CN117836581A

CN117836581A - Lightweight ceramic aggregate made by agglomerating ceramic fibers

Info

Publication number: CN117836581A
Application number: CN202280057784.4A
Authority: CN
Inventors: J·德克尔
Original assignee: Unifrax Corp
Current assignee: Unifrax I LLC
Priority date: 2021-08-24
Filing date: 2022-08-24
Publication date: 2024-04-05

Abstract

The method of agglomerating the bulk ceramic fibers includes mixing the bulk ceramic fibers with water to form wet fibers; mixing the wet fibers with a binder comprising an organic binder and/or an inorganic binder to form agglomerates; and drying the agglomerates. The agglomerates may be mixed with additional binders and fillers to form an insulating mixture that may be used to insulate a furnace or other heat source. Foaming nozzles may be used to apply the agglomerates. The foaming agent and water are atomized by air within the foaming nozzle and the resulting foam is mixed into pneumatically conveyed agglomerates, resulting in a lightweight refractory layer on the target substrate.

Description

Lightweight ceramic aggregate made by agglomerating ceramic fibers

Cross Reference to Related Applications

The present application claims priority from U.S. provisional patent application No. 63/236,392, issued 24 at 8, 2021 and entitled "Light weight ceramic aggregates made by agglomerating ceramic fibers" and U.S. provisional patent application No. 63/364,773, issued 16 at 5, 2022 and entitled "Light weight ceramic aggregates made by agglomerating ceramic fibers", each of which is incorporated herein by reference in its entirety.

Technical Field

The present disclosure relates to lightweight ceramic aggregates made by agglomerating ceramic fibers, foaming nozzles for applying lightweight refractory concrete by pneumatic gunning, and methods of use thereof.

Background

Lightweight (LW) refractory concrete mixtures are used in industry (e.g., metal production, hydrocarbon processing, cement, electricity and biomass incineration) as thermal insulation liners and backup liners for furnace hotfaces. Dense refractory furnace liners protect the furnace shell from mechanical wear and chemical attack at high temperatures in the presence of molten metal, aggressive low melting slag, and gaseous compounds. Due to the higher density of refractory hot-face liners, in most cases a second insulating layer is required to protect the furnace shell and structure from overheating.

The insulating back-up layers are typically ceramic fiber boards, blankets and felts. Insulating refractory brick (IFB) is also used, or for lower temperatures, highly porous calcium silicate or diatomaceous earth based bricks and panels are also used. The disadvantage of these dry materials is their low mechanical strength and the need to install these materials around the anchors necessary to hold the subsequently applied dense hot face in place. The open voids around the anchors can easily lead to hot spots that compromise the integrity of the anchor weld joint and the overall liner system. Thus, installation on high-rise applications (e.g., stovetops) is very time consuming and nearly impossible.

To allow for more economical installation, insulating concrete may be used. Although the insulation value is not as good as the high porosity fiber material, the insulation concrete can be cast or sprayed with a conventional concrete spray repair machine even at high locations and the installation time is greatly reduced. The insulated concrete utilizes lightweight aggregates (e.g., perlite, vermiculite, diatomaceous earth, or expanded clay) and a binder component (e.g., portland cement or calcium aluminate cement ("CAC")). The pre-blended dry components were introduced into the bowl of the guniting machine and pneumatically conveyed through a hose with an attached spray nozzle. At the spray nozzle, water is added to the dry mixture through a perforated water ring and distributed into the dry mixture. The resulting wet mixture is transferred to the target substrate due to the kinetic energy of the material gas stream. Upon impact with the substrate, the level of densification of the material varies depending on the material and air flow rate.

The disadvantage of this conventional method of preparing and applying refractory concrete is the large amount of dust generated at the spray nozzle. To overcome the high levels of dust generation, this process typically requires a pre-wetting step before the material is placed into the machine feed bowl. High material streams combined with improper mixing of water and dry material at the spray nozzles often produce high rebound and fluctuating densities when impinging on a target substrate. To avoid slumping and rebound, the material flow is typically increased, which results in a denser material substrate layer. Further disadvantages therefore include a greater liner thickness compared to the fibrous product and a longer drying time due to the relatively high liquid content trapped behind the dense refractory liner.

Lightweight refractory concrete uses raw materials such as expanded clay, pre-fired porous shale, slate, perlite, vermiculite, or diatomaceous earth aggregates. All of these aggregates are derived from naturally occurring raw materials and have the disadvantage of containing a variable high content of alkali and silica, which limits the maximum operating temperature to below 1100 ℃. The respirable crystalline silica component is also of concern due to human exposure during initial installation and subsequent lining replacement.

To overcome these problems, a number of more well-defined synthetic refractory lightweight materials have been developed. These include calcium hexaluminate aggregates, crushed and graded IFB with additives, and high temperature fired expanded porous mullite-based aggregates. However, these aggregates typically have a weight of greater than 35lb/ft ³ (561kg/m ³ ) And a specific bulk density of less than 25lb/ft ³ (400kg/m ³ ) Is more expensive than lighter perlite or vermiculite aggregates. As a result, these denser aggregates generally remain for thermal insulation hot-face liners operating at temperatures above 1100 ℃ in the furnace where lower mechanical strength and chemical resistance can be tolerated.

To improve the temperature stability of the thermal liner and to make it easier to install the ceramic fiber product, unifrax I LLC developed a use under the trade nameKnown is a fiber spraying method of a special spraying apparatus. In this method, components including, for example, liquid and solid binders and foaming compounds are blended with bulk fibers in a mixing nozzle and sprayed onto the furnace wall as a backup, hot-face facing, or full-thickness hot-face liner. Typically, the mixing nozzle is located a few meters before the end of the spray nozzle to allow for proper mixing of the product between the mixing chamber and the spray nozzle. Due to the combination of binder and foam, a very light fibrous liner (with less than 25lb/ft ³ (400kg/m ³ ) Is not present in the air at the jet nozzle).

Disadvantages of this method of installation relate to the complexity of the spraying equipment and the handling of the multi-component adhesive system at the installation site.The process uses special blower equipment with low gas flow and low material throughput of about 0.4 bar. For->The mixing nozzle of the method cannot be used in conventional concrete spray repair machines because of its size, weight and location. Thus (S)>The process works only for ceramic fibers, but for higher bulk densities (i.e. greater than 0.25g/cm ³ ) Is not functional. The requirements of trained personnel and specific field conditions regarding power supply and equipment maintenance capabilities are also limitations on greater acceptance in the marketplace. Accordingly, there remains a need for an easily installed, lightweight insulation liner, and methods and systems for installing the insulation liner.

Drawings

The various embodiments of the present disclosure will be more fully understood from the detailed description given below and from the accompanying drawings of the various embodiments of the disclosure. In the drawings, like reference numbers may indicate identical or functionally similar elements. Embodiments are described in detail below with reference to the attached drawing figures, wherein:

FIG. 1 is a diagram of a pneumatic gunning system including agglomerated fibers and a foaming nozzle according to one or more embodiments of the present disclosure;

FIG. 2 is a photograph of agglomerated fibers according to an embodiment of the present disclosure, as compared to non-agglomerated bulk fibers;

FIG. 3 is a perspective view of a foaming nozzle according to an embodiment of the disclosure; and

fig. 4 is a schematic side view of a foaming nozzle in accordance with an embodiment of the disclosure.

Fig. 5 is a photograph of a portion of a foaming nozzle and a concrete gunning system according to an embodiment of the present disclosure.

Detailed Description

The following disclosure provides many different embodiments or examples. Specific examples of components and arrangements are described below to simplify the present disclosure. Of course, these are merely examples and are not intended to be limiting. Further, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed.

The present disclosure relates to methods of agglomerating bulk ceramic fibers into more manageable particles to control the characteristics of transport, handling, and performance of the particles. The resulting particles are particularly useful as thermally insulating light aggregates, which are blended with additional binders, performance additives and fines to allow for: mounting and pneumatic conveying by pneumatic gunning by adopting a conventional concrete gunning machine; casting and pumping a wet mix of lightweight concrete for insulation; dry or semi-dry pressed lightweight bricks and shapes; and/or drying the bulk insulation mixture. In all of the above uses, there is a need for a dust-free flowable product that does not disintegrate during mechanical mixing, blending, transportation and moisture exposure. That is, there is a need for a large block of product that easily flows into the cavities of dry gunning machines, compaction tools, and building walls.

The present disclosure also relates to foaming nozzles that may be used in conventional pneumatic dry gunning systems and allow for the jetting of various lightweight refractory concrete materials, for example, agglomerated bulk ceramic fibers ("agglomerated fibers") and/or having a mass of greater than 0.25g/cm ³ Is a bulk density material. The foaming nozzle may also allow installation with lower density (i.e., less than 0.8 g/cm) than conventional refractory lightweight concrete ³ ) And an associated lightweight refractory lining of higher insulation value. In addition, the foaming nozzle promotes lower rebound and lower dust generation, which improves concrete spraying in confined spaces, among other benefits.

Fig. 1 depicts an embodiment of a concrete gunning system 2. The concrete gunning system 2 includes a dry aggregate container 4, a concrete gun 10, an air compressor 14, a water supply 20, a blowing agent supply 24, a spray nozzle 28, and a foaming nozzle 32. Aggregate container 4 contains agglomerated fibers 8 (shown in fig. 2) and/or other aggregates and is operably coupled to or in communication with concrete gun 10. Aggregate container 4 supplies agglomerated fibers 8 and/or other aggregates to concrete gun 10. The concrete gun 10 is operatively connected to a spray nozzle 28 by an aggregate supply hose 12. The air compressor 14 supplies compressed air to the concrete gun 10 through a first air line 16, which enables the concrete gun to move agglomerated fibers 8 and other aggregates through the aggregate supply hose 12 to the spray nozzle 28.

In one or more embodiments, the aggregate container 4 can contain agglomerated fibers 8, perlite, vermiculite, expanded clay, diatomaceous earth, or combinations thereof.

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

In some embodiments, the foaming nozzle 32 is operatively and fluidly coupled to the injection nozzle 28 via the foaming tube outlet hose 52 via the water distribution body 62. The foaming nozzle 32 converts the foaming agent and water mixture into a fine cellular foam and supplies the foam to the spray nozzle 28 through the water distribution body 62. The foam is mixed with the agglomerated fibers 8 and/or other aggregates in the spray nozzle 28 in the water distribution body 62 before being sprayed from the outlet 29 of the spray nozzle 28 and onto the target substrate 30. In some embodiments, the water distribution body 62 may be located further upstream (i.e., farther from the spray nozzle 28) along the aggregate supply hose 12 to allow the foam, agglomerated fibers 8, and other aggregates to mix through a greater distance before exiting the outlet 29 of the spray nozzle 28.

Fig. 2 depicts the bulk ceramic fibers 6 prior to agglomeration and the agglomerated fibers 8 after they have been agglomerated. In order to convert ceramic fiber cotton (also referred to herein as "ceramic fiber" or "ceramic cotton") into particles, the following methods have been developed. Ceramic fibers that may be used in the method of the present invention include, but are not limited to, refractory Ceramic (RCF) fibers, low Biopersistence (LBP) fibers, polycrystalline Cotton (PCW) fibers, glass fibers, zirconium aluminum silicate (alumino zirconia silicate, AZS) fibers, and Alkaline Earth Silicate (AES) fibers. Some examples of ceramic fibers include those available from Unifrax hllc for marking3010、/>And->Those commercially available. To be used for3010 are glass fibers based on a calcium silicate, magnesium silicate composition.

In the wetting step, ceramic wool is mixed with water to form wet fibers. The weight ratio of cotton to water may be, for example, 1:1 to 5:1 or 2:1 to 3:1. In some embodiments, mixing is performed at low intensity to break down fiber volume. A mixer such as a vertical shaft paddle mixer or a high intensity dial mixer with a booster (e.g., an intensive mixer sold by Eirich Machines inc.) may be used. Other suitable mixers include horizontal axis mixers or any type of high intensity mixer that can provide rolling motion of bulk material during mixing.

Next, in the bonding step, a binder or combination of binders is added to the wet fiber mixture. The binder used in the agglomeration process may be a polyvinyl alcohol-based binder, carboxymethyl cellulose (CMC), a plant-based starch (e.g. potato or rice starch), an inorganic binder such as clay (montmorillonite, bentonite, illite, kaolin) and colloidal silica, colloidal alumina or combinations 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.

In some embodiments, the cellulosic fibers may be added to the wet fiber mixture during the agglomeration process. The cellulosic fibers may be present in an amount of about 0.5%, about 1%, about 1.5%, about 2%, about 2.5%, based on the total weight of the wet mixture or based on the total weight of the agglomerates,About 3%, 0.5-3%, 1-2.5%, or 1.5-2%. The addition of cellulosic fibers supports reducing the bulk density of the agglomerates to below 20lb/ft ³ And further support to reduce spray density below 25lb/ft ³ . In some embodiments, the slump resistance of the sprayed agglomerate fibers comprising cellulose fibers may decrease when sprayed at a height or at an angle greater than 45 degrees, 50 degrees, 60 degrees, 70 degrees, 80 degrees, 45-90 degrees, 50-80 degrees, or 60-70 degrees relative to the ground (i.e., horizontal plane).

In some embodiments, the bonding step may be combined with the wetting step such that water is added to the ceramic wool along with the binder. In other embodiments, the bonding step may be preceded by a wetting step such that a binder is added to the dry ceramic wool. In any embodiment, the binder is dispensed with the fibers by mixing during the bonding step. The mixing may be performed at moderate intensity and the same mixer as described above may be used. In some embodiments, the mixing strength for the bonding step is greater than the mixing strength for the wetting step.

After the wetting and bonding steps, the mixture of water, ceramic wool and binder includes agglomerates. These agglomerates may be broken up into smaller agglomerates by additional mixing. For example, larger agglomerates may break up at a high mixing strength that is higher than the mixing strength used in the wetting and bonding steps.

In some embodiments, it may be desirable to obtain larger agglomerates than those formed by the wetting and bonding steps. In such cases, additional water may be added to the agglomerates to obtain the desired average particle size. If too much water is added, the agglomerates may break up into soft cakes. In some embodiments, the moisture content of the agglomerates is controlled to be less than 51%, less than 49%, less than 47%, less than 45%, less than 30%, 10-55%, 20-55%, 35-55%, 39-52%, 40-50%, or about 45%.

In some embodiments, spherical particles may be formed by transferring the fiber agglomerates into a disk granulator. Any other suitable shaping or classifying operation may be performed on the agglomerates before or after they are dried.

In some embodiments, all agglomerates have a particle size of less than 20mm, less than 15mm, less than 12mm, less than 10mm, or less than 6 mm. In some embodiments, at least 95% by weight of the agglomerates have a particle size of less than 20mm, less than 15mm, less than 12mm, less than 10mm, or less than 6 mm. In some embodiments, the agglomerates have a median particle size of 1 to 5mm, 2 to 4mm, or about 3 mm. In some embodiments, the agglomerates do not include any particles having a size of less than 0.5mm, less than 0.3mm, less than 0.1mm, or less than 0.01 mm. In embodiments, after the agglomerates are sieved in a 0.06mm screen, no dust remains in the screen tray, i.e., substantially all of the ceramic wool is incorporated into the agglomerates.

In the drying step, the agglomerates are transferred to a dryer. In some embodiments, drying may be performed at a temperature of 80 ℃ to 110 ℃. Optionally, the drying step may include firing the agglomerates at a temperature of 110 ℃ to 1300 ℃; this may be in place of or in addition to drying at a temperature of 80 to 110 ℃.

Agglomerated fibers made by the methods of the present disclosure can be used in a variety of applications and can replace inconsistent natural raw material based light aggregates in conventional concrete, paint, and fire resistant materials. Agglomerated fibers can be used in the insulated concrete wet mix, for example, by applying a hydrophobic additive or surfactant (e.g., silicone emulsion) at the end of the agglomeration process.

In some embodiments, the agglomerated fibers may be combined with additional binders to form a feedstock for a refractory lightweight concrete or a fire-resistant concrete. In some embodiments, the additional binder comprises calcium aluminate cement, portland cement, phosphate, colloidal silica, colloidal alumina, liquid aluminum phosphate, phosphoric acid, or a combination thereof.

In some embodiments, the agglomerated fibers may also include mineral based fillers. In some embodiments, the mineral-based filler comprises andalusite, mullite, alumina-silicate, microsilica (microsilica), calcined alumina, reactive alumina, platy alumina, or a combination thereof. The ratio of agglomerates, additional binder, and mineral-based filler may be adjusted to provide the desired density, strength, and thermal conductivity.

In some embodiments, the agglomerated fibers may be incorporated into a feedstock that may be applied by casting, ramming, manual filling, pumping, shotcrete, and/or pneumatic gunning using conventional gunning machines. In other embodiments, the agglomerated fibers may be formed into a pressed shape by axial pressing, isostatic, semi-isostatic, and/or extrusion. In yet other embodiments, the agglomerated fibers may be incorporated into a dust-free bulk insulation mixture that may be blown into or poured into a cavity of a building.

In fig. 3 and 4, an embodiment of a foaming nozzle 32 is shown. The foaming nozzle 32 comprises a foaming agent and water mixture inlet 34, a foaming tube 40, a water distribution body 62 and one or more outlets 64. In some embodiments, the foaming nozzle 32 further comprises a water shut-off valve 36. In some embodiments, the foaming nozzle 32 further comprises an air valve 38. It should be understood that in various embodiments, these elements may be assembled in various arrangements.

In some embodiments, a water shut-off valve 36 is fluidly coupled to the mixture inlet 34, and an air valve 38 is fluidly coupled to the water shut-off valve 36. In some embodiments, an additional flexible hose may be located between the water shut-off valve 36 and the air valve 38. The additional flexible hose fluidly couples the water 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 inch and 12 inches, or may be between 1 foot and 6 feet in length.

The air valve 38 is fluidly coupled to the foam tube 40, and the foam tube 40 is fluidly coupled to the water dispensing body 62 through the foam tube outlet hose 52. In some embodiments, the foam tube outlet hose 52 is a flexible hose and may have any length suitable for the application. The foam tube outlet hose 52 may be between 1 inch and 12 inches in length, or may be between 1 foot and 6 feet in length. In some embodiments, and referring again to fig. 1, the water distribution body 62 is fluidly coupled to the spray nozzle 28 prior to the outlet 29 of the spray nozzle 28. In other embodiments, the water distribution body 62 may be connected along the aggregate supply hose 12 and fluidly coupled to the aggregate supply hose 12.

In operation, and with continued reference to fig. 1, 3 and 4, the pump 22 pumps the foaming agent and water mixture from the foaming agent and water supplies 20,24 via the foaming agent and water hose 26 to the mixture 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 sulfonate, or any protein-based foaming additive. In some embodiments, the blowing agent may be a polyvinyl compound foaming solution containing polyvinyl alcohol. The concentration (by weight) of the polyvinyl compound foaming solution may be 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, between 0.5% and 10%, between 2% and 5%, between 2% and 6%, between 0.2% and 2%, between 0.9% and 1.5%, less than 10%, or greater than 1%. The foaming mixture passes through the water shut-off valve 36 and the air valve 38 and into the foaming tube 40. The air valve 38 supplies atomizing air to the foaming nozzle 32, which helps promote foaming of the foaming agent and water mixture within the foaming tube 40. In some embodiments, the air valve may supply air at a pressure 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 and 1.5 bar.

The foam tube 40 has a body defining an interior, a first end and a second end. The foaming tube 40 is configured to allow the foaming agent and water mixture to pass through the interior. In some embodiments, the foam tube 40 has a cylindrical shape. In some embodiments, the foam tube may have a ratio of length to diameter of between 4:1 or 2:1 to 6:1. In other embodiments, the foam tube 40 may be rectangular prisms, hexagonal prisms, octagonal prisms, or any other shape desired for a particular application.

The interior of the foam tube 40 contains an abrasive high surface area material. In some embodiments, the high surface area material contained within the interior of the foam tube 40 is metal wool. In some embodiments, the metal wool may be made of steel or stainless steel. It is contemplated that the metal wool may be organic or inorganic steel wool. In other embodiments, the abrasive high surface area material may be a polymeric material. The polymeric material advantageously helps to avoid corrosion.

The metal wool or other abrasive high surface area material has a large surface area that agitates the foaming agent and water mixture as it passes through the foaming tube 40. The combination of the large surface areas of the atomizing air and the metal wool supplied by the air compressor 14 via the air valve 38 causes the blowing agent and water mixture to become a fine cellular foam. To avoid back pressure, the fluid pressure of the blowing agent and water mixture supplied to the blowing tube 40 is greater than the air pressure supplied by the air valve 38.

The fine cellular foam exits the foam tube 40 and flows through the foam tube outlet hose 52 to the water distribution body 62. The foam tube 40 is fluidly coupled to a foam tube outlet hose 52 by a foam tube outlet connection 50. In some embodiments, the foam tube outlet connection 50 is a 90 ° elbow connection that diverts the foam flow 90 ° after exiting the foam tube 40. In other embodiments, the foam tube outlet connection 50 has an angle between 0 ° and 120 °.

In some embodiments, the foam tube outlet hose 52 may carry the foam flow directly to the water distribution body 62. In other embodiments, the foam tube outlet hose 52 may be split into a plurality of foam hoses (i.e., at least one foam hose) that carry foam to the water distribution body 62. In the embodiment shown in fig. 3 and 4, the foam tube outlet hose 52 is divided into a first foam hose 54 and a second foam hose 56. The foam tube outlet hose 52 is fluidly coupled to the first foam hose 54 and the second foam hose 56 by Y-connectors. Dividing the foam flow from the foam tube outlet hose 52 into a plurality of foam hoses may result in better distribution of the foam at one or more outlets 64 of the water distribution body 62.

The first and second foam hoses 54, 56 are fluidly coupled to the water distribution body 62 by first and second body connectors 58, 60. In the embodiment shown in fig. 3 and 4, the first body connector 58 and the second body connector 60 are fluidly coupled to the water distribution body 62 at a 90 ° angle. In other embodiments, the first and second body connectors 58, 60 may be connected to the water distribution body 62 at an angle between 0 ° and 120 °.

The water distribution body 62 is fluidly coupled to the spray nozzle 28. The water distribution body 62 has the shape of a cylindrical tube with its side walls radially spaced from the central axis and circumferentially inwardly receiving the inner portion. The water distribution body 62 is fluidly coupled to the spray nozzle 28 such that a central axis of the water distribution body 62 and a central axis of the spray nozzle 28 are axially aligned. In other embodiments, the water distribution body 62 is fluidly coupled to the aggregate supply hose 12 further upstream of the spray nozzle 28. In those embodiments, the water distribution body 62 is axially aligned with the central axis of the aggregate supply hose 12. In either configuration, the water distribution body 62 is in fluid communication with the aggregate supply hose 12 and the spray nozzle 28.

At the water distribution body 62, the foam flow enters an interior portion of the water distribution body 62 through one or more outlets 64. The number of one or more outlets 64 in the water distribution body 62 is equal to the number of foam hoses 54, 56. In some embodiments, the number of one or more outlets 64 may be greater than the number of foam hoses 54, 56. Because the water distribution body 62 is in fluid communication with the aggregate supply hose 12 and the spray nozzle 28, agglomerated fibers 8 and other aggregate material pass through the water distribution body 62.

In the water distribution body 62 and continuing through the spray nozzle 28 to the spray nozzle outlet 29, the material flow of agglomerated fibers 8 and other aggregates is mixed with the foam. The high volume of foam captures almost all of the dust particles generated by the material flow. This can greatly improve the application process performed in a closed and 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 a greatly reduced density compared to the refractory lining produced by the conventional gunning method. The light, viscous and highly porous structure of the foam and material flow mixture also produces very low rebound and slump rates and greatly improves insulation compared to conventional gunning methods.

The flow of the blowing agent and water mixture into the system may be controlled by a water shut-off valve 36. The flow may be adjusted according to the application, user preferences, etc. Depending on the substrate, the direction of the spray, the environment surrounding the substrate, and other similar factors, it may be desirable to have a regulated moisture content or volume of the foam. In any application of the system, the flow rate of material through the aggregate supply hose 12 is greater than the flow rate of foam into the water distribution body 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 to avoid backflow/backpressure in the system.

The nature of this refractory concrete allows it to more effectively and efficiently fill tighter spaces and around the filler anchors. It further allows high-end jetting without additional anchoring, as compared to conventional gunning methods. In addition, the concrete gunning system 2 requires less water than conventional gunning methods because the foam more effectively adds moisture to the material stream and more effectively captures dust particles.

In fig. 5, an embodiment of the foaming nozzle 32 and portions of the concrete gunning system 2 (particularly the spray nozzle 28 and the aggregate supply hose 12) is shown. In this embodiment, the water shut-off valve 36 is fluidly coupled at either end to an additional flexible hose between the mixture inlet 34 and the air valve 38. This additional flexible hose allows the water shut-off valve 36 to be mounted to the spray nozzle 28 or, in other embodiments, to the aggregate supply hose 12 proximate the spray nozzle 28. Such placement of the water shut-off valve 36 provides a more ergonomic valve acquisition and control for a user of the system.

An additional flexible hose from the water shut-off valve 36 is fluidly coupled to the air valve 38. The air valve 38 is fluidly coupled to the foam tube 40. The foam tube 40 is fluidly coupled to a foam tube outlet connector 50 that is fluidly coupled to a foam tube outlet hose 52. The foam tube outlet hose 52 is split at a Y-junction into a first foam hose 54 and a second foam hose 56. The first and second foam hoses 54, 56 are fluidly coupled to the water distribution body 62 via the first and second body connectors 58, 60. The water distribution body 62 is fluidly coupled within the aggregate supply hose 12 near the spray nozzle 28.

Examples

Example 1:

agglomerates were formed by mixing the components shown in table 1 below. In particular, the ceramic cotton is treated3010 Mixed with a first portion of water to form wet fibers. Montmorillonite clay and CMC binder are then added to the wet fibers and mixed. A second portion of water is added and mixed into the agglomerates. The agglomerates are then dried.

TABLE 1

Fig. 2 shows a bulk ceramic fiber 6 (right) adjacent to agglomerated fiber 8 (left).

Example 2:

the agglomerated fibers of example 1 were blended with 15% calcium aluminate cement to give 520kg/m ³ Bulk density. The dried mixture was placed in a bowl of a conventional Piccola type concrete spray repair machine equipped with shallow pocket wheels (shallow pocket wheel). A 3 wt% polyvinyl alcohol foaming solution was added and pre-blended with water. According to fig. 3 and 4, foaming solution and water are supplied to the foaming nozzle. The foaming nozzle is connected with the spraying nozzle of the spraying and repairing machine.

The material gas flow pressure of the agglomerate was 1.3 bar and the foaming nozzle atomizing air pressure was 1.4 bar. The liquid foaming mixture was pumped with a membrane pump into a foam tube filled with metal wool at a pressure of 6.8 bar. The material flow from the spray repairing machine to the spray nozzle was 0.8m ³ /hr. The "set density" of the resulting refractory lining on the target substrate was 720kg/m ³ And a "firing density" of about 500kg/m ³ . The rebound was less than 6% and there was no significant dust emission at the spray nozzle during installation.

Example 3:

the agglomerated fiber of example 1 was blended with a magnesium phosphate cement containing 12% magnesium phosphate hydrate and 5% magnesium oxide to give 500kg/m ³ Bulk density. The dried mixture was placed in the bowl of a conventional Piccola type concrete spray repair machine equipped with shallow pocket wheels. A 5 wt% polyvinyl alcohol foaming solution was added and pre-blended with water. According to fig. 3 and 4, foaming solution and water are supplied to the foaming nozzle. The foaming nozzle is connected with the spraying nozzle of the spraying and repairing machine.

The material gas flow pressure of the agglomerate was 1.6 bar and the foaming nozzle atomizing air pressure was 1.4 bar. The liquid foaming mixture was pumped with a membrane pump into a foam tube filled with metal wool at a pressure of 6.8 bar. The material flow from the concrete gun to the spray nozzle was 0.8m ³ /hr. The "set density" of the resulting refractory lining on the target substrate was 720kg/m ³ And a "firing density" of about 480kg/m ³ . The rebound was less than 6% and there was no significant dust emission at the spray nozzle during installation.

While various embodiments have been shown and described, the present disclosure is not limited to such embodiments, and the present disclosure is to be understood as including all modifications and alterations apparent to those of ordinary skill in the art. It should be understood, therefore, that this disclosure is not intended to be limited to the particular forms disclosed; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the disclosure as defined by the appended claims.

Claims

1. A method, comprising:

mixing the bulk ceramic fiber with water to form a wet fiber;

mixing the wet fibers with a binder comprising an organic binder and/or an inorganic binder to form agglomerates; and

drying the agglomerates.

2. The method of claim 1, further comprising classifying the agglomerates by:

adding water and mixing the agglomerates to increase the average particle size of the agglomerates; and/or

The agglomerates are transferred to a disk granulator to produce spherical particles.

3. The method of claim 1, wherein the bulk ceramic fibers comprise refractory ceramic fibers, low biological durability fibers, polycrystalline ceramic fibers, and/or glass fibers; and

wherein the agglomerates comprise from 0.5 to 3% by weight of cellulose fibers, based on the total weight of the agglomerates.

4. The method of claim 1, wherein the binder comprises polyvinyl alcohol, carboxymethyl cellulose, plant-based starch, surfactants, inorganic binders, colloidal silica, colloidal alumina, or a combination thereof.

5. The method of claim 1, wherein mixing the bulk ceramic fibers and/or mixing the wet fibers utilizes a horizontal axis mixer or a vertical axis mixer.

6. The process of claim 1, wherein the agglomerates have a particle size of less than 15mm or less than 6 mm;

wherein the agglomerates have a median particle size of 1-5mm, 2-4mm, or about 3 mm; and

wherein the agglomerates do not comprise any particles having a size of less than 0.1 mm.

7. Agglomerates produced by the process according to claim 1.

8. The method of claim 1, further comprising applying the agglomerates to an object by casting, ramming, manual filling, pumping, and/or pneumatic gunning.

9. The method of claim 1, further comprising forming a pressed shape by axial pressing, isostatic pressing, semi-isostatic pressing, and/or extruding the agglomerates.

10. The method of claim 1, further comprising applying the agglomerates to an object by:

mixing a foaming agent with water to form a foaming mixture;

foaming the foaming mixture in a foaming nozzle to form a foam;

mixing the foam with the agglomerates in a spray nozzle; and

using the spray nozzle, the foam and aggregate mixture is sprayed onto the object.

11. The method of claim 10, wherein the foaming nozzle comprises a foaming tube that facilitates foaming of the foaming mixture.

12. The method of claim 11, wherein the foam tube comprises metal wool.

13. The method of claim 10, wherein the foaming agent comprises polyvinyl alcohol, ammonium lauryl sulfate, or a protein-based foaming additive.

14. The method of claim 10, wherein the aggregate comprises perlite, vermiculite, ceramic fiber, expanded clay, diatomaceous earth, or combinations thereof.

15. A material for refractory lightweight concrete or fire-resistant concrete comprising:

agglomerates produced by: mixing the bulk ceramic fiber with water to form a wet fiber; mixing the wet fibers with a binder comprising an organic binder and/or an inorganic binder to form the agglomerates; and drying the agglomerates; and

additional binders comprising calcium aluminate cement, portland cement, phosphate, colloidal silica, colloidal alumina, liquid aluminum phosphate, phosphoric acid, or combinations thereof.

16. The material of claim 15, further comprising:

a mineral-based filler comprising andalusite, mullite, alumina-silicate, microsilica (microsilica), calcined alumina, reactive alumina, platy alumina, or a combination thereof; and/or

0.5-3 wt% cellulose fibers, based on the total weight of the material.

17. A foaming nozzle for mounting lightweight refractory material, the foaming nozzle comprising:

an inlet, wherein the inlet is configured to receive a foaming agent and water mixture;

an air valve, wherein the air valve is configured to supply atomizing air to the foaming nozzle;

a foaming tube containing metal wool; and

a water distribution body, wherein the water distribution body is configured to be fluidly coupled with a spray nozzle of a spray repair machine.

18. The foaming nozzle of claim 17 further comprising a foaming tube outlet hose fluidly coupling the foaming tube to the nozzle body.

19. The foaming nozzle of claim 18 wherein the foaming tube outlet hose is divided into a first foam hose and a second foam hose, each fluidly coupled to the water distribution body.

20. The foaming nozzle of claim 17, further comprising a water shut-off valve disposed between the inlet and the air valve.