Fiber reinforced air hardenable refractory slurry and method of making same

Abstract

The application provides a fiber-reinforced air hardening refractory mortar, which is prepared from raw materials including the following components: 28-32 parts by weight of mullite brick return material; 10-15 parts by weight of kaolin; 27-35 parts by weight of high alumina material; 23-34 parts by weight of soda ash; and 10-40 parts by weight of alumina fiber. Compared with the prior art, the fiber-reinforced air hardening refractory mortar provided by the application realizes good mutual interaction of the whole by using specific components with specific contents, and has good construction performance, and the setting time is within 2 minutes at normal temperature; and meets various performance requirements for use as a refractory mortar; the fiber-reinforced air hardening refractory mortar mainly uses soda ash, which can be quickly combined with the masonry during the construction process, and the bending strength of the mortar after bonding can reach 4.0 MPa, and meanwhile, the mortar has good construction performance and can also reduce the thermal conductivity of the mortar after solidification.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of unshaped refractory, more particularly, to a fiber-reinforced air hardening refractory mortar and a preparation method thereof. BACKGROUND

[0002] Refractory mortar is a commonly used refractory material, widely used in various industrial kilns for high alumina brick masonry; hot blast furnace is used for masonry on the top of the furnace, regenerator, combustion chamber, etc., for the bottom of the blast furnace, the furnace, the furnace, the furnace, etc. Part, also can be used for repairing the top of the industrial kiln, the wall of the furnace, etc.

[0003] Refractory mortar can be classified into the following categories according to its composition and application: (1) silicate-based refractory mortar: the main components of silicate-based refractory mortar are silicate cement and silica sand; this mortar has excellent high-temperature resistance and cold-hot cycle resistance, and is suitable for the construction of refractory lining of high-temperature kiln, furnace and chimney, etc. (2) aluminate-based refractory mortar: the main components of aluminate-based refractory mortar are aluminate cement and bauxite; it has excellent refractory performance and chemical corrosion resistance, and is often used for the refractory lining of high-temperature equipment such as high-speed trains, glass kilns, etc. (3) phosphate-based refractory mortar: the main components of phosphate-based refractory mortar are phosphate cement and phosphate rock; this mortar has high acid corrosion resistance, and is suitable for lining engineering in acid-resistant environments such as chemical equipment, pickling tanks and storage tanks, etc. (4) alumina-based refractory mortar: the main component of alumina-based refractory mortar is alumina. It has good high-temperature resistance and corrosion resistance, and is often used for lining and repair of high-temperature industrial equipment such as metallurgical equipment, aluminum electrolysis tank, etc. In addition to the above several main categories, there are also some special refractory mortars, such as silicon carbide-based refractory mortar, magnesium carbide-based refractory mortar, etc., which are selected for use according to specific application requirements and working environment.

[0004] However, the refractory mortar in the prior art still has the following technical problems: (1) poor construction performance and low bonding strength; (2) after the mortar is applied on the bricks, the mortar may lose its workability due to water loss before the bricks are properly laid, resulting in construction quality defects such as uneven and unsaturated brick joints; the mortar may also flow out of the brick joints; (3) due to the easy water loss of the mortar, the mortar only exists loosely in the brick joints after the laying, and cannot bond the laying into a solid and dense whole; (4) the mortar needs to be dried at 110℃ to have strength, and if the sintering is not good, the mortar is difficult to well bond the bricks together; therefore, some countries (such as the United States, Japan, etc.) have developed air hardening refractory mortar, which hardens at room temperature after construction, produces a certain hardness, and forms a firm bond with the laying during use by sintering at high temperature; (5) cracks may occur during the drying process of the kiln after the completion of the kiln construction; (6) the thermal conductivity of the ordinary refractory mortar is high after solidification. SUMMARY

[0005] Therefore, the present application aims to provide a fiber reinforced air hardening refractory mortar and a preparation method thereof.

[0006] The present application provides a fiber reinforced air hardening refractory mortar, which is prepared from raw materials comprising:

[0007] mullite brick return material 28wt%-32wt%;

[0008] kaolin 10wt%-15wt%;

[0009] high alumina material 27wt%-35wt%;

[0010] soda ash 23wt%-34wt%;

[0011] alumina fiber 10wt%-40wt%.

[0012] Preferably, the mullite brick return material has an aluminum content of 54wt%-60wt%.

[0013] Preferably, the kaolin has an aluminum content of 32wt%-38wt% and a silicon content of 48wt%-52wt%.

[0014] Preferably, the high alumina material has an aluminum content of 45wt%-50wt%.

[0015] Preferably, the high alumina material is one or more of alumina powder, coal gangue powder and lanxide powder.

[0016] Preferably, the alumina fiber has a length of ≤5mm and a diameter of ≤5μm.

[0017] The present application also provides a preparation method of the fiber reinforced air hardening refractory mortar as described above, comprising the following steps:

[0018] mixing the mullite brick return material, the kaolin, the high alumina material, the soda ash and the alumina fiber, and stirring to obtain the fiber reinforced air hardening refractory mortar.

[0019] Preferably, the mixing process specifically comprises:

[0020] adding the soda ash into a stirrer, then adding the mullite brick return material, the kaolin and the high alumina material for pre-mixing, and then adding the alumina fiber to complete the mixing process;

[0021] or,

[0022] Put half of the soda ash into the stirrer, then add the mullite brick back material, half of the high alumina material, and pre-mix, then add the other half of the soda ash and the other half of the alumina powder and stir until uniform, then add the alumina fiber and complete the mixing process.

[0023] Or,

[0024] Put the soda ash into the stirrer, then add half of the high alumina material, half of the mullite brick back material, and pre-mix, then add the other half of the high alumina material, the other half of the mullite brick back material, and stir until uniform, then add the alumina fiber and complete the mixing process.

[0025] Preferably, the pre-mixing time is 10-30 minutes.

[0026] Preferably, the stirring time is 20-30 minutes.

[0027] The present application provides a fiber-reinforced air hardening refractory mortar prepared from raw materials comprising: mullite brick back material 28-32 parts by weight; kaolin 10-15 parts by weight; high alumina material 27-35 parts by weight; soda ash 23-34 parts by weight; and alumina fiber 10-40 parts by weight. Compared with the prior art, the fiber-reinforced air hardening refractory mortar provided by the present application uses specific components with specific contents to achieve better overall interaction, resulting in a fiber-reinforced air hardening refractory mortar with good workability, with a setting time of 2 minutes at room temperature; and meets the performance requirements for use as a refractory mortar: the fiber-reinforced air hardening refractory mortar mainly uses soda ash, which can quickly bond with the masonry during construction, and the bending strength of the mortar after bonding can reach 4.0 MPa (according to GB / T 22459.4-2022), while being easy to apply, repair cracks in the kiln, improve the strength of the mortar during the drying process of the kiln, eliminate crack hazards, and also reduce the thermal conductivity of the solidified mortar.

[0028] In addition, the preparation method provided by the present application has simple process, mild and easy-to-control conditions, readily available raw materials and low cost, and has broad application prospects. DETAILED DESCRIPTION

[0029] The technical solutions of the present application will be described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0030] The present application provides a fiber-reinforced air hardening refractory mortar, which is prepared from raw materials comprising:

[0031] mullite brick return material 28 parts by weight to 32 parts by weight;

[0032] kaolin 10 parts by weight to 15 parts by weight;

[0033] high-alumina material 27 parts by weight to 35 parts by weight;

[0034] soda ash 23 parts by weight to 34 parts by weight;

[0035] alumina fiber 10 parts by weight to 40 parts by weight.

[0036] In the present application, the fiber-reinforced air hardening refractory mortar is prepared from raw materials comprising mullite brick return material, kaolin, high-alumina material, soda ash and alumina fiber, preferably prepared from mullite brick return material, kaolin, high-alumina material, soda ash and alumina fiber. The present application does not have special restrictions on the sources of the mullite brick return material, kaolin, high-alumina material, soda ash and alumina fiber, and commercially available products known to those skilled in the art can be used.

[0037] In the present application, the aluminum content of the mullite brick return material is preferably 54wt% to 60wt%, more preferably 56wt% to 58wt%.

[0038] In the present application, the fiber-reinforced air hardening refractory mortar comprises 28 parts by weight to 32 parts by weight of mullite brick return material.

[0039] In the present application, the aluminum content of the kaolin is preferably 32wt% to 38wt%, more preferably 34wt% to 36wt%, and the silicon content is preferably 48wt% to 52wt%, more preferably 49wt% to 51wt%. The use of kaolin with the above-mentioned silicon content in the present application can increase the strength of the refractory mortar.

[0040] In the present application, the fiber-reinforced air hardening refractory mortar comprises 10 parts by weight to 15 parts by weight of kaolin.

[0041] In the present application, the aluminum content of the high-alumina material is preferably 45wt% to 50wt%; the high-alumina material is preferably one or more of alumina powder, coal gangue powder and lanxide powder, more preferably alumina powder or coal gangue powder. In the present application, the high-alumina material can increase the aluminum content and form a firm bond with the masonry after application (sintering).

[0042] In the present application, the fiber-reinforced air hardening refractory mortar comprises 27 parts by weight to 35 parts by weight of high-alumina material.

[0043] In the present application, the sodium silicate can improve the viscosity of the refractory mortar.

[0044] In the present application, the fiber reinforced air hardening refractory mortar comprises 23-34 parts by weight of sodium silicate, more preferably 23-31 parts by weight.

[0045] In the present application, the length of the alumina fiber is preferably ≤5mm, and the diameter is preferably ≤5μm; the alumina fiber can enhance the mortar bonding strength while reducing the mortar thermal conductivity.

[0046] In the present application, the fiber reinforced air hardening refractory mortar comprises 10-40 parts by weight of alumina fiber, more preferably 15-25 parts by weight.

[0047] In the present application, the above-mentioned mullite brick return material and high alumina material mainly provide aluminum source; the kaolin and sodium silicate mainly provide silicon source and increase viscosity; the alumina fiber enhances the mortar bonding strength while reducing the mortar thermal conductivity.

[0048] The fiber reinforced air hardening refractory mortar provided by the present application adopts specific components with specific contents, realizes good mutual interaction as a whole, and has good construction performance. The setting time of the obtained fiber reinforced air hardening refractory mortar is within 2 minutes at normal temperature; and meets various performance requirements for use as a refractory mortar. The fiber reinforced air hardening refractory mortar mainly adopts sodium silicate, which can quickly combine with the masonry during construction. The normal temperature bending strength of the mortar after bonding can reach 4.0MPa (according to GB / T 22459.4-2022), and the mortar can be applied for construction, repair of kiln cracks, improvement of mortar strength during kiln drying process, elimination of crack hazards, and reduction of thermal conductivity of the solidified mortar.

[0049] The present application also provides a preparation method of the fiber reinforced air hardening refractory mortar described in the above technical solution, comprising the following steps:

[0050] Mixing mullite brick return material, kaolin, high alumina material, sodium silicate and alumina fiber, and stirring to obtain a fiber reinforced air hardening refractory mortar.

[0051] In the present application, the mullite brick return material, kaolin, high alumina material, sodium silicate and alumina fiber are the same as in the above technical solution, and will not be repeated here.

[0052] In the present application, the mixing process is preferably as follows:

[0053] Add sodium silicate into a stirrer, then add mullite brick return material, kaolin, high alumina material, pre-mix, and then add alumina fiber to complete the mixing process.

[0054] or,

[0055] Half of the soap flower alkali is added into a stirrer, then mullite brick back material, half of the high alumina material and kaolin are pre-mixed, then the other half of the high alumina material, kaolin and mullite brick back material are added and stirred uniformly, and then alumina fiber is added to complete the mixing process.

[0056] or,

[0057] The soap flower alkali is added into a stirrer, then half of the high alumina material, kaolin and mullite brick back material are pre-mixed, then the other half of the high alumina material, kaolin and mullite brick back material are added and stirred uniformly, and then alumina fiber is added to complete the mixing process.

[0058] In the present application, the pre-mixing time is preferably 10-30 minutes, more preferably 20 minutes; the stirring technical solution known to those skilled in the art can be used to ensure that the raw materials are uniformly mixed.

[0059] In the present application, the stirring time is preferably 20-30 minutes, more preferably 25 minutes; the stirring technical solution known to those skilled in the art can be used to ensure that the raw materials are uniformly mixed.

[0060] The preparation method provided by the present application has simple process, mild and easy-to-control conditions, readily available raw materials and low cost, and has wide application prospect.

[0061] The present application provides a kind of fiber reinforced air hardening refractory mortar, which is prepared from raw materials including: mullite brick back material 28-32 parts by weight;Kaolin 10-15 parts by weight;High alumina material 27-35 parts by weight;Soap flower alkali 23-34 parts by weight;Alumina fiber 10-40 parts by weight.Compared with the prior art, the fiber reinforced air hardening refractory mortar provided by the present application uses specific components with specific content to achieve better mutual interaction, resulting in a fiber reinforced air hardening refractory mortar with good workability, with a setting time of 2 minutes at room temperature;And meet the various performance requirements for use as a refractory mortar: the fiber reinforced air hardening refractory mortar mainly uses soap flower alkali, which can quickly combine with the masonry during construction, and the bending strength after bonding can reach 4.0MPa (according to GB / T 22459.4-2022), while it can be applied to construction, repair kiln cracks, improve the strength of the mortar during the drying process of the kiln, eliminate crack hazards, and also reduce the thermal conductivity of the solidified mortar.

[0062] In addition, the preparation method provided by the present application has simple process, mild and easy-to-control conditions, readily available raw materials and low cost, and has wide application prospect.

[0063] To further illustrate the present application, the following examples are described in detail below. The raw materials used in the following examples of the present application are all commercially available; among them, the aluminum content of the mullite brick return material is 56wt%-58wt%, the aluminum content of the kaolin is 34wt%-36wt%, and the silicon content is 49wt%-51wt%.

[0064] Example 1

[0065] A air hardening refractory mortar formula using temperature 1000℃: mullite brick return material 28wt%, kaolin 14wt%, alumina powder 27wt%, sodium silicate 31wt%, plus 20% of the total mass of the above raw materials alumina fiber.

[0066] The preparation method includes the following steps: first, add sodium silicate into the stirrer according to the proportion, then add mullite brick return material, kaolin, and alumina powder, stir for 20min, after the mortar is stirred uniformly, add alumina fiber with length≤5mm and diameter≤5μm, stir again for 25min, after it is fully stirred uniformly, put the mortar into a barrel, seal the barrel and store it in the warehouse, to obtain fiber-reinforced air hardening refractory mortar.

[0067] After testing, the cold bending strength of the mortar after bonding is 3.6MPa (according to GB / T22459.4-2022), the thermal conductivity after curing is 0.25W / m.K (according to YB / T4130-2005), the addition of fiber forms a protection for the moisture in the mortar, which is not easy to dehydrate, the exposed part of the brick joint rapidly solidifies due to the influence of air, while the mortar inside the brick joint is still moist, the water content is 35% (according to GB / T3007-2006) within 2 minutes of masonry detection, has strong bonding and kneading properties, and the overall appearance of the masonry after construction is neat and beautiful.

[0068] Example 2

[0069] A air hardening refractory mortar formula using temperature 1500℃: mullite brick return material 32wt%, kaolin 10wt%, alumina powder 35wt%, sodium silicate 23wt%, plus 25% of the total mass of the above raw materials alumina fiber.

[0070] The preparation method includes the following steps: first, add sodium silicate into half of the stirrer according to the proportion, then add mullite brick return material, kaolin, and half of the alumina powder, stir for 20min, then add the other half of the sodium silicate and the other half of the alumina powder in turn, after the mortar is stirred uniformly, add alumina fiber with length≤5mm and diameter≤5μm, stir again for 25min, after it is fully stirred uniformly, put the mortar into a barrel, seal the barrel and store it in the warehouse, to obtain fiber-reinforced air hardening refractory mortar.

[0071] Tested, normal temperature flexural strength after bonding detection of the mud flexural bonding strength is 2.6MPa (according to GB / T22459.4-2022), the thermal conductivity of 0.28W / m.K (according to YB / T4130-2005) after curing, the water in the mud forms a kind of protection after adding fiber, not easy to dehydrate, the exposed part of the brick joint is rapidly solidified by air, while the mud inside the brick joint is still moist, the detection of water content is 33% (according to GB / T3007-2006) within 2 minutes of masonry, with strong cohesiveness and kneading, the overall appearance of the masonry after construction is neat and beautiful.

[0072] Example 3

[0073] A kind of air hardening refractory mud formula that can rapidly solidify at normal temperature: mullite brick return material 28wt%, kaolin 15wt%, Shanxi coal gangue powder 27wt%, sodium carbonate 30wt%, plus 15% of the total mass of the above raw materials alumina fiber.

[0074] The preparation method comprises the following steps: first, add sodium carbonate into the stirrer according to the proportion, then add half of kaolin, mullite brick return material and Shanxi coal gangue powder, fully stir for 20min, then add the other half of kaolin, mullite brick return material and Shanxi coal gangue powder, after the mud is stirred uniformly, add alumina fiber with length ≤5mm and diameter ≤5μm, stir again for 25min, then put the mud into a barrel, seal the barrel and store in the warehouse, to obtain fiber reinforced air hardening refractory mud.

[0075] Tested, normal temperature flexural strength after bonding detection of the mud flexural bonding strength is 1.9MPa (according to GB / T22459.4-2022), the thermal conductivity of 0.25W / m.K (according to YB / T4130-2005) after curing, the water in the mud forms a kind of protection after adding fiber, not easy to dehydrate, the exposed part of the brick joint is rapidly solidified by air, while the mud inside the brick joint is still moist, the detection of water content is 33% (according to GB / T3007-2006) within 2 minutes of masonry, with strong cohesiveness and kneading, the overall appearance of the masonry after construction is neat and beautiful.

[0076] Comparative example 1

[0077] A kind of air hardening refractory mud formula that can rapidly solidify at normal temperature: mullite brick return material 28wt%, kaolin 15wt%, Shanxi mullite powder 27wt%, sodium carbonate 30wt%, plus 15% of the total mass of the above raw materials alumina fiber.

[0078] The preparation method comprises the following steps: firstly, proportionally adding the sodium silicate into a stirrer, then adding half of the kaolin, the mullite brick return material and the mullite powder of Shanxi respectively, fully stirring for 20 minutes, then adding the other half of the kaolin, the mullite brick return material and the mullite powder of Shanxi, after the mud is uniformly stirred, adding the alumina fiber with a length of ≤5 mm and a diameter of ≤5 μm, stirring for 25 minutes again, after the mud is fully stirred, the mud is put into a barrel, the barrel is sealed and stored, and the refractory mud slurry is obtained.

[0079] Through tests, the cold bending strength of the mud slurry after bonding is 0.6 MPa (according to GB / T22459.4-2022), the thermal conductivity after solidification is 0.3 W / m.K (according to YB / T4130-2005), the water in the mud slurry forms a protection after the fiber is added, but the common effect of the fiber with other components is general, the mud slurry is easy to dehydrate, the exposed part of the brick joint is rapidly solidified under the influence of air, the mud slurry in the brick joint is still wet, the water content is 25% (according to GB / T3007-2006) within 2 minutes of masonry, the bonding and kneading properties are general, and the overall appearance and aesthetic property of the masonry after construction are poor.

[0080] In conclusion, the fiber-reinforced hard refractory mud slurry provided by the application solves the problems that the refractory mud loses kneading property due to dehydration during construction, resulting in construction quality defects such as uneven and unsaturated brick joints, the mud is not easy to dehydrate, the masonry after masonry can be bonded into a solid and dense whole, the hardness of the mud after solidification is high, the use temperature range is below 1500℃, the strength of the mud during the drying process of the kiln is improved, the crack hidden danger is eliminated, the mud can be applied and constructed to repair the cracks of the kiln, and the thermal conductivity of the mud after solidification is reduced.

[0081] The above description of disclosed embodiments enables one of ordinary skill in the art to make or use the application. Various modifications to these embodiments will be readily apparent to those of ordinary skill in the art, and the generic principles defined herein can be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A fiber-reinforced air hardening refractory slurry, characterized in that, Prepared from raw materials comprising: Mullite brick return material 28wt%, kaolin 14wt%, alumina powder 27wt%, soda ash 31wt%, plus 20% of the total mass of the above raw materials alumina fiber; Or Mullite brick return material 32wt%, kaolin 10wt%, alumina powder 35wt%, soda ash 23wt%, plus 25% of the total mass of the above raw materials alumina fiber; The mullite brick return material has an aluminum content of 54wt%-60wt%; The kaolin has an aluminum content of 32wt%-38wt% and a silicon content of 48wt%-52wt%; The alumina fiber has a length of ≤5mm and a diameter of ≤5μm.

2. A process for the preparation of the fibre reinforced air hardening refractory slurry as claimed in claim 1, characterized in that, Comprising the following steps: Mixing mullite brick return material, kaolin, alumina powder, soda ash and alumina fiber, and stirring to obtain fiber-reinforced air hardening refractory mortar.

3. The production method according to claim 2, characterized by, The mixing process is specifically: Adding soda ash into the stirrer, then adding mullite brick return material, kaolin and alumina powder, pre-mixing, then adding alumina fiber to complete the mixing process; Or, Adding half of the soda ash into the stirrer, then adding mullite brick return material, kaolin and half of the alumina powder, pre-mixing, then adding the other half of the soda ash, the other half of the alumina powder, stirring until uniform, then adding alumina fiber to complete the mixing process; Or, Adding soda ash into the stirrer, then adding half of the kaolin, mullite brick return material and alumina powder, pre-mixing, then adding the other half of the kaolin, mullite brick return material and alumina powder, stirring until uniform, then adding alumina fiber to complete the mixing process.

4. The production method according to claim 3, characterized by, The pre-mixing time is 10min-30min.

5. The preparation method according to claim 2, characterized in that, The stirring time is 20min-30min.