Acid-resistant coating material for hot blast stove and preparation method of acid-resistant coating material

Abstract

The invention provides an acid-resistant coating material for a hot blast stove and a preparation method of the acid-resistant coating material. The acid-resistant coating material comprises the following raw materials in parts by mass: 40-60 parts of alumina clinker; 5 to 10 parts of kyanite; 5-10 parts of waste clay brick powder; 15 to 20 parts of first-grade clay powder; recovering 3-5 parts of silicon dioxide micro powder from an electric furnace; 20-50 parts of instant sodium silicate; the weight of the added water is 20-40% of the total weight of the raw materials. The acid-resistant coating material has the characteristics of high compression strength, good acid corrosion resistance, strong adhesive ability and the like.

Description

Technical Field

[0001] The invention relates to the field of amorphous refractory materials, in particular to an acid-resistant coating material for a hot blast stove and a preparation method thereof. Background Art

[0002] In the prior art, a layer of coating is generally applied inside the hot blast furnace, which, on the one hand, plays the role of heat insulation and increasing air tightness, and on the other hand, can ensure the safety of the furnace shell. Currently, the commonly used coating is a lightweight spray coating (such as aluminum-silicon spray coating). However, due to the large apparent porosity and low volume density of the lightweight spray coating, the internal structure does not form an effective and dense connection. Therefore, compared with dense refractory materials, its compressive strength is relatively low, and its wear resistance and acid corrosion resistance are poor.

[0003] Based on this, it is necessary to design a coating with high compressive strength, excellent wear resistance and acid corrosion resistance. Summary of the invention

[0004] In order to solve the deficiencies in the prior art, the present invention provides an acid-resistant coating for a hot blast furnace and a preparation method thereof. The acid-resistant coating has the characteristics of high compressive strength, good acid corrosion resistance, strong adhesion and the like.

[0005] In order to achieve the above object, the specific scheme adopted by the present invention is: On the one hand, the present invention discloses an acid-resistant coating material for a hot blast furnace, comprising the following raw materials in parts by weight: 40-60 parts of alumina clinker; 5-10 parts of kyanite; 5-10 parts of waste clay brick powder; 15-20 parts of first-grade clay powder; 3-5 parts of silicon dioxide powder are recovered by electric furnace; 20-50 parts of instant sodium silicate; Add water according to 20%-40% of the total weight of the above raw materials.

[0006] Furthermore, the invention comprises the following raw materials in parts by weight: 60 parts of alumina clinker, 10 parts of kyanite, 10 parts of waste clay brick powder, 17 parts of primary clay powder, 3 parts of silica powder recovered from an electric furnace, and 23 parts of instant sodium silicate; and 20% of the total weight of the above raw materials is added with water.

[0007] Further, the particle size of the alumina clinker is 0.5-0 mm; The particle size of kyanite is less than 0.088 mm; The particle size of waste clay brick powder is less than 0.088mm; The particle size of the first-grade clay powder is less than 0.088mm; The particle size of silica powder recovered from the electric furnace is less than 5μm.

[0008] Furthermore, the mass fraction of Al2O3 in the alumina clinker is ≥45%, the mass fraction of Al2O3 in the kyanite is ≥56%, the mass fraction of Al2O3 in the waste clay brick powder is ≥42%, the mass fraction of Al2O3 in the primary clay is ≥33%, and the mass fraction of SiO2 in the silicon micropowder is ≥98.5%.

[0009] On the other hand, the present invention discloses a method for preparing an acid-resistant coating material for a hot blast furnace, comprising the following steps: (1) Weigh each raw material according to the formula; (2) Place alumina clinker and instant sodium silicate into a stirring device and stir for 1-2 minutes; (3) Place kyanite, waste clay brick powder, primary clay powder, and silica powder recovered from an electric furnace in a premixer and mix for 1-2 minutes to obtain a premixed fine material; (4) Add the premixed fine powder matrix in step (3) into the stirring device in step (2), add an appropriate amount of water, and stir for 1-2 minutes.

[0010] It should be noted that in the process of preparing the acid-resistant coating, the instant sodium silicate is fully and evenly dispersed with alumina clinker in step (2). The powder premixing in step (3) can prevent the powder with a small content from being unevenly distributed and avoid segregation.

[0011] The role of each raw material in the present invention is described below.

[0012] Alumina clinker: As the main component with high refractoriness, it has strong chemical stability and high temperature resistance.

[0013] Kyanite: As an expansion agent component, it expands slightly at high temperature to offset the shrinkage between raw materials. If added in large amounts, it will cause too much expansion, reduce material strength, and the cost is too high, which is not cost-effective.

[0014] Waste clay brick powder: As a binder in plastic material components, it can make the mortar soft and ductile, while utilizing waste resources and saving costs.

[0015] First-grade clay powder: good plasticity and bonding properties, suitable shrinkage and high refractoriness.

[0016] Electric furnace recycling of silica powder: enhance the fluidity of the coating and improve the bonding strength of the coating.

[0017] Instant Sodium Silicate: used as a binder, it can improve the strength of the coating and resist acid corrosion. Its addition does not introduce low-melting-point substances, thus ensuring high-temperature performance.

[0018] Beneficial effects:

[0019] (1) The present invention adds a certain amount of kyanite to cause the coating material to expand slightly at high temperature, thereby avoiding cracking due to shrinkage and preventing the furnace shell from being corroded by acid.

[0020] (2) The instant sodium silicate is added as a binder in the present invention, which has a high viscosity at room temperature and can prevent the coating from peeling off. It also has excellent acid and heat resistance, which can make the coating have good acid corrosion resistance.

[0021] (3) The present invention adds a certain amount of silicon dioxide powder so that the prepared coating material has good fluidity at a lower water addition amount, thereby ensuring convenient construction and obtaining higher strength.

[0022] (4) In addition to recycling silicon dioxide powder in an electric furnace, the present invention uses 0-0.5 mm small-particle alumina clinker aggregate and powder less than 0.088 mm. The small-particle aggregate effectively prevents slurry sedimentation during construction, and the 0.088 mm powder effectively prevents large shrinkage caused by extremely fine powder.

[0023] (5) The acid-resistant coating material for the hot blast furnace of the present invention has better slag resistance, acid corrosion resistance and wear resistance, and the hot blast furnace has a longer service life. The present invention is convenient to construct, does not go through a firing process, and can be directly baked for use, has obvious economic benefits, and has the advantages of simple process, energy saving, easy construction, and low cost. DETAILED DESCRIPTION

[0024] The technical solution of the present invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0025] In order to more clearly understand the technical content of the present invention, the following examples are given in detail. Among the raw materials used in the following examples, the mass fraction of Al2O3 in the alumina clinker is ≥45%, the mass fraction of Al2O3 in the kyanite is ≥56%, the mass fraction of Al2O3 in the waste clay brick powder is ≥42%, the mass fraction of Al2O3 in the primary clay is ≥33%, and the mass fraction of SiO2 in the silicon micropowder is ≥98.5%.

[0026] Example 1 An acid-resistant coating material for a hot blast stove of the present embodiment is prepared according to the following steps: (1) Weigh 50 parts of alumina clinker with a particle size of 0.5-0 mm, 10 parts of kyanite with a particle size of less than 0.088 mm, 10 parts of waste clay brick powder with a particle size of less than 0.088 mm, 17 parts of primary clay powder with a particle size of less than 0.088 mm, 3 parts of electric furnace recovered silica powder with a particle size of less than 5 μm, and 30 parts of instant sodium silicate; (2) Place alumina clinker and instant sodium silicate into a stirring device and stir for 2 minutes; (3) Place kyanite, waste clay brick powder, primary clay powder, and silica powder recovered from an electric furnace in a premixer and mix for 2 minutes to obtain a premixed fine material; (4) Add the premixed fine powder matrix in step (3) into the stirring device in step (2), add 30% of the total weight of the above raw materials with water, and stir for 2 minutes.

[0027] Example 2 An acid-resistant coating material for a hot blast stove of the present embodiment is prepared according to the following steps: (1) Weigh 60 parts of alumina clinker with a particle size of 0.5-0 mm, 10 parts of kyanite with a particle size of less than 0.088 mm, 10 parts of waste clay brick powder with a particle size of less than 0.088 mm, 17 parts of primary clay powder with a particle size of less than 0.088 mm, 3 parts of electric furnace recovered silica powder with a particle size of less than 5 μm, and 25 parts of instant sodium silicate; (2) Place alumina clinker and instant sodium silicate into a stirring device and stir for 2 minutes; (3) Place kyanite, waste clay brick powder, primary clay powder, and silica powder recovered from an electric furnace in a premixer and mix for 1 minute to obtain a premixed fine material; (4) Add the premixed fine powder matrix in step (3) into the stirring device in step (2), add water according to 37% of the total weight of the above raw materials, and stir for 2 minutes.

[0028] Example 3 An acid-resistant coating material for a hot blast stove of the present embodiment is prepared according to the following steps: (1) Weigh 60 parts of alumina clinker with a particle size of 0.5-0 mm, 10 parts of kyanite with a particle size of less than 0.088 mm, 10 parts of waste clay brick powder with a particle size of less than 0.088 mm, 17 parts of primary clay powder with a particle size of less than 0.088 mm, 3 parts of electric furnace recovered silica powder with a particle size of less than 5 μm, and 23 parts of instant sodium silicate; (2) Place alumina clinker and instant sodium silicate into a stirring device and stir for 2 minutes; (3) Place kyanite, waste clay brick powder, primary clay powder, and silica powder recovered from an electric furnace in a premixer and mix for 1 minute to obtain a premixed fine material; (4) Add the premixed fine powder matrix in step (3) into the stirring device in step (2), add water according to 20% of the total weight of the above raw materials, and stir for 1 minute.

[0029] Comparative Example 1 The acid-resistant coating material for a hot blast furnace disclosed in this comparative example is prepared according to the following steps: (1) Weigh 40 parts of alumina clinker with a particle size of 0.5-0 mm, 20 parts of kyanite with a particle size of less than 0.088 mm, 10 parts of waste clay brick powder with a particle size of less than 0.088 mm, 27 parts of primary clay powder with a particle size of less than 0.088 mm, 3 parts of electric furnace recovered silica powder with a particle size of less than 5 μm, and 50 parts of instant sodium silicate; (2) Place alumina clinker and instant sodium silicate into a stirring device and stir for 1 minute; (3) Place kyanite, waste clay brick powder, primary clay powder, and silica powder recovered from an electric furnace in a premixer and mix for 2 minutes to obtain a premixed fine material; (4) Add the premixed fine material in step (3) to the mixing device in step (2), add water according to 25% of the total weight of the above raw materials, and stir for 2 minutes to obtain the product.

[0030] The laboratory test indicators of the acid-resistant coatings prepared in Examples 1-3 and Comparative Example 1 are shown in Table 1. The standards used for the tests are: GB / T 6900 for chemical analysis, GB / T 7322 for refractoriness, GB / T3001 for room temperature flexural strength, GB / T 5072 for room temperature compressive strength, GB / T 5988 for heating permanent linear change, and YB / T 5202.1 for the preparation method of acid-resistant coating samples.

[0031] Table 1 Performance indicators of acid-resistant coatings prepared in Examples 1-3 and Comparative Example 1 Example 1 Example 2 Example 3 Comparative Example 1 Refractoriness, ℃ ≥1430 ≥1500 ≥1550 ≥1500 <![CDATA[Chemical composition, (Al2O3%)]]> 48.32 51.71 49.42 50.1 Flexural strength at room temperature, MPa (after acid treatment) 4.3 3.5 5.3 2.5 Compressive strength at room temperature, MPa (after acid treatment) 15 12 18 10 Linear change rate after burning 1300×3h, % -(1.0～1.1) -(1.0～1.1) +(1.0～1.1) -(1.0～1.1)

[0032] It can be seen from Table 1 that, compared with Comparative Example 1, the room temperature flexural strength of the acid-resistant coating prepared in Examples 1-3 is not less than 3.5 MPa, and the room temperature compressive strength is not less than 12 MPa. The present invention improves the flexural and compressive strength of the acid-resistant coating by optimizing the process ratio, enhances its corrosion resistance, greatly improves the service life of the hot blast furnace, and creates economic value.

[0033] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any equivalent changes or modifications made according to the essence of the present invention should be included in the protection scope of the present invention.

Claims

1. An acid-resistant coating material for a hot blast stove, characterized in that: Contains the following raw materials in parts by weight: 50-60 parts of alumina clinker; 5-10 parts of kyanite; 5-10 parts of waste clay brick powder; 15-20 parts of first-grade clay powder; 3-5 parts of silicon dioxide powder are recovered by electric furnace; 20-30 parts of instant sodium silicate; Add water according to 20-40% of the total weight of the above raw materials.

2. The acid-resistant coating material for hot blast stoves according to claim 1, characterized in that: The method comprises the following raw materials in parts by weight: 60 parts of alumina clinker, 10 parts of kyanite, 10 parts of waste clay brick powder, 17 parts of primary clay powder, 3 parts of silicon dioxide powder recovered from an electric furnace, and 23 parts of instant sodium silicate; and 20% of the total weight of the above raw materials is added with water.

3. The acid-resistant coating material for hot blast stove according to claim 1, characterized in that: The particle size of alumina clinker is 0.5-0mm; The particle size of kyanite is less than 0.088 mm; The particle size of waste clay brick powder is less than 0.088mm; The particle size of the first-grade clay powder is less than 0.088mm; The particle size of silica powder recovered from the electric furnace is less than 5μm.

4. The acid-resistant coating material for hot blast stoves according to claim 1, characterized in that: The mass fraction of Al2O3 in the alumina clinker is ≥45%, the mass fraction of Al2O3 in the kyanite is ≥56%, the mass fraction of Al2O3 in the waste clay brick powder is ≥42%, the mass fraction of Al2O3 in the primary clay is ≥33%, and the mass fraction of SiO2 in the silicon micropowder is ≥98.5%.

5. A method for preparing an acid-resistant coating material for a hot blast stove, characterized in that: The following steps are involved: (1) Weigh each raw material according to the formula; (2) Place alumina clinker and instant sodium silicate into a mixing device and stir for 1-2 minutes; (3) Place kyanite, waste clay brick powder, primary clay powder, and silica powder recovered from an electric furnace in a premixer and mix for 1-2 minutes to obtain a premixed fine material; (4) Add the premixed fine powder matrix in step (3) into the stirring device in step (2), add an appropriate amount of water, and stir for 1-2 minutes.