Glass shell expanded perlite as well as preparation method and application thereof

Abstract

The invention provides glassy shell expanded perlite as well as a preparation method and application thereof, and the preparation method comprises the following steps: pretreating perlite ore to obtain first perlite particles; proportioning the first perlite particles and a binder according to a mass ratio, and uniformly mixing the first perlite particles and the binder to obtain second perlite particles; proportioning the second perlite particles and the vitreous cladding powder according to a mass ratio, uniformly mixing and granulating to obtain third perlite particles; drying and preheating the third perlite particles to obtain fourth perlite particles; and carrying out high-temperature expansion treatment on the fourth perlite particles to obtain the vitreous shell expanded perlite. The expanded perlite prepared by the invention has the characteristics of high expansion time, small bulk density, high cylinder compressive strength, low heat conduction coefficient, small water absorption rate, acid and alkali corrosion resistance and the like; the material can be widely used for producing light materials, heat preservation and insulation materials, sound absorption and insulation materials, decorative materials and fireproof flame-retardant materials, and can be used as water surface floating heat preservation materials, sunscreen materials, reflective materials and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to mineral rock material processing and its new material, in particular to a vitreous shell expanded perlite and its preparation method and application. BACKGROUND

[0002] The perlite ore is a kind of glassy rock formed by the rapid cooling of acidic lava after volcanic eruption, which is famous for its unique burning expansion. Under appropriate high temperature (generally 1000-1300℃) conditions, perlite ore particles can rapidly expand several times to form expanded perlite with light weight, porosity, and properties of heat insulation, sound insulation, fire resistance, etc. Expanded perlite shows a wide application potential in many fields, especially as a raw material for producing light and thermal insulation materials, which plays an important role in the construction industry and manufacturing industry.

[0003] However, the expanded perlite produced by traditional methods has the defects of open cavities left by gas escaping during the expansion of perlite ore, irregular shape, low strength, easy moisture absorption, etc. These problems often lead to a decline in product performance during preparation and use, such as open cavities that easily lead to the pouring of cementing / cementitious material slurry, reducing the lightness and thermal insulation performance, etc., thereby limiting its application range. In order to overcome these defects, researchers have tried various improvement methods, including organic modification and surface coating technology, but these methods often bring new problems, such as affecting the bonding strength, etc.

[0004] In recent years, with the progress of technology, the method of producing closed-cell expanded perlite by heating the expanded perlite in an electric expansion furnace has made a breakthrough. This method controls the temperature accurately to melt the glassy surface layer of the expanded perlite particles, forming a closed shell, which significantly improves the strength and water resistance of the material. However, the complex processing technology and the equipment including the control of the furnace temperature to melt the surface layer of the expanded perlite without melting the inside are still a difficult problem to solve, which affects the bulk density, thermal conductivity and performance of the final product of the expanded perlite.

[0005] Therefore, it is of great significance to explore new production methods for closed-cell expanded perlite and overcome the defects of the expanded perlite produced by traditional methods, such as the open cavities on the surface of the expanded perlite, which easily lead to the pouring of cementing / cementitious material slurry and reduce the lightness and thermal insulation performance of the expanded perlite, etc.

[0006] The present application coats the surface of perlite ore particles with a heterogeneous material that can form a glassy shell by a method of adhesive coating. When the coated perlite ore particles are subjected to expansion processing, the heterogeneous material coated on the surface first melts and traps the gas released during the expansion of the perlite ore particles, not only forming a glassy shell on the surface of the expanded perlite, but also further improving the expansion ratio, sphericity and overall performance. The new shell / core structure of the expanded perlite material has excellent properties such as low bulk density, low thermal conductivity, high sphericity and high strength. In particular, during the molding process of lightweight, thermal insulation materials, the closed pore structure of the expanded perlite does not allow the cement / gel material slurry to be filled, and the high sphericity allows for a higher tight packing, thereby reducing the amount of cement / gel material used, and thus the resulting expanded perlite lightweight, thermal insulation material has more excellent performance. SUMMARY

[0007] The present application aims to solve at least one of the above-mentioned deficiencies in the prior art. For example, one of the objectives of the present application is to provide a glassy shell expanded perlite and a method for preparing the same; the second objective of the present application is to provide a glassy shell expanded perlite; the third objective of the present application is to provide an application of a glassy shell expanded perlite.

[0008] To achieve the above-mentioned objectives, the present application provides, in one aspect, a method for preparing a glassy shell expanded perlite, the method comprising: 1) pretreating a perlite ore to obtain first perlite particles; 2) mixing the first perlite particles with a binder in a mass ratio to obtain second perlite particles; 3) mixing the second perlite particles with a glassy shell powder in a mass ratio, granulating to obtain third perlite particles; 4) drying and pre-heating the third perlite particles to obtain fourth perlite particles; and 5) high-temperature expanding the fourth perlite particles to obtain the glassy shell expanded perlite.

[0009] Alternatively, the perlite ore includes one or more of perlite type, obsidian type, pitchstone type and pumice-like perlite.

[0010] Alternatively, the pretreatment includes crushing, screening and dust removal; the crushing is crushing with an inspection and screening section, the inspection and screening includes continuing to crush the oversize perlite ore, which can avoid over-crushing of the undersize perlite ore; the screening and dust removal includes screening the crushed perlite ore into different particle size specifications, and collecting the micropowder with a particle size less than 100 mesh as a raw material for the glassy shell powder.

[0011] Optionally, the first perlite particles are processed perlite ore sand of perlite rock, having a particle size range of +100 mesh to -10 mesh; and the particle size specifications of the first perlite particles include multiple kinds of -10 mesh to +20 mesh, -20 mesh to +30 mesh, -30 mesh to +50 mesh, -50 mesh to +80 mesh, and -80 mesh to +100 mesh.

[0012] Optionally, the mass ratio in step 2) is 100:(3-8);

[0013] The mixing uniformly includes spraying the binder onto the first perlite particles in stirring by a spraying method, and the binder is uniformly coated on the surface of the first perlite particles; and the second perlite particles are the perlite particles coated with the binder.

[0014] Optionally, the binder includes one or more of inorganic binder and organic binder configured into an aqueous solution or hydrosol with water;

[0015] The inorganic binder includes one or more of water glass, sodium silicate, and potassium silicate having a modulus of 1.0-2.9, configured into an aqueous solution having a density of 1.36-1.50 g / cm3, and a Baume degree of 38.4-48.3;

[0016] The organic binder includes one or more of carboxymethyl cellulose, sodium carboxymethyl cellulose, acrylic emulsion, vinyl acetate emulsion, polyvinyl acetal glue, emulsion glue, animal glue, and vegetable glue, configured into a hydrosol having a solid content percentage of 0.5-2.0%.

[0017] Optionally, the mass ratio in step 3) is (90-80):(10-20); and the granulation includes binding and uniformly coating the vitreous shell powder on the surface of the second perlite particles, the vitreous shell powder is bound by the binder on the surface of the perlite particles and forms a vitreous component coating layer, and the specific process includes:

[0018] The second perlite particles and the vitreous shell powder are weighed according to the proportion;

[0019] The weighed second perlite particles are placed in a granulator, and the vitreous shell powder is uniformly added into the running granulator, so that the vitreous shell powder is uniformly coated on the second perlite particles, and a composite particle of vitreous shell component / second perlite particle, i.e., a third perlite particle, is obtained.

[0020] The glassy shell component powder is evenly coated on the second perlite particles, and the glassy shell component powder does not exist independently after the coating is completed, but is entirely coated on the surface of the second perlite particles, is dense in texture, and tends to be spherical.

[0021] Alternatively, the glassy shell powder in step 3) is obtained by mixing ordinary silicate waste glass, the perlite ore micro-powder less than 100 mesh produced in step 1), borax, and boric acid in a mass ratio of (20-50):(40-70):(0-10):(0-5), and then performing selective crushing and mixing and grinding treatment.

[0022] Alternatively, the drying in step 4) is a drying process of the third perlite particles in an oven-drying-preheating device, in which the temperature is increased from room temperature to 200-300℃ at a temperature increasing rate of 8-20℃ per minute.

[0023] The preheating treatment is a preheating process of the third perlite particles in the oven-drying-preheating device, in which the temperature is increased from the drying section to the heating section at a temperature increasing rate of 50-80℃ per minute, and the air flow in the oven-drying-preheating device automatically flows from the heating section to the room temperature section.

[0024] Alternatively, the fourth perlite particles are preheated fourth perlite particles, and the water content of the fourth perlite particles is 2-3%.

[0025] Alternatively, the high-temperature expansion treatment in step 5) includes: uniformly sprinkling the fourth perlite particles onto a high-temperature flame with a temperature of 1100-1250℃ in an expansion furnace while the fourth perlite particles are hot, or uniformly spreading the fourth perlite particles and directly feeding them into an electric heating expansion furnace with a high-temperature section with a temperature of 1100-1350℃, so that the fourth perlite particles are rapidly heated and expanded.

[0026] The fourth perlite particles stay in the high-temperature flame or the high-temperature section of the electric heating furnace for 2-80 seconds, i.e., the time for rapid expansion, to obtain the glassy shell expanded perlite.

[0027] Another aspect of the present application provides a glassy shell expanded perlite, which is obtained by the above preparation method, has an expansion ratio of 3.5-8.0, a bulk density of 200-300 kg / m3, a cylinder compressive strength of 0.8-2 MPa, a thermal conductivity of 0.04-0.06 W / (m·K), a water absorption of <1.2%, an acid etching amount of <5%, and an alkali etching amount of <1%.

[0028] Still another aspect of the present application provides an application of the glassy shell expanded perlite, which is the above-mentioned glassy shell expanded perlite, has a higher expansion ratio and mechanical strength, a lower water absorption and pulp absorption, a higher sound absorption rate and a lower thermal conductivity than ordinary expanded perlite, and can be applied to the production of lightweight materials, thermal insulation materials, sound absorption and insulation materials, decorative materials, fireproof and flame-retardant materials, and used as water surface floating insulation materials, sun protection materials, and reflective materials.

[0029] Compared with the prior art, the present application has the following beneficial effects:

[0030] (1) The glassy shell expanded perlite prepared by the present application has a shell / core composite structure design, which can effectively trap and retain gas during the calcination and expansion process of the perlite ore particles, thereby significantly increasing the expansion ratio, reducing the density and thermal conductivity of the expanded perlite, improving its lightweight, thermal insulation and sound insulation effects, and meeting various application requirements.

[0031] (2) The glassy shell of the shell / core structure of the glassy shell expanded perlite prepared by the present application is a glassy material, which not only improves the mechanical strength of the expanded perlite, but also enables it to replace various traditional materials such as ceramsite and floating beads, providing more choices and possibilities for different application scenarios.

[0032] (3) The glassy shell of the shell / core structure of the glassy shell expanded perlite prepared by the present application effectively seals the pores generated during the expansion of the perlite ore particles, and the organic binder and inorganic cementitious material will not enter the pores during the preparation of the expanded perlite composite material. Furthermore, the glassy shell has a higher sphericity than ordinary expanded perlite, and can form a more compact packing body during the preparation of the expanded perlite composite material. The amount of organic binder or inorganic cementitious material required can be greatly reduced, thereby reducing the preparation cost of the expanded perlite composite material and improving the performance of the composite material, including lightweight, mechanical strength, and thermal insulation performance.

[0033] (4) The composite material or product prepared by using the shell / core structure expanded perlite according to the present application has more excellent light weight, heat preservation, sound absorption and sound insulation, etc. because the pores of the expanded perlite are closed and the problems of water absorption and moisture absorption do not occur. The multi-functionality makes it perform well in various environments and become a more ideal choice of building material and new material.

[0034] (5) In the process of preparing the glassy shell expanded perlite, the tail powder which cannot be used to prepare the expanded perlite and is formed in the process of processing the perlite ore particles is used as a raw material, which realizes the waste utilization, effectively reduces the amount of the binder or cementing material, reduces the production cost, and meets the sustainable development concept of resource recycling, environment-friendly and energy saving and cost reduction. BRIEF DESCRIPTION OF DRAWINGS

[0035] The above and other objects and / or characteristics of the present application will become more apparent by describing in detail the present application with reference to the attached drawings, wherein:

[0036] Figure 1 A preparation process flow chart of the glassy shell expanded perlite according to the present application is shown.

[0037] Figure 2 A photo of the ordinary expanded perlite is shown.

[0038] Figure 3 A photo of the glassy shell expanded perlite according to the present application is shown.

[0039] Figure 4 An optical microscope photo of the ordinary expanded perlite is shown.

[0040] Figure 5 An electron microscope photo of the ordinary expanded perlite is shown.

[0041] Figure 6 An optical microscope photo of the glassy shell expanded perlite according to the present application is shown.

[0042] Figure 7 Another optical microscope photo of the glassy shell expanded perlite according to the present application is shown.

[0043] Figure 8 An enlarged optical microscope photo of the glassy shell expanded perlite according to the present application is shown.

[0044] Figure 9 An electron microscope photo of the glassy shell expanded perlite according to the present application is shown.

[0045] Explanation of reference signs: Figure 9 a is an enlarged view of the yellow box in the middle. DETAILED DESCRIPTION

[0046] Hereinafter, a glassy shell expanded perlite and a preparation method and application thereof will be described in detail in conjunction with exemplary embodiments.

[0047] It should be noted that "first", "second", "third", "fourth" and the like are merely for the convenience of description and differentiation, and cannot be understood as indicating or implying relative importance. "Up", "down", "front", "back", "left", "right", "inside", "outside" and the like are merely for the convenience of description and constitute relative orientation or position relationship, and do not indicate or imply that the components must have the specific orientation or position.

[0048] Exemplary Embodiment 1

[0049] The present exemplary embodiment provides a preparation method of a glassy shell expanded perlite, which comprises:

[0050] S1, pretreating a perlite ore to obtain first perlite particles.

[0051] In the present embodiment, the perlite ore includes one or more of perlite type, obsidian type, pitchstone type and pumice-like perlite.

[0052] In the present embodiment, the pretreatment includes crushing, screening and dedusting; the crushing is crushing with an inspection screening section, the inspection screening includes continuously crushing the oversize coarse perlite ore, which can avoid over-crushing of the undersize perlite ore sand; the screening and dedusting includes screening the crushed perlite ore sand into different particle size specifications, and collecting the micropowder with a particle size less than 100 mesh in the perlite ore sand as a raw material for the glassy shell powder.

[0053] In the present embodiment, the first perlite particles are perlite ore sand processed from perlite rocks, and the particle size range is +100 mesh to -10 mesh; the particle size specifications of the first perlite particles include multiple of -10 mesh to +20 mesh, -20 mesh to +30 mesh, -30 mesh to +50 mesh, -50 mesh to +80 mesh and -80 mesh to +100 mesh.

[0054] S2, mixing the first perlite particles with a binder at a mass ratio to obtain second perlite particles.

[0055] In the present embodiment, the mass ratio is 100:(3-8), such as 100:3, 100:3.5, 100:5, 100:6.2, 100:7.2 and 100:7.9, etc.

[0056] The mixing uniformly comprises spraying the binder into the stirring first perlite particles by a spraying method, and the binder is uniformly coated on the surface of the first perlite particles; the second perlite particles are perlite particles coated with the binder on the surface.

[0057] In the embodiment, the binder comprises a water solution or hydrosol configured by one or more of inorganic binder and organic binder and water;

[0058] The inorganic binder comprises one or more of water glass, sodium silicate and potassium silicate with a modulus of 1.0-2.9, and is configured into a water solution with a density of 1.36-1.50 g / cm3 and a Baume degree of 38.4-48.3;

[0059] The organic binder comprises one or more of carboxymethyl cellulose, sodium carboxymethyl cellulose, acrylic emulsion, vinyl acetate emulsion, polyvinyl acetal glue, emulsion glue, animal glue and vegetable glue, and is configured into a hydrosol with a solid content percentage of 0.5-2.0%.

[0060] S3, the second perlite particles and the glassy shell powder are proportioned and mixed uniformly, granulated, and the third perlite particles are obtained.

[0061] In the embodiment, the mass ratio is (90-80):(10-20), such as 90:10, 88:12, 85:15, 81:19, etc.; the granulation comprises bonding and uniformly coating the glassy shell powder on the surface of the second perlite particles, the glassy shell powder is bonded by the binder on the surface of the perlite particles and forms a glassy component coating layer, and the specific process comprises:

[0062] The second perlite particles and the glassy shell powder are proportioned and weighed;

[0063] The weighed second perlite particles are placed in a granulator, and the glassy shell powder is uniformly added into the running granulator, so that the glassy shell powder is uniformly coated on the second perlite particles to obtain the composite particles of the glassy shell component / second perlite particles, i.e. the third perlite particles;

[0064] The glassy shell component powder is uniformly coated on the second perlite particles, which means that the glassy shell powder does not exist independently when the coating is completed, and is all coated on the surface of the second perlite particles, which is compact in texture and tends to be spherical.

[0065] In the embodiment, the glassy sheath powder in step 3) is obtained by mixing ordinary silicate waste glass, the less than 100 mesh perlite ore micro powder produced in step 1) pretreatment, borax and boric acid in the mass ratio of (20-50):(40-70):(0-10):(0-5), such as 20:40:0.2:0.1, 25:45:1.5:1, 30:50:2:1.5, 40:55:5:2 and 48:65:8:4, etc.; after selective crushing, mixing and grinding, the particle size of the glassy sheath component powder is-200 mesh to-600 mesh.

[0066] S4, drying and preheating the third perlite particles to obtain fourth perlite particles.

[0067] In the embodiment, the drying in step 4) is a drying process of the third perlite particles in the drying-preheating device, from room temperature section to 200-300℃ drying section with a heating rate of 8-20℃ / min.

[0068] The preheating process is a preheating process of the third perlite particles in the drying-preheating device, from drying section to 500-850℃ heating section with a heating rate of 50-80℃ / min; during the drying-preheating process, the air flow of the drying-preheating device is automatically from the heating section to the room temperature section.

[0069] In the embodiment, the fourth perlite particles are preheated fourth perlite particles, and the water content of the fourth perlite particles is 2-3%.

[0070] The drying and preheating processes are necessary steps. The drying process is to reduce the water content on the surface of the fourth perlite particles, and the preheating process is to reduce the water content inside the fourth perlite particles. If the drying and preheating processes are not performed and the expansion is directly performed, due to the excessive water content on the surface and inside the fourth perlite particles, a large amount of heat will be absorbed during the evaporation of the excessive water content during the expansion, which will reduce the temperature difference of the rapid heating of the fourth perlite particles and prolong the expansion time of the fourth perlite particles, so that the fourth perlite particles cannot achieve instant expansion, which will affect the expansion multiple of the fourth perlite particles. At the same time, the preheating can increase the temperature of the fourth perlite particles before entering the expansion furnace, which is beneficial to the rapid reaching of the expansion temperature point of the fourth perlite particles in the expansion furnace and the instant expansion of the fourth perlite particles, and improves the expansion multiple of the fourth perlite particles.

[0071] S5, high-temperature expansion treatment of the fourth perlite particles to obtain the glassy shell expanded perlite.

[0072] In the present embodiment, the high-temperature expansion treatment comprises: uniformly sprinkling the fourth perlite particles onto a high-temperature flame with a temperature maintained at 1100-1250°C in an expansion furnace while hot, or uniformly spreading the fourth perlite particles directly into an electrically heated expansion furnace with a high-temperature section maintained at 1100-1350°C, so that the fourth perlite particles are rapidly heated and quickly expanded; the residence time of the fourth perlite particles in the high-temperature flame or the high-temperature section of the electrically heated expansion furnace, i.e. the time for quick expansion, is 2-80 s, to obtain the glassy shell expanded perlite; the glassy shell expanded perlite has a shell / core composite structure.

[0073] The shell in the shell / core composite structure is a glassy shell, which is mainly composed of a glass body formed by melting the coated glassy shell component, and the surface layer thereof is a refractory sintered layer with a thickness of 0.01-0.2 mm; the inner layer of the shell is a glassy layer sintered from the glassy shell component, with a thickness of 0.2-0.5 mm; the core is the expanded perlite body formed by the expansion of the first perlite particles, and the diameter of the core is determined by the particle size and expansion multiple of the first perlite particles, and ranges from 1.5 mm to 28 mm; the combination of the shell (sintered ceramic layer-melted glassy layer) and the core (surface portion of the first perlite expansion product) in the shell / core composite structure is a gradient change combination relationship of component mutual penetration in the sintering-melting-expansion process.

[0074] In the high-temperature expansion process, the glassy shell powder material coated on the outer surface of the first perlite ore particles is first melted, and the formed viscous glass melt coats the perlite particles; the viscous glass melt coating layer becomes a continuous coating layer as the first perlite particles rapidly expand, and can also trap the gas released during the expansion of the first perlite particles. As a result, not only a glassy shell is formed on the surface of the expanded perlite, but also a closed-cell expanded perlite is formed, and the expansion multiple of the expanded perlite is significantly increased.

[0075] Example 2

[0076] The present example provides a glassy shell expanded perlite, which is prepared by the preparation method of example 1.

[0077] In the embodiment, the glassy shell expanded perlite has a shell / core composite structure and has the following properties: high expansion ratio, 3.5-8.0; light weight: bulk density, 200-300 kg / m3; high strength: cylinder compressive strength, 0.8-2 MPa; good thermal insulation performance: thermal conductivity, 0.04-0.06 W / (m·K); low water absorption: water absorption, <1.2%; good chemical stability: acid etching amount, <5%; and alkali etching amount, <1%.

[0078] Example 3

[0079] The present example provides an application of a glassy shell expanded perlite, which is the glassy shell expanded perlite of Example 2.

[0080] In the embodiment, the glassy shell expanded perlite has higher expansion ratio and mechanical strength, lower water absorption and pulp absorption, higher sound absorption and lower thermal conductivity than ordinary expanded perlite, and can be applied to the production of light materials, thermal insulation materials, sound absorption and insulation materials, decorative materials, fireproof and flame-retardant materials, and used as water surface floating insulation materials, sun protection materials and reflective materials.

[0081] In order to better understand the above-mentioned example of the present application, the following further describes it in conjunction with specific examples.

[0082] Example 1

[0083] A glassy shell expanded perlite and a preparation method thereof, as shown in the figure, the preparation method comprises the following steps: Figure 1

[0084] (1) crushing, screening and dedusting the perlite ore to obtain first perlite particles;

[0085] (2) selecting the first perlite particles of-10 to +20 mesh, selecting a water glass adhesive solution with a modulus of 1.0 as the binder, configuring the adhesive solution with a density of 1.36 g / cm3 and a Baume degree of 38.4, and according to the mass ratio of the first perlite particles to the binder of 100:3, spraying the binder on the surface of the first perlite particles and mixing uniformly to obtain second perlite particles;

[0086] (3) mixing ordinary silicate waste glass, less than 100 mesh perlite powder or ore produced by pretreatment, borax and boric acid in a mass ratio of 20:70:10:0, and then crushing and grinding to obtain a glassy shell component powder with a particle size of-200 mesh to +325 mesh; then adding the second perlite particles and the glassy shell component powder into a granulator according to a mass ratio of 90:10, and then granulating to obtain third perlite particles; ​

[0087] (4) the third perlite particles are placed in a drying device, dried at a temperature of 200°C with a temperature increasing rate of 8°C / min, and then placed in a drying-preheating device, preheated at a temperature of 550°C with a temperature increasing rate of 70°C for 8 min to remove the water on the surface of the perlite, to obtain fourth perlite particles with a water content of 2.5%;

[0088] (5) the preheated fourth perlite particles are evenly spread and directly fed into a flame expansion furnace with a temperature of 1200°C for high-temperature expansion treatment, and the expansion time is 10 s, so that the fourth perlite particles are rapidly heated and expanded, to obtain the glassy shell expanded perlite.

[0089] The prepared glassy shell expanded perlite has excellent moisture-proof and waterproof performance, heat insulation and sound insulation performance, and the bulk density of the expanded perlite is 200 kg / m 3 , the compressive strength is 0.8 MPa, the thermal conductivity is 0.041 W / (m·K), the water absorption is 1.15%, the acid etching amount is 4.52%, and the alkali etching amount is 0.75%.

[0090] Example 2

[0091] A glassy shell expanded perlite and a preparation method thereof, the preparation method comprising the following steps:

[0092] (1) a black obsidian type ore is crushed, screened and dedusted to obtain first perlite particles;

[0093] (2) the first perlite particles with a size of -30 mesh to +50 mesh are selected, a sodium silicate glue solution with a modulus of 2.0 is selected as the binder, the glue solution is configured to have a density of 1.42 g / cm3 and a Baume degree of 42.89, and the first perlite particles and the binder are mixed according to a mass ratio of 100:8, the binder is sprayed on the surface of the first perlite particles by using a spray gun, and the second perlite particles are obtained after mixing uniformly;

[0094] (3) ordinary portland glass waste and less than 100 mesh perlite powder or ore, borax and boric acid are mixed according to a mass ratio of 50:47:0:3, and then subjected to selective crushing and mixing and grinding treatment to obtain a glassy shell component powder, the particle size of the glassy shell component powder is -325 mesh to +400 mesh; the second perlite particles and the glassy shell component powder are added into a granulator according to a mass ratio of 80:20, and then granulated to obtain third perlite particles;

[0095] (4) the third perlite particles are placed in a drying device, dried at a temperature of 250°C with a temperature increasing rate of 12°C / min, and then placed in a drying-preheating device, preheated at a temperature of 500°C with a temperature increasing rate of 60°C, and kept at the temperature for 10 min to remove the water on the surface of the perlite, to obtain fourth perlite particles with a water content of 2.3%;

[0096] (5) the preheated fourth perlite particles are evenly spread and directly fed into a flame expansion furnace kept at a temperature of 1100°C for high-temperature expansion treatment, and the expansion time is 40 s, so that the fourth perlite particles are rapidly heated and expanded, to obtain the glassy shell expanded perlite.

[0097] The prepared glassy shell expanded perlite has excellent moisture-proof and waterproof properties, and heat insulation, sound absorption and sound insulation properties. The bulk density of the expanded perlite is 265 kg / m3, the compressive strength is 2.0 MPa, the thermal conductivity is 0.045 W / (m·K), the water absorption is 0.96%, the acid etching amount is 2.63%, and the alkali etching amount is 0.38%.

[0098] Example 3

[0099] A glassy shell expanded perlite and a preparation method thereof, the preparation method comprising the following steps:

[0100] (1) a pumice-like ore is crushed, screened and dedusted to obtain first perlite particles;

[0101] (2) the first perlite particles with a size of -20 mesh to +30 mesh are selected, a potassium silicate glue solution with a modulus of 2.9 is selected as the binder, and the glue solution is configured to have a density of 1.50 g / cm 3 and a Baume degree of 48.3; the binder is sprayed on the surface of the first perlite particles and mixed uniformly according to a mass ratio of the first perlite particles to the binder of 100:5, to obtain second perlite particles;

[0102] (3) ordinary portland glass waste and less than 100 mesh perlite powder or ore, borax and boric acid produced by pretreatment are mixed according to a mass percentage of 30:60:5:5, and then subjected to selective crushing and mixing and grinding treatment to obtain glassy shell component powder, the particle size of the glassy shell component powder is -400 mesh to +500 mesh; the second perlite particles and the glassy shell component powder are added into a granulator according to a mass ratio of 85:15, and then granulated to obtain third perlite particles;

[0103] (4) The third perlite particles are placed in a drying device, and dried at a temperature of 220°C with a temperature increasing rate of 15°C / min, and then placed in a drying-preheating device, and preheated at a temperature of 650°C with a temperature increasing rate of 50°C, and preheated for 14 min at the temperature, so as to remove the water on the surface of the perlite, and obtain the fourth perlite particles with a water content of 2.0%.

[0104] (5) The preheated fourth perlite particles are evenly spread and directly sent into a flame expansion furnace with a temperature of 1250°C for high-temperature expansion treatment, and the expansion time is 30 s, so that the fourth perlite particles are rapidly heated and expanded, and the glassy shell expanded perlite is obtained.

[0105] The prepared glassy shell expanded perlite has excellent moisture-proof, waterproof, heat insulation, sound absorption and sound insulation properties. The bulk density of the expanded perlite is 220 kg / m3, the compressive strength is 1.5 MPa, the thermal conductivity is 0.051 W / (m·K), the water absorption is 1.04%, the acid etching amount is 4.12%, and the alkali etching amount is 0.63%.

[0106] From the optical microscope photos of Figure 2 and the electron microscope photos of Figure 3 it can be found that the sphericity of the ordinary expanded perlite particles obtained by the traditional method is low, and the sphericity of the glassy shell expanded perlite prepared by the present application is high; from Figure 4 and Figure 5 it can be found that the surface of the ordinary expanded perlite has pores and voids formed when the gas escapes during the burning and expansion process, the surface is not smooth, and has sharp edges and corners. Therefore, the pores are easy to absorb the binder (such as cement paste, water glass, etc.).

[0107] From the optical microscope photos of Figure 6-8 and the electron microscope photos of Figure 9 it can be found that the glassy shell prepared by the present application completely wraps the surface of the expanded perlite, closes the pores of the expanded perlite and makes the surface smooth. Therefore, it has excellent moisture-proof, waterproof, heat insulation, sound absorption and sound insulation properties.

[0108] Table 1 is the preparation parameters of the glassy shell expanded perlite prepared in Examples 4-7, Table 2 is the parameters of the drying, preheating and heating expansion process in the preparation of Examples 4-7, and Table 3 is the properties of the glassy shell expanded perlite prepared in Examples 4-7. From the parameters in Tables 1-3, it can be known that the expansion of the glassy shell expanded perlite prepared in Examples 4-7 is 3.5-6.6 times, the bulk density is 250-300 kg / m 3, the cylinder pressure strength is 1.6-2 MPa, the heat conduction coefficient is 0.045-0.051 W / (m.K), the water absorption is 0.93%-0.99%, the acid etching amount is 2.77%-4.23%, and the alkali etching amount is 0.25%-0.64%.

[0109] Table 1. Preparation parameters for Examples 4-7

[0110]

[0111] Table 2. Parameters for drying, preheating, and heating expansion processes in the preparation of Examples 4-7

[0112]

[0113] Table 3. Properties of glassy shell expanded perlite prepared in Examples 4-7

[0114]

[0115] Although the present application has been described in connection with the exemplary embodiments and the accompanying drawings, it will be understood that various modifications can be made to the embodiments without departing from the spirit and scope of the claims.

Claims

1. A method for preparing glassy expanded perlite, characterized in that, The preparation method includes: 1) Pre-treat perlite ore to obtain the first perlite particles; 2) Mix the first perlite particles and the binder according to the mass ratio and mix them evenly to obtain the second perlite particles; 3) Mix the second perlite particles and the glassy coating powder according to the mass ratio, and granulate to obtain the third perlite particles; 4) The third perlite particles are dried and preheated to obtain the fourth perlite particles; 5) The fourth perlite particles are subjected to high-temperature expansion treatment to obtain the glassy shell expanded perlite.

2. The method for preparing glassy expanded perlite according to claim 1, characterized in that, The perlite ore includes one or more of various types of ore such as perlite-type, obsidian-type, pitchstone-type, and pumice-like perlite; The pretreatment includes crushing, screening, and dust removal; the crushing is crushing with a screening section for inspection; the screening and dust removal include separating the crushed perlite sand into different particle sizes by screening, and collecting the micro powder with a particle size of less than 100 mesh from the perlite sand for use as raw material for glassy coating powder.

3. The method for preparing glassy expanded perlite according to claim 1, characterized in that, The mass ratio mentioned in step 2) is 100:(3-8); The uniform mixing includes: spraying the binder onto the first perlite particles being stirred using a spraying method, and uniformly coating the surface of the first perlite particles with the binder to obtain the second perlite particles.

4. The method for preparing glassy expanded perlite according to claim 1, characterized in that, The adhesive includes one or more of inorganic and organic adhesives in aqueous solutions or hydrosols prepared with water; The inorganic binder comprises one or more of water glass, sodium silicate, and potassium silicate with a modulus of 1.0 to 2.9, and is prepared as an aqueous solution with a density of 1.36 to 1.50 g / cm3 and a Baume degree of 38.4 to 48.

3. The organic binder includes one or more of carboxymethyl cellulose, sodium carboxymethyl cellulose, acrylic emulsion, vinyl acetate emulsion, polyvinyl alcohol acetal, emulsion glue, animal glue, and plant glue, and is formulated into a water-soluble adhesive with a solid content of 0.5% to 2.0% by mass.

5. The method for preparing glassy expanded perlite according to claim 1, characterized in that, The mass ratio in step 3) is (90-80):(10-20); the granulation includes bonding and uniformly coating the glassy coating powder onto the surface of the second perlite particles, wherein the glassy coating powder is bonded by the surface binder of the perlite particles to form a glassy component coating layer, and the specific process includes: Weigh the second perlite particles and the glassy coating powder according to the specified ratio; The weighed second perlite particles are placed in a granulator, and then the glassy coating powder is evenly added to the running granulator so that the glassy coating powder is evenly coated on the second perlite particles to obtain the third perlite particles.

6. The method for preparing glassy expanded perlite according to claim 1, characterized in that, The glassy coating powder mentioned in step 3) is obtained by mixing ordinary silicate waste glass, perlite ore powder with a particle size of less than 100 mesh produced by the pretreatment in step 1), borax and boric acid in a mass ratio of (20-50):(40-70):(0-10):(0-5), and then selectively crushing and mixing and grinding the mixture. The particle size of the glassy coating component powder is -200 mesh to -600 mesh.

7. The method for preparing glassy expanded perlite according to claim 1, characterized in that, The drying process described in step 4) is the drying process of the third perlite particles in the drying-preheating device, where the temperature is increased from the ambient temperature section to the drying section at a rate of 8℃~20℃ to 200~300℃. The preheating treatment is a process in which the third perlite particles are preheated in a drying-preheating device by the drying section at a heating section at a heating rate of 50°C to 80°C to 500°C to 850°C.

8. The method for preparing glassy expanded perlite according to claim 1, characterized in that, The fourth perlite particles are preheated fourth perlite particles, and the water content of the fourth perlite particles is 2-3%. The high-temperature expansion treatment in step 5) includes: while the fourth perlite particles are still hot, they are evenly sprinkled onto a high-temperature flame in an expansion furnace where the temperature is maintained at 1100-1250°C; or, the fourth perlite particles are evenly spread out and directly fed into a high-temperature section in an electrically heated expansion furnace where the temperature is maintained at 1100-1350°C, so that the fourth perlite particles are rapidly heated and expand quickly. The fourth perlite particle is placed in a high-temperature flame or a high-temperature section of an electric heating furnace for a period of 2 to 80 seconds to rapidly expand, thereby obtaining the glassy shell expanded perlite. The glassy shell expanded perlite has a shell / core composite structure, wherein the shell is a glassy shell composed of a glassy body formed by melting the encapsulating glassy shell components, with a thickness of 0.01 to 0.2 mm.

9. A type of glassy expanded perlite, characterized in that, The glassy expanded perlite is obtained by the method described in any one of claims 1-8, wherein the expansion ratio of the glassy expanded perlite is 3.5 to 8.0, and the bulk density is 200 to 300 kg / m³. 3 The cylinder compressive strength is 0.8–2 MPa, the thermal conductivity is 0.04–0.06 W / (m·K), the water absorption rate is <1.2%, the acid corrosion rate is <5%, and the alkali corrosion rate is <1%.

10. The application of the glassy expanded perlite according to claim 9, characterized in that, The glassy expanded perlite has a higher expansion ratio and mechanical strength than ordinary expanded perlite, lower water absorption and slurry absorption rates, higher sound absorption and lower thermal conductivity. It can be used in the production of lightweight materials, thermal insulation materials, sound-absorbing and sound-insulating materials, decorative materials, fire-retardant materials, and as a floating thermal insulation material, sun protection material and reflective material.

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