AN ANTI-STICKING COATING FOR SLAG POTS

A) TECHNICAL FIELD

[0001] The present invention generally relates to anti-sticking coatings and particularly to anti-sticking coating for slag pots / thimbles / liquid or semisolid slag carrying equipment. The present invention more particularly relates to a composition of an anti-sticking coating and its application for slag pots / thimbles / slag carrying equipment to provide an eco-friendly and ready to use antisticking coatings for slag pots in Steel and Iron Industries.

B) BACK GROUND OF THE INVENTION

[0002] The slag pots / thimbles used in integrated steel plants are conventionally coated with a solution of powdered lime mixed in water as a way for easy deslagging of the slag pots / thimbles. But, the use of lime and water does not provide a satisfactory result with respect to the dumping of the pots / thimbles. Majority of the pots / thimbles are cleared by either hammering or by dumping the pot on the ground or on iron plates. Also, sometimes the pots / thimbles are cleared by hammering the big steel ball inside / outside the wall to make jerk to the stuck liquid / solid / semi solid with or without steel. Even after this the dumping is not 100 % clean and hence reduces the available volume of the slag pot / thimble for subsequent operation. This process of dumping and cleaning damages the pot / thimbles to considerable amount. The availability of pot gets reduced substantially and hence the plant production is affected.

[0003] Then graphite based coating powder was developed to replace the use of powdered lime. The graphite based coating powder is mixed in tank with water and sprayed. This practice was not effective due to lack of uniform mixing of powder and water resulting in ineffective coating and hence affecting clean dumping of pots. This practice was only effective at lower surface temperature of pot / thimble. Hence when pots are hot, there is need for regular cooling of the pots / thimble.

Even though the performance was better than lime coating results were not consistent on large scale of operation.

[0004] Another practice was followed to quench the slag with spray of water and then dump. This practice was requiring long time for cleaning and hence affects the availability of pots / thimble.

[0005] Thus, none of the prior art methods helps in easy removing of the slag. Thereby the life of the pots thimble is reduced and the availability of the pots / thimbles for successive operations affected. Also none of the prior arts provide an effective antisticking composition for the slag pots / thimbles for consistent results on large scale.

[0006] Hence there is a need to develop an effective antisticking composition for slag pots / thimbles to enable easy dumping and emptying of the pots / thimbles without causing any damage to the slag pots / thimbles and increasing the availability of the pots/thimble for successive operations.

[0007] The above mentioned shortcomings, disadvantages and problems are addressed herein, as detailed below.

C) OBJECTS OF THE INVENTION

[0008] An objective of the present invention is to provide an anti-sticking coating to enable easy dumping / deslagging of the slag pots / thimble without causing any damage to the slag pots.

[0009] Another objective of the present invention is to provide an anti-sticking coating that is economical, eco-friendly and ready-to-use in the form of a suspension with shelf life up to six months when stored in covered dry place.

[0010] Yet another objective of the present invention is to provide an effective anti-sticking coating composition that can be easily sprayed within short time up to 10 min to provide a uniform coating inside the slag pot / thimbles. This ensures faster turnaround of coated pots/thimbles.

[0011] Yet another objective of the present invention is to provide an anti-sticking coating composition that aids in dumping or deslagging of the liquid, solid, semisolid slag with or without steel skull without any use of external force such as hammering or striking the big steel ball inside / outside the slag pots / thimbles thereby increasing a life of the slag pots and the availability of the slag pots / thimbles.

[0012] Yet another objective of the present invention is to provide an anti-sticking coating composition that remains in rheopectic condition for atleast 6 months.

[0013] Yet another objective of the present invention is to provide an anti-sticking coating composition that is used in all temperature ranges of the surface pot / thimbles i.e., from plant operating atmospheric temperature up to 800 deg C ensuring operational flexibility with complete coverage and without any forced cooling.

[0014] Yet another objective of the present invention is to provide an anti-sticking coating composition that immediately sticks and forms a uniform layer inside the pot / thimbles surface.

[0015] Yet another objective of the present invention is to provide an anti-sticking coating composition that is used for any surface where anti slag sticking property in Steel and Iron Industries is required.

[0016] Yet another objective of the present invention is to provide an anti-sticking coating composition that is in a ready-to-use form and does not require any further addition of water or any other liquid.

[0017] Yet another objective of the present invention is to provide an anti-sticking coating composition to provide and maintain a film in the slag pot / thimbles, when the slag is poured inside the pot thereby maintaining the integrity and the effectiveness of the anti sticking film.

[0018] Yet another objective of the present invention is to provide an anti-sticking coating composition with a residual film thickness after dumping the slag thereby helps in optimizing the overall quantity per use in subsequent applications.

[0019] Yet another objective of the present invention is to provide an anti-sticking coating composition with a gradual and uniform cooling effect reduces the early bulging of the pots / thimbles

[0020] Yet another objective of the present invention is to provide an anti-sticking coating composition to increase the availability of the pots / thimbles for successive operations.

[0021] Yet another objective of the present invention is to provide the anti-sticking coating composition on the inner surface of transfer equipments for the liquid hot metal / liquid ductile iron / liquid metal processed for pouring / transfer launders used for spurn pipe making / other like equipments.

[0022] The above mentioned objects and other advantages will be understood by reading and studying the following specification.

D) SUMMARY OF THE INVENTION

[0023] The various embodiments of the present invention provide an anti-sticking composition and a method of synthesizing the anti-sticking composition for slag pots / thimbles that provides an easy deslagging of liquid / semisolid slag material.

[0024] According to an embodiment of the present invention, an anti-sticking composition coated over a slag pot comprises carbon / carbon based material, silicon dioxide, a plurality of binders, an anti-fungal agent, oil and water. As in dried composition, the carbon is present with an amount of 40-45% and silicon dioxide in range of 52-60%.

[0025] The plurality of binders includes a combination of organic binders with an amount of 2 - 5 %, plasticizers with an amount of 3-5%, a high temperature binder in a ratio of 2-3%. The combination of organic binders includes xanthum gum/guar gum/CMC and resin. The plasticizers include clay, bentonite, etc. The high temperature binder includes boric acid, phosphoric acid /SHMP /STTP, sodium silicate in the form of powder or liquid. The anti-fungal agent is selected from a group consisting of Sodium Pentachlorophenate / Biocide . The oil is selected from a group consisting of non-edible and edible vegetable oil and mineral oil. The water is used in sufficient quantity. The oil and water form up to 70% of the composition.

[0026] The composition is in the form of a suspension and is readily sprayed on the slag pots / thimbles is in a ready to use form for its application. The composition forms a coating on a surface of the slag pot / thimbles. The coating has a thickness of up to 3 mm. The composition has a pH in the range of 6.5-7.5. The composition has a viscosity of 10000-25000 cps. The specific gravity of the composition is within the range of 1.00-1.30.The coating is usable in a temperature range of plant atmospheric temperature to 800°C. The residual of the first coating is reusable. The reuse of the coating depends upon the plant operating conditions, type of the slag, method of dumping and time between pouring and dumping. The coating forms a film with a residual thickness after dumping. The coating has a residual percentage up to 20% even after a cycle of operation.

[0027] According to one embodiment herein, a method of synthesizing an anti-sticking composition for slag pots / thimbles for an easy deslagging of liquid / semisolid the slag. The method comprises mixing carbon, silicon dioxide, a plurality of binders, an anti-fungal agent, oil and water together to form a suspension.

[0028] As in a dried composition, the carbon is present with an amount of 40-45% and silicon dioxide in range of 52-60%. The plurality of binders is mixed in an amount of 2 - 5 % and further includes a combination of organic binders. The combination of organic binders includes xanthum gum /guar gum/CMC and resin. The plasticizers are added in an amount of 3-5% and include plasticizers such as clay, bentonite, etc. The high temperature binder is added in an amount of 2-3% and includes boric acid, phosphoric acid /SHMP/STPP, and sodium silicate in the form of powder or liquid. The anti-fungal agent is selected from a group consisting of Biocide. The oil is selected from a group consisting of non edible / edible vegetable oil and mineral oil. The water is added in sufficient quantity. The oil and water are added to form up to 70% of the composition. The composition has a viscosity of 10000-25000 cps. The specific gravity of the composition is within the range of 1.00-1.30. The coating is sprayed on the slag pot using a high pressure air of 2-7kg/cm2.

[0029] According to the embodiments of the present invention, the composition is in the form of a suspension. The fluid composition is poured in the applicator and sprayed. The coating composition has to be sprayed at appropriate pressure depending up on the distance between the surface of pot/ thimble and nozzle. Normally the spraying has to be done at pressure of 2 to 7 Kg/cm2. The composition is sprayed on the inner surface of the slag pots. Air acts as a carrier media during the spraying of the composition. The coating is sprayed uniformly so as to cover the entire inner surface of the equipment to facilitate easy deslagging / dumping operation.

[0030] These and other aspects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description. It should be understood, however, that the following descriptions, while indicating preferred embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.

F) DETAILED DESCRIPTION OF THE INVENTION

[0031] In the following detailed description, a reference is made to the accompanying drawings that form a part hereof, and in which the specific embodiments that may be practiced is shown by way of illustration. These embodiments are described in sufficient detail to enable those skilled in the art to practice the embodiments and it is to be understood that the logical, mechanical and other changes may be made without departing from the scope of the embodiments. The following detailed description is therefore not to be taken in a limiting sense.

[0032] According to one embodiment herein, the anti-sticking composition comprises a base material, a binder system and a carrier. The base material is made up of carbon and silica. The amount of carbon present in the composition is within a range of 40-45%. The carbon is any micronized carbonaceous material. The micronized Silicon dioxide is present in a ratio of 52-60%. The carrier is oil/water emulsion.

[0033] The binder system includes a combination of organic binders, plasticizers and a high temperature binder. The organic binders are xanthum gum/guar gum /CMC and resin. The amount of organic binders in the composition is 2% to 5%. The combination of organic binders helps in binding the composition at lower temperatures and also gives the required viscosity. The plasticizers include clay, bentonite, etc. The plasticizers are present in a ratio of 3-5%. The high temperature binder includes any boron based binder or phosphorous based binder or a sodium based binder. The high temperature binder further includes boric acid, phosphoric acid/SHMP/STPP and sodium silicate in a ratio of 2-3%.

[0034] The composition further includes oil, water and anti-fungal agents. The oil and water forms the carrier system for the composition. The oil is selected from a group consisting of edible and non edible vegetable oil and mineral oil. The oil which is used preferably is mineral oil. The water is used in sufficient quantity. The oil and water forms about 70% of the total composition. The anti-fungal agent is selected from a group consisting of sodium pentachlorophenate and Biocide

[0035] The composition is in the form of a suspension and is readily sprayed on the slag pots. The composition has a viscosity of 10000-25000 cps and a specific gravity of 1.00-1.30. The composition forms a uniform coating on a surface of the slag pot. The thickness of the coating upto 3 mm. The pH of the composition is in the range of 6.5-7.5. The coating is able to withstand a temperature range of pot / thimble surface from plant operating atmospheric temperature up to 800°C. The coating is reusable for single or two times after a first application based on plant parameters. The residual percentage after a cycle is around 20%.

[0036] According to an embodiment herein, a method of synthesizing an anti-sticking composition for slag pots is provided. The method involves mixing the carbon, silica, plurality of binders, anti-fungal agent, oil and water together to form a suspension. The carbon is micronized carbonaceous material and is mixed with an amount to obtain as dried Carbon of 40-45%. The silicon dioxide is mixed in a ratio to obtain as dried Si02 of 52-60%. The plurality of binders is mixed with an amount of 2% to 5% and further includes a combination of organic binders. The plasticizers are added in an amount of 3-5% and the high temperature binder is added in an amount of 2-3%. The combination of organic binders includes xanthum gum/guar gum/CMC and resin. The plasticizers include clay, bentonite, etc. The high temperature binder includes boric acid, phosphoric acid/SHMP/STPP , sodium silicate in the form of powder or liquid. The anti-fungal agent is selected from a group consisting of sodium pentachlorophenate/biocide. The oil is selected from a group consisting of edible /nonedible vegetable oil, and mineral oil. The water is added in sufficient quantity. The oil and water are added to form upto 70% of the composition.

[0037] According to the embodiments of the present invention, the composition is in the form of a suspension to facilitate a uniform spray coating on the slag pot. The fluid composition is poured in the applicator and sprayed. The coating material is sprayed under a air pressure of 2 to 7 Kg/cm2. A uniform coating film is formed to provide an easy deslagging operation.

[0038] According to the embodiments of the present invention, the rheopectic property of the coating allows it to be spread evenly over the surface of the slag pot / thimbles and the binder system helps to stick to the surface of the slag pot / thimbles. The viscosity of the coating restricts it from dripping and rebounding. The carbon along with silicon dioxide in the material acts as anti-sticking layer.

[0039] According to the embodiments of the present invention, the composition is in the form of a suspension which can be sprayed uniformly. The fluid material is poured in the applicator and sprayed with air under a pressure of 2 to 7 Kg/cm2. The coating composition is sprayed uniformly to facilitate an easy deslagging operation.

[0040] The composition is in ready to use form and always remains as uniform suspension. The composition is stored at room / plant operating climatic temperature. The composition can be stored for 4-6 months. The composition is viscous fluid and also flows easily with air pressure.

[0041] The composition of the present invention can be commercially used for all kinds of pots / thimbles carrying liquid slag, semisolid slag or limited quantity of steel coming along with slag. The composition is also used in the refractories in free board area of liquid hot metal transfer ladles for satisfying a requirement of the antisticking properties. The composition with similar base material can be developed for similar applications in other metal industries like ductile iron, aluminum, copper and zinc.

[0042] The anti-sticking coating composition of the present invention is commercially used for the antisticking coating for the transfer equipment of liquid hot metal / liquid ductile iron/ liquid metal processed for pouring / transfer launders used for spurn pipe making / other like equipments

G) ADVANTAGES OF THE INVENTION

[0043] The anti-sticking coating of the present invention is applied easily to form a uniform coating. The composition maintains the integrity / uniform sticking of the film while the liquid slag is poured. The deslagging is assured without the use of force like hammering or breaking with steel ball or use of slag breaking equipment. The composition forms a residual film after dumping thereby helping in controlling the quantity per use in subsequent applications. The composition has a cooling effect so that the residual quantity ensures the natural cooling of hot pots and hence there is a lesser thermal negative effect on the pot / thimble life. The composition is very effective in increasing the availability of pots / thimble. The composition helps to increase the amount of the slag poured for granulation, reduce spilling of liquid slag over the tracks and reduce the frequency of crane operations for dumping of pots / thimble. The composition is easy to be synthesized, very cost effective and environment friendly. The composition ensures an increased life of the pot / thimble and the regular availability of the pot. The composition ensures that there is less damage to rakes / carriers of pots / thimble due to clear dumping of the pots / thimbles and due to a less use of the hammering to pots / thimble.

[0044] The composition also ensures that the complete volume of the pot / thimble is available for subsequent liquid slag pouring thereby resulting in a very less spillage over of slag on the tracks / carrier / rakes resulting in an increase in productivity of steel as the stoppages for want of pots / thimbles are minimized and for time saved for cleaning of rail tracks / area below the steel making furnace / converters.

[0045] The composition is in a form of rheopectic plastic fluid that is in ready to use form. The binder system is so designed such that the composition remains in rheopectic condition even under harsh plant storage conditions in open yard for atleast 6 months. Also the composition is designed in such a way that it can be applied at all temperature ranges of pot / thimble surfaces ensuring a complete coverage. The composition immediately sets / solidifies and forms a uniform thin film inside the pot / thimble surface after a spray coating process.

[0046] The composition can be used on new or used metallic surfaces of pots / thimbles and even for mechanically damaged pots / thimbles especially for slag pots in Steel and Allied Metallurgical Industries. The composition can be used on refractory castables, brick surfaces or on any surface where properties of anti-slag sticking of slag / liquid hot metal / ductile iron are required.

[0047] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying a current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments.

[0048] It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the appended claims.

[0049] Although the embodiments herein are described with
various specific embodiments, it will be obvious for a person skilled in the art to practice the invention with modifications. However, all such modifications are deemed to be within the scope of the claims.

CLAIMS:
What is claimed is:

1. An anti-sticking composition coating over a slag pot / thimbles comprises:

carbon in as dried composition with an amount of 40-45 wt%; silicon dioxide in as dried composition present at a ratio of 52-60 wt%;;

a plurality of binders mixed with an amount of 2 to 5 wt%, and wherein the plurality of binders includes organic binder or inorganic binders, plasticizers and a high temperature binder, and wherein the plurality of binders is selected from a group consisting of organic binders, inorganic binders, plasticizers and a combination thereof;
an anti-fungal agent, and wherein the antifungal agent is selected from a group consisting of Sodium Pentachlorophenate,/biocide oil, and wherein the oil is selected from a group consisting of edible / non edible vegetable oil, and mineral oil; and water.

2. The composition according to claim 1, wherein the carbon is a micronized carbon based material.

3. The composition according to claim 1, wherein the organic binders includes xanthum gum/guar gum/CMC and resin.

4. The composition according to claim 1, wherein the plasticizers include clay and bentonite, and wherein the plasticizers are added in an amount of 3-5 wt %.

5. The composition according to claim 1, wherein the high temperature binder includes boric acid, phosphoric acid SHMP/STPP, sodium silicate in the form of powder or liquid, and wherein the high temperature binder is added in an amount of 2-3 wt%.

6. The composition according to claim 1, wherein the oil and
water forms upto 70% of the composition.

7. The composition according to claim 1, wherein the composition has a viscosity of 10000-25000 cps.

8. The composition according to claim 1, wherein the composition has a pH of 6.5-7.5.

9. The composition according to claim 1, wherein the composition has a specific gravity of 1.0-1.30

10. The composition according to claim 1, wherein the composition is in the form of a suspension and is sprayed on the slag pots with a thickness upto 3 mm.

11. The composition according to claim 1, wherein the composition is in the form of a suspension and is sprayed on the slag pots to form a coating with a thickness upto 3 mm.

12. The composition according to claim 1, wherein the composition is able to with stand a temperature upto - 800°C

13. A method of synthesizing an anti-sticking composition for slag pots, the method comprises mixing carbon, silicon dioxide, a plurality of binders, an anti-fungal agent, oil and water to form a suspension.

14. The method according to claim 13, wherein the carbon is a micronized carbonaceous and wherein the carbon is mixed to get as dried carbon at an amount of 40-45 wt %.

15. The method according to claim 13, wherein the silicon dioxide in as dried is mixed at an amount of 52-60%.

16. The method according to claim 13, wherein the plurality of binders is mixed with an amount of 2 to 5 wt%, and wherein the plurality of binders includes organic binder or inorganic binders, plasticizers and a high temperature binder, and wherein the plurality of binders is selected from a group consisting of organic binders, inorganic binders, plasticizers and a combination thereof, and wherein the organic binders includes xanthum gum/guar gum/CMC and resin, and wherein the plasticizers include clay and bentonite, and

wherein the plasticizers are added in an amount of 3-5 wt %, and wherein the high temperature binder includes boric acid, phosphoric acid/SHMP/STPP, sodium silicate in the form of powder or liquid, and wherein the high temperature binder is added in an amount of 2-3 wt % .

17. The method according to claim 13, wherein the anti-fungal agent is selected from a group consisting of Sodium Pentachlorophenate/biocide

18. The method according to claim 13, wherein the oil in claim 1 is selected from a group consisting of edible/non edible vegetable oil and mineral oil.

19. The method according to claim 13, wherein the oil and water forms upto 70% of the composition.

20.The method according to claim 13, wherein the composition has a viscosity of 10000-25000 cps.

21. The method according to claim 13, wherein the composition has a pH of 6.5-7.5.

22. The method according to claim 13, wherein the composition has a specific gravity of 1.00-1.30.

23. The method according to claim 13, wherein the composition is in the form of a suspension and is sprayed on the inner surface of slag pots / thimbles to form a coating with a thickness of upto 3 mm.

24. The method according to claim 13, wherein the composition is able to with stand a temperature upto 800°C.

25. The method according to claim 13 further comprises using high air pressure from specially designed applicator and a lance with / without nozzle for the spraying of the composition

26. The method according to claim 13 further comprises using industrial brush to apply the material manually on the surfaces of small carriers / launders.

27. The method according to claim 13 further comprises packing and sealing the coating composition material in a plastic bag to avoid contamination and leakage, and wherein the plastic bag is sized to carry 10-30 Kg of coating composition material, and wherein the bags are then packed in card board boxes weighing 20 - 60 kg and wherein the coating composition material is packed in one ton recyclable plastic drums.