Fireproof board and its preparation method

Abstract

The present invention relates to the technical field of cement-based building materials, and in particular to a fireproof board and a preparation method thereof. By using magnesium oxide desulfurization waste residue, supplemented with light-burned magnesium oxide and dead-burned magnesium oxide, and adding potassium dihydrogen phosphate, ultra-fine steel slag powder, and red mud as the main active substances, using steel slag coarse and fine aggregates as all-solid waste aggregates, and cooperating with admixtures and hybrid fibers, a fireproof board with excellent compressive strength and fireproof effect, and environmental protection and waste utilization is prepared.

Description

Technical Field

[0001] The present invention relates to the technical field of cement-based building materials, and in particular to a fireproof board and a preparation method thereof. Background Art

[0002] With the continuous development of construction projects and transportation projects, more and more building boards are being used. For some structures such as partition walls, steel beam cladding, skirt walls, tunnel inner walls, underground projects, and bulkheads, building boards such as calcium silicate boards and fiber-reinforced cement boards are often used.

[0003] However, although ordinary building boards such as calcium silicate boards are mainly made of inorganic materials and have excellent physical properties, processing properties, and certain non-combustible characteristics, they are prone to losing strength and even bursting under high-temperature environments. Especially for cement products, generally above 800 °C, the mechanical properties will drop sharply, and cracks and peeling will occur on the surface of the boards, affecting the appearance and use effect.

[0004] During industrialization, many industrial wastes are generated. Generally, they are often stored on the ground or buried underground, which is extremely likely to cause environmental pollution. For example, desulfurization ash slag, red mud, etc. Some highly active industrial solid wastes such as fly ash, mineral powder, and silica fume are often added to cement products as active admixtures and have been well reused. Magnesium oxide desulfurization, as a new generation of desulfurization technology, has more advantages than calcium oxide desulfurization. The by-product is magnesium oxide desulfurization waste residue, and its main components are magnesium sulfate, magnesium hydroxide, unreacted magnesium oxide, and some diatomaceous earth filter aids, etc. This waste residue has not been effectively recycled. Summary of the Invention

[0005] To solve the problems existing in the prior art, the present invention provides a fireproof board. Specifically, the present invention uses magnesium oxide desulfurization waste residue, supplements light-burned magnesium oxide and dead-burned magnesium oxide, and adds potassium dihydrogen phosphate, ultra-fine sulfided steel slag powder, and red mud as the main active substances. Steel slag coarse and fine aggregates are used as all-solid waste aggregates, and an admixture and hybrid fibers are added to prepare a fireproof board with excellent compressive strength, fireproof effect, and environmental protection and waste utilization.

[0006] Specifically, the fireproof board of the present invention is composed of the following raw materials in parts by weight:

[0007] 190-200 parts of magnesium oxide desulfurization waste residue, 50-70 parts of light-burned magnesium oxide, 70-90 parts of dead-burned magnesium oxide, 100-110 parts of potassium dihydrogen phosphate, 50-60 parts of ultra-fine sulfided steel slag powder, 20-25 parts of red mud, 1080-1120 parts of steel slag coarse aggregate, 830-850 parts of steel slag fine aggregate, 5-6 parts of borax, 4-5 parts of glass fiber, 3-4 parts of basalt fiber, 3-5 parts of calcium sulfate whisker, 7-10 parts of water reducer, and 158-165 parts of water.

[0008] According to the composition characteristics of magnesium oxide desulfurization waste residue, after a large number of tests, no modification treatment is required for the waste residue, and the waste residue is used as the main raw material to prepare a fireproof board, thereby realizing the resource utilization of magnesium oxide desulfurization waste residue. However, the mechanical properties of the product with magnesium oxide desulfurization waste residue as the main material are poor, and the slurry workability is poor during the preparation process, and a large number of tests and optimizations are required for other compound materials. Specifically, the present invention adopts magnesium oxide desulfurization waste residue, adds light-burned magnesium oxide and heavy-burned magnesium oxide, and adds potassium dihydrogen phosphate, and hydration produces a large amount of magnesium hydration products with good fireproof effect. In order to improve the mechanical properties and high temperature resistance of the fireproof board, after a large number of tests, ultrafine sulfide steel slag powder and red mud are added to supplement the magnesium-based hydration products, and the slurry workability can be combined, and the compound use effect is good.

[0009] The present invention adopts steel slag as coarse and fine aggregate, and combines glass fiber, basalt fiber and calcium sulfate whisker as mixed fiber, which can improve the high temperature resistance of the fireproof board, reduce the volume deformation and mechanical property loss of the fireproof board after high temperature, and has good use effect.

[0010] Preferably, the particle size of the magnesium oxide desulfurization waste slag is ≤45 μm.

[0011] Preferably, the light-burned magnesium oxide is prepared by calcining magnesite at 900-1000° C., and has a particle size of ≤75 μm.

[0012] Preferably, the dead-burned magnesium oxide is prepared by calcining magnesite at 1450-1500° C., and has a particle size of ≤45 μm.

[0013] Preferably, the ultrafine sulfided steel slag powder is prepared by sulfiding and grinding steel slag powder, and the particle size is ≤10μm. Steel slag is a byproduct of the steelmaking industry, and its mineral phase composition is similar to cement clinker, and it has certain activity, but its free calcium oxide content is high, which poses a potential safety hazard. The commonly used treatment methods are ultrafine grinding or carbonization, but the present invention has found in experiments that if ultrafine carbonized steel slag powder is used, the fire resistance stability of the product is slightly poor, while the fireproof board using ultrafine sulfided steel slag powder has a better high temperature resistance effect.

[0014] Preferably, the red mud particle size is ≤75 μm.

[0015] Preferably, the particle size of the steel slag coarse aggregate is 5-16 mm, and the particle size of the steel slag fine aggregate is 0.1-0.425 μm.

[0016] Preferably, the glass fiber has a diameter of 10-12 μm and a length of 12-14 mm, the basalt fiber has a diameter of 15-16 μm and a length of 10-12 mm, and the calcium sulfate whisker has a diameter of 2-6 μm and a length of 50-160 μm.

[0017] Preferably, the water reducer is a polycarboxylate water reducer.

[0018] The present invention also relates to a preparation method of the above fireproof board. Specifically, it includes the following steps:

[0019] 1) Weigh each raw material according to parts by weight.

[0020] 2) Mix all the raw materials evenly to obtain a slurry.

[0021] 3) Shape the slurry, demold it, and cure it to obtain the product.

[0022] More preferably, in step 2), first mix magnesium oxide desulfurization waste residue, lightly burned magnesium oxide, heavily burned magnesium oxide, potassium dihydrogen phosphate, ultrafine sulfided steel slag powder, red mud, borax, glass fiber, basalt fiber, and calcium sulfate whiskers evenly to obtain a dry material. Mix the water reducing agent and water evenly to obtain a liquid material. Then mix the dry material, steel slag coarse aggregate, steel slag fine aggregate, and liquid material evenly to obtain a slurry.

[0023] The present invention has the following technical advantages:

[0024] 1. The present invention uses a large amount of magnesium oxide desulfurization waste residue, ultrafine sulfided steel slag powder, and red mud as active materials, and selects steel slag as coarse and fine aggregates to realize the high-value utilization of industrial solid waste.

[0025] 2. The present invention uses a magnesium-based cementitious material as the main material, adds ultrafine sulfided steel slag powder and red mud for active supplementation, and the hydration products are intertwined, having good density and fireproof effect.

[0026] 3. The cementitious material of the present invention is compounded with raw materials to overcome the disadvantages such as low mechanical strength and poor workability of the slurry caused by the use of magnesium oxide desulfurization waste residue.

[0027] 4. The special composition of the hybrid fiber with the coarse and fine steel slag aggregates and the hydration products together improve the high-temperature stability of the fireproof board.

[0028] 5. The preparation process of the present invention is simple and has good environmental benefits. Description of the Drawings

[0029] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the related art, the following will briefly introduce the drawings required to be used in the description of the specific embodiments or the related art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0030] Figure 1 : Schematic diagram of the high-temperature detection results of each example and comparative example in the embodiments of the present invention. Specific Embodiments

[0031] To characterize the technical effects of the present invention, a fireproof board was prepared and its performance was tested. During the test, the particle size of the magnesium oxide desulfurization waste residue was ≤ 45 μm, the lightly burned magnesium oxide was calcined from magnesite at 950 °C with a particle size of ≤ 75 μm, the heavily burned magnesium oxide was calcined from magnesite at 1500 °C with a particle size of ≤ 45 μm, the ultra-fine sulfided steel slag powder was prepared by sulfiding and grinding steel slag powder with a particle size of ≤ 10 μm, the red mud had a particle size of ≤ 75 μm, the steel slag coarse aggregate had a particle size of 5 - 16 mm, the steel slag fine aggregate had a particle size of 0.1 - 0.425 μm, the glass fiber had a diameter of 10 - 12 μm and a length of 12 - 14 mm, the basalt fiber had a diameter of 15 - 16 μm and a length of 10 - 12 mm, the calcium sulfate whisker had a diameter of 2 - 6 μm and a length of 50 - 160 μm, the water reducer was a polycarboxylate water reducer, and the performance test included normal temperature test and high temperature test. The high temperature test was to heat the specimens cured under standard conditions for 28 days in an 800 °C device for 6 hours, then let them cool to room temperature and conduct relevant tests. For the test results, please refer to Figure 1 . Among them, the mechanical property test was carried out according to GB-T17671, and the volume stability test was carried out according to JGJ-T70. Example 1

[0032] The fireproof board is composed of the following raw materials in parts by weight: 190 parts of magnesium oxide desulfurization waste residue, 60 parts of lightly burned magnesium oxide, 90 parts of heavily burned magnesium oxide, 110 parts of potassium dihydrogen phosphate, 56 parts of ultra-fine sulfided steel slag powder, 21 parts of red mud, 1100 parts of steel slag coarse aggregate, 850 parts of steel slag fine aggregate, 5.5 parts of borax, 5 parts of glass fiber, 3 parts of basalt fiber, 4 parts of calcium sulfate whisker, 9 parts of water reducer, and 163 parts of water.

[0033] After testing, the initial fluidity of the slurry was 680 mm, the workability was good, the 28-day compressive strength was 43.6 MPa. After the high temperature test, the volume change rate of the specimen was +0.05%, the mass residue was 98.3%, the compressive strength was 37.1 MPa, and there was no cracking or peeling phenomenon. Example

[0034] The fireproof board is composed of the following raw materials in parts by weight: 200 parts of magnesium oxide desulfurization waste residue, 70 parts of lightly burned magnesium oxide, 80 parts of heavily burned magnesium oxide, 102 parts of potassium dihydrogen phosphate, 60 parts of ultra-fine sulfided steel slag powder, 23 parts of red mud, 1120 parts of steel slag coarse aggregate, 840 parts of steel slag fine aggregate, 6 parts of borax, 4 parts of glass fiber, 4 parts of basalt fiber, 5 parts of calcium sulfate whisker, 10 parts of water reducer, and 163 parts of water.

[0035] After testing, the initial fluidity of the slurry was 690 mm, the workability was good, the 28-day compressive strength was 45.2 MPa. After the high temperature test, the volume change rate of the specimen was +0.03%, the mass residue was 98.6%, the compressive strength was 37.7 MPa, and there was no cracking or peeling phenomenon.

[0036] Comparative Example 1

[0037] The fireproof board is composed of the following raw materials in parts by weight: 200 parts of magnesium oxide desulfurization waste residue, 150 parts of lightly burned magnesium oxide, 102 parts of potassium dihydrogen phosphate, 60 parts of superfine sulfided steel slag powder, 23 parts of red mud, 1120 parts of steel slag coarse aggregate, 840 parts of steel slag fine aggregate, 6 parts of borax, 4 parts of glass fiber, 4 parts of basalt fiber, 5 parts of calcium sulfate whisker, 10 parts of water reducing agent, and 163 parts of water.

[0038] After testing, the initial fluidity of the slurry is 620 mm, the workability is average, there is a phenomenon of exposed stones, the 28-day compressive strength is 37.5 MPa. After high-temperature testing, the volume change rate of the specimen is +0.11%, the mass residue is 93.1%, the compressive strength is 26.3 MPa, and there is no cracking or peeling phenomenon.

[0039] Comparative Example 2

[0040] The fireproof board is composed of the following raw materials in parts by weight: 200 parts of magnesium oxide desulfurization waste residue, 150 parts of dead-burned magnesium oxide, 102 parts of potassium dihydrogen phosphate, 60 parts of superfine sulfided steel slag powder, 23 parts of aluminum ash, 1120 parts of steel slag coarse aggregate, 840 parts of steel slag fine aggregate, 6 parts of borax, 4 parts of glass fiber, 4 parts of basalt fiber, 5 parts of calcium sulfate whisker, 10 parts of water reducing agent, and 163 parts of water.

[0041] After testing, the initial fluidity of the slurry is 590 mm, the workability is average, the viscosity is high, the 28-day compressive strength is 30.2 MPa. After high-temperature testing, the volume change rate of the specimen is +0.16%, the mass residue is 92.6%, the compressive strength is 25.0 MPa, and there are microcracks on the surface.

[0042] Comparative Example 3

[0043] The fireproof board is composed of the following raw materials in parts by weight: 200 parts of magnesium oxide desulfurization waste residue, 70 parts of lightly burned magnesium oxide, 80 parts of dead-burned magnesium oxide, 102 parts of potassium dihydrogen phosphate, 60 parts of superfine carbonized steel slag powder, 23 parts of fly ash, 1120 parts of steel slag coarse aggregate, 840 parts of steel slag fine aggregate, 6 parts of borax, 4 parts of glass fiber, 4 parts of basalt fiber, 5 parts of calcium sulfate whisker, 10 parts of water reducing agent, and 163 parts of water.

[0044] After testing, the initial fluidity of the slurry is 500 mm, the workability is poor, it is caked, the 28-day compressive strength is 38.1 MPa. After high-temperature testing, the volume change rate of the specimen is +0.24%, the mass residue is 91.7%, the compressive strength is 21.6 MPa, and there are microcracks and slight peeling on the surface.

[0045] Comparative Example 4

[0046] Fireproof board, which is composed of the following raw materials in parts by weight: 200 parts of magnesium oxide desulfurization waste residue, 150 parts of light-burned magnesium oxide, 102 parts of potassium dihydrogen phosphate, 60 parts of fly ash, 23 parts of ore powder, 1120 parts of steel slag coarse aggregate, 840 parts of steel slag fine aggregate, 6 parts of borax, 6 parts of glass fiber, 6 parts of basalt fiber, 10 parts of water reducer, and 163 parts of water.

[0047] After testing, the slurry has no fluidity, the 28-day compressive strength is 32.9 MPa. After high-temperature testing, the volume change rate of the specimen is +0.34%, the mass residue is 89.7%, the compressive strength is 8.2 MPa, and the surface cracks and peels off.

[0048] Comparative Example 5

[0049] Fireproof board, which is composed of the following raw materials in parts by weight: 200 parts of magnesium oxide desulfurization waste residue, 70 parts of light-burned magnesium oxide, 80 parts of heavy-burned magnesium oxide, 102 parts of potassium dihydrogen phosphate, 60 parts of ultrafine sulfided steel slag powder, 23 parts of red mud, 1120 parts of granite coarse aggregate, 840 parts of manufactured sand, 6 parts of borax, 13 parts of glass fiber, 10 parts of water reducer, and 163 parts of water.

[0050] After testing, the initial fluidity of the slurry is 660 mm, the workability is good, the 28-day compressive strength is 37.3 MPa. After high-temperature testing, the volume change rate of the specimen is +0.16%, the mass residue is 91.3%, the compressive strength is 20.5 MPa, and the surface slightly peels off.

[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A fireproof board, characterized in that: It is composed of the following raw materials in parts by weight: 190-200 parts of magnesium oxide desulfurization waste residue, 50-70 parts of light-burned magnesium oxide, 70-90 parts of heavy-burned magnesium oxide, 100-110 parts of potassium dihydrogen phosphate, 50-60 parts of ultrafine sulfided steel slag powder, 20-25 parts of red mud, 1080-1120 parts of steel slag coarse aggregate, 830-850 parts of steel slag fine aggregate, 5-6 parts of borax, 4-5 parts of glass fiber, 3-4 parts of basalt fiber, 3-5 parts of calcium sulfate whisker, 7-10 parts of water reducer, 158-165 parts of water; The particle size of the magnesium oxide desulfurization waste slag is ≤45 μm.

2. The fireproof board according to claim 1, characterized in that: The light-burned magnesium oxide is prepared by calcining magnesite at 900-1000° C., and has a particle size of ≤75 μm.

3. The fireproof board according to claim 1, characterized in that: The dead-burned magnesium oxide is prepared by calcining magnesite at 1450-1500° C., and has a particle size of ≤45 μm.

4. The fireproof board according to claim 1, characterized in that: The ultrafine sulfided steel slag powder is prepared by sulfiding and grinding steel slag powder, and the particle size is ≤10 μm.

5. The fireproof board according to claim 1, characterized in that: The red mud particle size is ≤75 μm.

6. The fireproof board according to claim 1, characterized in that: The particle size of the steel slag coarse aggregate is 5-16 mm, and the particle size of the steel slag fine aggregate is 0.1-0.425 μm.

7. The fireproof board according to claim 1, characterized in that: The glass fiber has a diameter of 10-12 μm and a length of 12-14 mm, the basalt fiber has a diameter of 15-16 μm and a length of 10-12 mm, and the calcium sulfate whisker has a diameter of 2-6 μm and a length of 50-160 μm.

8. The fireproof board according to claim 1, characterized in that: The water reducer is a polycarboxylate water reducer.

9. The method for preparing the fireproof board according to any one of claims 1 to 8, characterized in that: The steps include: 1) Weigh each raw material by weight, 2) Mix all the raw materials evenly to obtain slurry. 3) Shape the slurry, demould and cure it.

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