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Zinc oxide production by French process
1 2
(2007)
Dear friends,
We are using zinc metal for manufacturing of zinc oxide with lead<
20 ppm as required by the Indian Pharmacopoeia. However due to steep rise in price of zinc metal we are unable to be viable. As such material is available at prices slightly higher than that made from dross, means that dross can be used for making pharma grade lead fee material.
Could you help me with the process parameters for producing this kind of material from dross ? Any kind of guidelines would be greatly appreciated.
Sometimes we do get this material from dross but that is a very rare chance.
Regards -
zinc oxide manufacturing - Kanpur, UP, India
(2007)
We are a dental material/cosmetics manufacturer and we consume zinc oxide pharmaceutical allot.Due to price increase of this material the cost of our production has gone up and we are not competitive any more.
We have zinc metal available in Iran and also fuel as well as low wage labour cost in Iran leads us to contemplate to produce this material in our plant.
We will appreciate allot receiving proposals/guidance/suggestion enabling us to decide.
- TEHRAN, IRAN
(2007)
Production of 95% ZnO
Dear all friends
I am already producing ZnO (99.97%) from French Process. I need to develop a process for ZnO (95%)-Low purity.
Can you suggest me?
chemicals - Lahore, Pakistan
(2007)
I work for an international company that manufactures ZnO as well as many other products.
We routinely recover 122% ZnO from HG and 110% from galvanizing top dross. These conversions are achieved whether using a 2 MT per day furnace or a 30 MT per day furnace.
At one time our organization thought 120% was adequate, but we have learned to achieve better results.
These results were not achieved overnight, but through years of improvements.
- Pittsburgh, Pennsylvania
(2007)
Dear Sir,
We are interested in putting up zinc oxide plant using zinc hydroxide
(a byproduct of sodium formaldehyde sulfoxylate) as raw material. Any assistance shall be highly appreciated.
Thanks,
- Baroda, Gujarat, India
(2007)
Hi, Friends:
I meet a problem in manufacturing the high purity (>95%) of zinc oxide and looking for help:
The problem is zinc oxide always containing 2~3% of lead oxide which we hope to reduce to <1%. Our manufacture is dry process. Right now our only solution is control the ore quality, but it is very difficulty and costing.
Any idea, Please help !
We also looking for expert who have interesting to open the business in manufacture Aluminium Oxide in China.
Chemist - Rockville, Maryland
(2007)
hello,
we have been manufacturing zinc oxide (lead free grade, electroplating grade,silver seal,white seal, 99.5%- 99.9%) for the last 15 years and with the hard work of all our employees and well wishers have been able to live up to the expectations of our valued customers in delivering a quality product.
now we want to start manufacturing active zinc oxide through wet process. we are totally new in this field and any kind of help in this regard ( process of manufacturing, raw materials and substitutions, applications, discharge of effluents and wastes, recycling of wastes etc)would be duly appreciated. people who are already into this should please forward their experiences so that we can also learn from their valuable ideas and experiences.
please share your ideas.
Thanking You,
CEO - RAJPURA , PUNJAB, INDIA
(2007)
REALLY NICE TO FIND SUCH A ONLINE GROUP.ANYWAY PLEASE ALL READER ARE REQUESTED TO PROVIDE US WITH YOUR SUGGESTIONS.
WE ARE MINING ZINC WHERE WE OBTAIN THEM IN THE FORM OF LUMPS WHERE WE WASH,PULVERIZE,DRY AND PACK THEM.IT IS WHITE COLOUR POWDER ZINC OXIDE WITH ZnO - 80% AND ZINC Zn ALONG 65+ ALONG WITH THIS WE ALSO FIND LEAD Pb - 3 PPM,MAGNESIUM Mg-7%,CALCIUM Ca - 4%.WE UNDERSTAND AND AWARE ITS REALLY A RARE FORM OF DEPOSITS.
ANYWAY I WISH TO KNOW FOR WHAT ALL PURPOSE THIS MATERIALS CAN BE USED?
CAN ZINC METAL BE EXTRACTED BY USING THIS AS RAW MATERIALS. CAN THIS BE CONSUMED OR USED BY CHEMICAL INDUSTRIES TO PRODUCE HIGH GRADE ZINC OXIDE.
IS IT POSSIBLE FOR US TO PRODUCE HIGH GRADE THAT IS 99.5%+ ZnO - IF SO UNDER WHAT METHOD WE HAVE TO MAKE A PLANT.ALSO PLEASE PROVIDE ME YOUR VALUABLE SUGGESTIONS.
THANKING YOU,
REGARDS,
DIRECTOR - INDIA
(2007)
Dear all,
we are leading manufacturer of Zinc Oxide in India by French process. we are using raw material zinc dross containing impurities like Pb, Fe, & Al We are facing problem for raw material containing higher
% of iron (Fe) i.e. up to 4-5% when we charge such material in a crucible, saturation of Iron takes place at bottom of crucible after
2-3 duty crucibles volume get decrease. I want to know is there any specific flux available for removing iron content from crucible.if it is please let me know. your information is highly appreciated.
Q. A. Manager - Jammu, India
(2007)
Dear MARIA ABELEDO,
As you are new in this zinc oxide mfg. field you have to take care for lot of things like raw material quality,Suppose If you are using raw material containing higher impurities like Lead & iron it will affect your product as well as increase the f. o. consumption . Most of impurities will get settled at the bottom of crucible which increase the thickness of crucible & due to increasing thickness consumption of F.O. consumption will increase.Secondly process parameter is most important you should have control on your process parameter like evaporation period, Blower RPM, collection of Zinc Oxide at diff tank etc. Thanks
Q. A. Manager - Jammu, India
(2007)
Please can anyone tell me what is exactly the French process of making zinc oxide of 99.99% purity with zinc dross.Where can I get the plant and machinery from.And what will be the cost for 10 MT/day plant.
Thanks
buyer - Ludhiana, Punjab, India
(2007)
Dear Ravi Rajput,
This is the problem of all zinc oxide manufacturer but nobody can search this type of flux.you have two way to avoid the problem, first you take furnace cleaning after 3 days, second you blend the material like top and bottom dross and lower impurity with higher impurity material.
then you feel 80% realisation.
R.R.Yadav
zinc oxide - India
(2007)
Dear Mr Shaurya Mittal
Zinc oxide was discovered by Cramer in 1750 while the French process was popularized by LeClaire in 1844 during when he mass-produced ZnO for white oil paint. Pure zinc metal was used then. The use of cheaper zinc dross has been popular lately due to the zinc high price LME of USD 3440 per MT. However the French process is not designed for recycled raw materials since there is no convenient way to leak out the accumulated dross impurities during operation, ie there is no leaking valve on the crucible. If there exist a crucible with a leaking valve, it would have lower working life due to intricate design. Dr Robinson and I suggest that the best practical way is to purify the dross to a purity of above 99.9% zinc before charging into the French process furnace, meaning a purification plant is required.
Best wishes,
- Penang, Malaysia
(2007)
Dear Mr. Shahrom Mahmud,
For producing zinc oxide 99.9% pure from dross, can we go by using self-refluxing column for fractionation of incoming vapours. As new jersey process is used for zinc fractionation with external refluxing of liquid zinc and the purified zinc vapours are condensed to get pure zinc above 99.9% purity. The same process can be used for purification of zinc vapours and subsequent oxidation will give us pure zinc oxide. This oxidation will happen far above floor level so contamination of atmospheric dust (foreign particles)will reduce. Instead of purifying zinc dross to zinc metal, this process will help for lower cost manufacturing as energy is major part of manufacturing cost.
Please revert with your valuable inputs upon this issue,
Thanking you,
Umesh
Umesh Charki
MetalliKon Consultancy Services - Thane, India
(2007)
Dear Mr Umesh Charki,
I agree with you that the best way to purify zinc dross is by vapourising it. If you can build a furnace that can vaporize dross into vapours, you can oxidize it to make ZnO and you can obtain a good purity if you oxidize the vapour far above the ground level, as you said earlier; however, the particle size and morphology will be different than that obtained from French process. The French process is based on high velocity zinc vapour at speed of Mach 0.1 followed by rapid air-quenching. ZnO size and morphology are highly sensitive to temperature and Zn/O ratios. You may have to spend money and time to experiment on several furnace designs in order to simulate the French process. Perhaps you need professional help to expedite results.
Good luck.
- Penang, Malaysia
(2007)
Dear Mr. Shahrom Mahmud,
Sir, I have tried this process in 500 Kg/ day furnace for experiment trials. We got 5.5 square meter per gm with 99.86% zinc oxide. 65% of total production by the setup was of this grade. lead was 16 ppm. Dross used for this trial was 94.5% zinc with lead 0.4%, which is normal grade of dross available.
Sir, I was working as COO with one of the leading zinc oxide manufacturer in India. I have installed 24 zinc oxide furnaces in last 5 years and 6 for zinc metal recovery. I have tried zinc metal distillation, zinc dross to zinc metal for experiment which gives 93% recovery of 99.3% pure metal from dross. All these experiments are carried on 500 Kg/ day capacity furnace. Scale up of these trials on
4 MT/Day furnace is easily possible as equipment sizing is already completed.
I am also interested in nano zinc oxide by hydrothermal discharging-gas method and second is flame spray pyrolysis.
As nano zinc oxide is in increasing demand for various applications.
Anyone who are working on the same please share.
Thanking you,
Umesh
Umesh Charki
MetalliKon Consultancy Services - Thane, India
(2007)
Hello Umesh,
You have done great engineering innovation by building your own distillation furnaces for zinc recovery from dross. To my knowledge, flame pyrolysis has not been commercialized yet. There is one professor from ETH Zurich, Prof Pratsinis Sotiris, who has been doing flame synthesis on ZnO for many years. You may contact him for advice from this link http://www.ptl.ethz.ch/people/director/pratsinis . He has synthesized nano particles of ZnO at a lab scale.
Good job!
- Penang, Malaysia
(2007)
Dear sir,
we are manufacturer of Zinc Oxide by French process for last 20 years.
We are facing problem with Zinc Dross having aluminium content more then 2%.
When ever we have to use this kind of dross it doesn't melt in the furnace,and starts evaporating instantly,and we are not able to clean the Dross of impurities.the result is that the ZnO formed is blackish in colour.
Can anybody suggest any chemical,which can be mixed with dross ,while charging it in to crucibles,so that the Dross gets cleaned,and the resulting Zinc Oxide is white in colour free of impurities.
Hope to receive an answer,and early date.
thanks,
CEO - RAJASTHAN, INDIA
(2007)
Mr. Ankur Agrawal,
I have experience in processing dross up to 4.5% aluminum. In the same process we cant skim liquid metal. So we can go with aluminum in the liquid metal. Try to skim liquid metal with ammonium chloride and Keep @8 inches space below crucible cover. Take care of splashing liquid metal. If you will not skim non-metallic impurities with ammonium chloride it blocks the hole for vapors in cover, and the crucible cover can throw away by zinc vapors. Because of this liquid metal got flashed and can cause hazards in the plant.
For high aluminum containing dross better to go for high capacity crucibles furnace.
Umesh Charki
MetalliKon Consultancy Services - Thane, India
(2007)
Dear Readers:
(1)I came across the thread very recently and amazed that people have taken lots of interest. I shall be pleased to know how many persons have been benefited with this discussion.
(2)I am with Zinc Oxide industry for last more than 30 years serving all area of working of the industry. During course of my marketing I faced lots of problems faced by the consumers and I had to interact with our Technical people for the proper quality products.I have been able to pursue and solve the problems faced by the manufacturers of Zinc Oxide who are investing huge amount of money.
(3)I have understood that main impurities like Iron, Lead, Alu. etc are contained in Zinc Dross are most in form of compounds (oxide, sulfate, carbonate etc) depending on the process adopted by the Galvanisers (there are several different processes) that is why the material purchased by the ZnO Mfgrs are not found uniform and they face end product problems. It is understood that at about 800 deg. C. Temp. most of the Iron, Lead etc compounds are decomposed to metallic particles and if it is allowed to stand for few hours after stirring at the same temp. metallic particles will settle down leaving zinc to be free from these impurities. Use of Fluxes will add some other impurities such as chloride etc which are not desirable in certain grades of ZnO.
(4)For economy of the fuel, I shall seek advise from my friends, while only surface area of Zinc in the crucible is reacted to form zinc vapour, what is the necessity to keep the whole 500 to 700 Kgs of Zinc in one crucible boiling for hours consuming valuable fuel?
I think instead of more depth more wide with less depth crucible should be used and continuous molten zinc should be fed. Such device could be done. I feel since standard sizes of crucibles are available
(which are used for melting of iron and other metals and alloy and are more in demand they are being produced) other suitable for zinc oxide is not desired/demanded by the ZnO mfgrs.
(5)I can say that ratio of Zinc HG should be Min. 100:123 and for Zinc Dross (from Steel Plant continuous process) it could be 100:115. This result is regularly achieved.
(6)For Furnace Oil consumption, Burner with auto-control with proper insulation with latest refractories materials, etc will improve on fuel consumption.
(7)I had tried wet process for making Zinc Oxide from Zinc Ash, but due to pollution problems could not proceed but achieved the quality.
designer, consultant - Kolkata, West Bengal, India
(2007)
We are producing zinc oxide by French process. I have come through some material that is used to clean residue of iron from bottom, which is a major headache.
unfortunately I do not know the name of the material but it is like crystals of sugar and bluish in colour. it gives us good results in cleaning bottom iron. can any one throw some light on it?
2. when we use dross with aluminium it is difficult for us to clean ash and other impurities from top and we get inferior quality zinc oxide in off white colour. can any one solve the problem?
director - Morbi, India
(2007)
Dear Ranashayer,
Lot of thanks for your suggestion. Already we are doing same exercise. Thanks,
Q. A. Manager - Jammu, India
(2007)
Dear Mr. Shah, Kolkata
we are at present producing zinc oxide white seal from Dross.
we mainly supply to ceramic industry. when we use dross with Al we find zinc oxide which is not as white compare to bottom dross of structure galvanising. but in terms of % both are more than 99.5%. can you solve our problem?
we are also interested in producing oxide from ash.
can you help me in this way?
industrialist - Morbi, Gujarat, India
(2007)
HI,
EVERYBODY,
CAN ANYONE TELL ME WHAT IS ZINC OXIDE FEED GRADE, AND MOST IMPORTANTLY HOW CAN IT BE PRODUCED AT JUST HALF THE PRICE OF WHITE SEAL ZnO.
WHAT IS THE METHOD ADOPTED TO KEEP THE HEAVY METALS LOW.
HOPE TO RECEIVE EXPERT ADVICE AT AN EARLY DATE.
THANKS
- INDIA
(2007)
Pls. clarify how to calculate the capacity of the zinc oxide plant keeping in view the size of the crucible,Two No. of crucibles/furnace and output of zinc oxide /hour viz a viz weight gain and type of raw materials employed by zinc oxide industry.
RAHUL
STUDENT - JAMMU, India
(2007)
Dear Rahul Sharma,
I am answering your queries step by step,
1) Capacity of ZnO furnace- two crucibles per furnace is most suitable combination of ZnO furnace. And Not only crucible size but burner capacity also have very important role in capacity calculation of ZnO furnace. Vapourising rate of zinc metal is important factor in productivity of ZnO furnace. Holding is defined by crucible size but it does not affect zn vapourisation rate.
2) Output of zinc oxide furnace is not easy to determine by per hour basis. as vapourisation rate does not remain fix over time because this is not continuous process but batch process. Crucible cleaning also interrupt production. ZnO furnace capacity is defined by vapourisation rate per day after deducting downtime like charging time, heating time etc.
3) Weight gain is weight of oxygen added to zinc while formation of zinc oxide. It is theoretically 24% weight gain. But in actual there is 22% of weight gain, When we minimize by products generation, and loses in the processing. Weight gain for dross and other scrap is defined by, {wt of zinc oxide =%metallic zinc content * 1.2}
4)Raw materials:- French process is concern only to metallic zinc content in raw material and raw material is deciding factor for quality of zinc oxide formed. So in ZnO industry we use raw material with more metallic zinc content above 88% metallic zinc.
Galvanisers dross is major source of RM. zinc roofings, scrap, turnings, scores, wires,blowings,etc.
Umesh Charki
MetalliKon Consultancy Services - Thane, India
(2007)
Respected sir,
Mr. Charki,
I am very impressed to your all answers in finishing.com. Sir I know you are a expert in about zinc oxide plant.
I am working in zinc oxide plant As a officer production from last three years,Now I understand all the process parameters in the plant but I want to know from you about French process from beginning to End. I want to know process in between zinc Dross to Zinc Oxide.
sir, I hope you will give me reply.
employee - India
(2007)
Mr. Ramashare,
Zinc Dross to Zinc oxide is very simple gas phase reaction between zinc vapours and oxygen. Metallic zinc from zinc dross vapourises and due to high temp ( 950 degree C) it starts spontaneous oxidizing with atmospheric oxygen. This is as simple to burning of carbon in air, as it gives CO2. Zinc combustion gives zinc oxide.
This reaction happens in fraction of seconds, and after zinc oxide formation we can not purify it. So it is very important to set parameters proactively to form desirably pure form. Controlling factors for this process are flow rates of zinc vapours and air, which gives different partial pressures of reactants; as well while and after formation temp. control gives desired physical form means particle size distribution for ZnO. And dispersion of zinc vapours in air while oxidizing is important for complete combustion of zinc, as zinc oxide forms impermeable and hard coating over unreacted zinc particle surface.which gives free metallic zinc in zinc oxide.
I hope you have cleared most of your queries,
I request to you all fellow ZnO enthusiasts to be environmentally careful while manufacturing zinc oxide. It is very much important as French process is energy intensive process and Major problem in this industry is air pollution.
Thanking you,
Umesh Charki
MetalliKon Consultancy Services - Thane, India
(2007)
Dear all,
I am an engineer from a non-ferrous metal powder company. In French process how zinc vapour is collected from furnace and react with air
(O2).what are the precautions to made avoid explosion?after the reaction completed how you cool and collect the ZnO powder?
Thanks
Engineer - Madurai,Tamil Nadu, India
(2007)
Dear muthupandi,
Good inquiry but its very difficult to explain so that you must be visit any ZnO plant for your query.
- India
(2007)
Dear Ramashare yadav,
thanks for your kind reply.
Engineer - Madurai
(2007)
Dear Muthupandi,
I think you have gone through the total forum.I am explaining you the process,
1)In French process, crucibles are used to boil zinc metal, Crucibles keep covered by refractory tile with 2-3 inches hole for vapour outlet. When zinc metal starts boiling, vapours come out with velocity of 0.1 mach ( 30 m/s) and enters in hood above the furnace. continues air flow maintained in hood with help of blower, this air used for oxidation; carrying away zinc oxide to collection system and sudden cooling of zinc oxide.
2)As explosive limit of zinc dust in air is 0.6 kg zinc dust in one cubic meter air at 600 degree Celsius. but in this process zinc vapours starts burning spontaneously as they comes out of crucibles and contacted with air. This process is exothermic so temp. of flame suddenly increases to 1500 degree Celsius. When it comes in contact with air flow at 30 degree Celsius formed zinc oxide quenched to below 450 degree Celsius. This quenching define zinc oxide particle properties. how fine it should be?
3)This formed zinc oxide at 400-450 Degree Celsius carried through long duct, where it gets cooled further by natural convection. It passed through settlers to separate heavy particles. after cooling below 100 degree Celsius air filtered to separate zinc oxide.
Umesh Charki
MetalliKon Consultancy Services - Thane, India
(2007)
Dear all,
I have learn a lot from your discussions. I am an Engineer for refractory-Crucible and have one customer to manufacture zinc oxide. This customer use 2 kinds of different crucible furnaces for French process, one is for high pure zinc ingot and one is for zinc dross, both try to use the fuel efficient. For the high purity zinc ingot, the crucible can be used for over 3 months. For zinc dross, the average lifetime for crucible is about 40 days; There are much dross left in this crucible, the dross will be powdered after a few days when they shut down the furnace. Analysis shows that there are much Fe/Al/Pb/Sb in the dross, I think these comes from galvaniser and these impurities result in the short life of crucible. does anyone find this problem before? how is the crucible lifetime in your plant?
I have searched the internet, all the zinc oxide plant I found use a similar furnace as shown in Dr. Shahrom Mahmud's paper. What I have seen in my customer is totally different, I believe my customer's experience can use the fuel more efficient.
- Suzhou, China
^-- this reader rates this thread:
(2007)
I making zinc oxide with French process since two years .I want to know how I can make active zinc oxide
Anurag Jain- Ganga Nagar, Rajesthan, India
January 3, 2008
Dear all,
We are one of the Zinc Oxide production in Thailand using French process. As we know, the Fuel oil price is very high now. Could anybody suggest us for replacing FO to Natural gas?
Also, we have problem with contamination from FO combustion (carbon from FO flame) in our Zinc Oxide product. We think Natural gas will help us for this problem.
Last question, we set the target for fuel oil per Mt ZnO at 200. Would it be correct for 200 Lit/mt ZnO?
Best Regards,
Production manager - Bkk, Thailand
February 23, 2008
Zinc Oxide Yield using PWG Grade Zinc
Dear Readers,
I am running 4 furnaces and using both SHG and PWG grade zinc.
I am mixing PWG grade zinc in a 10-15% but have a notices a drop in pure oxide
yield from 1.20% down to 1.17% . I was expecting a drop in yield of
1% only.
Can anybody help & explain on how to control this Yield ?
thank you,
- Bangkok -Thailand
March 4, 2008
Dear Mr. Vinay Dhawan,
PWG zinc( prime western) contains up to 1.5% lead. Which does not converted in oxide. only zinc is converted in Oxide with additional oxygen weight. Reduction of yield could be because of loss of zinc in bottom of crucible with lead, increase of by-product like ZnO pipe on vapour opening. There are many reasons for reduction of yield.
Also mixing of PWG zinc gives increased lead content in zinc oxide. As lead comes with zinc vapours at 0.005 times percentage of lead in liquid metal in crucible.
Regards,
Umesh
Umesh Charki
MetalliKon Consultancy Services - Thane, India
May 24, 2008
Dear All,
I am in this field for last 7 years. I have installed 24 ZnO furnaces till date. Now While thinking over rising oil prices. I think electrical furnace will be better option. Oil 150 ltrs/ MT is std. consumption which we are getting. but for 1 MT ZnO production electrical furnace consumes 450 KWH power. which is most cheap in some part of world. This furnace is producing 3 MT/ day ZnO. This furnace cost is also same compare to oil fired furnace(with combustion control system).
I think this will be most profitable furnace in these days for rising oil prices.
Any input regarding this are most welcome.
Umesh Charki
MetalliKon Consultancy Services - Thane, India
May 28, 2008
Hi,
I am into Hot Dip Galvanising Business. I am planning to venture into Zinc Oxide and Zinc Sulphate production business. I have gone through the posting in the forum. They are invaluable.
As first information, I would appreciate if you could provide me information on
1) what amount of Zinc Dross would produce what amount of Zinc Oxide.
2) cost of machinery.
Keeping in mind, the plant would target a production of 150 MT/month of ZnO.
I would appreciate if anyone is aware of the same regarding production of Zinc Sulfate.
Thanks in Advance.
- Hyderabad, India
June 3, 2008
Dear Umesh,
Thank you for the explanation on reasons for drop in Yield with use of HG.
as I understand if I begin with 95% pure Zinc Ingot, then effectively,
I should be able to get only 1: 1.15% Oxide Yield depending on the Pb & Fe impurities ?
also, I wanted to further enquire on process conditions which could help
reduce the Grit & Ash and improve the Yield ? should I reduce the charge/time/furnace ?
regards, Vinay
manufacturer - BKK -Thailand
June 11, 2008
Dear Mr. Vinay Dhawan,
Sir,
using dross in zinc oxide process is commercial decision. You can utilize most of metallic zinc from dross by avoiding skimming. for grit and heavy particles removal use gravity settlers effectively. You can get 99.7% zinc oxide from dross. in this process dross of 90% minimum can be used efficiently.
Process controls, variable settling systems will give good quality zinc oxide from dross.
Umesh Charki
MetalliKon Consultancy Services - Thane, India ^-- this reader rates this thread:
June 16, 2008
Dear Umesh,
I agree to your views regarding Use of Electric furnace for ZnO production.However following issues are vital.First,Can All types of Zinc Dross be efficiently used in E-Furnace ? Or only Molten Zinc is to be transferred in the Furnace.
Secondly the Life of the Furnace and skilled manpower to run these e-furnaces,as mostly in India 99% furnaces are still Oil fired ones.
Lastly the availability of Continuous power of min 100 kW to run one furnace ?
Awaiting your views.
Thanks
- Alwar, Rajasthan, India
June 17, 2008
Dear Ankurji,
I am also working on electrical furnace. The power consumption is
800-900 KWH per Mt zinc oxide. This is single crucible furnace. Using heating elements. This resistance heating type furnace. You can operate as oil fired furnace. no special skilled workers are required. care is taken to deal with liquid zinc spillage, dust, crucible breakage detection etc. issues.
In some part of India electricity is no problem. Like in South India, you can install wind mill and get power from Electricity board. There are so many ways to go for non-conventional energy sources.
This is time to go for such things never thought in zinc oxide field.
Inputs are welcome,
Umesh Charki
MetalliKon Consultancy Services - Thane, India ^-- this reader rates this thread:
September 14, 2008
we are manufacturing zinc oxide white seal from galvanising bottom dross. we are getting yield as 1 : 1.12 generally. we use furnace oil as a fuel and it generally takes 220 liters per ton of zinc dross. initially when crucible is new fuel consumption is lower but after using nearly 20 MT dross it takes more time as well as consumes more fuel. we use LAP 1 type burner and 3 HP 2800 RPM air blower.
can I do any modification in burner or air blower to reduce fuel consumption?
Director - Morbi, Gujarat, India
September 29, 2008
Dear Mr. Umesh Charki,
Thanks for clarifications on HG & Dross Yield.
now, we are looking to expand/add more 4 furnaces
& want to completely redesign our plant .
best regards, Vinay
Manufacturer - Thailand
October 22, 2008
Dear Friends,
Nice to meet you all..
We are Zinc Oxide manufacturer in Indonesia..
We want to know new information, innovation, research and maybe new application of Zinc Oxide..
I hope will get something important from this discuss for me to develop my factory in Indonesia.
Thank you for your kind attention..
Best regards
manufacturer of zinc oxide - Indonesia
November 3, 2008
Dear Mr Umesh Charki our company is a leading manufacturer in ceramic field. Currently we have a plan to produce zinc oxide from zinc with the total capacity of at least 1000 tons/months. If you are interested in cooperating with us, please contact me as soon as possible. I hope with your expertise we can save a great deal of time for not testing all the configurations.
Khanh Nguyen- Vietnam
----
Ed. note: People have offered great info on this page, especially Umesh Charki. Thanks! This site made possible by supporting advertisers for camaraderie and public exchange of technical tips. Our advertisers are pleased to see that camaraderie and the exchange of tips, but they obviously don't want their money spent putting potential customers into private contact with their competitors, nor steering people towards someone else's proprietary technology. Share what non-proprietary public tips you can, but if you wish to get commercial benefit from this site, you need to be a supporting advertiser. Thanks.
November 12, 2008
Greetings Readers - For your information - The second International ZnO conference (organised by the International Zinc Association, Brussels) will be held at Rancho las Palmas, Palm Springs, California, USA on February 24th and 25th, 2009. We hope to build on the success of last year's meeting and we look forward to meeting readers again next year.
Best wishes,
- Fergus, Ontario, Canada
November 13, 2008
Dear Mr. Nguyen,
Installing plant with capacity 1000 MT/Month is good job. Before installing we should check for the quality required. So finalisation of plant setup and raw material can be specified.
Umesh Charki
MetalliKon Consultancy Services - Thane, India
December 12, 2008
Dear readers,
I'm just new into ZnO and we are putting up a plant in Haryana for Zinc oxide by French process and only source with virgin Zinc ingots. I have some Q regarding my project
1. How to get smaller particle size at least to introduce in pharma sector ? And does the diameter of cooling duct effect the particle size?
2. What are the other factors involved in particle size like , size of hood and duct, suction speed of blower , furnace temperature , and handling or packing ?
3. By which test I can get the surface area in M sqr / gram for zinc oxide?
I would appreciate for any answer.
Thanks .
- Delhi, India
December 15, 2008
Dear Suvneetji,
Zinc oxide particle size is depend upon cooling pattern of ZnO after formation. This is gas phase reaction with product in solid form.
French process limitation is to produce ZnO with surface area from 2 m2/ gm to 10 m2/gm with wide particle size distribution.
Hood design is also important as it gives such flow pattern to disperse and mix zinc vapour and atmospheric oxygen, just like combustion of fuel.
As this is gas phase reaction, partial pressures of reactants are also important.
You can measure surface area with BET method of nitrogen condensation.
Umesh Charki
MetalliKon Consultancy Services - Thane, India
December 17, 2008
Dear Mr.Umesh Charki ji,
Thanks for your reply. Sir, as u said we get surface area between
2-10 with wide distribution, but our requirement is for between 7-10, So Can you tell that what should be the proper separation to get maximum output of 7-10 and in what percentage we can expect out of total production.
On the other hand I want to ask is there any defined cooling system for cooling duct or it is naturally done. Presently we are getting
5-7 surface area.
One more thing what is partial pressure of reactants actually?
Hope to see you again.
Regards
- New Delhi, India
December 28, 2008
Dear Suvneetji,
French process can produce 2-10 Sq mt./ gm. But it requires different set of parameters. Generally this setup produces 4-7 sq.mt./gm. For higher surface area we need to design reaction in proper manner.
We are using natural cooling for this process as it is cheapest method available. And surface area is depend upon cooling rate to 450 degree Celsius; below this temp. surface area does not changes effectively.
Partial pressure is percentage of every reactant in reaction mixture for gas phase reaction.
Umesh Charki
MetalliKon Consultancy Services - Thane, India
December 30, 2008
Dear Umesh ji,
Thanks for your mail again,
we are putting up a new furnace of one crucible of capacity 800 kgs to get the better results.
I have a query regarding the distance between the top of the crucible and lower end of the hood. Does it help me to get the better results regarding surface area?
I want to increase the distance because to get the more air intake. presently we have 10-12 inches of gap.
If I put insulation on hood to keep it hot does it help me to get better results ?
Hope you have answers for that.
Thanks and regards
- New Delhi, India
January 1, 2009
Dear Suvneetji,
We install two crucible furnace to increase holding capacity of the furnace. Due to high holding capacity zinc dilution is possible for reducing lead content in product. In this case we can increase vapourisation time to increase productivity. Because more zinc we vapourise in 24 hrs will be add more production capacity with good fuel efficiency.
Distance between crucible top and lower end of hood defines velocity of the air at entry point. here high velocity results in better mixing of air and zinc vapours. the distance you are having is sufficient. For more surface area we need to cool down zinc oxide formed. More cold air will result in more quenching of zinc oxide formed. so you concentrate on the air volume to be suck in the system.
Putting insulation will damage the hood earlier, as it is made of MS and need to operate below 300-400 degree Celsius. And cooling of the zinc oxide is done by the air entering in the hood from bottom.
I hope most of the queries cleared,
Umesh Charki
MetalliKon Consultancy Services - Thane, India
February 20, 2009
Dear Sunil,
About energy consumption for French process of Zinc Oxide production, it ranges in a wide scope, from 120 L to over 250 L heavy oil per ton Zinc Oxide. Basically, the energy consumption is quite dependent on the furnace design.
During zinc oxide production, since the crucible wall is porous, the zinc vapor is trying to penetrating the crucible wall. This penetration accelerates especially when the furnace operates at very high temperature. And the penetrated zinc will oxide and deposit on the outside of the crucible wall. Once this deposit happens, the crucible will start to lower its thermal conductivity and fuel consumption will go up. So if you monitor the fuel consumption, you will find the fuel consumption is lower when the new crucible is used and after a few weeks the energy consumption will go up. In this case, an Isostatic pressed crucible with higher density/lower porosity will be better for French process.
For higher surface(higher BET) Zinc oxide:
zinc oxide produced from French process usually is lower surface area below 10 m2/g. However I believe it is possible to produce a higher surface area zinc oxide by French process. As said by Mr. Umesh Charki, French process for zinc oxide is a gas reaction, so it is quite possible to produce a higher Surface area ZnO by adjusting the parameters in the following reaction:
Zn(l) =>Zn(g)
Zn(g)+O2(g) =>ZnO(g)
ZnO(g) =>ZnO(s)
Such parameters as temperatures, pressure of Zn(g),O2 would be very important.
Normally these parameters are not controlled by the zinc oxide producers.
Hope this helps you.
- SuZhou, China
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
- 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 to 3 manufacturers are doing this process.
Regards,
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 ºC 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.
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,
http://ntur.lib.ntu.edu.tw/bitstream/246246/92069/1/26.pdf
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
- Delhi
April 9, 2009
Dear Suvneetji,
Stearic acid and zinc oxide reacts but at 5 kg/cm2 pressure and 140 Celsius. 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.
Regards,
Umesh
Umesh Charki
MetalliKon Consultancy Services - Thane, India
February 6, 2010
sir,
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
- 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
Sattari
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
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
Thanks,
Sai
- 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.
Regards,
Hemanth
- Lagos, Lagos, Nigeria
December 20, 2010
Our consumption of furnace oil is 225 litres in manufacture of Zinc Oxide. Please help us on how to reduce the consumption?
sahil guptatop 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
Sir,
any one can tell me whether zinc oxide powder can be packed by automation.
If so, please inform the details.
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
Sir
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 RajputManager 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?
- 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!
- 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 degree celsius. 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
September 16, 2011
Dear Sir,
I am dealing with wet process zinc oxide by ammonium carbonate (us patent 4071357) . We have to make project on a chemical plant.
So I have selected ZINC OXIDE POWDER making plant which is useful in making zinc oxide active.
I have to make total process for making zinc oxide powder(wet process).
I have some of the question regarding this which are as follows
1) What is the process of making zinc oxide powder(wet process)?
2) What type of machinery is required for making it?
3) From which Material it requires?
4)The product purity is 97% to 98%? Why Opaque white or yellow color is?
5) Where can we use it? (state all the useful area)
6) If you have any picture of plant, please send it to me?
Please provide me all guidance about wet process zinc oxide plant, process, equipment required, and uses.
I will be very thankful to you if you are answering my questions.
Thanks,
Regards,
Arash akbary
chemical - iran tehran
September 16, 2011
Dear Mr. Arash Akbary,
The process you are using is Ammoniacal ammonium carbonate leaching method. This method is used as recovery is maximum in this method. And we can recycle Ammonia again and again. In India there are plants using same method.
1) What is the process of making zinc oxide powder (wet process)?
There are different wet processes for making of zinc oxide. You can leach zinc from zinc bearing waste (mostly non-metallic) using different acids. Purify the solution and precipitate in the form of zinc hydroxide or carbonate. Filter and dry the precipitate and further calcination produces zinc oxide. Wet process is mainly used for non-metallic waste of zinc.
2) What type of machinery is required for making it?
Plant and machinery includes reactors, filters, centrifuge, dryers, calcinators. In Ammonium carbonate we need steam distillation column (ammonia strippers).
3) From which Material it requires?
Zinc ash from galvanizer, waelz oxide, other zinc bearing waste. It has wide scope for zinc recycling.
4) The product purity is 97% to 98%? Why Opaque white or yellow color is?
Pure zinc oxide is opaque white powder. Yellowish color is due to impurity in oxide. The purity we check by checking Zn+ and then calculate for zinc oxide. But if there is zinc carbonate purity indications become wrong. You can first calcinate sample at 900 degree Celsius and then check for purity. Even then sample is lower in purity then there are some impurities and the purification of zinc solution is not done properly.
5) Where can we use it? (State all the useful area)
Zinc oxide has wide applications. But calcination of zinc carbonate gives high surface area zinc oxide having application in catalysts and desulphurization in petroleum industry.
You can refer the article from Iran
www.sid.ir/en/VEWSSID/J_pdf/92220080416.pdf
For more questions you are welcome.....
Umesh Charki
Umesh Charki
MetalliKon Consultancy Services - Thane, India
October 24, 2011
Dear Respectable & honourable personalities.
1. We need to know about how we can reduce our gas expenditure?
2. Is there any other way without crucible to reduce expenditure.
Your response would be appreciated.
qamar
gujranwala, Pakistan
November 1, 2011
Dear Umesh,
1.we need full information about f/o adjustment all specific surface area because we are adjusting new cruciable on this is our new exprement on f/o. your co-opration will be appreciated.
2.which one suitable burner for f/o.
3.what will expense on 1mt for f/o.
your cooperation will be honourable.
- Gujranwala
November 30, 2011
With respect
Mzahmtvn Myshm of Iran. I wanted a series about the production of zinc oxide. In the case of slag in the production process and also produces zinc oxide Mytvnym do?
- Maybod, Yazd, Iran
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