KR100348662B1 - Spray composition for repairing furnace inner wall - Google Patents

Abstract

PURPOSE: Provided is a spray composition for repair of furnace wall, which can increase a life of the furnace wall when used for repairing walls of various furnaces such as LDS(Linze Donawite Stirring). CONSTITUTION: The spray composition useful for repairing walls of various furnaces for holding hot molten steels, and so on, is produced by mixing dolomite(CaO), magnesia(MgO), chamotte(SiO2) materials, as main materials, by using sea water, wherein the salinity of the sea water is 6-8%, and the mixing ratio of the main materials to sea water is 88-90:10-12(in mass%).

Description

Spray composition for repairing furnace wall {Spray composition for repairing furnace inner wall}

The present invention relates to Dolomite or Magnesia, which reinforces the fire walls of the furnace walls of LDS (Linze Donawite Stirring) converters for refining molten steel, which is hot material, and similar (molten steel containers). In order to improve the efficiency during hot repair, the material and water are kneaded and attached, and at this time, the present invention relates to a spray material composition for repair to increase the adhesion efficiency.

Generally, the wall of the vessel, that is, the LDS converter, by stirring the melt refined at a high temperature during the refining of the scrap iron and the molten iron and the separation of impurities by refining the scrap iron and the molten iron during the refining of the LDS converter charging and refining the scrap iron and the molten iron. The interior material built with Chamotte (SiO ₂ ) on 13mm exterior is made of specially manufactured refractory bricks made of Mg-C.

The built-in refractory is continuously worn out by high-temperature steel refining, and it is repaired and repaired at an appropriate time in order to use it for a long time.In this case, an amorphous (quality of standard) material of magnesia material or dolomite material is used as the inner wall of the LDS converter furnace body. Apply by spraying with heat.

However, in order to increase the life of the furnace body, that is, the number of times of use, it is kneaded with the above-mentioned material and general industrial water and adhered to the furnace wall.

At this time, about 70% of the spray material to be attached is not attached, 30% is not attached, and 70%, which is estimated to be attached, also fails to serve as a poor adhesion to the refractory due to evaporation of water.

Conventionally, when spraying by spraying an amorphous refractory material made of magnesia with water on the inner wall of an LDS converter, the temperature of the inner wall of the furnace is 1400-1500 ° C., and a general powder (amorphous refractory material) is mixed with water. As a result of kneading and attaching, it is not effective as a result, and the material to be attached differs depending on whether it is chamotte material or magnesia material. Refractories in the places to be protected are Mg-C (ie, m-carbon) refractories, and the magnesite material is kneaded with industrial water only to a material that is triangular with water. For this purpose, that is, the water adheres to the refractory material of the Mg-C material is poor adhesion with the Mg-C.

This is due to the generation of H ₂ gas by MgO and water, the instantaneous adhesion is poor and also triangular with carbon.

The adhesion effect and the subsequent operating examples when used in the conventional water and mixing was examined as shown in Table 1 below.

TABLE 1

Operation result by spray mixing with water

As shown in Table 1 above, it is calculated to fall by 200 ~ 250 ℃ in view of the use of cooling temperature for adjusting dental temperature during the first operation after spraying due to kneading with water, and the adhesion is divided into three stages of initial, middle, and late stages. As a result, it was found that the effect had to be sprayed at the appropriate point in the end, and it was also found that the material was different from the area to be attached, so that it did not affect the actual life of the body. Mg-C-like refractory bricks of Mg-C-like refractory bricks may be attached to the gap between the Mg-C-like refractory bricks. Moisture was lated between the cracks in the fire wall, and when it evaporated to H ₂ , the fire wall and the recrystallization temperature were generated.

According to the number of furnace body used and spraying time (appropriate according to the number of body body used), it was confirmed that it was poor at the time of old paper (fire: stop for rebuilding according to internal smoke and wear rate). The results are shown in Table 2 below.

TABLE 2

Performance performed by spray cycle (3,500 fires)

As shown in Table 2 above, the spray was different depending on the number of times the body was used, but the situation was also different. Since the adhesion rate of the chamotte material is shown to be visible, the spray was changed to early, middle and late stages in light of LDS converter furnace life, but it was effective to carry out at the final waste paper. It is shown in Table 3 to continue to adhere to the refractory material of magnesia.

TABLE 3

Results of the sustained state of the material when reinforcing by body

Table 3 above shows the results of checking the results of spraying for each internal lead and material of the LDS converter in recent years, and the difference between materials is also large.

The present invention has been made to solve the above problems in consideration of the above problems, and the spray material composition for repairing the furnace wall to improve the life of the furnace wall when repairing the wall of the LDS converter or similar various furnaces. The purpose is to provide.

The present invention having the above object in the formation of a spray material for repairing various furnace walls for accommodating high-temperature molten steel, the main material is dolomite (CaO), magnesia (MgO), chamomile (SiO ₂ ) seawater Mixing is carried out using a salt water of 6 to 8%, and the mixing ratio of the main material and the sea water is mass%, the main material is 88 to 90%, and the sea water is 10 to 12%.

In the present invention, in forming a spray material for repairing various furnace walls for accommodating high-temperature molten steels, dolomite (CaO) and magnesia (M 2 O) chamomile (SiO 2), which are main materials, are mixed using seawater. The salinity of seawater is 6-8%, and the mixing ratio of the main material and the seawater is mass%, the main material is 88-90%, and the seawater 10-12%.

Referring to the operation of the present invention configured as described above is as follows.

Prior to the description, in the technique of the present invention, it is revealed that% used as the material mixing ratio means mass%.

According to the present invention, it is known that seawater contains 1.4 to 1.45 g / L as Mg ²⁺ , and as a reaction, it is produced and precipitated as microcrystalline particles of Mg (OH) ₂ .

Mg ²⁺ Ca (OH) ₂ = Mg (OH) ₂ + Ca ²⁺

Mg ²⁺ 4 (CaO + MgO) + ₂ H ₂ O = 2 Mg (OH) ₂ + Ca ²⁺

This Mg (OH) ₂ is an artificial brucite which is filtered and washed, and this brucite is produced with fine MgO (70 to 150Å) to complete pyrolysis at 450 ° C, and after complete cleavage at 1400 to 1500 ° C, H ₂ It can be directly confirmed that O evaporates as H ₂ and adheres and is supported as light or magnesia.

In the present invention using the same, the content of NaCl is 6 to 8% and 10 to 12% with the material, so that the test results applied to the furnace from the beginning of solid state to the end of papermaking are contained in Table 4 below. Compared with.

TABLE 4

Comparison between NaCl addition and non-addition

Table 4 shows the results of converter furnace life and the number of times the furnace was stopped according to the total number of attachments and the amount of material used. It is attached to carbon (Mg-C) -based softwads, and after 3,000 times, it is a chamotte, and when it is attached only with water, Mg-C material and NaCl mixture with 5 ~ 6Ch is 6-8%, and the material cost is 10%. Normally, it was supported by 9 to 10 times when the mixture was mixed with -12%. As a result, a small amount of material was used, but the life of the furnace until the paper was improved. As a result of the aging process, the sprayed and unbonded sites and the NaCl added and unadded sites were clearly identified.

As mentioned above, the magnesite resource requires excavation of Mg resources equivalent to salts in seawater. the ratio is different in the small-is the decarboxylation NaOH, the Ca (OH) by using the water in preparation for industrialization, Ca ⁺⁺ as NaCO ₂ except ₂ and Mg (OH) _2, Ca (OH) ₂ as a raw material in industry It can be used as a raw material having economical CaO content.

Its decarbonate is usually about 100 ppm of CO ₂ in seawater, but it becomes decarbonated at about 15 ppm. 15ppm is (CO ₂ ^-) and has since become a solubility ever 9 ⁹ × 10 ⁹ (℃ 15) of from about 33x 10-4 mol / l CaCO ₃ becomes active is shown the reaction of water and lime solution, (Ca ^{+ +} ) CaCO precipitates as it becomes larger than (CO ₃ ⁻ ) 2 × 10 −7 mol / l calculated from 0.05 mol / l, indicating that the salt is contained in a small amount, which is already known.

The present invention using the above is kneaded as a general material (industrial water), whether magnesia or dolomite, and attached to the Mg-C vaginal lining wall having a high temperature of 1400-1500 ° C. Nopilsu the concentration of sea water reuk strong needle power, the gyeoljipryeok material spray was stronger, during mixing only H ₂ O As a result of using the same are severe thermal change slightly which was which was dolomite materials magnesia material as H ₂ O is evaporated to H ₂ In the impact of, the adhesion strength is weak, so it is dropped or disintegrated, but NaCl has its own high temperature sedimentation adhesion effect so it does not fall off and its life is long.The results of magnesia hydration test showed that (SiO ₂ : 1.24%, Al ₂ O ₃ + Fe ₂ O ₃ : 1.32%, CaO: 1.94%, MgO: 44.4%, lgLoss: 51.06%) The calcined magnesia (100mesh milling) reduces the power to 102 ~ 105 ℃ when dried for 1 day in a similar desiccator when kneading with water. Is to have.

At 500 ° C, calcination is insufficient, calcination at 600 to 800 ° C is fully hydrated after 3 days, and at 800 to 900 ° C, Silicate and Alminate are formed upon decomposition into Calcuite, and more water is required for hydration of MgO. It is necessary to see the optimum of MgO hydration at 100 ~ 1100 ℃, and close to the firing temperature of cement at over 1450 ℃, reaching 61.4% of the planned amount of total hydration. This power is known to be used for burning metal mugs of white powder with lattice constant a = 4.203Å, bond spacing Mg-0-2.10Å), and it is known to be used in thermal interlocks or refractory materials due to its high melting point (2800 ℃). Indeed, the LDS-gerger was applied to internal lead and protection methods.

As described above, the test results of 10 to 12% of the MgO and CaO precipitated in industrial water so as to precipitate the NaCl concentration (6 to 8%) in the industrial water so as to adhere to the hot refractory material is best mixed. It was found that the surface of the attached surface was also flat without pore hole, and found the best among several methods. This is because the brucite pyrolyzes at 450 ℃ and converts to full MgO at 1400 ℃, so that the thermal reaction of Mg lasts up to 2800 ℃ and the cover of thermal conductivity is high. It is considered that it is an optimal method for reinforcing the body, which can extend the service life because there is no thermal change in the case of LDS converter, which is a water handling container, and the life of the body due to reinforcement of Mg-C quality is also more than 4500 times. have.

Therefore, the water is made of HOH to oxidize Ca or Mg, and in CaO, MgO form, hot water Ca or Mg contains NaCl, etc. And since the adhesive has a very high result during hot repair.

The above-mentioned chamogum is an acid refractory silicate, which is composed of SiO ₂ : 55-65%, MgO and Al ₂ O ₃ containing 30-50%, and magnesia is basic, MgO: 75-95% , SiO ₂ , Fe ₂ O ₃ and the like, and MgO: 20 to 50% of SiO ₂ , Fe ₂ O _3, etc. are added. Dolomite is also basic, CaO: 30 to 65%, MgO: 20 to 40% contains SiO ₂ , Al ₂ O ₃ , Fe ₂ O _3, and the like.

Their forms and irregularities are the ones that are manufactured to the size of the regular standard, and the irregular ones are used in various places as needed as powder (with appropriate particles) (ie, the amorphous form is coagulant and binder product).

Looking at the composition of these materials are shown in Table 5.

TABLE 5

As described above, the present invention has the effect of extending the life of the LDS converter and various containers by spraying and repairing the repairing material of the present invention on the wall surface of the LDS converter or other containers containing the hot steel.

Claims (1)

In forming a spray material for repairing various furnace walls for accommodating high-temperature molten steels, dolomite (CaO), magnesia (MgO) and chamomile (SiO ₂ ), which are main materials, are mixed with seawater. The salinity of 6 to 8%, and the mixing ratio of the main material and sea water is a mass%, the main material 88-90%, sea water 10 to 12%, characterized in that the spray material composition for repairing the furnace body.