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CN-121994027-A - Furnace lining structure and preparation method thereof

CN121994027ACN 121994027 ACN121994027 ACN 121994027ACN-121994027-A

Abstract

The invention discloses a furnace lining structure and a preparation method thereof, and belongs to the technical field of ferrous metallurgy. The furnace lining structure sequentially comprises a furnace wall steel shell, a heat preservation layer, an isolation layer and a working layer from outside to inside, wherein the working layer is made of corundum refractory material, the heat preservation layer is made of aluminum-silicon refractory material, the isolation layer is a nano oxide coating, and the nano oxide is at least one of nano alumina and nano zirconia. The invention promotes the stable and reliable operation of the related equipment of the hydrogen reduction process, prolongs the service life of the refractory material and strengthens the safety production.

Inventors

  • ZHANG WEI
  • HAN ZIWEN
  • TANG JIZHONG
  • LIU BINGNAN
  • QIN YANG
  • Hu Daichao
  • LIU SIYANG
  • SU XIAOLI
  • DU SHIPENG
  • LIU XINBO

Assignees

  • 鞍钢股份有限公司

Dates

Publication Date
20260508
Application Date
20260209

Claims (10)

  1. 1. The furnace lining structure is characterized by comprising a furnace wall steel shell, a heat preservation layer, an isolation layer and a working layer from outside to inside in sequence, wherein the working layer is made of corundum refractory material, the heat preservation layer is made of aluminum-silicon refractory material, and the isolation layer is a nano oxide coating.
  2. 2. The furnace lining structure according to claim 1, wherein the thickness of the heat preservation layer is 100-350mm, the thickness of the isolation layer is 0.01-0.1mm, and the thickness of the working layer is 50-300mm.
  3. 3. The furnace lining structure according to claim 1, wherein the mass content of Al 2 O 3 in the working layer is more than or equal to 96%, the total mass content of SiO 2 and Fe 2 O 3 is less than or equal to 0.5%, the total mass content of K 2 O and Na 2 O is less than or equal to 0.3%, and the apparent porosity of the working layer is less than or equal to 10%; The mass content of Al 2 O 3 is more than or equal to 60%, the mass content of SiO 2 is less than or equal to 30%, the mass content of Fe 2 O 3 is less than or equal to 0.5%, the total mass content of K 2 O and Na 2 O is less than or equal to 0.5%, and the apparent porosity of the heat insulation layer is more than or equal to 50%; the nano oxide is at least one of nano aluminum oxide and nano zirconium oxide.
  4. 4. The furnace lining structure according to claim 1, wherein the furnace lining structure is further provided with an anchor, one end of the anchor is fixed to the inner side of the furnace wall steel shell, and the other end of the anchor extends into the heat insulation layer and the working layer.
  5. 5. The furnace lining structure according to claim 4, wherein the anchoring parts are V-shaped or Y-shaped anchoring parts, the number of the anchoring parts is a plurality of the anchoring parts, and the anchoring parts are made of stainless steel.
  6. 6. A method of manufacturing a lining structure according to any one of claims 1-5, characterized by the steps of: (1) Cleaning the inner wall of the furnace wall steel shell, adopting a formwork casting mode according to the thickness of the heat preservation layer, performing aluminum-silicon refractory castable construction on the inner wall of the furnace shell, and performing maintenance and heat treatment after casting molding to prepare the heat preservation layer; (2) Brushing or spraying the surface of the heat-insulating layer manufactured in the step (1), forming a coating layer on the surface of the heat-insulating layer by using nano oxide sol, and performing maintenance and heat treatment to manufacture an isolation layer; (3) And (3) constructing corundum refractory castable on the basis of the isolation layer manufactured in the step (2) by adopting a formwork casting mode according to the thickness of the working layer of the furnace lining, and performing maintenance and heat treatment after casting molding to manufacture the working layer to obtain the furnace lining structure.
  7. 7. The method according to claim 6, wherein in the step (1), when the anchor is used, after cleaning the inner wall of the furnace shell, the anchor point is marked and the anchor is fixed, and the anchor is subjected to surface treatment of brushing asphalt paint or wrapping refractory fiber paper, and then the heat-insulating layer is prepared.
  8. 8. The method according to claim 6, wherein in the step (2), the solid content of the nano-oxide sol is not less than 25%.
  9. 9. The process according to claim 6, wherein in the step (1), the molded article is left to stand for at least 24 hours and is released from the mold, the surface is covered with a plastic film and is cured at room temperature for 24 to 48 hours, heating to 110-120 ℃ from normal temperature at 10-15 ℃ per hour, preserving heat for 15-48 hours, continuously heating to 150-160 ℃ and preserving heat for 15-48 hours, heating to 350-360 ℃ and preserving heat for 15-48 hours, and naturally cooling to prepare a heat preservation layer; in the step (2), after the coating layer is naturally solidified for 2-3 hours, the temperature is raised to 110-120 ℃ for 2-3 hours at 2-3 ℃ per minute, then the temperature is raised to 350-360 ℃ for 2-3 hours, and then the coating layer is naturally cooled to prepare the isolation layer; In the step (3), standing for at least 24 hours after casting molding, demolding, covering the surface with a plastic film, curing for 24-48 hours at normal temperature, heating to 110-120 ℃ from normal temperature at 10-15 ℃ per hour, preserving heat for 15-48 hours, continuously heating to 150-160 ℃ and preserving heat for 15-48 hours, continuously heating to 350-360 ℃ and preserving heat for 15-48 hours, heating to 600-610 ℃ at 15-20 ℃ per hour, preserving heat for 10-15 hours, heating to 950-1000 ℃ at 25-30 ℃ per hour, preserving heat for 24-36 hours, and naturally cooling to prepare the working layer.
  10. 10. The preparation method of claim 6, wherein in the step (3), alumina fibers accounting for not more than 1% of the volume fraction of the castable of the working layer are added during construction of the castable of the working layer, and the mass content of Al 2 O 3 in the alumina fibers is not less than 99%.

Description

Furnace lining structure and preparation method thereof Technical Field The invention belongs to the technical field of ferrous metallurgy, and mainly relates to a furnace lining structure of a hydrogen direct reduction process and a preparation method thereof. Background Because the reaction temperature of the direct reduction process is relatively low, the solid phase reaction does not melt in the reaction process, the molten iron cannot erode, and many people attach insufficient importance to the furnace lining refractory, so that the production can be satisfied only by using the common refractory. In practice, hydrogen has the characteristics of high permeability, strong reducibility, inflammability and explosiveness, and is easy to cause hydrogen embrittlement and corrosion to metal materials, and even causes leakage to cause safety accidents, so that a direct reduction technology using hydrogen puts a brand new requirement on lining refractory materials. In the existing shaft furnace direct reduction process using mixed gas as reducing gas, the used furnace lining refractory material is mainly an aluminum-silicon series product, such as mullite material, refractory bricks or pouring materials of mullite/corundum material, and the like, a general working layer is low-iron high-aluminum bricks, corundum hollow sphere pouring materials, a heat preservation layer is made of feldspar bricks, light mullite bricks and low-iron heat preservation pouring materials, the existing furnace lining refractory material structure is used in a high-temperature hydrogen environment of 600-950 ℃, and the problems that on one hand, hydrogen molecules are small, particularly hydrogen has strong permeability at high temperature, easily diffuses into the heat preservation layer or a metal shell through defects such as open pores and microcracks in the refractory material, on the other hand, hydrogen has extremely strong reducibility at high temperature of 600-950 ℃ and high pressure of 0.2-0.8MPa, and particularly, the hydrogen can react with silicon dioxide at high temperature, the conventional heat preservation layer is generally made of silicon-aluminum material, and other impurity components such as ferric oxide which can be corroded by hydrogen or water reaction are inevitably exist, so that the hydrogen can gradually cause the problems of hydrogen corrosion resistance of the furnace lining and the shell, and the hydrogen is damaged by hydrogen, and the hydrogen is gradually broken down, and the risk of causing the hydrogen-gas-resistant shell is reduced when the hydrogen is in contact with the high-temperature environment, and the problem of causing the hydrogen-resistant shell is reduced. The prior research institutions and enterprises mainly develop the type selection research of refractory raw materials and the development of novel refractory materials for the problems, for example, patent (CN 202310415306.2) discloses a corundum refractory material for hydrogen metallurgy and a preparation method thereof, which takes 70-85wt% of platy corundum, 8-15wt% of calcium aluminate cement, 0.5-9wt% of titanium dioxide and 2-7wt% of alumina micro powder as raw materials, and water reducer (the water reducer is any one or a mixture of two of polyether, polycarboxylic acid, sodium tripolyphosphate, sodium tetrapolyphosphate and sodium hexametaphosphate) is added, wherein the mass of the water reducer is 0.1% of the mass of the raw materials0.8 Percent) of aluminum oxide and aluminum oxide, adding water into the premix, stirring uniformly, casting and molding, curing at room temperature, demolding and drying to obtain a corundum precast block, then carrying out carbon burying on the corundum precast block at 1600-1800 ℃ for 3-8H to obtain the aluminum oxide and aluminum oxide 2O3-Cr2O3 refractory material for a hydrogen-based shaft furnace, wherein patent (CN 202411844100.2) discloses an H 2 and CO erosion resistant Al 2O3-Cr2O3 refractory material for a hydrogen-based shaft furnace, the preparation method comprises the following raw materials, by weight, 30-40 parts of chromium corundum particles with the granularity of 4-1mm, 10-15 parts of aluminum chromium slag particles with the granularity of 1-0mm, 10-20 parts of fused brown corundum particles with the granularity of 3-1mm, 5-10 parts of alumina micropowder with the granularity of less than 0.074mm, 3-5 parts of chromium oxide green with the granularity of less than 0.074mm, 3-4 parts of phosphoric acid and 3-10 parts of erbium oxide, and the preparation method is characterized by weighing the raw materials according to the parts by weight, and placing the raw materials in a kiln, by weight, and uniformly mixing the raw materials with the alumina green alumina powder with the granularity of 1450 in a kiln with the kilnFiring at 1500 ℃ with heat preservation 24H, after kiln discharge, ball milling 2Step three, the mixture is obtained for standby after 4 hours, and the gra