carry out a lot of literature survey & potentiality of investigation has to be ascertained. Hearing from you I may provide little clue, and the rest is your dedication.


Dr. Pradeep kumar Maitra
- BHILAI, Chhattisgarh, INDIA

"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

-- this entry appended to this thread by editor in lieu of spawning a duplicative thread

How can we reduce the dross generation in galvanizing line having armco iron pot, with aluminium, lead, antimony, tin, iron, & zinc.

Rajib Chatterjee
- Jamshedpur, Jharkhand, India

June 2, 2009

Hi, Rajib. letters 47534, and 49295 look like good starting points. I see 106 threads about dross & galvanizing on this site alone. Although some remain unanswered, patient application of the search engine should find plenty of food for thought!

Good luck!


Ted Mooney, Teds signature
Ted Mooney, P.E. - Pine Beach, New Jersey
Striving to live Aloha

March 31, 2016 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread

Q. I want to know what is the best temperature range for galvanizing to reduce dross formation.


March 2016

A. Hi Ashwani. We appended your inquiry to a thread where Dolf has offered his opinion that, if you maintain customary temperatures of about 450 °C, small variations have no effect, but high temperatures like 490-520 °C can be a problem. Please do your best to pose your ongoing questions in terms of the actual details of your own situation so we can learn from you :-)

Thanks & Regards,

Ted Mooney, Teds signature
Ted Mooney, P.E. - Pine Beach, New Jersey
Striving to live Aloha

February 9, 2019

Q. Greetings, I want to know that what should be the acceptable aluminium %age in top dross and my second question is what is the healthy chemistry of dross in galvanizing?

steel business - jamshedpur, jharkhand, india

February 2019

thumbsdown Posters! You can retain one of the consultants advertising in the banner at the top of this page and they will probably be happy to start accumulating whatever data you wish to pay for. But for the 3rd time on this one short page: if you want this free mutual assistance public forum to be helpful for you, your postings have to be helpful for others as well :-)

Please give us your data, tell us your situation, explain your problems, don't simply post abstract requests for one-directional technology transfer because it chases the readers away :-)


pic of Ted Mooney
Ted Mooney, P.E. RET - Pine Beach, New Jersey
Striving to live Aloha

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