Lightweight ceramic aggregates made by agglomerating ceramic fibers

Abstract

A method for agglomerating bulk ceramic fibers includes mixing bulk ceramic fibers with water to form wet fibers, mixing the wet fibers with a binder, including an organic binder and / or an inorganic binder, to form an aggregate, and drying the aggregate. The aggregate can be mixed with additional binder and filler to form an insulating mixture that can be used to insulate a furnace or other heat source. A foaming nozzle can be used to apply the aggregate. A foaming agent and water are air-sprayed in the foaming nozzle, and the resulting foam is mixed into the air-transported aggregate, resulting in the formation of a lightweight refractory layer on a target substrate.

Description

[Technical Field]

[0001] This application claims priority to U.S. Provisional Patent Application No. 63 / 236,392, filed on 24 August 2021, titled "Lightweight ceramic aggregates made by agglomerating ceramic fibers," and to U.S. Provisional Patent Application No. 63 / 364,773, filed on 16 May 2022, both of which are incorporated herein by reference in their entirety. The following are prior art documents related to the invention of this application (including documents cited in the international phase after the international filing date and documents cited when the application entered the national phase in other countries): (Prior art document) (Patent Document) (Patent Document 1) U.S. Patent Application Publication No. 2014 / 0274818 (Patent Document 2) U.S. Patent No. 5,803,665 (Patent Document 3) U.S. Patent Application Publication No. 2004 / 0061098 (Patent Document 4) U.S. Patent No. 4,564,485 (Patent Document 5) U.S. Patent No. 5,803,596 [Overview of the project] [Means for solving the problem]

[0002] This disclosure relates to a lightweight ceramic aggregate manufactured by agglomerating ceramic fibers, a foaming nozzle for applying lightweight refractory concrete by pneumatic gunning, and a method for using the same.

[0003] Lightweight (LW) refractory concrete mixes are used as insulating linings for furnace hot faces and backup linings in industries such as metal production, hydrocarbon processing, cement, power generation, and biomass incineration. High-density refractory furnace linings protect the furnace shell from high-temperature mechanical wear and chemical attack in the presence of molten metal, corrosive low-melting-point slag, and gaseous compounds. Due to the high density of refractory hot face linings, a second insulating layer is almost always required to protect the furnace shell and furnace structure from overheating.

[0004] The insulating backup layer is typically made of ceramic fiberboard, blankets, or felt. Insulated refractory bricks (IFBs) and, for low temperatures, porous calcium silicate or diatomaceous earth-based bricks or boards are also used. The drawbacks of these dry materials are their low mechanical strength and the need to install them around anchors required to secure the dense hot face that will be applied later. Cavities around the anchors are prone to leading to hot spots, compromising the integrity of the anchor welds and the entire lining system. As a result, installation is extremely time-consuming and nearly impossible for overhead applications such as furnace roofs.

[0005] Insulated concrete can be used to enable more economical construction. Although its thermal insulation is inferior to that of high-porosity fibrous materials, it can be poured or sprayed using conventional concrete pouring machines, can be applied overhead, and significantly reduces construction time. Insulated concrete utilizes lightweight aggregates such as perlite, vermiculite, diatomaceous earth, and expansive clay, and binder components such as Portland cement or calcium aluminate cement ("CAC"). Pre-mixed dry components are introduced into a bowl of a gnite machine and air-conveyed through a hose fitted with spray nozzles. Water is added through the spray nozzles and distributed to the dry mix through a perforated watering ring. As a result of the kinetic energy of the material airflow, the resulting wet mix is ​​transported onto the target substrate. The level of densification of the material upon impact with the substrate varies depending on the material and airflow rate.

[0006] A drawback of this conventional method of preparing and applying refractory concrete is the large amount of dust generated by the spray nozzle. To overcome the high level of dust generation, this process often requires a pre-wetting step before the material is placed in the machine's feed bowl. High material airflow combined with improper mixing of water and dry material at the spray nozzle often results in a high rebound rate and fluctuating density upon impact with the target substrate. To avoid slump and rebound, material airflow is often increased, resulting in a denser material substrate layer. This also has the disadvantage of a thicker lining compared to fibrous products, and a longer dry-out time due to the relatively high liquid content trapped behind the dense refractory lining.

[0007] LW refractory concrete uses raw materials such as expansive clay, calcined porous shale, slate, perlite, vermiculite, and diatomaceous earth aggregate. These aggregates are all naturally derived and have the drawback of containing large amounts of alkali and silica, thus limiting their maximum operating temperature to below 1100°C. Furthermore, inhalable crystalline silica components are a concern, as exposure to human health during initial installation and subsequent furnace lining replacements is a potential issue.

[0008] To overcome these problems, numerous more clearly defined synthetic refractory light water (LW) materials have been developed. These include calcium hexaaluminate aggregate, pulverized and sized IFB with additives, and mullite-based highly calcined porous aggregate. However, these aggregates typically have a yield of 351 b / ft (registered trademark) (561 kg / m³). * They have a bulk density exceeding 251 b / ft (400 kg / m') and are far more expensive than lightweight perlite or vermiculite aggregates with a bulk density of less than 251 b / ft (400 kg / m'). Therefore, these high-density aggregates are commonly used in insulated hot-face linings operating at temperatures above 1100°C in furnaces where low mechanical strength and chemical resistance are acceptable.

[0009] To improve the temperature stability of thermal insulation linings and facilitate the installation of ceramic fiber products, Unifrax I LLC has developed a fiber spray process using a special spraying device known by the trademark name FOAMFRAX®. In this process, components such as liquid and solid binders and foaming compounds are mixed with bulk fibers in a mixing nozzle and sprayed onto the furnace wall as a backup, hot face veneer, or full-thickness hot face lining. Typically, the mixing nozzle is positioned several meters before the tip of the spray nozzle to ensure proper mixing of the product between the mixing chamber and the spray nozzle. The combination of binder and foaming agent allows for the creation of extremely lightweight fiber linings (bulk density 25 lb / ft) without generating airborne fibers at the spray nozzle. 3 (400kg / m 3 It became possible to create something less than ).

[0010] The drawbacks of this construction method are related to the complexity of the spraying equipment and the handling of the multi-component binder system at the construction site. The FOAMFRAX® process uses a special blower with a low airflow of approximately 0.4 bar and low material handling capacity. The mixing nozzle used in the FOAMFRAX® process cannot be used with conventional concrete pouring machines due to its size, weight, and installation location. Therefore, the FOAMFRAX® process is only suitable for ceramic fibers and cannot handle materials with high bulk density (0.25 g / cm' or more). In addition, the need for well-trained workers and special site conditions regarding power supply and equipment maintenance capabilities are constraints on widespread market acceptance. Therefore, there remains a need for an easy-to-install, lightweight insulating lining, as well as its installation method and system. [Brief explanation of the drawing]

[0011] Various embodiments of the present disclosure will be more fully understood from the following detailed description and the accompanying drawings of various embodiments of the present disclosure. In the drawings, like reference numerals may indicate the same or functionally similar elements. Hereinafter, embodiments will be described in detail with reference to the accompanying drawings, in which the embodiments are as follows:

[0012] [Figure 1] FIG. 1 is a diagram of a pneumatic gunning system including agglomerated fibers and a foam nozzle according to one or more embodiments of the present disclosure; [Figure 2] FIG. 2 is a photograph of agglomerated fibers according to an embodiment of the present disclosure compared to non-agglomerated bulk fibers. [Figure 3] FIG. 3 is a perspective view of a foam nozzle according to an embodiment of the present disclosure. [Figure 4] FIG. 4 is a schematic side view of a foam nozzle according to an embodiment of the present disclosure. [Figure 5] FIG. 5 is a photograph of a foam nozzle and a portion of a concrete placing system according to an embodiment of the present disclosure.

Mode for Carrying Out the Invention

[0013] The following disclosure provides many different embodiments or examples. For the sake of simplifying the present disclosure, specific examples of components and arrangements are described below. Of course, these are merely illustrative and are not intended to be limiting. Further, the present disclosure may repeat reference numerals and / or letters in various examples. This repetition is for the purpose of simplification and clarity and does not in itself indicate the relationship between the various embodiments and / or configurations being discussed.

[0014] The present disclosure relates to a process for aggregating bulk ceramic fibers into more easily handled granules to control the particulate properties for transport, handling, and performance. The resulting granules are used, inter alia, as lightweight insulating aggregates blended with additional binders, performance additives, and fines, enabling installation by pneumatic conveyance and pneumatic placement using conventional concrete placers, placement and pumping of wet lightweight concrete mixtures for insulation, dry or semi-dry pressing of lightweight bricks and shaped materials, and / or dry bulk insulation mixtures. In all of the foregoing applications, a mechanically mixed, formulated, transported, and dust-free, flowable product that does not disintegrate even when exposed to moisture is required. That is, a dry gunning machine, press tool, and bulk product that easily flows into cavities in building walls are required.

[0015] The present disclosure also relates to a foam nozzle that can be used in conventional pneumatic dry gunning systems and enables spraying of various lightweight refractory concrete materials, such as aggregated bulk ceramic fibers (“aggregated fibers”) and / or materials having a bulk density greater than 0.25 g / cm 3 The foam nozzle can also enable construction of lightweight refractory linings having a lower density (i.e., less than 0.8 g / cm 3 ), and the associated higher insulation values, compared to conventional refractory lightweight concrete. Further, the foam nozzle has the advantage of promoting low rebound rates and low dust generation, particularly improving concrete spraying in confined spaces.

[0016] FIG. 1 shows an embodiment of a concrete placement system 2. The concrete placement system 2 includes a dry aggregate container 4, a concrete gun 10, a pneumatic compressor 14, a water supply 20, a foaming agent supply 24, a spray nozzle 28, and a foam nozzle 32. The aggregate container 4 houses the aggregated fibers 8 (shown in FIG. 2) and / or other aggregates and is operatively connected to or in communication with the concrete gun 10. The aggregate container 4 supplies the aggregated fibers 8 and / or other aggregates to the concrete gun 10.

[0017] The following provides a more complete description of various aspects. However, such aspects can be embodied in many different forms and should not be construed as being limited to the embodiments described herein. Rather, these embodiments are provided to ensure that this disclosure is thorough and complete and fully conveys its scope to those skilled in the art.

[0018] In some embodiments, the foaming solution and water mixture are pre-blended in a large container. The pre-blended foaming solution and water mixture is pumped by pump 22 through foaming agent and water hoses 26 to the foaming nozzle 32. In some embodiments, pump 22 may be a diaphragm / membrane pump or a centrifugal / impeller pump. An air compressor (e.g., air compressor 14) is fluidically coupled to the foaming nozzle 32 by a second air line 18.

[0019] In some embodiments, the foaming nozzle 32 is operably and fluidly coupled to the spray nozzle 28 via a water distributor 62 through a foaming pipe outlet hose 52. The foaming nozzle 32 forms a mixture of foaming agent and water into fine cellular bubbles and supplies these bubbles to the spray nozzle 28 via the water distributor 62. The bubbles are mixed in the water distributor 62 with the aggregated fibers 8 and / or other aggregates in the spray nozzle 28 before being sprayed onto the target substrate 30 from the outlet 29 of the spray nozzle 28. In some embodiments, the water distributor 62 may be positioned further upstream along the aggregate supply hose 12 (i.e., further from the spray nozzle 28) to allow a greater distance for the bubbles, aggregated fibers 8, and other aggregates to mix before exiting the outlet 29 of the spray nozzle 28.

[0020] Figure 2 shows the bulk ceramic fiber 6 before aggregation and the aggregated fiber 8 after aggregation. To convert ceramic fiber wool (also referred to herein as "ceramic fiber" or "ceramic wool") into granules, the following process has been developed. Ceramic fibers that can be used in this method include, but are not limited to, refractory ceramic (RCF) fibers, low biopersistent (LBP) fibers, polycrystalline wool (PCW) fibers, glass fibers, aluminozirconia silicate (AZS) fibers, and alkaline earth silicate (AES) fibers. Examples of ceramic fibers include those commercially available under the trademarks of Unifrax I LLC, such as Insulfrax (登録商標) 3010, ISOFRAX (登録商標) , FIBERMAX (登録商標) . Some are commercially available under the trademark of INSULFRAX (登録商標) . The product sold under the trademark of INSULFRAX 3010 is a glass fiber based on the composition of calcium, magnesium, and silicate.

[0021] In the wetting step, the ceramic wool is mixed with water to form wet fibers. The weight ratio of wool to water can be, for example, from 1:1 to 5:1 or from 2:1 to 3:1. In some embodiments, the mixing is performed at low intensity to break down the volume of the fibers. Mixers such as a vertical shaft paddle mixer or a high-intensity pan mixer with intensifier (e.g., a mixer with intensifier sold by Eirich Machines Inc.) can be used. Other suitable mixers include horizontal shaft mixers and any type of high-intensity mixer that can provide a rolling motion of the bulk material during mixing.

[0022] Next, in the bonding step, a binder or a combination of binders is added to the wet fiber mix. The binders used in the flocculation step may be polyvinyl alcohol-based, carboxymethylcellulose (CMC), plant-derived starches such as potato starch or rice starch, inorganic binders such as clay (smectite, bentonite, illite, kaolin), and colloidal silica, colloidal alumina, or a combination thereof. In some embodiments, the binder may include calcium aluminate cement, calcium silicate cement, colloidal silica, liquid phosphoric acid, dry phosphate, or a combination thereof.

[0023] In some embodiments, cellulose fibers may be added to the wet fiber mix during the agglomeration process. The cellulose fiber content may be about 0.5%, about 1%, about 1.5%, about 2%, about 2.5%, about 3%, 0.5–3%, 1–2.5%, or 1.5–2%, based on the total weight of the wet mixture or the total weight of the aggregate. The addition of cellulose fibers is 20 lb / ft 3 Supporting a decrease in the bulk density of aggregates below 25 lb / ft 3 This further supports a reduction in spray density to less than 100 degrees. In some embodiments, the slump resistance of sprayed aggregated fibers containing cellulose fibers may decrease when sprayed overhead or at angles greater than 45, 50, 60, 70, 80, 45–90, 50–80, or 60–70 degrees relative to the ground (i.e., horizontal).

[0024] In some embodiments, the bonding step may be combined with the wetting step, such that water and binder are added together to the ceramic wool. In other embodiments, the bonding step may precede the wetting step, such that the binder is added to the dry ceramic wool. In any embodiment, the binder is dispersed with the fibers in the bonding step by mixing. This mixing can be done at a moderate intensity, and the same mixer as described above can be used. In some embodiments, the mixing intensity used in the bonding step is greater than the mixing intensity used in the wetting step.

[0025] After the wetting and bonding steps, the mixture of water, ceramic wool, and binder contains aggregates. These aggregates can be broken down into smaller aggregates by further mixing. For example, larger aggregates can be broken down at a mixing strength higher than that used in the wetting and bonding steps.

[0026] In some embodiments, larger aggregates than those formed by the wetting and bonding steps may be desired. In such cases, more water may be added to the aggregates to obtain the desired average particle size. Too much water may cause the aggregates to break down and become a flexible cake. In some embodiments, the water content of the aggregates is controlled to be less than 51%, less than 49%, less than 47%, less than 45%, less than 30%, 10-55%, 20-55%, 53-55%, 93-52%, 40-50%, or about 45%.

[0027] In some embodiments, spherical granules may be formed by transferring the fiber aggregates to a disc pelletizer. Other suitable shaping or sizing operations may be performed on the aggregates before or after they are dried.

[0028] In some embodiments, all aggregates have a particle size of less than 20 mm, less than 15 mm, less than 12 mm, less than 10 mm, or less than 6 mm. In some embodiments, at least 95 wt% of the aggregates have a particle size of less than 20 mm, less than 15 mm, less than 12 mm, less than 10 mm, or less than 6 mm. In some embodiments, the aggregates have a median particle size of 1 to 5 mm, 2 to 4 mm, or about 3 mm. In some embodiments, the aggregates do not contain particles having a size of less than 0.5 mm, less than 0.3 mm, less than 0.1 mm, or less than 0.01 mm. In one embodiment, after sieving the aggregates with a 0.06 mm sieve, no dust remains in the sieving pan, i.e., substantially all of the ceramic wool is incorporated into the aggregates.

[0029] In the drying process, the aggregates are transferred to a dryer. In some embodiments, drying can be carried out at a temperature of 80°C to 110°C. Optionally, the drying process may include calcining the aggregates at a temperature of 110°C to 1300°C.

[0030] The cohesive fibers produced by the process of this disclosure can be used in a wide range of applications and can replace inconsistent, natural-based lightweight aggregates in conventional concrete, coatings, and refractory materials. For example, by applying a hydrophobic additive or surfactant, such as a silicone emulsion, at the end of the cohesive process, the cohesive fibers can be used in thermal insulation concrete wet mixes.

[0031] In some embodiments, the cohesive fibers can be combined with additional binders to form a raw material for refractory lightweight concrete or refractory concrete. In some embodiments, the additional binders consist of calcium aluminate cement, Portland cement, phosphates, colloidal silica, colloidal alumina, liquid aluminum phosphate, phosphoric acid, or a combination thereof.

[0032] In some embodiments, the aggregated fibers may also include mineral-based fillers. In some embodiments, the mineral-based fillers consist of andalusite, mullite, alumina silicates, microsilica, calcined alumina, reactive alumina, tabula alumina, or combinations thereof. The ratios of aggregates, additional binders, and mineral-based fillers can be adjusted to provide the desired density, strength, and thermal conductivity.

[0033] In some embodiments, the cohesive fibers can be incorporated into applicable materials by casting, ramming, hand packing, pumping, shotcreting, and / or pneumatic gunning using conventional gunning machines. In other embodiments, the cohesive fibers can be formed into pressed shapes by axial pressing, hydrostatic pressing, semi-hydrostatic pressing, and / or extrusion molding. In further additional embodiments, the cohesive fibers can be incorporated into a dust-free bulk insulation mix that can be sprayed or poured into building cavities.

[0034] Figures 3 and 4 show one embodiment of the foaming nozzle 32. The foaming nozzle 32 consists of a foaming agent and water mixture inlet 34, a foaming tube 40, a water distributor 62, and one or more outlets 64. In some embodiments, the foaming nozzle 32 further comprises a shut-off valve 36. In some embodiments, the foaming nozzle 32 further comprises an air valve 38. It should be understood that these elements can be assembled in various arrangements in various embodiments.

[0035] In some embodiments, the water shut-off valve 36 is fluidically coupled to the admixture inlet 34, and the air valve 38 is fluidically coupled to the water shut-off valve 36. In some embodiments, an additional flexible hose may be positioned between the shut-off valve 36 and the air valve 38. This additional flexible hose fluidly couples the shut-off valve 36 and the air valve 38 and may be of any length suitable for the application. The length of the additional flexible hose may be between 1 and 12 inches, or between 1 and 6 feet.

[0036] The air valve 38 is fluidically coupled to the foam tube 40, which is fluidly coupled to the water distributor 62 by the foam tube outlet hose 52. In some embodiments, the foam tube outlet hose 52 is a flexible hose and may be of any length suitable for the application. The foam tube outlet hose 52 may be 1 to 12 inches long, or 1 to 6 feet long. In some embodiments, referring again to Figure 1, the water distributor 62 is fluidly coupled to the spray nozzle 28 before the outlet 29 of the spray nozzle 28. In other embodiments, the water distributor 62 may be connected along the manifold supply hose 12 and fluidly coupled to the manifold supply hose 12.

[0037] During operation, and continuing to refer to Figures 1, 3, and 4, the pump 22 pumps the foaming agent and water admixture from the foaming agent and water supply units 20, 24 through the foaming agent and water hose 26 to the admixture inlet 34 of the foaming nozzle 32. In some embodiments, the foaming agent may include a surfactant such as polyvinyl alcohol, ammonium lauryl sulfate, or other sulfonates, or any protein-based foaming additive. In some embodiments, the foaming agent may be a polyvinyl foaming solution containing polyvinyl alcohol.

[0038] The polyvinyl foam solution concentration (by weight %) can be 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 0.5% or more but less than 10%, 2% or more but less than 5%, 2% or more but less than 6%, 0.2% or more but less than 2%, 0.9% or more but less than 1.5%, less than 10%, or 1% or more. The foaming admixture passes through the water shut-off valve 36 and the air valve 38 and enters the foaming tube 40. The air valve 38 supplies atomized air to the foaming nozzle 32, which helps to promote the foaming of the foaming agent and water mixture inside the foaming tube 40. In some embodiments, the air valve can supply air at pressures of 1 bar, 1.1 bar, 1.2 bar, 1.3 bar, 1.4 bar, 1.5 bar, 1.6 bar, 1.7 bar, 1.8 bar, 1.9 bar, 2.0 bar, between 0.5 and 2 bar, or between 1 bar and 1.5 bar.

[0039] The foam tube 40 has a body that defines the interior and first and second ends. The foam tube 40 is configured to allow a foaming agent and water mixture to pass through its interior. In some embodiments, the foam tube 40 is cylindrical. In other embodiments, the foam tube 40 may be a rectangular prism, a hexagonal prism, an octagonal prism, or any other shape desired for a particular application.

[0040] The foam tube 40 contains an abrasive high-surface-area material. In some embodiments, the high-surface-area material contained inside the foam tube 40 is metal wool. In some embodiments, the metal wool may be made of steel or stainless steel. The metal wool may be organic or inorganic steel wool. In other embodiments, the abrasive high-surface-area material may be a polymer material. Polymer materials are advantageous as they help to avoid corrosion.

[0041] Metal wool or other highly abrasive, high-surface-area materials have a large surface area that agitates the foaming agent and water mixture as it passes through the foaming tube 40. The combination of atomizing air supplied from the air compressor 14 via the air valve 38 and the large surface area of ​​the metal wool causes the foaming agent and water mixture to form fine cellular bubbles. The fluid pressure of the foaming agent and water mixture supplied to the foaming tube 40 is greater than the air pressure supplied from the air valve 38 in order to avoid back pressure.

[0042] Fine cellular bubbles exit the foaming tube 40 and flow through the foaming tube outlet hose 52 to the water distributor 62. The foaming tube 40 is fluidically connected to the foaming tube outlet hose 52 by a foaming tube outlet connector 50. In some embodiments, the foaming tube outlet connector 50 is a 90° elbow connector that rotates the flow of bubbles by 90° after they exit the foaming tube 40. In other embodiments, the foaming tube outlet connector 50 has an angle between 0° and 120°.

[0043] In some embodiments, the foam outlet hose 52 can directly deliver the foam flow to the water distributor 62. In other embodiments, the foam outlet hose 52 may branch into multiple foam hoses (i.e., at least one) that deliver foam to the water distributor 62. In the embodiments shown in Figures 3 and 4, the foam outlet hose 52 is divided into a first foam hose 54 and a second foam hose 56. The foam outlet hose 52 is fluidically coupled to the first and second foam hoses 54 and 56 by a Y-connector. By dividing the foam flow from the foam outlet hose 52 into multiple foam hoses, the distribution of foam at the outlet(s) 64 of the water distributor 62 can be improved.

[0044] The first and second foam hoses 54 and 56 are fluidically connected to the water distributor 62 by the first and second body connectors 58 and 60. In the embodiments shown in Figures 3 and 4, the first and second body connectors 58 and 60 are fluidically connected to the water distributor 62 at an angle of 90°. In other embodiments, the first and second body connectors 58 and 60 may be connected to the water distributor 62 at an angle between 0° and 120°.

[0045] The water distributor 62 is in fluid communication with the spray nozzle 28. The water distributor 62 has a cylindrical shape with side walls that are radially spaced from its central axis and inscribed in the circumferential direction within its internal portion. The water distributor 62 is fluidly coupled to the spray nozzle 28 such that the central axis of the water distributor 62 and the central axis of the spray nozzle 28 are aligned axially. In other embodiments, the water distributor 62 is fluidly coupled to the aggregate supply hose 12 further upstream from the spray nozzle 28. In those embodiments, the water distributor 62 is axially aligned with the central axis of the aggregate supply hose 12. In all configurations, the water distributor 62 is in fluid communication with the aggregate supply hose 12 and the spray nozzle 28.

[0046] In the water distributor 62, the foam flow enters the interior of the water distributor 62 through the outlets 64. The number of outlets 64 in the water distributor 62 is equal to the number of foam hoses 54, 56. In some embodiments, the number of outlets 64 may be greater than the number of foam hoses 54, 56. Since the water distributor 62 is in fluid communication with the aggregate supply hose 12 and the spray nozzle 28, the material flow of the aggregate fibers 8 and other aggregates passes through the water distributor 62.

[0047] In the water distributor 62, the material flow of the aggregated fibers 8 and other aggregates continues through the spray nozzle 28 to the spray nozzle outlet 29, where it is mixed with foam. The large amount of foam captures almost all dust particles generated by the material flow. This can significantly improve the coating process, which is carried out in a closed, confined space. The foam also reduces the kinetic energy of the material flow. As a result, the refractory lining deposited on the target substrate 30 has a highly porous structure with significantly reduced density compared to refractory linings produced by conventional gunning processes. The light, sticky, highly porous structure of the foam and material flow mix also results in very low rebound and slump rates compared to conventional gunning processes, and significantly improves thermal insulation.

[0048] The flow rate of the foaming agent and water mixture entering this system can be controlled by the shut-off valve 36. The flow rate can be adjusted according to the application and user preference. Depending on the substrate, spray direction, environment surrounding the substrate, and other similar factors, an adjusted water content or foam volume may be desired. In any application of this system, to avoid backflow / back pressure within the system, the material flow rate through the aggregate supply hose 12 is greater than the foam flow rate entering the water distributor 62, and the pressure of the foaming agent and water mixture entering the foaming nozzle 32 is greater than the air pressure entering the air valve 38.

[0049] The properties of this fire-resistant concrete allow for more effective and efficient filling of narrower spaces and around anchors. Furthermore, compared to conventional gunning processes, overhead spraying can be performed without the need for additional anchors. In addition, the concrete spraying system 2 requires less water than conventional spraying processes because the foam more effectively adds moisture to the material flow and more effectively captures dust particles.

[0050] Figure 5 shows an embodiment of the foaming nozzle 32 and part of the concrete pouring system 2, specifically the spray nozzle 28 and aggregate supply hose 12. In this embodiment, the shut-off valve 36 is fluidly coupled at both ends to an additional flexible hose between the admixture inlet 34 and the air valve 38. The additional flexible hose allows the shut-off valve 36 to be attached to the spray nozzle 28, or, in other embodiments, to the aggregate supply hose 12 near the spray nozzle 28. Such an arrangement of the shut-off valve 36 provides the system user with more ergonomic access and control of the valve.

[0051] An additional flexible hose extending from the shut-off valve 36 is in fluid communication with an air valve 38. The air valve 38 is fluidically coupled to a foam pipe 40. The foam pipe 40 is fluidically coupled to a foam pipe outlet connector 50, which is fluidly coupled to a foam pipe outlet hose 52. The foam pipe outlet hose 52 is divided into a first foam hose 54 and a second foam hose 56 by a Y-joint. The first and second foam hoses 54 and 56 are fluidly coupled to a water distributor 62 via first and second main body connectors 58 and 60. The water distributor 62 is fluidly coupled to a manifold supply hose 12 near the spray nozzle 28. [Examples]

[0052] Example 1: Aggregates were formed by mixing the components shown in Table 1 below. In particular, ceramic wool (INSULFRAX (登録商標)3010) was mixed with the first portion of water to form wet fibers. Next, smectite clay and CMC binder were added to the wet fibers and mixed. A second portion of water was added and mixed into the aggregate. The aggregate was then dried. Table 1 TIFF0007854261000001.tif70164

[0053] Figure 2 shows a bulk ceramic fiber 6 (right) next to an aggregated fiber 8 (left). [Examples]

[0054] Example 2 The aggregated fibers of Example 1 were mixed with 15% calcium aluminate cement to achieve a bulk density of 520 kg / m³. 3 This dry mixture was placed in the bowl of a conventional Piccola-type concrete pouring machine equipped with a shallow pocket wheel. 3% by weight of polyvinyl alcohol foaming solution was added and pre-blended with water. The foaming solution and water were supplied to the foaming nozzle according to Figures 3 and 4. The foaming nozzle was attached to the spray nozzle of the gunning machine.

[0055] The aggregated fibers of Example 1 were mixed with 15% calcium aluminate cement to achieve a bulk density of 520 kg / m³. 3 This dry mixture was placed in the bowl of a conventional Piccola-type concrete pouring machine equipped with a shallow pocket wheel. 3% by weight of polyvinyl alcohol foaming solution was added and pre-blended with water. The foaming solution and water were supplied to the foaming nozzle according to Figures 3 and 4. The foaming nozzle was attached to the spray nozzle of the gunning machine. [Examples]

[0056] Example 3 The aggregated fibers from Example 1 were mixed with magnesium phosphate cement consisting of 12% magnesium phosphate hydrate and 5% magnesium oxide, resulting in a bulk density of 500 kg / m³. 3This dry mixture was placed in the bowl of a conventional Piccola-type concrete pouring machine equipped with shallow pocket wheels. 5% by weight of polyvinyl alcohol foaming solution was added and pre-mixed with water. The foaming solution and water were supplied to the foaming nozzle according to Figures 3 and 4. The foaming nozzle was attached to the spray nozzle of the gunning machine.

[0057] The material airflow pressure for the aggregate was 1.6 bar, and the spray air pressure for the foaming nozzle was 1.4 bar. The liquid foaming admixture was pumped into a foaming tube filled with metal wool at a pressure of 6.8 bar using a membrane pump. The material flow from the concrete gun to the spray nozzle was 0.8 m 3 The result was / hr. As a result, the "placement density" of the refractory lining on the target substrate was 720 kg / m². 3 The "firing density" is approximately 480 kg / m³. 3 The rebound was less than 6%, and no large dust particles were generated from the spray nozzle during application.

[0058] Although various embodiments have been shown and described, this disclosure is understood to include all modifications and variations that would be obvious to those skilled in the art, and is not limited to such embodiments. Therefore, it should be understood that this disclosure is not intended to be limited to any particular form disclosed, but rather to cover all modifications, equivalents, and substitutes that fall within the spirit and scope of this disclosure as defined by the appended claims.

Claims

1. It is a method, A step of mixing bulk ceramic fibers with a binder having an organic binder and / or an inorganic binder to form aggregates, A step of supplying the aggregate to the spray nozzle via a first supply hose, A step of mixing a foaming agent and water to form a foamed mixture, The process involves supplying the foam mixture to a foam nozzle via a second supply hose, which is different from the first supply hose. A step of generating foam by foaming the foaming mixture in the foaming tube of the foaming nozzle, wherein the foaming tube contains metal wool that promotes foaming of the foaming mixture, A step of supplying foam from the foam nozzle to the spray nozzle via a foam outlet hose of the foam nozzle, which is different from the first supply hose, A step of mixing the foam with the aggregate in the spray nozzle, and The steps include spraying the mixture of foam and aggregate onto an object using the spray nozzle, A method having

2. In the method according to claim 1, A method further comprising the step of sorting the aggregates by transferring them to a disc pelletizer to create spherical granules.

3. The method according to claim 1, wherein the bulk ceramic fiber comprises a fire-resistant ceramic fiber, a low biopermeability fiber, a polycrystalline ceramic fiber, and / or a glass fiber, A method wherein the aggregate has 0.5 to 3 wt% cellulose fibers based on the total weight of the aggregate.

4. The method according to claim 1, wherein the binder comprises polyvinyl alcohol, carboxymethylcellulose, plant-derived starch, a surfactant, colloidal silica, colloidal alumina, or a combination thereof.

5. The method according to claim 1, wherein the mixing of the bulk ceramic fibers is performed using a horizontal shaft mixer or a vertical shaft mixer.

6. The method according to claim 1, wherein the aggregate has a particle size of less than 15 mm, The aggregate has a median particle size of 1 to 5 mm, 2 to 4 mm, or about 3 mm, and A method wherein the aggregate does not contain particles having a size of less than 0.1 mm.

7. A method according to claim 1, further comprising the step of forming a pressed shape of the aggregate by axial pressing, hydrostatic pressing, semi-hydrostatic pressing, and / or extrusion molding.

8. The method according to claim 1, wherein the foaming agent comprises polyvinyl alcohol, ammonium lauryl sulfate, or a protein-based foaming additive.

9. A method according to claim 1, further comprising the step of supplying an aggregate comprising perlite, vermiculite, ceramic fiber, expanded clay, diatomaceous earth, or a combination thereof, together with the aggregate to the spray nozzle via the first supply hose.

10. A foam nozzle system for applying lightweight refractory materials, wherein the foam nozzle system is A first supply hose configured to be coupled to a spray nozzle of a gunning machine and to supply an aggregate to the spray nozzle, wherein the aggregate comprises bulk ceramic fibers mixed with a binder having an organic binder and / or an inorganic binder, A second supply hose is connected to a foaming nozzle and configured to supply a foaming mixture, which is a mixture of a foaming agent and water, to the foaming nozzle, wherein the second supply hose is different from the first supply hose. Includes, The foaming nozzle is configured to receive the foaming mixture from the second supply hose, and the foaming nozzle is configured A foaming tube containing metal wool, configured to foam the aforementioned foaming mixture to generate foam, A foam outlet hose connected to the foam tube and the water distributor, wherein the foam outlet hose is configured to supply foam from the foam tube to the water distributor, and the foam outlet hose is different from the first supply hose, and The water dispensing body is coupled to the spray nozzle, and the water dispensing body is configured to supply the foam to the spray nozzle, and includes the water dispensing body, The aforementioned spray nozzle is The foam is received from the water distributor of the foaming nozzle. The aggregate is received from the first supply hose, The foam is mixed in the spray nozzle to form the lightweight refractory material, and A foam nozzle system configured to spray the aforementioned lightweight refractory material onto an object.

11. A foam nozzle system according to claim 10, wherein the foam outlet hose of the foam nozzle branches into a first foam hose and a second foam hose, and the first foam hose and the second foam hose are each connected to the water distributor.

12. In the foaming nozzle system according to claim 10, the foaming nozzle is An air valve configured to supply atomizing air to the foaming tube in order to promote foaming of the foaming mixture, and A foaming nozzle system further comprising a shut-off valve configured to control the flow rate of the foaming mixture to the foaming tube.

13. In the method according to claim 1, A method further comprising the step of adjusting the flow rate of the foam supplied to the spray nozzle using a valve that is fluidly coupled to a second supply hose.

14. In the method according to claim 1, The aggregate is supplied to the spray nozzle at a first flow rate via the first supply hose, and A method wherein the foam is supplied to the spray nozzle via a second supply hose at a second flow rate less than the first flow rate.

15. In the method according to claim 1, the step of mixing the bulk ceramic fiber with the binder is: A method comprising the step of mixing the bulk ceramic fiber with water to form a wet fiber.

16. In the method according to claim 15, The ceramic fiber is mixed with water at a first mixing strength, The wet fibers are mixed with the binder at a second mixing strength higher than the first mixing strength, and The method further comprises a step of adjusting the size of the aggregates by additional mixing at a third mixing strength higher than a second mixing strength.

17. In the method according to claim 15, A method comprising the steps of mixing the bulk ceramic fiber with water and mixing the bulk ceramic fiber with the binder, wherein the water and the binder are added to the bulk ceramic fiber simultaneously.

18. In the method according to claim 1, 0.25 g / cm³ ３ A method having a higher bulk density.

19. In the foaming nozzle system according to claim 10, 0.25 g / cm³ ３ A foaming nozzle system with a higher bulk density.

20. The foaming nozzle system according to claim 10, wherein the bulk ceramic fiber comprises fire-resistant ceramic fiber, low biopermeability fiber, polycrystalline ceramic fiber, and / or glass fiber, A foaming nozzle system wherein the aggregate has 0.5 to 3 wt% cellulose fibers based on the total weight of the aggregate.

21. A foaming nozzle system according to claim 10, wherein the binder comprises polyvinyl alcohol, carboxymethylcellulose, plant-derived starch, surfactant, colloidal silica, colloidal alumina, or a combination thereof.

22. In the method according to claim 1, A method further comprising the step of supplying atomized air to the foaming tube at a pressure of 0.5 to 2 bar in order to promote foaming of the foaming mixture.

23. The method according to claim 22, wherein the step of supplying the foam from the foam nozzle to the spray nozzle via the foam outlet hose further includes the step of supplying the foam from the foam tube and the foam outlet hose to a water distributor fluidly coupled to the spray nozzle, and supplying the foam from the foam nozzle to the spray nozzle via the water distributor.

24. In the method according to claim 23, A method further comprising the step of branching the supply of foam from the foam outlet hose to the water distributor to first and second foam hoses, thereby promoting the distribution of foam to the spray nozzle via the water distributor.

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