Method for preparing foam glass by using diatomite with high organic matter content

Abstract

The invention discloses a method for preparing foam glass by using diatomite with high organic matter content, and particularly relates to the technical field of building materials. The invention aims to utilize abundant residual organic matters in diatomite with high organic matter content as a natural pore-forming agent and utilize a porous structure of a diatomite algae disc to obtain high-quality foam glass. The preparation method of the foam glass comprises the following steps: (1) respectively grinding the waste glass and the diatomite to a certain fineness level; (2) uniformly mixing glass powder, diatomite, a small amount of foaming agent and foam stabilizer according to a certain proportion; (3) forming the mixture; and (4) firing and foaming, and then annealing according to a certain temperature gradient. The foamed glass is low in raw material cost, simple in process and suitable for batch production, the problem that waste glass and low-grade high-organic-matter-content diatomite cannot be fully utilized is solved, and the obtained foamed glass is excellent in quality, high in porosity and sound absorption coefficient and firm in texture and is a good heat-preservation, sound-absorption and fireproof material.

Description

Technical Field

[0001] The invention relates to a method for preparing foam glass by using diatomite with high organic matter content, and in particular to a method for preparing highly sound-absorbing, highly heat-insulating and lightweight foam glass by using porous diatomite rich in natural organic matter as a mixed material. Background Art

[0002] Diatomaceous earth is formed by the sedimentation of diatom debris growing in the ocean or lake, and has a natural porous structure. Its chemical composition is mainly SiO2, and it also contains a small amount of Al2O3, Fe2O3, CaO, MgO, etc. It has a rich pore structure inside and stable chemical properties. It is widely used as a filter, functional filler, and thermal insulation and sound insulation material.

[0003] Naturally produced diatomite generally contains a certain amount of biomass. Due to the large differences in geological historical conditions of mineralization, the diatomite produced in Yunnan and other places in China usually has a high biomass residue (can exceed 15wt%). The carbon content in these residual organic matter is very high, which will have an adverse effect on the color of the product and the bonding strength with cement. Therefore, in most application fields, there are relatively strict requirements for the ignition loss of diatomite, typically not exceeding 10wt%. This means that diatomite with high organic matter content (loss on ignition exceeds 10wt%) needs to be calcined at high temperature in advance to remove organic matter before use, which will bring a series of problems such as high energy consumption, air pollution, and increased costs. Therefore, diatomite with high organic matter content is inferior diatomite in the usual sense and has been difficult to develop and utilize. However, in diatomite with high organic matter content, rich pore structure and excellent physical and chemical stability are still maintained. Therefore, it is necessary to develop a new development and utilization method suitable for diatomite with high organic matter content from the perspective of turning waste into treasure for carbon-containing components.

[0004] Foam glass, also known as porous glass or foamed glass, is an inorganic insulating glass with a porosity of more than 80% and composed of uniform pores. Foam glass materials overcome the various defects of organic and inorganic thermal insulation materials such as perlite, light calcium carbonate, foam plastics, and cork, and have great advantages in terms of cost performance. It is a high-quality building material with fireproofing, heat preservation, and noise reduction functions, and is particularly suitable for the construction of high-rise residential exterior walls, large factory walls, highway sound insulation belts, etc. At present, the main obstacle restricting the large-scale application of foam glass products is the high cost. Because the foaming agents used to make foam glass are mainly calcium carbonate powder, carbon powder, silicon carbide, etc., these foaming agents need to be ground to an ultra-fine degree in advance (so that the particle size reaches the micron level) to achieve rapid and uniform foaming of the blank, resulting in high raw material costs. In addition, the production of foamed glass by grinding waste glass can reduce some of the raw material costs. However, due to the large differences in the components of waste glass, it is difficult to accurately control the pore wall size and pore structure during the foaming process, resulting in it being difficult to produce high-quality foamed glass using waste glass as raw material under traditional foaming processes.

[0005] The carbon components in high-organic-content diatomite can generate highly active carbon-rich micro-nano particles under high-temperature reducing atmosphere conditions. If they can replace part of the carbon powder foaming agent, the raw material cost of the product will be significantly reduced. In addition, the porous structure of diatomite itself can also provide a richer micron-level pore structure for foamed glass, thereby effectively improving its mechanical properties and sound absorption performance. Summary of the invention

[0006] In order to solve the problems that diatomite with high organic matter content is difficult to use and the quality of foam glass made from waste glass is not high, the present invention provides a method for preparing high-quality foam glass at low cost, which makes full use of the biomass rich on the surface of diatomite with high organic matter content as a micro-nano carbon pore-forming agent, and uses the porous skeleton structure of diatomite itself to form millimeter-micrometer-nanometer multi-level pores in the foam glass, and relies on the reliable mechanical properties of diatom disks to fully guarantee the quality of foam glass products from multiple angles.

[0007] In order to achieve the above objectives, the present invention adopts the following technical solutions.

[0008] A method for preparing foam glass using diatomite with high organic matter content comprises the following steps:

[0009] (1) crushing and wet-grinding high-organic-content diatomite with a loss on ignition of ≥15wt% to obtain a uniformly dispersed diatomite slurry with a solid content of 10-55wt%; (the loss on ignition here refers to the percentage of the mass lost by drying the raw material to lose external moisture at 110°C and burning it at a high temperature of 800±30°C for a sufficient time to the mass of the original sample.)

[0010] (2) crushing, grinding and sieving the waste glass to obtain glass powder with a fineness of 200 mesh;

[0011] (3) diatomite slurry, glass powder, foaming agent and foam stabilizer are mixed in a certain proportion to obtain a mixture, wherein the mass percentage of each component in the mixture is: glass powder 70% to 80%, diatomite 15% to 25%, foaming agent 1% to 2%, and foam stabilizer 4% to 8%;

[0012] (4) injecting the mixed material into a mold, drying and forming at 80-120° C., and demolding to obtain a green body;

[0013] (5) placing the green body in a high temperature furnace, rapidly heating it to 850-950° C., and keeping it at this temperature for foaming for 60-120 min, then annealing it at 520-570° C. for a sufficient time, and slowly cooling it to obtain a finished product;

[0014] The diatomaceous earth in step (1) has a purity of ≥80 wt% (the purity is calculated as the percentage of the mass of the diatom shell to the total mass of the high-temperature decarbonized and burned product).

[0015] Furthermore, the waste glass in step (2) is waste glass from buildings, leftover glass from glass industry production, etc.

[0016] Furthermore, the foaming agent described in step (3) is carbon powder, and the average particle size is ≤50 microns.

[0017] Furthermore, the foam stabilizer described in step (3) is one or both of trisodium phosphate and potassium tripolyphosphate.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The present invention uses diatomite with high organic content as a composite pore-forming raw material. Its high melting point and porous properties ensure that it can be compounded inside the pores of the foamed glass during the foaming process, thereby effectively constructing a millimeter-micrometer-nanometer multi-level pore structure. This complex porous structure can significantly improve the sound absorption coefficient of the foamed glass. At the same time, the organic matter rich in it forms nano-scale carbon particles under high-temperature carbonization conditions to act as a foaming agent, which cooperates with the original carbon powder in the system for foaming, which not only reduces the amount of foaming agent, but also promotes the formation of micron and nanometer pores, so that the success rate of obtaining a millimeter-micrometer-nanometer multi-level pore structure using waste glass raw materials is significantly improved. In addition, the high temperature stability of diatomite itself and the reliable mechanical properties of diatom disks also provide reliable guarantees for thin-walled foam glass to obtain ideal mechanical properties.

[0020] The present invention is developed based on the study of the interaction between biomass and mineral components in diatomite with high organic matter content under high temperature conditions. The method makes full use of the biomass carbon precursor in the original soil and the stable porous structure of the diatomite itself, so that it can be combined with the recycling of waste glass under appropriate process conditions to produce foam glass products with performance far superior to type II foam glass (the foam glass model made from waste glass as raw material in JC / T 647). The method can achieve the effective utilization of waste glass and significantly reduce the cost of raw materials. Part of the grinding process is carried out by wet method, which significantly reduces the dust pollution in the production process. The product has uniform foaming, good mechanical properties and sound absorption performance, simple equipment and process, and can be mass-produced using traditional foam glass equipment, with outstanding economic and social benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a process flow chart for preparing foam glass using diatomite with high organic content.

[0022] Figure 2 This is a scanning electron micrograph of diatomaceous earth with high organic content.

[0023] Figure 3 Physical picture of the finished foam glass in Example 1 DETAILED DESCRIPTION

[0024] In order to make those skilled in the art better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with specific embodiments. The specific embodiments described here are only used to illustrate the present invention, but are not used to limit the scope of the present invention.

[0025] like Figure 1 As shown, the process flow of preparing foam glass using diatomite with high organic matter content provided by the present invention includes five processes: raw material pretreatment, mixing, molding, firing and foaming, and annealing.

[0026] Example 1

[0027] The invention discloses a method for preparing foam glass by using diatomaceous earth with high organic matter content.

[0028] (1) Raw material pretreatment: The diatomite with high organic content and ignition loss of 15wt% and purity of 88wt% was crushed and wet-ground to obtain uniformly dispersed diatomite slurry. The waste glass was crushed, ground and sieved to obtain glass powder with a fineness of 200 mesh.

[0029] (2) Screening of the mixed material: 80 wt% of glass powder, 15 wt% of diatomaceous earth slurry, 1% of foaming agent and 4 wt% of foam stabilizer are uniformly mixed to obtain a mixed material.

[0030] (3) Molding: The mixed material is injected into a mold, dried at 110°C, and demolded to obtain a green body.

[0031] (4) Firing and annealing: The green body is placed in a high temperature furnace, rapidly heated to 850°C, and kept at this temperature for foaming for 120 minutes, then annealed at 550°C for a sufficient time, and slowly cooled to obtain the finished product. The properties of the obtained product are detailed in Table 1.

[0032] Example 2

[0033] The invention discloses a method for preparing foam glass by using diatomaceous earth with high organic matter content.

[0034] (1) Raw material pretreatment: The diatomite with high organic content and ignition loss of 15wt% and purity of 88wt% was crushed and wet-ground to obtain uniformly dispersed diatomite slurry. The waste glass was crushed, ground and sieved to obtain glass powder with a fineness of 200 mesh.

[0035] (2) Screening of the mixed material: 75 wt% of glass powder, 15 wt% of diatomaceous earth slurry, 2% of foaming agent and 8 wt% of foam stabilizer are uniformly mixed to obtain a mixed material.

[0036] (3) Molding: The mixed material is injected into a mold, dried at 110°C, and demolded to obtain a green body.

[0037] (4) Firing and annealing: The green body is placed in a high temperature furnace, rapidly heated to 900°C, and kept at this temperature for 110 min for foaming, then annealed at 550°C for a sufficient time, and slowly cooled to obtain the finished product. The properties of the obtained product are detailed in Table 1.

[0038] Example 3

[0039] The invention discloses a method for preparing foam glass by using diatomaceous earth with high organic matter content.

[0040] (1) Raw material pretreatment: Raw material pretreatment: The diatomite with high organic content and loss on ignition of 19wt% and purity of 80wt% was crushed and wet-ground to obtain a uniformly dispersed diatomite slurry. The waste glass was crushed, ground and sieved to obtain glass powder with a fineness of 200 mesh.

[0041] (2) Screening of the mixed material: 75 wt% of glass powder, 20 wt% of diatomaceous earth slurry, 1% of foaming agent and 4 wt% of foam stabilizer are uniformly mixed to obtain a mixed material.

[0042] (3) Molding: The mixed material is injected into a mold, dried at 110°C, and demolded to obtain a green body.

[0043] (4) Firing and annealing: The green body is placed in a high temperature furnace, rapidly heated to 900°C, and kept at this temperature for 110 min for foaming, then annealed at 550°C for a sufficient time, and slowly cooled to obtain the finished product. The properties of the obtained product are detailed in Table 1.

[0044] Example 4

[0045] The invention discloses a method for preparing foam glass by using diatomaceous earth with high organic matter content.

[0046] (1) Raw material pretreatment: Raw material pretreatment: The diatomite with high organic content and loss on ignition of 19wt% and purity of 80wt% was crushed and wet-ground to obtain a uniformly dispersed diatomite slurry. The waste glass was crushed, ground and sieved to obtain glass powder with a fineness of 200 mesh.

[0047] (2) Screening of the mixed material: 70 wt% of glass powder, 25 wt% of diatomaceous earth slurry, 1% of foaming agent and 4 wt% of foam stabilizer are uniformly mixed to obtain a mixed material.

[0048] (3) Molding: The mixed material is injected into a mold, dried at 110°C, and demolded to obtain a green body.

[0049] (4) Firing and annealing: The green body is placed in a high temperature furnace, rapidly heated to 950°C, and kept at this temperature for foaming for 100 min, then annealed at 550°C for a sufficient time, and slowly cooled to obtain the finished product. The properties of the obtained product are detailed in Table 1.

[0050] Table 1 Bulk density, porosity and noise reduction coefficient of different embodiments

[0051] sample <![CDATA[Bulk density (g / cm 3 )]]> Compressive strength(MPa) Porosity (%) Sound absorption coefficient Example 1 0.18 2.07 79.77 0.79 Example 2 0.17 2.01 81.65 0.85 Example 3 0.16 2.00 83.84 0.88 Example 4 0.16 2.05 80.58 0.86

[0052] Table 1

[0053] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, the technical solution of the present invention can be modified in various ways, and these simple modifications all belong to the protection scope of the present invention.

Claims

1. A method for preparing foam glass using diatomite with high organic content, characterized in that: The invention comprises the following steps: crushing and grinding diatomite with high organic matter content and loss on ignition of ≥15wt% and purity of ≥80wt%, mixing and grinding evenly with glass powder with a fineness of 200 mesh or better, a small amount of foaming agent and an appropriate amount of foam stabilizer to obtain a mixture, so that the mass percentage of each component in the mixture is controlled within the range of 70-80% of glass powder, 15-25% of diatomite, 1-2% of foaming agent and 4-8% of foam stabilizer; after the mixture is formed, placing it in a high-temperature furnace, rapidly heating it to 850-950°C and keeping it warm for an appropriate time to achieve sufficient foaming, and then obtaining a finished product after appropriate annealing treatment, and the finished product can be further cut into a required size according to demand after the surface is cut off to obtain a required foam glass product.

2. The method for preparing foam glass using diatomite with high organic matter content according to claim 1, characterized in that: The diatomaceous earth is diatomaceous earth with high organic matter content, and its purity reaches the level of high-quality diatomaceous earth.

3. The method for preparing foam glass using diatomite with high organic matter content according to claim 1, characterized in that: The glass powder is made by grinding waste glass powder, and the waste glass refers to waste glass from buildings or leftover glass from glass industry production.

4. The method for preparing foam glass using diatomite with high organic matter content according to claim 1, characterized in that: The foaming agent is carbon powder, and the average particle size is ≤50 microns.

5. The method for preparing foam glass using diatomite with high organic matter content according to claim 1, characterized in that: The foam stabilizer is one or both of trisodium phosphate and potassium tripolyphosphate.

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