Thick slag agent, preparation method thereof and slag splashing furnace protection method
阅读说明：本技术 稠渣剂及其制备方法、溅渣护炉方法 (Thick slag agent, preparation method thereof and slag splashing furnace protection method ) 是由 苏震霆 张庆国 程峥明 贾雅楠 秦登平 尹世超 王延飞 王飞 郭亚朋 孔祥涛 关 于 2021-06-30 设计创作，主要内容包括：本发明提供了一种稠渣剂及其制备方法、溅渣护炉方法,所述稠渣剂包括如下重量份数的原料,中间包干式料：30-50份；菱镁矿：10-20份；白云石：10-20份；焦炭粉末：5-10份；轻烧镁粉：10-20份；膨化淀粉：1-2份。采用本发明提供的稠渣剂溅渣护炉,可以使炉衬关键部位如耳轴的平均侵蚀速率比使用其它改质剂减缓0.02-0.05mm/炉次,其它部分侵蚀速率均有不同程度改善,有效提高转炉冶炼炉次。(The invention provides a thick slag agent, a preparation method thereof and a slag splashing furnace protection method, wherein the thick slag agent comprises the following raw materials in parts by weight: 30-50 parts; magnesite: 10-20 parts; dolomite: 10-20 parts; coke powder: 5-10 parts; light-burned magnesium powder: 10-20 parts; puffing starch: 1-2 parts. The slag splashing protection of the slag-thickening agent provided by the invention can reduce the average erosion rate of key parts of a furnace lining, such as trunnions, by 0.02-0.05 mm/heat compared with other modifiers, improve the erosion rates of other parts to different degrees, and effectively improve the smelting heat of a converter.)
1. The thick slag agent taking a tundish dry material as a raw material is characterized by comprising the following raw materials in parts by weight,
tundish dry material: 30-50 parts;
magnesite: 10-20 parts;
dolomite: 10-20 parts;
coke powder: 5-10 parts;
light-burned magnesium powder: 10-20 parts;
puffing starch: 1-2 parts.
2. The slag thickener taking the dry material of the tundish as the raw material as the claim 1, wherein the particle size of the dry material of the tundish is less than or equal to 5mm, and the dry material of the tundish comprises the following chemical components in percentage by mass: MgO: 55-60%, CaO: 10-15% of Al2O3≤3.5％：SiO2≤5％，C≤10％。
3. The slag thickener using the tundish dry material as the raw material as claimed in claim 1, wherein the particle size of the magnesite is less than or equal to 5 mm.
4. The slag thickening agent using the tundish dry material as the raw material according to claim 1, wherein the particle size of the coke powder is less than or equal to 5mm, and the carbon content fraction in the coke powder is greater than or equal to 60%.
5. The slag thickener taking a tundish dry material as a raw material according to claim 1, wherein the particle size of the light-burned magnesium powder is less than or equal to 5mm, and the mass fraction of MgO in the light-burned magnesium powder is more than or equal to 60%.
6. The preparation method of the slag modifier taking the dry type material of the tundish as the raw material according to any one of claims 1 to 5, which comprises the steps of,
adding water into the raw materials, stirring and mixing, and then making balls to obtain a slag modifier with the particle size of 10-50 mm; the raw materials comprise the following components in parts by weight: tundish dry material: 30-50 parts; magnesite: 10-20 parts; dolomite: 10-20 parts; coke powder: 5-10 parts; light-burned magnesium powder: 10-20 parts; puffing starch: 1-2 parts.
7. A slag splashing furnace protection method is carried out by adopting the slag regulating agent which takes a tundish dry material as a raw material and is defined in any one of claims 1 to 5, and is characterized by comprising the following steps,
carrying out slag retention operation on the converter final slag;
after the slag regulating agent is added into the remaining slagIn the converter and at 150-300Nm3And (3) carrying out slag splashing furnace protection at the flow rate of/h/t for 3-5min by nitrogen blowing.
8. The slag splashing protection method of claim 7, wherein the added mass of the slag modifier is 3-10kg/t steel.
9. The slag splashing protection method of claim 7, wherein the amount of the slag left is 15-30% of the final slag mass of the converter.
10. The slag splashing protection method of claim 7, wherein the final slag alkalinity is 3.00-3.30, the TFe mass fraction in the final slag is less than 20%, the Mg mass fraction in the final slag is 8-15%, and the oxygen mass fraction in the final slag is 0.03-0.05%.
Technical Field
The invention belongs to the technical field of slag thickening agents, and particularly relates to a slag thickening agent taking a tundish dry material as a raw material, a preparation method of the slag thickening agent, and a slag splashing furnace protection method.
Background
The thick slag agent can be added into the converter for slag splashing protection after tapping of the converter, so that the superheat degree of the slag is reduced, the viscosity of the slag is increased, the TFe of the final slag is reduced, solid phase mass points are increased, and the melting point of a slag splashing layer is improved.
The dry material of the tundish is used for building the lining of the tundish and has good high-temperature resistance and slag corrosion resistance. Turning over the ladle after each pouring, and pouring the dry materials in the turning materials of the tundish after turning over the ladle to be generally used as industrial garbage for recycling treatment.
Therefore, in order to better treat the tundish dry material in the pouring and turning material and realize efficient resource utilization, a new process route and a new idea need to be developed, the environmental protection pressure of the tundish dry material as industrial garbage is solved, the cost pressure in the converter smelting process is reduced, and the purposes of reducing the smelting cost and protecting the environment are achieved.
Disclosure of Invention
In order to solve the technical problems, the invention provides a thick slag agent taking a tundish dry material as a raw material, a preparation method thereof and a slag splashing furnace protection method, which can effectively utilize the tundish dry material, reduce the cost, realize resource utilization and have good slag splashing furnace protection effect.
On one hand, the invention provides a thick slag agent taking a tundish dry material as a raw material, which comprises the following raw materials in parts by weight,
tundish dry material: 30-50 parts;
magnesite: 10-20 parts;
dolomite: 10-20 parts;
coke powder: 5-10 parts;
light-burned magnesium powder: 10-20 parts;
puffing starch: 1-2 parts.
Further, the particle size of the tundish dry material is less than or equal to 5mm, and the tundish dry material comprises the following chemical components in parts by mass: MgO: 55-60%, CaO: 10-15% of Al2O3≤3.5％：SiO2≤5％，C≤10％。
Furthermore, the particle size of the magnesite is less than or equal to 5 mm.
Furthermore, the particle size of the coke powder is less than or equal to 5mm, and the carbon content fraction in the coke powder is more than or equal to 60%.
Furthermore, the grain diameter of the light-burned magnesium powder is less than or equal to 5mm, and the mass fraction of MgO in the light-burned magnesium powder is more than or equal to 60%.
On the other hand, the invention also provides a preparation method of the slag modifier taking the tundish dry material as the raw material, which comprises the following steps,
adding water into the raw materials, stirring and mixing, and then making balls to obtain a slag modifier with the particle size of 10-50 mm; the raw materials comprise the following components in parts by weight: tundish dry material: 30-50 parts; magnesite: 20-30 parts of a solvent; coke powder: 5-10 parts; light-burned magnesium powder: 10-20 parts; puffing starch: 1-2 parts.
In another aspect, the invention also provides a slag splashing furnace protection method, which is carried out by adopting the slag regulating agent taking the tundish dry material as the raw material, and the method comprises the following steps,
carrying out slag retention operation on the converter final slag;
adding the slag regulating agent into the converter after slag retention, and performing slag regulation at 166-266Nm3And (3) carrying out slag splashing furnace protection at the flow rate of/h/t for 3-5min by nitrogen blowing.
Furthermore, the adding mass of the slag modifier is 3-10kg/t steel.
Further, the amount of the remaining slag is 15-30% of the mass of the converter final slag.
Further, the final slag alkalinity is 3.00-3.30, the mass fraction of TFe in the final slag is less than 20%, the mass fraction of Mg in the final slag is 8-15%, and the mass fraction of oxygen in the final slag is 0.03-0.05%.
One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages:
the invention provides a thick slag agent taking a tundish dry material as a raw material, a preparation method thereof and a slag splashing furnace protection method, wherein the thick slag agent comprises the following raw materials in parts by weight: 30-50 parts; magnesite: 10-20 parts; dolomite: 10-20 parts; coke powder: 5-10 parts; light-burned magnesium powder: 10-20 parts; puffing starch: 1-2 parts. The dry material of the tundish contains a large amount of MgO, and the viscosity of the final slag can be improved by controlling the MgO within a specific range, so that the effect of slag splashing protection is improved; the magnesite, the dolomite and the coke powder can provide a kinetic condition of a slag splashing reaction, the lightly-burned magnesium powder and the dolomite can adjust the viscosity of final slag, the expanded starch enables the raw materials to be bonded together, and the expanded starch can also provide the kinetic condition of the slag splashing reaction. By adopting the thick slag agent slag splashing furnace protection provided by the invention, the erosion rate of key parts of a furnace lining, such as trunnions, is slowed down by 0.02-0.05 mm/heat than that of other modifying agents, the erosion rates of other parts are improved to different degrees, and the smelting heat of a converter is effectively improved.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on the drawings without creative efforts.
Fig. 1 is a process diagram of a method for using a slag modifier using a tundish dry material as a raw material according to an embodiment of the present invention.
Detailed Description
The present invention will be described in detail below with reference to specific embodiments and examples, and the advantages and various effects of the present invention will be more clearly apparent therefrom. It will be understood by those skilled in the art that these specific embodiments and examples are for the purpose of illustrating the invention and are not to be construed as limiting the invention.
Throughout the specification, unless otherwise specifically noted, terms used herein should be understood as having meanings as commonly used in the art. Accordingly, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. If there is a conflict, the present specification will control.
Unless otherwise specifically stated, various raw materials, reagents, instruments, equipment and the like used in the present invention are commercially available or can be prepared by existing methods.
It is noted that, in this document, relational terms such as "first" and "second," and the like, may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions.
In order to solve the technical problems, the embodiment of the invention provides the following general ideas:
on one hand, the embodiment of the invention provides a thick slag agent taking a tundish dry material as a raw material, which comprises the following raw materials in parts by weight,
tundish dry material: 30-50 parts;
magnesite: 10-20 parts;
dolomite: 10-20 parts;
coke powder: 5-10 parts;
light-burned magnesium powder: 10-20 parts;
puffing starch: 1-2 parts.
The tundish dry material has good high-temperature resistance and slag corrosion resistance, contains a large amount of MgO, can improve the viscosity and alkalinity of the converter final slag, enables the slag to be easily attached to the converter lining, and has good slag splashing protection effect. The dry materials of the tundish are excessive in parts by weight, so that the final slag is too high in viscosity and difficult to splash onto the furnace wall; the dry material of the tundish in too small part by weight can cause the final slag to have too small viscosity and good fluidity, and can not be hung on the wall of the converter, thereby influencing the effect of slag splashing and furnace protection.
The magnesite mainly comprises carbonate, the carbonate can be decomposed into carbon dioxide at high temperature in the slag splashing protection process, the reaction of the released gas provides the dynamic condition of slag splashing reaction, and the slag splashing protection effect is good; the magnesite has too many parts by weight, and the reaction of released gas is violent, so that the slag overflows in the slag splashing process and cannot be splashed; the magnesite is too little in parts by weight, and the effect of improving slag splashing furnace protection is not obvious.
Dolomite: the main component of dolomite is CaMg (CO)3)2The crystal belongs to trigonal carbonate mineral, can adjust the viscosity of the final slag and provides the dynamic condition of slag splashing reaction.
During slag splashing protection of the coke powder, carbon can react with oxygen in final slag, and the reaction is an exothermic reaction, so that heat is provided for slag splashing protection, the final slag is kept in a liquid state, and dynamic conditions of slag splashing protection can be provided. Too much coke powder in parts by weight causes slag stress due to violent reaction; too little coke powder by weight will cause insufficient heat.
The light-burned magnesium powder can provide magnesium, so that the ternary alkalinity of the slag-splashing furnace protection is improved, the melting point of the slag is reduced, and the fluidity of the slag is reduced, so that the slag is easy to hang on the wall of the converter. The light-burned magnesium powder is too much and has too poor fluidity, so that the slag cannot be splashed under the action of nitrogen and the furnace is difficult to be splashed for protecting; the light-burned magnesium powder is too little and has too good fluidity, so that slag is difficult to hang on the wall of the converter and slag splashing and furnace protection cannot be realized.
The expanded starch is a binder, the dry material of the tundish, magnesite, coke powder and light-burned magnesium powder are bonded together, and the expanded starch is decomposed in the slag splashing furnace protection process, so that the dynamic condition of slag splashing reaction is further provided. The expanded starch has excessive weight parts, the thick slag agent is difficult to crush, and the slag splashing reaction rate can be reduced; the expanded starch is too little in weight part, and the raw materials are difficult to bond.
As an implementation manner of the embodiment of the invention, the particle size of the tundish dry material is less than or equal to 5mm, and the tundish dry material comprises the following chemical components in parts by mass: MgO: 55-60%, CaO: 10-15% of Al2O3≤3.5％：SiO2≤5％，C≤10％。
As an implementation manner of the embodiment of the present invention, the particle size of the magnesite is less than or equal to 3mm, and the magnesite mainly comprises the following chemical components by mass: MgCO3≥40％。
The specific particle size of the magnesite can be adjusted according to the actual situation.
As an implementation manner of the embodiment of the invention, the particle size of the coke powder is less than or equal to 3mm, and the weight part of carbon in the coke powder is more than or equal to 60%.
The smaller the particle size of the coke powder is, the more favorable the granulation and reaction are, and the larger the carbon granulation fraction in the coke powder is, the higher the purity is.
As an implementation manner of the embodiment of the invention, the particle size of the light-burned magnesium powder is less than or equal to 5mm, and the mass fraction of MgO in the light-burned magnesium powder is more than or equal to 60%.
The particle size of the light-burned magnesium powder is too large to prepare balls. The higher the MgO content in the light-burned magnesium powder is, the higher the purity is.
On the other hand, the embodiment of the invention also provides a preparation method of the slag modifier taking the tundish dry material as the raw material, which comprises the following steps,
adding water into the raw materials, stirring and mixing, and then making balls to obtain a slag modifier with the particle size of 10-50 mm; the raw materials comprise the following components in parts by weight: tundish dry material: 30-50 parts; magnesite: 10-20 parts; dolomite: 10-20 parts; coke powder: 5-10 parts; light-burned magnesium powder: 10-20 parts; puffing starch: 1-2 parts.
If the slag modifier is too small, the slag modifier is too compact, so that the slag splashing reaction rate is prolonged; the slag modifier is too large, which is not beneficial to improving the dynamic condition of slag splashing reaction. In practice, the method may be as follows:
the continuous casting tundish is turned over after air cooling, the magnesium dry material forming the working layer of the tundish is mixed with other unshaped refractory materials and shaped refractory materials, the turned-over waste refractory materials are preliminarily sorted manually, and the dry material of the tundish is sorted out. And crushing and screening the sorted dry materials of the tundish to ensure that the size fraction of less than 5mm reaches more than 60%. Adding water into the reclaimed tundish dry material meeting the particle size requirement, magnesite, coke powder, light-burned magnesium powder and expanded starch, mixing according to a set proportion, and uniformly stirring. And (3) conveying the uniformly mixed materials to a ball pressing forming device through a belt, and performing extrusion forming according to set pressure to obtain the self-prepared high-magnesium thick slag agent. The self-made high-magnesium thick slag agent formed by extrusion molding is naturally aired or dried at a specified place, and meets the use requirement of converter charging.
In another aspect, an embodiment of the present invention further provides a slag splashing protection method, which is performed by using the above slag modifier using the tundish dry material as a raw material, and with reference to fig. 1, the method includes,
s1, carrying out slag retention operation on the converter final slag;
as an implementation mode of the embodiment of the invention, the amount of the remaining slag is 15-30% of the mass of the converter final slag.
The amount of the slag remained is too large, and in order to thicken the slag, the amount of the slag thickening agent is increased, so that the cost is increased; the slag remaining amount is too small, so that the effect of slag splashing and furnace protection can be limited.
As an implementation mode of the embodiment of the invention, the alkalinity of the final slag is 3.15-3.25, the mass fraction of TFe in the final slag is less than 20%, the mass fraction of Mg in the final slag is 8-20%, and the mass fraction of oxygen in the final slag is 0.03-0.05%.
Controlling the mass fraction of TFe in the final slag to improve the yield of molten steel; mg is controlled to improve the fluidity of the final slag, prevent slag foaming and improve the slag splashing protection effect. The mass fraction of oxygen in the final slag is too low, so that the viscosity of the final slag is reduced; the mass fraction of oxygen in the final slag is too high, which is not beneficial to improving the slag splashing furnace protection effect.
S2, adding the slag modifier into the converter after slag retention, and performing slag modification at the speed of 150-300Nm3And (3) carrying out slag splashing furnace protection at the flow rate of/h/t for 3-5min by nitrogen blowing.
Slag in the converter is splashed to the wall of the converter by nitrogen blowing to repair the lining. If the nitrogen blowing time is too short, the slag splashing furnace protection effect of the converter lining is not ideal; if the nitrogen flow is too small, the furnace lining at the upper part of the converter has no slag splashing furnace protection effect. If the nitrogen blowing time is too long, the converter can be cooled, the next smelting is influenced, and nitrogen is wasted; if the nitrogen blowing flow is too large, slag overflow can be caused.
As an implementation mode of the embodiment of the invention, the added mass of the slag modifier is 3-10kg/t steel.
The viscosity of the slag in the converter can be adjusted by adding the slag modifier; if the addition amount of the slag modifier is too large, the slag in the converter is too viscous and difficult to splash; if the addition amount of the slag modifier is too small, the slag in the converter has extremely good fluidity, can not be hung on the wall of the converter, and has poor slag splashing protection effect.
The slag modifier, the preparation method and the use method thereof will be described in detail with reference to examples, comparative examples and experimental data.
Example 1
Example 1 provides a slag modifier and a method for slag splashing protection using the same, the slag modifier comprises the raw materials in parts by weight shown in table 1, the raw materials in table 1 are mixed and pelletized to obtain the slag modifier with the particle size of 12-25mm, the composition of the slag modifier is shown in table 2, and the balance is inevitable impurities. Wherein the grain diameter of the dry material of the tundish is less than or equal to 5mm, and the dry material of the tundish comprises the following massFractional chemical composition: MgO: 40-60%, CaO: 10-20% of Al2O3:1-5％，SiO2：5-10％，Fe2O3: 1-5%, C: 5 percent; the particle size of the magnesite is less than or equal to 5mm, and the magnesite comprises the following chemical components in percentage by mass: MgCO3 is more than or equal to 30 percent; the grain size of the coke powder is less than or equal to 5mm, and the carbon content fraction of the coke powder is 75 percent. The grain diameter of the light-burned coal powder is less than or equal to 2mm, and the MgO content is 75 percent.
The slag splashing furnace protection method comprises the following steps:
1. carrying out slag remaining operation after tapping of the converter, wherein the slag remaining amount is 10% of final slag, the content of Mg is 5-10%, the content of oxygen is 350ppm, and the capacity of the converter is 300 t;
2. adding the slag modifier 1.5t into a converter after slag retention, and adding the slag modifier at 50000Nm3And (3) performing slag splashing protection at the flow rate of/h, namely top-blown nitrogen gas for less than or equal to 5min, deslagging after the slag splashing protection is finished, detecting the alkalinity and the TFe content of the deslagging, measuring the thickness of the converter wall by using a thickness gauge as shown in table 3, and counting the service life of the converter lining of the slag splashing protection by using the method as shown in table 3.
Example 2
Example 2 provides a slag modifier and a method for slag splashing protection using the same, the slag modifier comprises the raw materials in parts by weight shown in table 1, the raw materials in table 1 are mixed and pelletized to obtain the slag modifier with the particle size of 12-25mm, the composition of the slag modifier is shown in table 2, and the balance is inevitable impurities. The particle size of the dry material of the tundish is less than or equal to 5mm, and the dry material of the tundish consists of the following chemical components in percentage by mass: MgO: 65%, CaO: 10-20% of Al2O3:1-5％，SiO2：5-10％，Fe2O3: 1-5%, C: 5 percent. The particle size of the magnesite is less than or equal to 1.5mm, and the magnesite comprises the following chemical components in percentage by mass: MgCO3 is more than or equal to 40 percent; the particle size of the coke powder is less than or equal to 2mm, and the carbon content of the coke powder is 90%. The grain diameter of the light-burned coal powder is less than or equal to 2mm, and the MgO content is 80 percent. The using method comprises the following steps:
1. carrying out slag remaining operation after tapping of the converter, wherein the slag remaining amount is 20% of final slag, the content of Mg is 18%, the content of oxygen is 450ppm, and the capacity of the converter is 300 t;
2. adding the slag modifier 2t into a converter after slag retention, and controlling the temperature at 70000Nm3And (3) blowing nitrogen at the flow rate of/h for 4min for slag splashing protection, pouring slag after the slag splashing protection is finished, detecting the alkalinity and the TFe content of the poured slag, measuring the thickness of the converter wall by using a thickness gauge as shown in table 3, and counting the service life of the converter lining of the slag splashing protection by using the method as shown in table 3.
Example 3
Example 3 provides a slag modifier and a method for slag splashing protection using the same, the slag modifier comprises the raw materials in parts by weight shown in table 1, the raw materials in table 1 are mixed and pelletized to obtain the slag modifier with the particle size of 12-25mm, the composition of the slag modifier is shown in table 2, and the balance is inevitable impurities. Wherein the grain diameter of the dry material of the tundish is less than or equal to 2mm, and the MgO content is 75 percent. The tundish dry material comprises the following chemical components in percentage by mass: MgO: 78% of SiO2：5％，Fe2O3: 1.5%, C: 5 percent, and the balance of inevitable impurities. The particle size of the magnesite is less than or equal to 2mm, and the magnesite comprises the following chemical components in percentage by mass: MgCO3Not less than 40 percent; the grain size of the coke powder is less than or equal to 1.5mm, and the carbon content fraction of the coke powder is 80 percent. The grain diameter of the light-burned coal powder is less than or equal to 2mm, and the MgO content is 80 percent.
The slag splashing furnace protection method comprises the following steps:
1. carrying out slag remaining operation after tapping of the converter, wherein the slag remaining amount is 20% of the final slag, the content of Mg is 15%, the content of oxygen is 400ppm, and the capacity of the converter is 300 t;
2. adding the slag modifier 2.5t into a converter after slag retention, and adding the slag modifier at 80000Nm3And (3) blowing nitrogen at the flow rate of/h for 5min for slag splashing protection, pouring slag after the slag splashing protection is finished, detecting the alkalinity and the TFe content of the poured slag, measuring the thickness of the converter wall by using a thickness gauge as shown in table 3, and counting the service life of the converter lining of the slag splashing protection by using the method as shown in table 3.
Comparative example 1
Comparative example 1 provides a slag modifier in which the tundish dry material: 80 parts of a mixture; magnesite: 10 parts of (A); dolomite: 0 part of (C); coke powder: 3 parts of a mixture; light-burned magnesium powder: 5 parts of a mixture; puffing starch: and 2 parts.
Comparative example 2
Comparative example 2 provides a slag thickening agent and a slag splashing furnace protection method, and the comparative example 2 is different from the example 1 in that the weight part of the tundish dry material is 60 parts by taking the example 1 as a reference.
Comparative example 3
Comparative example 3 provides a slag thickening agent and a slag splashing furnace protection method, and the comparative example 2 is different from the example 1 in that the weight part of the tundish dry material is 20 parts by taking the example 1 as a reference.
TABLE 1
TABLE 2
Numbering
MgO/％
CaO/％
SiO2/％
C/％
Example 1
58
15
8
10
Example 2
51
11
14
6
Example 3
49
12
16
8
Comparative example 1
47
5
18
4
Comparative example 2
50
12
12
9
Comparative example 3
53
7
6
5
TABLE 3
As can be seen from Table 3, when the slag-splashing protection is carried out by using the slag-thickening agent provided in the embodiments 1 to 3 of the present invention, the erosion rate of the key parts of the lining of the converter, such as the trunnion, can be slowed down by 0.02 to 0.05 mm/heat than when other modifiers are used, the erosion rates of other parts are improved to different degrees, and the smelting heat of the converter is effectively increased. The slag regulating agent provided by the comparative examples 1-3 is adopted for slag splashing protection, the trunnion erosion rate is 0.03-0.07 mm/furnace, and the average erosion rate of the molten pool is 0.03-0.07 mm/furnace, which are all lower than those of the examples 1-3 of the invention.
Finally, it should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.
- 上一篇：一种医用注射器针头装配设备
- 下一篇：一种转炉用菱镁石留渣调渣护炉的方法