Spraying paint for reducing steel adhesion at converter mouth

Abstract

The invention relates to the technical field of converter smelting, and provides a spray coating for reducing steel adhesion at a converter mouth, the spray coating comprises the following components by weight: 30-40 parts of SiO2, 5-10 parts of Al2O3, 20-26 parts of a binder, and 12-20 parts of a component A, the component A is prepared from at least one of ZrO2, B4C and MoSi2; by means of the technical scheme, the problems that steel is prone to adhering to the converter mouth during converter smelting and the steel slag cleaning time is long in the related technology are solved.

Description

Technical Field

[0001] The invention relates to the technical field of converter smelting, and in particular to a spray coating for reducing steel sticking at a converter mouth. Background Art

[0002] During converter smelting, splashing will occur due to the violent reaction of CO, causing molten steel to adhere to the converter mouth, which will cause the converter mouth to shrink, making it difficult to add scrap steel, and prolonging the converter smelting cycle; in addition, the slag attached to the converter mouth is very difficult to remove, and a slag cleaning device is required to clean the slag. Each time the steel mill cleans the slag at the converter mouth, it takes more than 20 minutes, which seriously restricts the production rhythm. Therefore, there is an urgent need for a spray coating for the converter mouth that can alleviate the problem of steel sticking to the converter mouth, shorten the time for cleaning slag, and speed up the production rhythm. Summary of the invention

[0003] The invention provides a spray coating for reducing steel sticking at the converter mouth, solving the problem in the related art that steel is easily stuck at the converter mouth during converter smelting and the slag cleaning time is long.

[0004] The technical solution of the present invention is as follows: The present invention provides a spray coating for reducing steel sticking at the converter furnace mouth, comprising the following components in parts by weight: 30-40 parts of SiO2, 5-10 parts of Al2O3, 20-26 parts of a binder, and 12-20 parts of component A; The component A includes at least one of ZrO2, B4C, and MoSi2.

[0005] As a further technical solution, the component A includes the following components in parts by weight: 4-8 parts of ZrO2, 1-3 parts of B4C, and 7-9 parts of MoSi2.

[0006] In the present invention, ZrO2 has high bonding strength, good thermal shock resistance, corrosion resistance and high temperature resistance. It has a higher melting point than SiO2 and Al2O3, generally at 2700°C. Adding ZrO2 to the spray coating material and forming a coating after spraying can effectively reduce the porosity of the coating and have a lower thermal conductivity.

[0007] In the present invention, B4C is an effective antioxidant, which is added to the spray coating and then sprayed into a coating to prevent metal from decarburization at high temperature. The anti-oxidation mechanism of B4C is as follows: B atoms can react with O2 and CO to generate B2O3 in priority to C in the metal, and B2O3 reacts with Al2O3, SiO2, etc. to form molten borates, aluminates, silicates, etc., which can fill the pores inside the coating, block the oxygen diffusion channel, and change the surface quality of the metal to a certain extent. When the temperature is higher than 500°C, B4C is oxidized to B2O3, which will produce a volume expansion index of about 2.5 times, and the formed B2O3 phase has the ability of self-healing, which can repair cracks generated in the coating under high temperature conditions, and the molten B2O3 can change the internal structure by filling cracks and holes and reacting with SiO2 to form heat-resistant borosilicate glass.

[0008] As a further technical solution, the particle sizes of SiO2, Al2O3 and component A are all ≤0.5 mm.

[0009] As a further technical solution, the binder includes at least one of a silicate binder, a phosphate binder, and a silica sol.

[0010] As a further technical solution, when the binder is a phosphate binder and silica sol, the mass ratio of the phosphate binder to the silica sol is 2-4:1.

[0011] As a further technical solution, the phosphate binder includes at least one of an orthophosphate binder, a phosphite binder, and a modified phosphate binder.

[0012] As a further technical solution, the phosphate binder includes an aluminum phosphate binder.

[0013] As a further technical solution, the aluminum phosphate binder includes the following components in parts by weight: 7 to 9 parts of AlPO4 and 8 to 10 parts of Al(H2PO4).

[0014] In the present invention, the silicate binder is an environmentally friendly, non-toxic, easy to prepare, low-cost, and good bonding agent. Silicate will obtain high-energy Si-O bonds during high-temperature heating, so that the silicate binder has the advantages of strong bonding, high strength, good heat and acid resistance, etc., and can ensure the adhesion of the spray coating on the converter furnace mouth.

[0015] In the present invention, the phosphate binder can be orthophosphate, phosphite and modified phosphate. The phosphates composed of different metal elements have different bonding properties, and the constituent elements of the phosphate can be magnesium, aluminum, calcium, manganese, zinc, copper, iron, etc. Their bonding properties are from large to small: Al>Mg>Ca>Cu>Fe>Zn, so the phosphate binder is preferably an aluminum phosphate binder.

[0016] In the present invention, silica sol is a colloidal binder, which is a dispersion of nano-scale SiO2 particles in a solvent. The colloidal particles are very small, generally 10-20nm, and therefore can act as a filler in the coating to allow the spray coating to be densely coated on the converter furnace mouth. The SiO2 molecules in the silica sol binder carry many hydroxyl groups and can form a colloidal aqueous solution of SiO2·nH2O. During the heating process, the silica sol continuously loses water, and the single SiO2 molecules form a high-polymer silica gel. The generated SiO-O-SiO bond has the characteristics of high temperature resistance, oxidation resistance, and strong adhesion.

[0017] The present invention also proposes a method for preparing a spray coating for reducing steel sticking at a converter furnace mouth, comprising the following steps: The components of the spray coating material are mixed with water to obtain the spray coating material.

[0018] As a further technical solution, the mass of the water is 20% to 40% of the total mass of the components of the spray coating.

[0019] The present invention also proposes the use of the spray coating for reducing steel sticking at the converter mouth or the spray coating prepared by the preparation method in reducing steel sticking at the converter mouth, wherein the thickness of the spray coating during spraying is 3-5 mm and the spraying time is 2-4 min.

[0020] The working principle and beneficial effects of the present invention are: In the present invention, the chemical properties of SiO2 are relatively stable, with high melting point (generally 1723℃), small thermal expansion coefficient, corrosion resistance, high bond energy, large atomic size and other characteristics. It is the main material for the spray coating to be vitrified at high temperature; Al2O3 is a white solid that is difficult to dissolve in water, odorless, tasteless, extremely hard, easy to absorb moisture without deliquescing. The melting point of Al2O3 is generally 2054℃, the thermal expansion coefficient is small, the surface tension is moderate, and it can form mullite with SiO2. The thermal expansion coefficient of mullite is relatively low, generally less than 5.5×10 -6 K -1 , melting point is 1850℃, has good chemical inertness and excellent thermal shock resistance; at the same time, component A including at least one of ZrO2, B4C, and MoSi2 is added to the spray coating to achieve the purpose of reducing steel sticking to the converter mouth and making it easy to remove the sticking steel. Compared with the prior art, the use of the spray coating of the present invention can reduce steel sticking to the furnace mouth and shorten the time for cleaning slag. DETAILED DESCRIPTION

[0021] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] In the following embodiments and comparative examples, the particle size of SiO2 is 5~6nm, the particle size of Al2O3 is 5~6nm, the particle size of ZrO2 is 5~6nm, the particle size of AlPO4 is 5~6nm, the particle size of B4C is 5~6nm, the particle size of MoSi2 is 5~6nm, and the particle size of Al(H2PO4)3 is 5~6nm.

[0023] Example 1 The spray coating material for reducing the sticking of steel at the converter mouth comprises the following components in parts by weight: 40 parts of SiO2, 10 parts of Al2O3, 4 parts of ZrO2, 7 parts of AlPO4, 1 part of B4C, 9 parts of MoSi2, 10 parts of Al(H2PO4)3, and 5 parts of silica sol; A method for preparing a spray coating for reducing steel sticking at a converter furnace mouth comprises the following steps: The components of the spray coating are mixed with water to obtain the spray coating; wherein the mass of the water is 20% of the total mass of the components of the spray coating.

[0024] Example 2 The spray coating material for reducing the sticking of steel at the converter mouth comprises the following components in parts by weight: 35 parts of SiO2, 35 parts of Al2O, 6 parts of ZrO2, 9 parts of AlPO4, 2 parts of B4C, 27 parts of MoSi, 38 parts of Al(H2PO4), and 7 parts of silica sol; A method for preparing a spray coating for reducing steel sticking at a converter furnace mouth comprises the following steps: The components of the spray coating are mixed with water to obtain the spray coating; wherein the mass of the water is 30% of the total mass of the components of the spray coating.

[0025] Example 3 The spray coating for reducing the sticking of steel at the converter mouth comprises the following components in parts by weight: 30 parts of SiO2, 39 parts of Al2O3, 8 parts of ZrO2, 8.5 parts of AlPO4, 3 parts of B4C, 8.5 parts of MoSi2, 39.5 parts of Al(H2PO4), and 6.5 parts of silica sol; A method for preparing a spray coating for reducing steel sticking at a converter furnace mouth comprises the following steps: The components of the spray coating are mixed with water to obtain the spray coating; wherein the mass of the water is 40% of the total mass of the components of the spray coating.

[0026] Example 4 The only difference between this embodiment and embodiment 1 is that the spray coating for reducing steel sticking at the converter furnace mouth comprises the following components in parts by weight: 40 parts of SiO2, 10 parts of Al2O3, 14 parts of ZrO2, 7 parts of AlPO4, 10 parts of Al(H2PO4)3, and 5 parts of silica sol.

[0027] Example 5 The difference between this embodiment and embodiment 1 is that the spray coating material for reducing the sticking of steel at the converter mouth comprises the following components in parts by weight: 40 parts of SiO2, 10 parts of Al2O3, 7 parts of AlPO4, 14 parts of B4C, 10 parts of Al(H2PO4)3, and 5 parts of silica sol.

[0028] Example 6 The only difference between this embodiment and embodiment 1 is that the spray coating for reducing steel sticking at the converter furnace mouth includes the following components in parts by weight: 40 parts of SiO2, 10 parts of Al2O3, 7 parts of AlPO4, 14 parts of MoSi2, 10 parts of Al(H2PO4)3, and 5 parts of silica sol.

[0029] Example 7 The difference between this embodiment and embodiment 1 is that the spray coating material for reducing the sticking of steel at the converter furnace mouth includes the following components in parts by weight: 40 parts of SiO2, 10 parts of Al2O3, 4 parts of ZrO2, 7 parts of AlPO4, 1 part of B4C, 7 parts of MoSi2, 37 parts of Al(H2PO4), and 7 parts of silica sol.

[0030] Example 8 The difference between this embodiment and embodiment 1 is that the spray coating material for reducing the sticking of steel at the converter furnace mouth includes the following components in parts by weight: 40 parts of SiO2, 10 parts of Al2O3, 8 parts of ZrO2, 10 parts of AlPO4, 3 parts of B4C, 9 parts of MoSi2, 10 parts of Al(H2PO4)3, and 5 parts of silica sol.

[0031] Comparative Example 1 The difference between this comparative example and Example 1 is that the composition of the spray coating material for reducing steel sticking at the converter mouth does not include ZrO2, B4C and MoSi2.

[0032] The spray coatings prepared in Examples 1 to 8 and Comparative Example 1 were sprayed onto the converter mouth through a spraying device with a spray thickness of 4 mm, and a converter mouth without the spray coating was set as a blank example. After converter smelting, the slag removal time and slag removal interval were recorded. The results are shown in Table 1 below.

[0033] Table 1 Test results

[0034] Compared with the comparative example and the blank example, after the spray coating prepared in Examples 1 to 8 was sprayed onto the converter mouth, the slag beating was increased from once every 5 furnaces to once every 8 to 11 furnaces, which significantly shortened the slag beating time from more than 20 minutes per slag beating to a minimum of 8 minutes, which can speed up the converter steelmaking efficiency and improve the economic benefits.

[0035] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A spray coating for reducing steel sticking at the converter mouth, characterized in that: The invention comprises the following components in parts by weight: 30-40 parts of SiO2, 5-10 parts of Al2O3, 20-26 parts of a binder, and 12-20 parts of component A; The component A includes at least one of ZrO2, B4C, and MoSi2.

2. The spray coating material for reducing steel sticking at converter mouth according to claim 1, characterized in that: The component A comprises the following components in parts by weight: 4 to 8 parts of ZrO2, 1 to 3 parts of B4C, and 7 to 9 parts of MoSi2.

3. The spray coating material for reducing steel sticking at the converter mouth according to claim 1, characterized in that: The particle sizes of SiO2, Al2O3 and component A are all ≤0.5 mm.

4. The spray coating material for reducing steel sticking at the converter mouth according to claim 1, characterized in that: The binder includes at least one of a silicate binder, a phosphate binder, and a silica sol.

5. The spray coating material for reducing steel sticking at converter mouth according to claim 4 is characterized in that: When the binder is a phosphate binder and silica sol, the mass ratio of the phosphate binder to the silica sol is 2-4:

1.

6. The spray coating material for reducing steel sticking at converter mouth according to claim 5, characterized in that: The phosphate binder includes at least one of an orthophosphate binder, a phosphite binder, and a modified phosphate binder.

7. The spray coating material for reducing steel sticking at the converter mouth according to claim 6 is characterized in that: The phosphate binder includes an aluminum phosphate binder.

8. The spray coating material for reducing steel sticking at converter mouth according to claim 7, characterized in that: The aluminum phosphate binder includes the following components in parts by weight: 7 to 9 parts of AlPO4 and 8 to 10 parts of Al(H2PO4)3.

9. The method for preparing a spray coating material for reducing steel sticking at a converter furnace mouth according to any one of claims 1 to 8, characterized in that: The following steps are involved: The components of the spray coating material are mixed with water to obtain the spray coating material.

10. The method for preparing a spray coating material for reducing steel sticking at a converter furnace mouth according to claim 9, characterized in that: The mass of the water is 20% to 40% of the total mass of the components of the spray coating.

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