Method for preparing high-quality foam glass

Abstract

The invention relates to a preparation method of high-quality foam glass, in particular to a method for preparing foam glass with good heat insulation performance and strong sound absorption performance by using glass powder as a main raw material and diatomite as an auxiliary material. The preparation method comprises the following steps: (1) pretreatment: crushing formula glass, feeding the crushed formula glass into a ball mill, grinding to obtain glass powder, and sieving the obtained glass powder, diatomite, a foaming agent and the like; (2) uniformly mixing the pretreated glass powder, diatomite, a foaming agent and a foam stabilizer according to a specific mass ratio to prepare a raw material; (3) loading the obtained raw material into a specific high-temperature-resistant mold, and feeding the mold into a kiln for firing and foaming; (4) quenching the foamed sample, and demolding; and (5) annealing the demolded sample, and trimming to obtain a finished product. The foam glass obtained in the invention has high cost performance, high noise reduction coefficient and low thermal conductivity, is an ideal sound absorption material, thermal insulation material and fireproof material, and has a very wide application prospect in the engineering construction industry.

Description

Technical Field

[0001] The invention relates to a method for preparing high-quality foam glass, in particular to a method for preparing foam glass with good heat insulation performance and strong sound absorption performance by using glass powder as a main raw material and diatomaceous earth as an auxiliary material. Background Art

[0002] Currently, commonly used building sound-absorbing materials include sound-absorbing cotton, foam plastics, wooden boards, foam ceramics, etc. They all have sound-absorbing properties, but sound-absorbing cotton will generate dust during installation, which is irritating to the skin and respiratory tract; foam plastics may decompose after long-term use and release toxic gases; wooden boards may be easily affected by moisture and rot, and require regular maintenance; foam ceramics require a higher firing temperature, and have limited impact resistance, which limits their scope of application; and commonly used building insulation materials include polystyrene boards, rock wool boards, phenolic boards, etc., which have good insulation properties, but are expensive and difficult to install, especially poor strength and easy to fall off, which poses a huge safety hazard in urban high-rise buildings. Compared with the above materials, foam glass has significant advantages in cost, installation, sound absorption, insulation, and fire resistance.

[0003] Foam glass, also known as porous glass, is made of glass powder, kaolin or tailings mixed with foaming agent and foamed at high temperature. It has the advantages of high porosity, low density and high strength. It is these advantages that give foam glass the characteristics of non-toxicity, fireproof, light, heat insulation and sound absorption. At present, the foam glass with excellent sound absorption performance is an open-cell foam glass obtained by special process, and there are a large number of interconnected bubbles inside. Such a structure makes the sound cause the air in the inner hole to move after contacting the surface of the foam glass. Due to the effect of viscosity and friction, the mechanical energy is converted into heat energy, thereby achieving the sound absorption effect. The foam glass with excellent thermal insulation performance is a closed-cell foam glass, which is composed of numerous closed tiny pores inside. These pores are filled with gas, which effectively inhibits the convection heat transfer of the air, thereby achieving the effect of thermal insulation.

[0004] At present, the proportion of open pores and closed pores in the foam glass produced in the industry is mostly controlled in order to achieve both sound absorption and thermal insulation performance. However, it is difficult to strictly control the proportion of the two and their position distribution will also seriously affect the performance of the product. Therefore, research in this field has always been an urgent problem to be solved by relevant industry insiders.

[0005] Diatomaceous earth is generally formed by the silicate remains of dead single-cell algae collectively known as diatoms. Its essence is water-containing amorphous SiO2 with a melting point of 1650-1750℃. Diatomaceous earth is soft, loose and porous, with low density and large specific surface area. It is currently widely used in indoor and outdoor coatings, decoration materials and wall insulation materials. By utilizing the unique pore structure of diatomaceous earth and the high temperature resistance of diatomaceous earth in my country, high-quality foam glass with both sound absorption and heat insulation properties can be obtained at a lower firing cost and a wider process window, but there is no relevant report on the technical achievements in this area. Summary of the invention

[0006] The purpose of the present invention is to provide a method for preparing foam glass with good thermal insulation and sound absorption performance at a low cost. On the one hand, internal closed pores are formed through the thermal insulation foaming process, and then used as a thermal insulation material in the construction field; on the other hand, diatomaceous earth is attached to the pore wall of the glass matrix by utilizing its high melting point and porous properties, and the internal closed pores are connected by the many tiny pores formed by the fusion of the two, thereby realizing the sound absorption characteristics of open pores under a wider process window, and then used as a sound absorption material in the construction field. This method breaks the conventional idea of ​​regulating the ratio of open / closed pores, and utilizes the unique physical and chemical characteristics of my country's diatomaceous earth to provide a microporous open pore solution in a closed pore preparation system.

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

[0008] A method for preparing high-quality foam glass comprises the following steps:

[0009] (1) crushing, grinding and screening the formulated glass raw materials to obtain glass powder with an average particle size not exceeding 110 μm;

[0010] (2) mixing glass powder, diatomaceous earth, foaming agent, foam stabilizer, etc. that meet the requirements of fineness and purity in a specific mass ratio to form a raw material;

[0011] (3) the raw material powder is put into a specific high temperature resistant mold and sent into a kiln for firing and foaming;

[0012] (4) Rapidly cool the foamed sample and then demould it;

[0013] (5) The demoulded sample is annealed and trimmed to obtain the finished product.

[0014] Preferably, (1) the main components and their mass percentages of the formulated glass raw materials are: SiO2: 68wt% to 70wt%, Al2O3: 0.5wt% to 1.1wt%, CaO: 10.5wt% to 12%, MgO: 3.2wt% to 4wt%, Na2O: 14.5wt% to 15wt%, SO3: 0.20wt% to 0.25wt% and other trace substances.

[0015] Preferably, (1) the glass raw material is a block or granular raw material that has not been annealed.

[0016] Preferably, the mass percentages of the components in the foam glass raw material in (2) are: glass powder 68% to 74%, diatomaceous earth 18% to 28%, foaming agent: 0.5% to 3%, and foam stabilizer 3.5% to 5%.

[0017] Preferably, the diatomaceous earth used in the raw material (2) is grade I diatomaceous earth, and the average particle size does not exceed 110 μm.

[0018] Preferably, the diatomaceous earth used in the raw material (2) is grade I diatomaceous earth with a purity of ≥85wt% (the purity is calculated as the percentage of the mass of the diatom shell to the total mass of the high-temperature decarbonized calcined product).

[0019] Preferably, (2) the foaming agent used in the raw material is silicon carbide, and the average particle size does not exceed 25 μm. Preferably, (2) the foam stabilizer selected in the raw material is one or both of trisodium phosphate and potassium tripolyphosphate, and the average particle size is preferably 20 to 25 μm.

[0020] More preferably, when the sample described in (3) is fired, the temperature is first raised to 900-1000° C., and then kept at this temperature for foaming for 30-60 minutes.

[0021] More preferably, the quenching rate in (4) is 10-15°C / min, and when the temperature is cooled to 450-500°C, the mold is removed.

[0022] More preferably, the sample in (5) is kept at an annealing temperature of 600-650° C. for about 30 min, and then slowly cooled to room temperature.

[0023] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0024] (1) The present invention uses diatomaceous earth as the main functional filler, which can significantly expand the process window range under the premise of lower manufacturing cost and ensure stable product quality. Diatomaceous earth is low in cost, high in melting point, loose and porous, and its chemical composition is similar to that of the glass matrix, so that when the glass matrix is ​​melted, the diatomaceous earth powder can be evenly dispersed in the glass matrix without significant morphological changes. In addition, the interface between it and the glass matrix can easily form a pore wall structure during the foaming process, and then the closed pores formed by the foaming agent are connected to each other to form a complex multi-level pore structure, so that the product has the thermal insulation performance of closed-pore materials while also producing the unique sound absorption effect of open pores, and the process window is wide, the process control difficulty is small, and the manufacturing cost is not increased;

[0025] (2) The present invention adopts a "two-step method" for firing. By effectively controlling various technical indicators in the production process, the quality of the finished foam glass can be greatly improved and the multifunctional utilization can be achieved. The foam glass has excellent physical properties such as low density, high strength, and low thermal conductivity. At the same time, it has the functions of heat preservation, heat insulation, sound absorption, moisture resistance, waterproofness, and fire prevention. Compared with the "one-step method" firing process, the method of the present invention has higher production efficiency, more stable product performance, and lower mold cost and loss, which is more in line with the needs of large-scale production in factories.

[0026] (3) The present invention adopts a unique glass raw material formula, starting from the chemical composition ratio of the raw materials of the formula glass, improves the melting characteristics of the foam glass matrix, ensures that the glass melt is in a suitable viscosity range during the foaming process, greatly improves the yield and quality, and is an optimization of the traditional foam glass production process. The foaming agent forms closed pores inside the foamed foam glass to produce a good thermal insulation effect, and the diatomaceous earth uniformly dispersed in the glass matrix when the glass powder is melted spontaneously forms microporous pipes connecting the closed pores to produce an excellent sound absorption effect, so that the product has low cost and excellent performance, and has significant application advantages in the building materials industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Foam glass preparation flow chart

[0028] Figure 2 Electron micrograph of diatomaceous earth

[0029] Figure 3 Physical picture of the finished foam glass in Example 1 DETAILED DESCRIPTION

[0030] 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.

[0031] like Figure 1 As shown, the preparation process of a high-quality foam glass provided by the present invention includes six processes: pretreatment, stirring and mixing powder, molding and firing, heat preservation and foaming, rapid cooling and demoulding, and annealing.

[0032] Example 1

[0033] A method for preparing high-quality foam glass and the prepared foam glass

[0034] The composition of the formulated glass in this example is as follows: SiO2: 68wt%, Al2O3: 0.5wt%, CaO: 12%, MgO: 4wt%, Na2O: 15wt%, SO3: 0.25wt% and other trace substances.

[0035] (1) Pretreatment: crush the experimental formula glass and place it in a ball mill for 3 hours. The obtained glass powder is sieved through a 150-mesh sieve. The first-grade diatomaceous earth is sieved through a 150-mesh sieve to obtain a micro powder with an average particle size of 100 to 110 μm, which is set aside; the silicon carbide powder is sieved through a 500-mesh sieve, and the trisodium phosphate is sieved through a 500-mesh sieve to obtain a micro powder with an average particle size of 20 to 25 μm, which is set aside;

[0036] (2) Mixing powders by stirring: the pretreated raw materials are weighed on an analytical balance according to the mass percentage of glass powder 68%, diatomaceous earth 28%, foaming agent 0.5%, and foam stabilizer 3.5%. The raw materials are placed in a stainless steel mixer and stirred at a speed of 300 r / min for 2 min to obtain a foam glass raw material.

[0037] (3) Mold filling and firing: The foam glass raw material is placed into the mold, with the raw material occupying about 40% of the mold volume. The mold is then placed in a kiln and fired at a heating rate of 8°C / min.

[0038] (4) Heat preservation and foaming: When the firing temperature reaches 1000°C, stop heating and keep warm for 30 minutes;

[0039] (5) Rapid cooling and demoulding: After the insulation stage, immediately cool to 450°C at a cooling rate of 15°C / min, and then remove the mold;

[0040] (6) Annealing treatment: The demoulded sample is placed in an annealing furnace at 650°C for 20 minutes, and then cooled to room temperature to obtain the finished product.

[0041] Example 2

[0042] A method for preparing high-quality foam glass and the prepared foam glass

[0043] The composition of the formulated glass in this example is as follows: SiO2: 68.7wt%, Al2O3: 0.7wt%, CaO: 11.6%, MgO: 3.8wt%, Na2O: 14.8wt%, SO3: 0.20wt% and other trace substances.

[0044] (1) Pretreatment: crush the experimental formula glass and place it in a ball mill for 3 hours. The obtained glass powder is sieved through a 150-mesh sieve. The first-grade diatomaceous earth is sieved through a 150-mesh sieve to obtain a micro powder with an average particle size of 100 to 110 μm, which is set aside; the silicon carbide powder is sieved through a 500-mesh sieve, and the trisodium phosphate is sieved through a 500-mesh sieve to obtain a micro powder with an average particle size of 20 to 25 μm, which is set aside;

[0045] (2) Mixing powders by stirring: the pretreated raw materials are weighed on an analytical balance according to the mass percentage of glass powder 71%, diatomaceous earth 23%, foaming agent 1.5%, and foam stabilizer 4.5%. 50 g of glass powder, 16.2 g of diatomaceous earth powder, 1.06 g of silicon carbide powder, and 3.17 g of trisodium phosphate are placed in a stainless steel mixer and stirred at a speed of 300 r / min for 2 min to obtain a foam glass raw material;

[0046] (3) Mold filling and firing: The foam glass raw material is placed into the mold, with the raw material occupying about 40% of the mold volume. The mold is then placed in a kiln and fired at a heating rate of 9°C / min.

[0047] (4) Heat preservation and foaming: When the firing temperature reaches 950°C, stop heating and keep warm for 45 minutes;

[0048] (5) Rapid cooling and demoulding: After the insulation stage, immediately cool to 450°C at a cooling rate of 12°C / min, and then remove the mold;

[0049] (6) Annealing treatment: The demoulded sample is placed in an annealing furnace at 630°C for 25 minutes, and then cooled to room temperature to obtain the finished product.

[0050] Example 3

[0051] A method for preparing high-quality foam glass and the prepared foam glass

[0052] The composition of the formulated glass in this example is as follows: SiO2: 69.3wt%, Al2O3: 0.9wt%, CaO: 10.8%, MgO: 3.5wt%, Na2O: 14.9wt%, SO3: 0.24wt% and other trace substances.

[0053] (1) Pretreatment: crush the experimental formula glass and place it in a ball mill for 3 hours. The obtained glass powder is sieved through a 150-mesh sieve. The first-grade diatomaceous earth is sieved through a 150-mesh sieve to obtain a micro powder with an average particle size of 100 to 110 μm, which is set aside; the silicon carbide powder is sieved through a 500-mesh sieve, and the trisodium phosphate is sieved through a 500-mesh sieve to obtain a micro powder with an average particle size of 20 to 25 μm, which is set aside;

[0054] (2) Mixing powders by stirring: the pretreated raw materials are weighed on an analytical balance according to the following mass percentages: glass powder 74%, diatomaceous earth 18%, foaming agent 3%, and foam stabilizer 5%. 50 g of glass powder, 12.2 g of diatomaceous earth powder, 2 g of silicon carbide powder, and 3.38 g of trisodium phosphate are placed in a stainless steel mixer and stirred at a speed of 300 r / min for 2 min to obtain a foam glass raw material;

[0055] (3) Mold filling and firing: The foam glass raw material is placed into the mold, with the raw material occupying about 40% of the mold volume. The mold is then placed in a kiln and fired at a heating rate of 10°C / min.

[0056] (4) Heat preservation and foaming: When the firing temperature reaches 900°C, stop heating and keep warm for 60 minutes;

[0057] (5) Rapid cooling and demoulding: After the insulation stage, immediately cool to 500°C at a cooling rate of 10°C / min, and then remove the mold;

[0058] (6) Annealing treatment: The demoulded sample is placed in an annealing furnace at 630°C for 25 minutes, and then cooled to room temperature to obtain the finished product.

[0059] Table 1 Bulk density, compressive strength, porosity, thermal conductivity, and noise reduction coefficient of different embodiments

[0060]

[0061] 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 high-quality foam glass, characterized in that: The high-quality foam glass is obtained by the following steps: (1) crushing, grinding and screening the formulated glass raw materials to obtain glass powder with an average particle size not exceeding 110 μm; (2) mixing glass powder, diatomaceous earth, foaming agent, foam stabilizer, etc. that meet the requirements of fineness and purity in a specific mass ratio to form a raw material; (3) the raw material powder is put into a specific high temperature resistant mold and sent into a kiln for firing and foaming; (4) Rapidly cool the foamed sample and then demould it; (5) The demoulded sample is annealed and trimmed to obtain the finished product.

2. A method for preparing high-quality foam glass according to claim 1, characterized in that: The main components and mass percentages of the formulated glass raw materials in the step (1) are: SiO2: 68wt% to 70wt%, Al2O3: 0.5wt% to 1.1wt%, CaO: 10.5wt% to 12%, MgO: 3.2wt% to 4wt%, Na2O: 14.5wt% to 15wt%, SO3: 0.20wt% to 0.25wt% and other trace substances.

3. The method for preparing high-quality foam glass according to claim 1, characterized in that: The glass raw material in step (1) is a block or granular raw material that has not been annealed.

4. The method for preparing high-quality foam glass according to claim 1, characterized in that: The mass percentages of the components in the foam glass raw material in the step (2) are: glass powder 68% to 74%, diatomaceous earth 18% to 28%, foaming agent 0.5% to 3%, and foam stabilizer 3.5% to 5%.

5. The method for preparing high-quality foam glass according to claim 1, characterized in that: The diatomaceous earth used in step (2) is grade I diatomaceous earth with a purity of ≥85wt% (the purity is calculated as the percentage of the mass of the diatom shell to the total mass of the high-temperature decarbonized calcined product), and an average particle size of no more than 110 μm.

6. The method for preparing high-quality foam glass according to claim 1, characterized in that: The foaming agent selected in step (2) is silicon carbide, and the average particle size does not exceed 25 μm.

7. The method for preparing high-quality foam glass according to claim 1, characterized in that: The foam stabilizer used in step (2) is one or both of trisodium phosphate and potassium tripolyphosphate, and the average particle size does not exceed 25 μm.

8. The method for preparing high-quality foam glass according to claim 1, characterized in that: When the sample in step (3) is fired, the temperature is first raised to 900-1000° C. and then kept at this temperature for foaming for 30-60 minutes.

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