CA2124488A1

CA2124488A1 - Resin bond taphole closure refractory product

Info

Publication number: CA2124488A1
Application number: CA002124488A
Authority: CA
Inventors: Everett W. Sharp, Jr.; Robert Harper
Original assignee: Premier Refractories and Chemicals Inc
Current assignee: Premier Refractories and Chemicals Inc
Priority date: 1993-05-28
Filing date: 1994-05-27
Publication date: 1994-11-29
Also published as: MX9404033A

Abstract

A RESIN BOND TAPHOLE CLOSURE REFRACTORY PRODUCT ABSTRACT OF THE DISCLOSURE A composition for plugging a taphole includes a resin, a fatty acid pitch and refractory fillers. The resin is preferably novolac, resol, resorcinol, resorcinol formaldehyde, melamine, melamine formaldehyde, urea, urea formaldehyde, phenol, cashew nut oil, or any combinations thereof. The fatty acid pitch is preferably tall oil pitch.

Description

212~

A RBSIN ~OND TAPHOI,E CL08URE REFR~CTORY PRODUCT

The present invention relates to a taphole closure refractory product or mix typically used to plug the taphole of a blast furnace and more particularly to a resin bond taphole mix.

For the removal of molten metal from blast furnaces and the like, a taphole must be provided. This taphole extends through the lining of the furnace into tha hearth and communicates with a trough on the outside of the furnace for directing tapped, molten metal to a ladle or other receptacle. Between casts from the furnace, the taphole must of course be closed, and for closing it, it is conventional practice to impact or extrude a mass of a pliable anhydrous mix or plug from a "mud gun" into the hole.
A typical anhydrous mix consists of a mass or paste made of coal tar pitch, or petroleum pitch as a binder and an aggregate of refractory ma~erials. The materials are ground to a suitable mesh size, well known to sPEcU~n55 ' . ~ .

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manufacturers; the resulting masses becoming extremely hard after firing. This hardness is advantageous in that the taphole cannot be worn away by outflowing cast iron.
However advantageous anhydrous masses are, they cause various problems. The coking operation necessary for hardening the plug material makes it necessary to hold the mud gun in place for about 15 to 20 minutes to prevent the plug from blowing. The space occupied in front of the blast furnace and in the main trough or runner is particularly detrimental to the blast furnace operators who are confronted with the difficult task of cleaning and repairing the trough or runner between successive castings.
If the castings take place at relatively short intervals, the time available for allowing the closure material located inside the blast furnace to harden, char or be fired completely is too short. Thus, when the plug is removed, clots of unfired tar appear which produce flames thrown at relatively great distances, which can injure the men working at the front area of the blast furnace.
Moreover, the tar smell released by the anhydrous masses is extremely unpleasant and, sometimes, according to the nature of the tar contained in the paste, the smell is unbearable to the operators and causes known cases of discomfort and sickness among the casting crew.
Because of the emphasis today being placed on the environment and the need to reduce emissions in the blast furnace cast house, there is an interest to move to resin bond taphole clays which display little or no visible emissions.
There's also been a move to a soaking bar practice rather than drill for opening up the casting hole in the blast furnace. Resin bond products seem to be more SPL~39255 ':',~ ' ' ~ ' ::-: .: :, . :

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212~4~8 suited to this practice than coal tar bonded products.
However, some coal tar products do seem to lend themselves reasonably well to this practice.
A change to resin type products is not without problems. These problems are:
1. The inability to increase or build taphole length.

2. The tendency to thermally set up in the mud gun at temperatures less than 250F.

3. They are difficult to extrude because of the non-plastic nature of the material and during the winter months must be pre-heated.

4. Shelf life is typically relatively short. Many manufacturers must make the material very soft and hold it in inventory for a period of time before it is suitable for use. If held in inventory too long, e.g.
greater than six months, it becomes hard and is not suitable for use.
Most of the existing resin products on the market today have additions of coal tar pitch, petroleum pitch, dry resins and/or paraffin added to them as a plasticizer as a means of allowing the product to soften as it is heated. This technique does add some delay to the thermal setting and allows the product to be extruded into the taphole, but does not overcome the aforementioned problems.
! . Applicants are aware of the following references relating to the field of the invention:
U.S Pat. No. Date 3,556,822 19 Jun 1971 4,022,739 10 May 1977 4,072,531 07 Feb 1978 4,327,185 27 Apr 1982 4,337,193 29 Jun 1982 SPEC~39255 , }<", "`

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r 212~4~8 For'n.Doc.No. Country Date 1 189 200 G. Britain 22 Apr 1970 2 624 288 W. Germany 30 May 1975 4 0~1 116 Japan 28 Jun 1977 1 004 311 Soviet Union 14 Nov 1980 8 07~ 873 Japan 06 Nov 1981 2 091 396 G. Britain 28 Jul 1982 3 437 385 W. Germany 11 Oct 1983 The Japanese reference No. 4,011,116 teaches a taphole mix including a mixture of refractory materials (e.g. clay, grog, alumina, silicon carbide, silicon nitride, and carbon) and tall oil as a plasticizer, however, this reference does not relate to a resin-bonded taphole mix.
lS U.S. Patent No. 4,337,193 generally discloses the use of hardened tall oil pitch in combination with various additives, including resole type phenol formaldehyde and other resins. The modified pitch has "properties improved for use as binders" for briquetting, in coating compositions, in roofing compositions, in pipe joint compounds, etc. A range of properties are disclosed and may be achieved by varying the combinations with other additives.
U.S. Patent No. 3,556,822 discloses a carbon-based bonding system for refractories including as a binder a "neutralized unsaturated fatty acid pitch." The pitch is recovered residue from the distillation of vegetable oils, whereby fatty acids are removed with "a basic material" to provide a Ph in the basic range. The reference further claims the use of linseed pitch and soybean pitch.
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21244~8 U.S. Patent No. 4,072,531 discloses plugging compositions for blast furnace tapholes comprising a refractory filler, a wetting agent, and a binder. The binder consists of a phenol-aldehyde condensate resin chemically modified by reaction with lignin. The refractory filler may be clay, alumina, carbon, magnesia and/or pyrophyllites.
U.S. Patent No. 4,327,185 discloses an aggregate refractory composition that utilizes phenol formaldehyde resin in liquid form. The reference discloses that phenol formaldehyde resins have been found to produce reduced fumes upon heating of the refractory compositions containing them, along with a surprising increase in density and concomitant decrease in porosity over "conventional pitch bonded resins."
The Soviet Union reference No. 1,004,311 discloses a refractory sealing composition for metallurgical furnaces containing chamotte, asbestos and liquid phenol formaldehyde resin.
The West German reference No. 3,437,385 provides a refractory composition for closing the taphole of a blast furnace comprising a non-basic refractory material and solid polyhydric phenol resin. The resin is especially a resorcinol resin, optionally dissolved in ethylene glycol.
The composition may contain silicon metal, graphite and ! petroleum coke, in addition to crude kyanite, silicon carbide, silicon oxide, fire clay and ball clay.
The Japanese reference No. 8,079,873 teaches a blast furnace taphole refractory composition comprising alumina, graphite and silicon carbide with a binder such as pitch or phenol resin.
The Great Britain reference No. 2,091,396 provides a furnace taphole plug comprising a particulate sPEc~3nss , - . . .

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- `' 2124~8 refractory material such as firebrick grog bonded together with a thermally-degradable bonding agent such as a phenolic-based resin. The plug may also contain paper pulp, or some other fibrous carbonaceous material.
The Great Britain reference No. 1,189,200 discloses an anhydrous mass for plugging blast furnaces comprising a refractory charge consisting of at least one refractory clay and silica containing alumina in a quantity less than that which would produce an eutectic mixture with the silica, and a binder which includes tar and a thermosetting material which is heat stable at 200C. The thermosetting material is taught to be a resol-type phenol resin.
U.S. Patent No. 4,022,739 provides a composition for plugging blast-furnace tap-holes containing 70 to 80 percent of a mineral component, such as clay, bound with various mixtures of pitch or petroleum oil distillation products and certain natural resins including phenolformaldehyde resin.
The West German reference No. 2,624,288 teaches a tapping hole composition which gives no malodor on hardening containing novolac binder, formaldehyde former and an alcoholic solvent. The formaldehyde former is especially an acetal resin such as parafo~maldehyde, triozane, etc. Alternatively, the mixture may contain a resol thermosetting resin. The material is claimed to have high strength at high temperatures, and resists erosion by iron and clinker.

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It is an object of the present invention to provide a novel composition for plugging a taphole which obviates or mitigates at least one of the aforementioned disadvantages of the prior art.
Accordingly, in one of it5 aspects, the present invention provides a composition ~or plugging a taphole including a resin, a fatty acid pitch and refractory fillers.

, In a preferred embodiment, the resin is selected from the group consisting of novolac, resol, resorcinol, resorcinol formaldehyde, melamine, melamine formaldehyde, urea, urea formaldehyde, phenol, cashew nut oil, or any combinations thereof.
Preferably, the fatty acid pitches include pitches derived from the fractional distillation of animal sPEcun55 :, , . . ::

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r -212~4~'8 and vegetable materials, such as tall oil pitch. The animal and vegetable materials are selected from the group consisting of lard, tallow, palm oil, linseed, soybean, bone fat, garbage, sewage, wool, grease, packing house waste, or any combinations thereof.
In a preferred embodiment, the refractory fillers are selected for the group consisting of clay, silica, alumina, magnesia, silicon ganister, zircon, andalusite, kyanite, silicon nitride, ferrosilicon, silicon metal, lo ferrosilicon nitride or any combinations thereof.
Preferably, the composition thermally sets at temperatures above 250F.
Other f eatures and advantages of the present invention will become apparent from the following description of the invention which refers to the accompanying drawings.

For the purpose of illustrating the invention, there is shown in the drawings an embodiment which is presently preferred; it being understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown.
Fig. 1 is a temperature viscosity cu~ve of tall oil pitch and coal tar pitch.
Fig. 2 is a temperature extrusion curve of the resin bond taphole mix of the present invention and a coal tar bonded mix.

The present invention relates to an extrudable, resin bond taphole closure material or mix for plugging the tapping hole of an iron-making blast furnace. In practice sPEc~nss .-.

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2 1 ~ 8 g the taphole mix is preferably extruded into a block of suitable size, making it easier to handle. The block is then placed into the mud gun chamber of a mud gun, and then injected or extruded into a taphole.
A resin bond taphole mix is basically comprised of two components, namely refractor~ filler and a binder.
In the present invention a phenol-formaldehyde resol resin e.g., in liquid form synthesized by single-stage synthesis, is preferred as the binder because it simplifies the manufacturing and is compatible with the tall oil pitch, although it should be appreciated by those skilled in the art that other resins can be used such as novolac, resorcinol, resorcinol formaldehyde, melamine, melamine formaldehyde, urea, urea formaldehyde, phenol, cashew nut oil, or any combinations thereof.
It is necessary to add a plasticizer or extender to the resol resin binder because the expense of using all resin as the bind~r is not economically feasible. Tall oil pitch or any fatty acid pitches obtained in fractional distillation of animal and vegetable materials such as lard, tallow, palm oil, linseed, soybean, bone fat, garbage, sewage, wool grease are the preferred plasticizers.
Tall oil pitch, a resin fatty acid, is a major by-product obtained in the production of tall oil rosin and tall oil fatty acids. In the USA, from 15% to 25% of crude tall oil ends up as tall oil pitch.
Tall oil pitch has no constant well defined composition. Tall oil pitch consists predominately of saponifiable esters of rosin and fatty acids of the general type associated with tall oil, lesser amounts of the free forms of such acids, and a minor fraction of various high-molecular weight naturally occurring nsutral materials, S PEC~3 9255 ; ~: ., :
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'' '. ~.,':, 212~4~8 including sterols. A major ingredient of the neutral fraction of crude tall oil, sitosterol, is concentrated in the pitch.
Generally, tall oil pitch contains the non-distillable components originally present in the pine treeproduced during pulping and distillation. The alcohol components present in crude tall oil are comprised largely of sitosterol and smaller amounts of long chain alcohols.
Tall oil pitch also contains some acidic components. Some high molecular weight acidic material is present in the original crude tall oil and some is formed during distillation. During distillation, both resin acids and fatty acids undergo some thermal dimerization. This dimerization will also be catalyzed by traces of mineral acid not removed from the crude tall oil prior to distillation.
The number average molecular weight of tall oil pitch is 700-800, indicating that little or no real polymer is present - just large molecules obtained by thermal dimerization and esterification of the materials present in crude tall oil. Typical properties of tall oil pitch are listed in Table I below.

TABLE I

Color Dark Form Resinous, tacky, thermoplastic Softening, Point 0C 40 Specific Gravity at 25/25C 1.025 Weight per gal.,lb. ~.6 Saponification No. 80-120 Unsaponifiables, ~ 30~45 sP~CUnss , ...

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Rosin Acids, % 5-15 Fatty Acids, % 2-8 Sterols, % 8-12 Acid Number 15-50 Ash, ~ 0.3-1Ø

Tall oil pitch is commercially available from a number of companies including Georgia-Pacific Resins, Inc.
of Atlanta, Georgia and Arizona Chemical Company of Panama City, Florida. Tall oil pitch from the Arizona Chemical company sold under the name Acintol~ P Tall Oil Pitch is preferred.
Tall oil pitch is particularly preferred as a plasticizer. This is because it is thermoplastic in nature and because, as shown in Fig. 1, the tall oil pitch 10 has a temperature viscosity curve parallel to that of coal tar pitch 12. Furthermore, the tall oil pitch and the resol resin are compatible with each other. It is believed that this is because the phenol in the resin is an excellent solvent.
The addition of tall oil pitch to the resol resin has been found to have many benefits yielding a significantly improved taphole mix far superior to resin bond taphole mixes of the prior art. Resal resins are known to have a relatively short shelf life. The addition of the tall oil pitch was found to extend the shelf life of the product to a more than acceptable time period, i.e.
greater than six months, by preventing the resol resin from aging over extended time periods even when stored at elevated storage temperatures, e.g. 80 to 90F.
Another benefit of adding tall oil pitch to the resol resin is due to the thermoplastic nature of tall oil pitch. This yields a product that has a similar extrusion sPeC\39255 . .

, ~ :' ., . ~ , 212~488 to temperature curve to that of a coal tar bonded product.
As a result the product has a more desirable very plastic thermoplastic soft pliable body that will thermally set at temperatures above 250F. The taphole mix of the present invention has been found to still be workable at temperatures of over 250F for more than an hour. This reduces the chances of the mix thermally setting in the mud gun. Referring now to Fig. 2, there is shown therein a temperature extrusion curve which shows that the resin bond lo taphole mix 12 of the present invention will not thermally set until temperatures greater than 250F.
It is believed that the use of tall oil pitch, because of its thermoplastic nature, provides a more desirable thermal setting characteristic thus enhancing the taphole product by allowing the material to soften and lubricate during the injection process thus compensating for the stiffening taking place due to the resin thermosetting. This gives additional time for the material to be fully injected into the t.aphole before hardening.
Another benefit of adding tall oil pitch to the resol resin is that the tall oil pit~h allows for a much softer product than coal tar bonded and other resin bond materials allowing it to be used during the winter months with little or no preheating before use. For example, it was found that the resin bond taphole mix of the present invention can be extruded at 35F with a carver press with 1500 psi. The mud guns on a modern blast furnace are capable of extruding at 2000 to 3000 psi. Fig. 2 shows the lower pressure requirement of the resin bond taphole mix 12 of the present invention as compared to a coal tar bonded taphole product 14.

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~, It has been found that the preferred compositions for the taphole mix of the present invention are as follows, in weiyht percent, Composition l Composition 2 Fire Clay 0 - 97% Fire Clay 0 - 25%
Silica Ganister 0 - 90~ *Grog 5 - 80%
Carbon 0 - 20~ Carbon 0 - 20%
Silicon Carbide 0 - 25~ Silicon Carbide 0 - 25%
Resol Resin l - 15% Resol Resin l - 15%
Tall O~il Pitch ? - l5~. Tall Oil Pitch_2 - 15%

* Grog having Al2O3 content from 10% to 99.9%

Composition 3 Clay 30 - 60%
Quartz (SiO2) 20 - 60%
Silicon Carbide l0 - 30%
Coke 3 - 7%
Tall Oil Pitch 3 - 7%
Phenol, Polymer with Formaldeh~de _ _l - 10% :~

It should be appreciated by those skilled in the art that other refractory fillers can be used in accordance with the taphole mix of the present invention including, without limitation, zircon, andalusite, kyanite, silica, silicon nitride, ferrosilicon, silicon metal and the like.
Ferrosilicon nitride can be added to the taphole mix of the present invention to protect the mix from slag attack.

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2124~8 The following example will serve to illustrate the invention: .

EXAMPLE
6x20 Mesh Silica Ganister 20 High Silica Fire Clay 52%
Metallurgical Coke -8 Mesh 6 200 Mesh Silicon Carbide 6%
Phenol-formaldehyde Resin (Resol) 9 Tall Oil Pitch 5.5 Flower of Sulfur 1.5~

The in~redients were mixed by first adding the resol resin to the dry refractory ingredients. Tall oil pitch was then added until the proper plastic pliable consistency was reached in the mixer. The proper consistency was 15determined by extruding the mix at 100F in a Carver press to achieve an extrusion pressure of 100-300 psi. Once the proper consistency was achieved, the mix was then extruded ! into blocks of a size suitable for placing into the blast furnace mud gun chamber.
20The sulfur was added to the mix to increase the carbon bonding and to act as a wetting agent, thus reducing the amount of total liquids required to achieve the desired consistency. It should be realized that the taphole mix of sPE~3n55 ~ ' ': ' .

212~8 the present invention will work satisfactorily without the addition of sulfur, but its performance is enhanced with its addition.
The resin bond taphole mix of the present invention was found to build taphole length by merely increasing the volume of material injected into a taphole.
It did not thermally set until temperatures above 250F and required much less extrusion pressure than coal tar bonded and other resin bond materials, particularly at reduced temperatures. The mix did not need to be preheated during the winter months and was used as manufactured and aged very little over time even when stored at ~o to 90F
temperatures for long periods. It did not make use of coal tar pitch, petroleum pitch, paraffin or the like and was very plastic, pliable and thermoplastic in nature.
Although the present invention has been described in relation to particular embodiments thereof, many other variations and modifications and other uses will become apparent to those skilled in the art. It is preferred, therefore, that the present invention be limited not by the specific disclosure herein, but only by the appended claims.

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Claims

WHAT IS CLAIMED IS:

1. A composition for plugging a taphole, the composition comprising a resin, a fatty acid pitch and refractory fillers.

2. The composition of Claim 1, wherein the resin is selected from the group consisting of novolac, resol, resorcinol, resorcinol formaldehyde, melamine, melamine formaldehyde, urea, urea formaldehyde, phenol, cashew nut oil, or any combinations thereof.

3. The composition of Claim 1, wherein the fatty acid pitch includes pitches derived from the fractional distillation of animal and vegetable materials.

4. The composition of Claim 3, wherein the animal and vegetable materials are selected from the group consisting of lard, tallow, palm oil, linseed, soybean, bone fat, garbage, sewage, wool, grease, packing house waste, or any combinations thereof.

5. The composition of Claim 3, wherein the fatty acid pitch is tall oil pitch.

6. The composition of Claim 1, wherein the refractory fillers are selected for the group consisting of clay, silica, alumina, magnesia, silica ganister, zircon, andalusite, kyanite, silica, silicon nitride, ferrosilicon, silicon metal or any combinations thereof.

7. The composition of Claim 6, wherein the refractory fillers further include ferrosilicon nitride.

8. The composition of Claim 1, wherein the composition thermally sets at temperatures above 250°F.

9. The composition of Claim 2, wherein the resin is a resol resin in liquid form synthesized by single-stage synthesis of a phenol and formaldehyde.

10. A composition for plugging a taphole, the composition comprising a phenol-formaldehyde resol resin, tall oil pitch and refractory fillers.

11. The composition of Claim 10, wherein the refractory fillers are selected for the group consisting of clay, silica, alumina, magnesia, silica ganister, zircon, andalusite, kyanite, silica, silicon nitride, ferrosilicon, silicon metal or any combinations thereof.

12. The composition of Claim 11, wherein the refractory fillers further include ferrosilicon nitride.

13. The composition of Claim 10, wherein the resol resin is in liquid form synthesized by single-stage synthesis.

14. The composition of Claim 10, wherein the composition thermally sets at temperatures above 250°F.

15. A composition for plugging the taphole of a blast furnace, the composition comprising, by weight percent, Fire Clay 0-97%
Silica Ganister 0-90%
Carbon 0-20%
Silicon Carbide 0-25%
Resol Resin 1-15%
Tall Oil Pitch 2-15%.

16. The composition of Claim 15, wherein the composition thermally sets at temperatures above 250°F.

17. The composition of Claim 15, wherein the resol resin is in liquid form synthesized by single-stage synthesis of a phenol and formaldehyde.

18. A composition for plugging the taphole of a blast furnace, the composition comprising, by weight percent, Fire Clay 0-25%
Grog 5-80%
Carbon 0-20%
Silicon Carbide 0-25%
Resol Resin 1-15%
Tall Oil Pitch 2-15%.

19. The composition of Claim 18, wherein the grog includes an alumina content from about 10-99%.

20. The composition of Claim 18, wherein the composition thermally sets at temperatures above 250°F.

21. The composition of Claim 18, wherein the resol resin is in liquid form synthesized by single-stage synthesis of a phenol and formaldehyde.

22. A composition for plugging the taphole of a blast furnace, the composition comprising, by weight percent, Clay 30-60%
Quartz (SiO2) 20-60%
Silicon Carbide 10-30%
Coke 3-7%
Tall Oil Pitch 3-7%
Phenol, Polymer with Formaldehyde 1-10%

23. The composition of Claim 22, wherein the composition thermally sets at temperatures above 250°F.

24. The composition of Claim 22, wherein the phenol-formaldehyde polymer is a resol resin in liquid form synthesized by single-stage synthesis.

25. A composition for plugging the taphole of a blast furnace, the composition comprising, by weight percent, Silica Ganister (6x20m) 20%
High Silica Fire Clay 52%
Metallurgical Coke (-8m) 6%
Silicon Carbide (200m) 6%

Phenol-Formaldehyde Resol Resin 9%
Tall Oil Pitch 5-5%
Flower of Sulfur 1.5%

26. The composition of Claim 25, wherein the composition thermally sets at temperatures above 250°F.

27. The composition of Claim 25, wherein the resol resin is in liquid form synthesized by single-stage synthesis.