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letter 12373
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+++ DEAR MRCHARKI UMESH MALLAPPA, I´m a Industrial
Engineer working in a Plant in Pilar BUENOS AIRES
(ARGENTINA) where we produce all types of Zinc Oxide by the
French and American Process. Yours sincerely Ignacio Olcese
+++ Dear Sir, I am glad to see your letter, recently in month of August 2003, I have installed a new furnace which is giving us very good performance. It consumes 100 lots fuel oil of calorific value 9200 Cal/ litre for one metric ton ZnO production and gives us 4MT production per day. We are operating 9 furnaces of capacity 1.7 MT/ day for
oil consumption of 200 litres / MT ZnO. Now with the new
furnace we are able to operate with lower fuel consumption
and higher production rate. Please tell me about liquid metal feeding to French process furnace as we have tried but we can not work with galvanizing plant dross as this dross gives us very viscous liquid metal which is very difficult to transfer to crucibles. Please revert back, UMESH CHARKI |
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Dear Sir,
We are interested in putting up zinc oxide plant using zinc dross as raw material. Any assistance shall be highly appreciated.
Thanks,
Sharad Patni
- Indore, Madhya Pradesh
Hey Ignacio, I have recently joined my family business. The major
problem we are facing right now is our high cost of production. I
would like to know if you can help me out in this for our Zinc oxide
Plant.
Here is my two specific questions
1) Right now we have a furnace with production capacity of 1.7 MT/Day
- Oil consumption is 210 Liters( We use furnace oil for that)
--------------- Can any one help me in that? as in how much we can
improve our efficiency in terms of oil consumption(oil is the major
cost)
2)Our recovery from special high grade zinc metal is 120% ie we get
1200 kg of zinc oxide from 1000 kg of metal----- can any one suggest
what is the benchmark for that.
Awaiting your reply for these two question
Thanks,
Paritosh
- Udaipur
Dear Readers,
I have just visited this interesting site. I have produced several
research papers on ZnO French process and you may download for free
as follows http://uk.geocities.com/shahromx/nano.html .
Have a wonderful day
Dear Paritosh,
1. For diesel oil combustion, you need to ensure perfect combustion
from your burners - make air/fuel adjustment to get a blue flame. If
this is not possible, make effort to clean the burners. If you still
cannot get blue flame, check the quality of the diesel oil, it may
not be pure.
2. Theoretically speaking, the maximum recovery is 124%. But it is
impossible to achieve. Your 120% is good enough.
Cheers,
Shahrom Mahmud
- Penang, Malaysia
Dear UMESH CHARKI,
Your problem of viscous Liquid metal in melt transfer of Zinc Dross
is due to formation of ternary Alloy of Zn-Al-Fe.
The metal has to be pretreat and then remelt to be ready to feed for
ZnO production.
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Qaiser Majid |
Zinc oxide -French process-Is there any change in type of filter
bags used? Dear Sir, We are manufacturer of Zinc Oxide in India
through French process.
Till date we used filter bags made of cotton cloth.we have heard that
there is some new technology, which replaces this filter bags with
much advanced filter bags made up of some plastic like
material.
We would like to know something about it.
Secondly we are consuming around 225 litre of furnace oil per M.T of
Zinc oxide,we want to reduce it,kindly assist us.
ANKUR AGARWAL
- INDIA
Sir,
I am interested in zinc oxide by French process. I have started this
thread 4 years back , thanks to you all for the discussion.
Now I am interested in crucible less furnace for French process. in
this process natural gas will be used as fuel. in this furnace oxygen
level will be monitored by zirconia tip censor to prevent zinc
combustion inside furnace. flue gas as well as zinc vapors will come
out of furnace; which will be cooled using forced convection as
natural convection gives bulky cooling systems and cooling efficiency
also very low.
Benefit of the process is high fuel efficiency which is major cost of
production. low downtime as crucible charging and cleaning is
avoided. Zinc blocks of 2 to 3 MT can be charged in the furnace.in
small place we can install furnace of 10 MT per day capacity.Furnace
oil furnace is not giving efficiency above 40-45% but in gas fired
furnace with direct firing will give efficiency up to 60-65 %.
If anyone is working in such technology please revert back in
discussion.
Umesh Charki
- Mumbai
Dear Sir,
We are leading manufacturing of French process Zinc Oxide our problem
is that, we are not getting desired yield from metal as well as dross
grade Zinc ,we have use SHG grade zinc ie.99.99% pure as per theory 1
MT Zinc gives 1.2447 MT of Zinc Oxide but we are getting only 1.2 MT
Zinc Oxide and in case of dross we treat 94-95% Zinc dross in the
furnaces we get only 1.1 MT Zinc Oxide please guide us how to get
more yield in focus of which parameter.here dross grade zinc is
having alloy of Zinc ,aluminum,and Iron some % of Lead please guide
us melting temperature and conditions if there.
Regards,
DILIP .T.PATIL
- Daman
Dear Mr.Shahrom Mahmud,
This is the first time that I had a look at your Research papers on
Zinc Oxide ,the work is indeed very good and for a person like me who
has worked on Zinc Oxide for more than 12 years its a delight .
Would appreciate you keep us posted on your further work wherever you
can , I mean where you have no secrecy/confidentiality issues .
C.S.BIRLA
- Baroda, Gujarat, India
For My above 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.
If Any one have such helpful information please participate in the
discussion.
Thanking you all,
Umesh Charki
- Mumbai, India
Dear All,
I am an IIT-Kanpur graduate and one of the directors at a company in
India.
We are manufacturing zinc oxide by French as well as other processes,
20 tons/ day.
I would like to know if anyone has some idea how we can get acicular
zinc oxide in the French or in the rotary process. This type of
material is required by some speciality rubber compounding
application.
Sumit Agarwal
zinc oxide manufacturing - Kanpur, UP, India
Dear Sumitji,
I am working as COO at a company in Mumbai. As per my knowledge we
cannot form acicular zinc oxide directly by French process. I know
about two process one is hydrothermal discharging-gas method and
second is flame spray pyrolysis.
You can find more about these processes.
Umesh Charki
- Mumbai
Sir,
Kindly suggest me Free zinc particles free Zinc Oxide by French
process ,means how to controlled free zinc particles it is possible
by proper filter cloth or something please guide me i await your
valuable suggestion in this regard,
Thanks,
D.T.PATIL
- Daman
Greetings CS Birla and fellow ZnO enthusiasts,
A million thanks for your interest in my PhD work on ZnO. In my work,
I analyse the various primary particles that made up the ZnO
agglomerates that are commonly found in gas phase synthesis and flame
spray pyrolysis. It is true that you cannot obtain acicular
structures from French process or flame spray pyrolysis. But I
believe it can be done. From my research collaboration with one ZnO
factory, we are able to produce acicular nano particles of ZnO at a
rate of 1kg per hour. But the process is highly unstable and the
quality of the nanorods are poor. I am now designing a novel furnace
that can perform continuously (not batch type) and produce uniform
nanorods of ZnO. Process parameters are the most important control
variable especially the partial pressure of oxygen and the level of
zinc gas supersaturation. For knowledge of this novel process some
royalties must be affirmed.
Best wishes,
Shahrom Mahmud
- University of Science, Malaysia
Ed. note: Share only what you consider non-proprietary, Mr. Mahmud. We cannot expect the supporting adverisers who make this site possible to support postings that steer potential customers towards other people's services. Thanks.
Mr. Patil,
In French process zinc combustion is gas phase reaction, Which is
controlled by concentration control (Partial pressure of gases) of
both the gases. Also for burning of zinc totally zinc particles
should be properly dispersed. One method is try to burn zinc totally
by increasing oxygen partial pressure and after that you can separate
zinc particles by using proper gravity settler. as zinc particles are
heavier and larger than zinc oxide particles.
Umesh Charki
- Mumbai, India
Dear Mr Charki
We are manufacturer of Zinc Oxide and would like to know couple of
things
1) Right now we have a furnace with production capacity of 1.7 MT/Day
- Oil consumption is 210 Liters( We use furnace oil for that) : My
questions is is this the right consumption or it can be reduced
?
2) Our recovery from special high grade zinc metal is 120% ie we get
1200 kg of zinc oxide from 1000 kg of metal : Can you suggest what is
the benchmark for that.
Thanks,
Paritosh
Director
Paritosh Mehta
- Udaipur
Dear Readers
We are planning to set up a new zinc oxide production factory. We
have designed a furnace with two crucible with the help of
technician. many producers use only single crucible furnace. We are
going to use dross as a raw material. Kindly let me know advantages
and disadvantages of double crucible furnace.
Sunil Aghara
- Morbi, Gujarat
Dear Mr .Umesh,
You are the expert in this ,Is it possible to separate Free Zinc
particles in our process Or other effective classification system is
to be require please suggest.
Regards,
DILIP PATIL
- DAMAN
Dear readers,
Thanks you all as the discussion is going to be interesting.
Following are some points in which I am giving answers.
1)Mr. Paritosh, Furnace production capacity is defined by zinc
vaporization rate.Which is depend upon rate of heat input to the
furnace.Heat required by zinc to vaporize ( 30 degree C to 907 degree
C) is 540000 Kcal Per MT. On this basis your furnace efficiency is @
28-30%. You can improve furnace efficiency for lower furnace oil
consumption.About recovery It is good kind of recovery, But can
improved to 121.5%. by controlling byproduct generation
2)Mr. Sunil, In zinc oxide industry most of the furnaces are twin
crucible furnaces. In this type. Heat distribution is equal and
proper for both the crucibles. The Temp. required for zinc
vaporization is 950 dg C. So temp. difference ( Delta T) should be
about 150 to 200 dg C. For maintaining high temp. inside furnace,
cooling of the flame should not be done below 1000 dg C.
3)Mr. Patil, Excess reactant is Oxygen, you can increase oxygen level
by increasing conveying air. Which gives good dispersion for zinc
particles and quenching to zinc oxide for finer particles.After that
use better settler. You will find results after trial and
error.
In case of anyone have different setup please share the
experience.
Thanking you,
Umesh
Umesh Charki
- Mumbai, India
Dear All,
Discussion on French process is very fruitful and interesting for
getting such valuable knowledge from all of you,
my question is that what is the best combination of input material in
oil fired furnace normally top drosses are available available in
domestic market it containing Alumina /Zinc alloys due to this only
top dross charging is very difficult to use in the oil fired furnace
what is the best combination of raw material to be use for getting
desired yield and reduce furnace oil consumption please participate.
PATIL DILIP T.
chemist - India
Hi Mr Patil,
Dross contains several percentages of iron and aluminium that have
higher melting and boiling points. Iron and aluminium vaporise at
2862 and 2520 deg C, respectively; while zinc at 907 deg C. The final
Zn-Fe and Zn-Al eutectics may have boiling points exceeding 1000 deg
C, which may justify higher furnace oil consumption. Moreover the
oxidised product may contain iron oxide and aluminium oxide that may
produce yellowish/brownish tones to zinc oxide. You may use coke as a
fluxing agent to lower the boiling point, and in doing so, you will
be merging the French process with American process. Due to
appreciable levels of impurities in this French-American zinc oxide,
potential applications would be lower end ones.
Regarding fuel supply for crucibles, I suggest that you use electric
heating in the form of SiC globars that are heavily used in many
furnaces that I used to work with, whereby the process efficiency can
double. There is no heat loss via exhaust duct since there is no
exhaust. Most of the heat produced by the globars is transferred to
the zinc ingots. You may need 8 SiC globars for each furnace at a
price USD 300 per globar (I think) excluding the control panel, and
the globars can last for 10-12 months.
I hope you will find my suggestion fruitful.
Best wishes.
Shahrom Mahmud
- Penang, Malaysia
Dear all,
I am a Spanish Chemist, and I am interested in putting up a zinc
oxide plant. It is a new project for my company. We would use zinc
dross, including zinc powder. Any advise about the implementation
would be highly appreciated.
Best regards,
MARIA ABELEDO
ZINC PLANT - Vigo, Pontevedra, SPAIN
++++++
Dear Mr.Shahrom Mahmud,
We highly appreciate you for attempting,
We are using Oil fired furnace that place couple of silicon carbide
crucibles its heat up through burner- Furnace Oil as a fuel.
Please suggest us for use of fluxing agent (as coke) at what
temperature along with its conditions.
Regards,
D.T.PATIL
PATIL DILIP T
- DAMAN
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dear sir,
we are manufacturers of Zinc Oxide by using French method,
use Zinc Dross of 94-95% pure.Now a days as Zinc Dross /metal price
go big higher we are looking for cheap replacement as in our another
unit of Ceramic raw material we are consumer of Zinc Oxide.
is it possible to produce Zinc oxide from Zinc Hydroxide ?
we have some source of Zinc hydroxide which is byproduct for them so
it is cheap also.
please explain.
Kantilal Patel
- Morbi, Gujarat, India
Dear Mr.Kantilal Patel,
Ceramic manufacturer are using french process zinc oxide because this
zinc oxide is amorphous white in colour.Oxidation process from
hydroxide rout Zinc Oxide colour becomes yellowish and after
calcination pulverisation is also require. Yellow zinc oxide is
suitable for Tyre and rubber compounding but it is also depending
upon process control parameters ,Surface Area, Purity and other
impurity level ,I think French process is better option for Ceramic
application.
D.T.Patil.Daman
Patil D.T.
- Daman
Re calcination of yellow zinc oxide -
before I started work on ZnO (and that's some time ago)the company
where I worked used a small addition of sulfur to reduce the
grittiness caused by calcination. The process had already ceased when
I joined the company so I have no actual experience of this
possibility.
Peter J. Robinson
- Fergus, Ontario, Canada
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++++++ Greetings fellow ZnO enthusiasts – With respect to
calcination of yellow ZnO, a possible route to reduce grit
levels may be to add around 0.5% of sulfur powder to the ZnO
before calcination. This practice was used decades ago with
French process ZnO to make product suitable for paint
coatings. I have no first hand experience of this but
understand it was a commercial process that operated for
several years. (Apologies - my earlier submission slipped
away before I had chance to add to it) Peter J Robinson
++++++ DEAR SIR, ZAKERI,HADI
++++++ Re zinc silicate orebody & extraction process Peter J.
Robinson 1 2
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