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CN-121591524-B - Thermal state magnesium spinel brick surface coating and preparation method thereof

CN121591524BCN 121591524 BCN121591524 BCN 121591524BCN-121591524-B

Abstract

The application discloses a thermal state magnesia spinel brick surface coating and a preparation method thereof, wherein the surface coating comprises, by weight, 40% -70% of an aggregate system, 28% -50% of a bonding system, 1% -5% of a sintering aid and 1% -5% of an additive, the aggregate system comprises, by weight, 30% -50% of magnesia spinel brick regenerated powder, 10% -20% of functional fine powder, and the bonding system comprises, by weight, 10% -20% of activated alumina micropowder, 5% -15% of light burned magnesia powder and 3% -8% of silica micropowder. The coating forms a firm chemical bonding interface, has obviously higher bonding strength than the traditional normal-temperature coating, greatly improves the anti-peeling capability, reduces the cost by using waste bricks as raw materials, accords with the recycling economy concept, prolongs the service life of brick bodies, reduces the replacement frequency and saves the energy and the cost.

Inventors

  • CAO ZHIWEN
  • LIU JIANBO
  • LIU YU

Assignees

  • 湖南湘钢瑞泰科技有限公司

Dates

Publication Date
20260508
Application Date
20260129

Claims (10)

  1. 1. The preparation method of the thermal state magnesium spinel brick surface coating is characterized by comprising the following steps: Carrying out surface pretreatment on the thermal state magnesium spinel brick; Weighing the additive according to the proportion, adding the additive into a liquid carrier for mixing, and then adding the dry mixture to obtain suspension slurry; Coating the suspension slurry on the surface of the pretreated thermal state magnesium spinel brick to obtain a thermal state magnesium spinel brick surface coating; Preparing bottom layer slurry, middle layer slurry and surface layer slurry respectively, and sequentially spraying through a multi-fluid spray gun or sequentially brushing the bottom layer slurry, the middle layer slurry and the surface layer slurry by using a brushing tool to form a gradient coating on the surface of the thermal magnesium spinel; The bottom layer slurry comprises, by weight, 40% -50% of an aggregate system, 45% -50% of a bonding system, 3% -5% of a sintering aid and 2% -5% of an additive, the middle layer slurry comprises, by weight, 30% -45% of an aggregate system, 45% -50% of a bonding system, 8% -15% of a sintering aid and 2% -5% of an additive, and the surface layer slurry comprises, by weight, 20% -40% of an aggregate system, 45% -60% of a bonding system, 8% -10% of a sintering aid and 7% -10% of an additive. The aggregate system comprises, by weight, 30-50 parts of magnesium spinel brick regenerated powder, 10-20 parts of functional fine powder, 10-20 parts of activated alumina micropowder, 5-15 parts of light burned magnesia powder and 3-8 parts of silica micropowder.
  2. 2. The method according to claim 1, wherein the particle size of the magnesium spinel brick regenerated powder is less than or equal to 0.088mm, and the particle size of the functional fine powder is less than or equal to 0.044mm.
  3. 3. The preparation method of claim 1, wherein d 50 of the active alumina micro powder is less than or equal to 2.5 μm, the particle size of the light burned magnesia powder is less than or equal to 0.044mm, and the particle size of the silicon micro powder is less than or equal to 1 μm.
  4. 4. The method according to any one of claims 1 to 3, wherein the additive comprises a dispersant and a thickener, and the weight ratio of the dispersant to the thickener is 1:0.1-2.
  5. 5. The method according to claim 1 to 3, wherein the sintering aid is selected from one or more of boric acid, anhydrous borax, lithium carbonate, calcium fluoride, zinc oxide, barium salt, and/or, The functional fine powder is one or more selected from fused magnesia powder, sintered magnesia powder, zirconia powder and silicon carbide powder.
  6. 6. The preparation method according to any one of claims 1 to 3, wherein the raw materials comprise, by weight, 30-50 parts of magnesium spinel brick regenerated powder, 10-20 parts of functional fine powder, 10-20 parts of activated alumina micropowder, 5-15 parts of light burned magnesia powder, 3-8 parts of silica micropowder, 2-5 parts of sintering aid and 2-5 parts of additive.
  7. 7. The method according to claim 1, wherein the surface temperature of the thermal magnesium spinel brick is maintained at not lower than 800 ℃ when the thermal magnesium spinel brick is pretreated.
  8. 8. The method according to claim 1, wherein the step of coating is performed after the step of coating is performed, the temperature is raised to 1000 ℃ or higher and maintained for 10 to 30 minutes.
  9. 9. The method according to claim 1, wherein in the step, the coating operation temperature is 800 ℃ to 1200 ℃, the distance between the spray gun opening and the surface of the thermal state magnesium spinel brick is 200mm to 400mm, and the thickness of the coating is 1.0mm to 3.0mm.
  10. 10. A thermal state magnesium spinel brick surface coating prepared by the preparation method of any one of claims 1 to 9.

Description

Thermal state magnesium spinel brick surface coating and preparation method thereof Technical Field The application relates to the technical field of coatings of magnesium spinel bricks, in particular to a thermal state magnesium spinel brick surface coating and a preparation method thereof. Background The magnesia spinel brick is widely applied to key parts such as RH furnace vacuum chamber, cement rotary kiln transition zone, glass melting furnace regenerator and the like due to excellent alkali corrosion resistance and high temperature performance. However, in the actual use process, temperature fluctuation in the kiln and penetration and erosion of harmful components (such as alkali metal, sulfur, chlorine and the like) can gradually damage the surface of the magnesium spinel brick, such as peeling, loose structure and the like, so that kiln stopping and replacement are required, and the production efficiency and the economic benefit are seriously affected. The thermal state coating can be used as an 'active armor' to form a high-density corrosion-resistant barrier on the surface of the brick body in situ, and the property attenuation of the body material under extreme conditions is purposefully compensated. In the prior art, most of refractory material coatings are constructed at normal temperature or require the refractory bricks to be cooled to a lower temperature and then treated, so that the bonding strength, the thermal matching property and the permeation resistance of the coatings and a thermal state matrix are often poor. The coating and the thermal state matrix mainly depend on anchoring and limited physical and chemical combination, the strength attenuation of an interface is obvious at high temperature, the thermal mechanical properties are not matched, the thermal stress concentration is caused by the difference of the thermal expansion coefficients of the coating and the matrix, the protection timeliness of the coating is limited, the coating is easy to peel off or lose efficacy under the complex kiln working condition, and the effective on-line repair and protection of the thermal state magnesium spinel brick cannot be realized. Disclosure of Invention The invention provides a thermal state magnesium spinel brick surface coating and a preparation method thereof, which are used for solving the technical problems that a refractory material coating is easy to peel off or lose efficacy under a complex working condition and on-line repair or preventive reinforcement of the thermal state magnesium spinel brick cannot be realized in the prior art. In order to achieve the above purpose, the technical scheme provided by the invention is as follows: The invention provides a thermal-state magnesium spinel brick surface coating, which comprises, by weight, 40% -70% of an aggregate system, 28% -50% of a bonding system, 1% -5% of a sintering aid and 1% -5% of an additive, wherein the aggregate system comprises, by weight, 30% -50% of magnesium spinel brick regenerated powder, 10% -20% of functional fine powder, and the bonding system comprises, by weight, 10% -20% of activated alumina micropowder, 5% -15% of light-burned magnesium oxide powder and 3% -8% of silicon micropowder. Further, the particle size of the magnesium spinel brick regeneration powder is smaller than or equal to 0.088mm, and the particle size of the functional fine powder is smaller than or equal to 0.044mm. Further, d 50 of the active alumina micro powder is less than or equal to 2.5 mu m, the particle size of the light burned magnesia powder is less than or equal to 0.044mm, and the particle size of the silica micro powder is less than or equal to 1 mu m. Further, the additive comprises a dispersing agent and a thickening agent, wherein the weight ratio of the dispersing agent to the thickening agent is 1:0.1-2. Further, the sintering aid is selected from one or more of boric acid, anhydrous borax, lithium carbonate, calcium fluoride, zinc oxide and barium salt. Further, the functional fine powder is one or more selected from fused magnesia powder, sintered magnesia powder, zirconia powder and silicon carbide powder. The raw materials comprise, by weight, 30-50 parts of magnesium spinel brick regeneration powder, 10-20 parts of functional fine powder, 10-20 parts of active alumina micro powder, 5-15 parts of light burned magnesia powder, 3-8 parts of silicon micro powder, 2-5 parts of sintering auxiliary agent and 2-5 parts of additive. The invention provides a preparation method of the thermal state magnesium spinel brick surface coating, which comprises the following steps of carrying out surface pretreatment on the thermal state magnesium spinel brick, respectively weighing the aggregate system, the bonding system and the sintering aid according to a proportion, dry-mixing to obtain a dry mixture, weighing the additive according to a proportion, adding the additive into a liquid carrier, mixing, adding the dry mixture to obtain