JPH0235706B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a lining structure for a container for hot metal such as a hot metal trough or a hot metal pot. [Prior Art] In recent years, in order to improve the quality of steel, preliminary treatment of hot metal has been carried out in hot metal sluices, pig iron mixing cars, hot metal pots, etc. In other words, mill scale, soda ash, quicklime and fluorspar, to reduce silicon, phosphorus and sulfur in hot metal.
Also, processing agents such as quicklime, fluorspar, and calcium chloride are used. The above-mentioned treatment agent is added by placing it on top of the hot metal or by blowing it into the hot metal with a lance. However, these methods have drawbacks such as insufficient reaction, severe damage to the blowing lance, and low processing efficiency. In addition, SiO ₂ − _{Al 2} O ₃ based materials, Al ₂ O ₃ −
A C-based material or an Al ₂ O ₃ -SiC-C based material is used. The purpose of refractory lining using the above-mentioned materials is to ensure the life of the furnace of hot metal runners, hot metal ladle or pig iron mixing cars. In conventional hot metal pretreatment methods, the refractory lining and the hot metal pretreatment agent are considered to be completely different. Quicklime has traditionally been used as a pretreatment agent for hot metal, but this is quicklime that has been soft-burned at temperatures of 1300°C or higher, and its activity is significantly lower than that of CaO produced from limestone. In other words, it is preferable that soft-burned quicklime satisfies the following conditions: It has almost the same strength and moisture resistance as hard-burned CaO, and the reaction with hot metal due to the decrease in CaO activity exhibited by hard-burned CaO is It has high activity without the disadvantage of low activity. On the other hand, various uses of lime refractories have been made for molten steel containers. For example, JP-A-57-44669 discloses an example in which limestone bricks are used in the steel melting part of a molten steel ladle. Furthermore, Japanese Utility Model Application Publication No. 57-76956 gives an example of using a calcareous refractory with a CaO content of 90% or more in a tundish. In addition, Tokukai Akira
Publication No. 55-51763 cites an example in which limestone is used for the tundish. The above-mentioned inventions and devices other than JP-A-55-51763 have the problem of digesting lime and are inferior in reactivity because they use hard-burned lime. Furthermore, the invention disclosed in JP-A-55-51763 relates to molten steel and does not relate to the treatment of molten pig iron. Limestone is used as a coating for the tundish by reacting the oxide inclusions that occur in the steel with CaO and floating them in the tundish as low-melting slag, or by reducing the SiO ₂ in the lining refractory. It becomes Si and is used to prevent it from eluting into steel. In order to actively remove phosphorus and sulfur from hot metal and improve the quality of steel produced in steelmaking furnaces, it is desired to develop a superior process for the lining structure of hot metal containers. [Object of the invention] The present invention was made in view of the above-mentioned circumstances, and its object is to coat a material containing limestone, magnesia limestone, and calcium chloride or calcium chloride and calcium fluoride. It is an object of the present invention to provide a lining structure that can protect a refractory lining material and serve as a treatment agent for hot metal. [Structure of the invention] The present invention provides at least one of limestone and magnesia limestone.
It is characterized by coating the surface of the refractory lining of a hot metal container with a material made by adding 1 to 40 parts by weight of calcium chloride or both calcium chloride and calcium fluoride to 100 parts by weight of seeds, binder, and plasticizer. The purpose of the present invention is to provide a lining structure for a container for hot metal. The limestone and magnesium limestone used in the present invention are not particularly limited, but those having particle size configurations such as conventional spraying materials, pouring materials, stamp materials, etc. can be used satisfactorily. As the inorganic binder for cold or hot use in the present invention, alumina cement, magnesia cement, various phosphates, various silicates, borates, etc. can be used. The amount of the binder added is preferably 0.5 to 10 parts by weight per 85 to 99 parts by weight of limestone or magnesia. If it is less than 0.5 part by weight, it is undesirable because adhesiveness or bonding strength is poor, and 10
If the amount exceeds 1 part by weight, desulfurization and dephosphorization will become insufficient during hot metal treatment, which is not preferable. Plasticizers used in the present invention include various clays,
Ca(OH) ₂ and organic plasticizers can be used. The amount of plasticizer added is preferably 0.5 to 5 parts by weight. If it is less than 0.5 parts by weight, the viscosity will be insufficient and construction will become difficult, and if it exceeds 5 parts by weight, the viscosity will be high, which may cause nozzle clogging during spraying or failure to obtain fluidity during castable casting, which is not preferable. Furthermore, at least one of the above-mentioned limestone and magnesia limestone.
Slag-forming properties can be improved by adding 1 to 40 parts by weight of calcium chloride or both calcium chloride and calcium fluoride to 100 parts by weight of seeds, binder, and plasticizer. The amount of calcium chloride or both calcium chloride and calcium fluoride added is 1
If it is less than 40 parts by weight, it is not much different from the above-mentioned combination of limestone, magnesia limestone, inorganic binder, and plasticizer, and if it exceeds 40 parts by weight, it is not preferable because it causes large shrinkage after construction and floats on top of the hot metal. The above materials can be coated on a part or the entire surface of the refractory lining of a hot metal trough, a hot metal ladle, a pig iron mixing car, etc. The coating method of the present invention includes a pouring method,
A stamping method or a spraying method can be used. However, among the above-mentioned methods, the spraying method is the most desirable, as it is capable of cold construction and hot construction, and has the characteristics of easy construction. The thickness of the coating is preferably 1 to 80 mm. If it is less than 1 mm, the desulfurization and dephosphorization effects will be small, and if it exceeds 80 mm, no further effect will be obtained. [Examples] The present invention will be explained in more detail below using Examples and Comparative Examples, but the present invention is not limited to the following Examples unless it exceeds the gist thereof. Example 1 Coating materials (products of the present invention ~) were prepared in the proportions shown in Table 1 below, and sprayed onto the bottom and side wall portions of a hot metal trough manufactured by Company A. The thickness of the coating is approximately 80 mm. Dephosphorization in a hot metal trough coated with the product of the present invention
The desulfurization effects are summarized in the same table.

[Table] *Comparison before and after treatment The dephosphorization and desulfurization efficiency in Table 1 above is when dephosphorization and desulfurization are performed on hot metal after desiliconization treatment in the lower part of the same hot metal trough. With the conventional addition of quicklime and fluorspar, the dephosphorization and desulfurization efficiencies were 80% and 85%, respectively. Table 1 shows that the products of the present invention are superior to conventional products. Example 2 Coating materials (products of the present invention ~) were prepared in the proportions shown in Table 2 below, and sprayed onto the pigtail receiving port and bottom of a pig iron mixer manufactured by Company B. The thickness of the coating is approximately 50 mm. Incidentally, the pig iron mixer manufactured by Company B conventionally used a lance to inject quicklime, calcium chloride, and fluorite. Dephosphorization in a pig iron mixer coated with the product of the present invention
The desulfurization efficiency is summarized in the same table.

【table】

[Table] *Comparison before and after treatment By applying the product of the present invention, the efficiency increased by approximately 10% compared to conventional dephosphorization and desulfurization rates, and it was found that the lining method is sufficiently effective. [Effects of the Invention] The structure of the present invention protects the refractory lining and decarburizes the refractory lining at a temperature of about 800 to 1000°C depending on the temperature of the hot metal during passing or receiving of the hot metal to generate active CaO. At this time, the CO ₂ gas bubbles the hot metal,
In addition to being able to stir, it uses fine and active CaO to actively remove phosphorus, sulfur, etc. dissolved in hot metal. In addition, since it is limestone or magnesia limestone, it is easier to handle than quicklime and is superior in terms of storage and hygiene. Furthermore, refractory linings made of limestone or magnesia limestone have lower durability than conventional refractory linings, but they protect the hot metal container and improve durability. Furthermore, as is clear from Tables 1 and 2 above, the lining of the present invention improves the dephosphorization and desulfurization effects. It has also been found that the lining improves the furnace life of the hot metal gutter manufactured by Company A and the pig iron mixer car manufactured by Company B by about 5%, and has a positive effect on the furnace life.

Claims (1)

[Claims] 1. Calcium chloride or both calcium chloride and calcium fluoride in 100 parts by weight of at least one of limestone, magnesia limestone, binder and plasticizer.
A lining structure for a hot metal container, characterized in that the surface of the refractory lining of the hot metal container is coated with a material containing 40 parts by weight.