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topic 12373p3

Zinc oxide production by French process

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A discussion started in 2002 but continuing through 2020

March 10, 2009

Dear all,

One of my client asked me to provide ZnO granules, can any one help me to develop the same?

Regarding my research I found that we can make granules by two ways one is pre dispersed and other is by palletizing, please advise with your best knowledge.
Thanks and regards

Suvneet Kalsi
- Delhi, India

March 11, 2009

Dear Suvneetji,
Zinc oxide granules are less preferred in Indian market as no one is paying extra for granulated zinc oxide. There is no value addition.
Zinc oxide granulation is done by compaction (palletisation). white seal zinc oxide passed through rollers with 250 Kgs/cm2 pressure and formed flakes then broken in desired size. Here some times additives are used for particular applications.
Zinc oxide granulation by pre dispersed method is manufactured for particular application. As in rubber manufacturing rubber(elastomer) and zinc oxide is mixed in particular ratio and while compounding this ratio is adjusted.
As compaction granulation machine cost from 15 lacks to 1 crore. In India 2 or 3 manufacturers are doing this process.


Umesh Charki
MetalliKon Consultancy Services - Thane, India

March 17, 2009

Dear Sir,

I am researching about the production of ZnO from Zn(OH)2 I wonder if you could tell me what is the optimum calcination temperature. I worked at 650 °C but the mass loss was huge, not only the corresponding to the molecular mass difference between ZnO and Zn(OH)2.

Thank you very much for all your attention.

Diego Herrero
Researcher - Bilbao, Spain

March 31, 2009

Dear Mr. Diego,
In India, We are producing Zinc oxide by decomposition of Zn(OH)2. Actual decomposition temp. is 500-600 °C. But it contains sulphur compounds, which required 950 °C to decompose.
If mass loss is more than material balance. then review your calcinator design. It is normally rotary kiln with direct heating. But flow pattern inside kiln matters, as material carry over happens. Proper sizing and design of the furnace is important for desired results of conversion and yield.
In this issue I found good article on internet,

Umesh Charki
MetalliKon Consultancy Services - Thane, India

April 8, 2009

Thanks for your all support.

As we are planning to make Zinc oxide granules, we don't know what kind of binder we shall use to have some hardness.

I want to try with st. acid, only worries is for that we have to melt S.Acid first during feeding into granulator, I have a query regarding the reaction between ZnO and S.Acid. Does it react enough to loose their basic properties as an activator in rubber compound.

Thanks and Regards

Suvneet Kalsi
- Delhi

April 9, 2009

Dear Suvneetji,
Stearic acid and zinc oxide reacts but at 5 kg/cm2 pressure and 140 °C. This reaction forms zinc stearate melt. Or zinc hydroxide and stearic acid directly reacts to produce zinc stearate in powder form. Zinc stearate used as lubricant in tire manufacturing.
Mixture of both compound is not reactive.
Binder materials used in zinc oxide are as per application. These materials used less than 1% in zinc oxide. You can try natural gum in dilute form. and sprinkle it in rotary drum filled 30% with zinc oxide. this is one type of granulation I have seen; but after it is to be dried.


Umesh Charki
MetalliKon Consultancy Services - Thane, India

February 6, 2010

Now our company is dealing with zinc oxide that is being produced through French process.the company is going for expansion and is looking to introduce new methodology in this field.
The company is looking for introducing new method of production .it is planning to introduce active zinc oxide, but we are not able to get the technical know to produce active zinc oxide
Please help me this issue...
Thanking you

Hemanth Ravindran
- Bangalore, Karnataka, India

June 11, 2010

Respected Sir,

I am chemical engineer working in zinc oxide plant, as plant manager. We are using French process for zinc oxide production. Our capacity is 10,000 TPA I would like to know more about French Process, with respect to productivity, controlling, cost and environmental cares.

Please do the helpful, thanking you


product designer - IRAN

June 16, 2010

Dear Mr. Sattari,
This is the same message I posted at start of this discussion. If it the same question from your side, then it is very difficult to answer in one answer. You can go through the total discussion to understand different aspects of zinc oxide manufacturing.
In case of any specific question, please ask.
Thanking you,

Umesh Charki
MetalliKon Consultancy Services - Thane, India

Ed. note: Exactly, Mr. Charki!

Mr. Sattari: Please study the thread and keep the discussion moving forward. People sometimes ask why we still recommend technical books in this Internet age, and your posting demonstrates that the Internet sometimes just runs you in circles :-)

June 16, 2010

Thanks for one and all for the information you are providing on this forum.

I am planning for 1000T capacity Zinc Oxide plant, can I get some information like

1. Who can do the erection and supply the machinery for manufacturing ZnO
2. Rough estimation for 1000T capacity
3. Whether to go for 500T or 1000T capacity



sai chennupati
- Hyderabad India

June 22, 2010

Dear Sirs,

I would like to know, what is the common process used to convert galvanizing zinc ash/dust into zinc oxide with higher purity. Is the only way to do it hydrometallurgical, or are there pyrometallurgical ways to achieve the above.

Thanks in advance for the answers.



Hemanth Vijayan
- Lagos, Lagos, Nigeria

December 20, 2010

Our consumption of furnace oil is 225 liters in manufacture of Zinc Oxide. Please help us on how to reduce the consumption?

sahil gupta
top management - haryana india

January 8, 2011

To reduce furnace oil consumption, Furnace should be developed to save heat energy. This is done by proper designing of furnace, suitable and good quality insulation of furnace, Proper temp & pressure of furnace oil, Heat saving equipment such as heat regenerators in furnace.

Umesh Charki
MetalliKon Consultancy Services - Thane, India

February 9, 2011

Can we manufacture zinc oxide without crucible?

Irfan Darogha
- Gujranwala, Punjab, Pakistan

February 5, 2011

any one can tell me whether zinc oxide powder can be packed by automation.
If so, please inform the details.

partha sarathy
engineer - Chennai, T.N . India

February 16, 2011

Dear Sir,
1)For My query about 'crucible-less furnace' I got more information From Dr. Peter Robinson (Canada)As follows,
ZnO will be produced in the furnace due to the Boudouard reaction-
Zn + CO2 = ZnO + CO

This reaction is at equilibrium at around 950 C, at higher temperature, formation of Zn metal is favored.
Presence of ZnO will make process very difficult to control because there will be a cold interface with the liquid zinc.

Only direct heat method that I know of that is working is the Larvik furnace. This uses a resistance element above the zinc liquid. Cost of electricity is prohibitive in most cases.

I believe crucibles are the most cost effective route to ZnO. Crucibles need to be large, semi continuous liquid charged and configured for regenerative heating.
I believe crucibles are the most cost effective route to ZnO. Crucibles need to be large, semi continuous liquid charged and configured for regenerative heating.

2)We can pack zinc oxide in automated system, only we have to workout on economy. Presently we pack 25Kg oxide precisely in HDPE bags. Machine with this kind of precision is costly. We use 2 labors for oxide unloading, packing, weighing and stacking 5 MT oxide per 12 hr. shift.
This is possible by proper and simplified mechanization of system.

Hope your queries are solved,

Umesh Charki
MetalliKon Consultancy Services - Thane, India

February 22, 2011


We currently have installed capacity of 300 MTs per month.

Can we run 2 furnaces with same capacity together ? If yes is there any other change to be made in the plant & machinery.

Ritesh Kumar
manufacturer - Karnataka

March 11, 2011

Thanks you all as the discussion is going to be interesting, I would like to know how to controlled insoluble particle in a acid solution. we have customers having specification of CLEAR SOLUTION , it is very difficult to obtain clear solution.

Ravi Rajput
Manager Q.A. - Palghar

March 14, 2011

Dear Mr. Ravi,
Insoluble are dust and ash in zinc oxide. This impurity is mixed with zinc oxide at suction point on furnace. You can avoid insolubles easily by following steps,
1) Maintaining clean furnace area, ash free.
2) If using furnace oil, try to block and avoid black suit generations and leakage at furnace top.
3) Avoid skimming, crucible cleaning when process blower is on and suction on furnace.
These are easy steps in operations to avoid insolubles. Also you can use settlers efficiently to separate heavy impurities.

Umesh Charki
MetalliKon Consultancy Services - Thane, India

June 15, 2011

I am interested to learn more about controlling factors in running a furnace to manipulate the ZnO powder produced, especially in the parameters of lower particle sizes and with low surface areas at the same time. I know there are a few different crystal structure of ZnO particles which would explain why I am currently only able to manipulate my surface areas but always in the combination of larger particles giving lower surface area but smaller particles having higher surface area. What I need to produce is smaller particles size with low surface area.
what kind of furnace and suction blower parameters do I need to control?

Mervyn Goh
- Rawang, Selangor, Malaysia

August 24, 2011

Dear all.

I'm a student and I'm trying to produce zinc oxide from an electric arc furnace dust. I actually have zinc hydroxide and I want to furnace that, but I'm not sure of what temperature is the best to do it, can anybody help me, please?

Thank you!

Daniel Palacios
- Monterrey, Nuevo Leon, Mexico

August 29, 2011

Dear Mr. Daniel Palacios,
There are two different things you are asking for?
1) electrical arc furnace dust contains Fe, Zn, Ca, Si etc. Out of which Zinc (in oxide form) is vaporized after carbothermal reduction and further oxidation to zinc oxide. this is done in Wealz process in rotary kiln. This process increases concentration of Zinc content and separate it from Fe impurity. Wealz zinc oxide is further processed to get electro zinc or zinc chemicals.
2) To convert zinc hydroxide to zinc oxide, we use rotary kiln and temp. required for hydroxide to convert to oxide is @ 480 to 550 °C. In certain cases if hydroxide contains sulphur then temp rises to 950 degree to remove sulphur compounds.

For more queries you are most welcome,

Umesh Charki
MetalliKon Consultancy Services - Thane, India

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