Sagger

Abstract

A sagger having a body comprising a base plate and one or more side walls wherein the base plate and the one or more side walls have a thickness of not greater than about 13 mm and the sagger comprises not more than about 50 wt% Al2O3 based on the total weight of the sagger; the invention further discloses a method for manufacturing the saggar.

Description

Technical Field

[0001] The present disclosure relates to saggars and methods of making saggars. Background Art

[0002] A sagger is a box-shaped kiln furniture used to hold and / or protect powders. Saggers are commonly used for firing or calcining powders, such as catalytic powders and / or battery electrode material powders used in modern electric vehicles.

[0003] The process of producing saggers typically involves pressing ceramic powder into a mold to create a green body or preform.

[0004] As the demand for these powders increases, so does the need for improved methods and equipment for their production. A particular need is for improved saggers that are stronger and / or lighter and chemically resistant to the powders at high temperatures. Summary of the Invention

[0005] According to the present invention there is provided a sagger and a method as defined in any one of the accompanying claims.

[0006] In one embodiment, the present invention provides a sagger having a body comprising a bottom plate and one or more side walls, wherein:

[0007] The thickness of the bottom plate and one or more side walls is no greater than about 13 mm, e.g., no greater than about 12 mm, or no greater than about 11 mm, or no greater than about 10 mm, or no greater than about 8 mm; the sagger comprises no greater than about 50 wt. % Al2O3, preferably no greater than about 45 wt. % Al2O3, based on the total weight of the sagger; and

[0008] The density of the sagger is about 1.6g / cm 3 to about 3.0g / cm 3 , for example about 1.6 g / cm 3 to about 2.3g / cm 3 and / or

[0009] The thermal expansion coefficient of the sagger is about 1.5×10 -6 K -1 to about 5.0×10 -6 K -1 , for example, about 2.0×10 -6 K -1 to about 4.0×10 -6 K -1 and / or

[0010] The modulus of rupture of the sagger is not less than about 15 MPa, such as not less than about 20 MPa, or not less than about 23 MPa; and / or

[0011] The ratio of the modulus of rupture to the thickness of the sagger is not less than about 1.5 MPa / mm, such as not less than about 1.7 MPa / mm, or not less than about 2.0 MPa / mm, preferably 1.5 MPa / mm to 4.0 MPa / mm.

[0012] The sagger of the present invention provides desirable structural characteristics that enable the weight of the sagger to be reduced, thereby improving its handling and transportation.

[0013] The sagger may contain about 20 wt % to about 55 wt % mullite, about 30 wt % to about 45 wt % cordierite, and about 0 wt % to about 25 wt % spinel, preferably about 0 wt % to about 5 wt % spinel, or about 0 wt % to about 4 wt % spinel, based on the total weight of the sagger.

[0014] The sagger may comprise from about 5 wt% to about 30 wt% amorphous phase, based on the total weight of the sagger. For example, the sagger may comprise from about 10 wt% to about 20 wt% amorphous phase, based on the total weight of the sagger.

[0015] The water absorption of the sagger may be about 5% to about 20%, for example about 8% to about 16%, based on the total weight of the sagger.

[0016] Alternatively, the sagger may include: about 40 wt % to about 60 wt % SiO 2 , based on the total weight of the sagger, and about 30 wt % to about 50 wt % Al 2 O 3 , based on the total weight of the sagger; optionally, the sagger may contain: no more than about 2.0 wt %, for example, about 0.1 wt % to about 2.0 wt % Fe 2 O 3 , based on the total weight of the sagger; no more than about 1.0 wt %, for example, about 0.05 wt % to about 1.0 wt % TiO 2 , based on the total weight of the sagger; no more than about 1.0 wt %, for example, about 0.01 wt % to about 1.0 wt % CaO, based on the total weight of the sagger; about 4 wt % to about 10 wt % MgO, based on the total weight of the sagger; no more than about 2.0 wt %, for example, about 0.01 wt % to about 2.0 wt % K 2 O, based on the total weight of the sagger; and / or no more than about 0.5 wt %, for example, about 0.01 wt % to about 0.5 wt % Na 2 O, based on the total weight of the sagger.

[0017] The sagger can be used to hold powders during the calcination process, for example, where the sagger is used to hold battery electrode material powders, such as battery cathode material powders, for example, where the sagger is used to hold one or more oxides, hydroxides, carbonates, sulfates and / or phosphates of lithium, titanium, vanadium, chromium, manganese, iron, cobalt, tungsten and / or nickel.

[0018] Surprisingly, it was found that saggers produced by compression casting are stronger (eg, the modulus of rupture of the saggers is higher).

[0019] Surprisingly it was found that saggers produced by high pressure casting are stronger (eg the modulus of rupture of the sagger is higher) than saggers produced by low pressure casting if the thickness of the sagger is low, ie not more than 10 mm.

[0020] In turn, the improvement in the sagger strength can reduce the thickness of the sagger body (including its bottom plate and / or walls), thereby reducing handling, transportation and cost efficiencies.

[0021] Reducing the thickness of the sagger base and / or sagger walls also reduces raw material consumption, reduces the amount of material that needs to be recycled at the end of the sagger’s life, and reduces thermal inertia and thermal gradients. Furthermore, this reduces the weight of the sagger, making it easier to handle and transport.

[0022] It was also surprisingly found that according to the present invention, saggars with a low Al2O3 content can be produced by pressure casting. The strength of the saggars obtained with a low Al2O3 content (for example, in terms of the modulus of rupture of the saggars) is at least comparable to that of saggars with a high Al2O3 content, and a greater weight reduction is achieved at a lower production cost.

[0023] Also provided is a method of manufacturing a sagger for a kiln, the method comprising: pressure-casting a slip composition in a mold cavity at a pressure of about 200 kPa to about 4000 kPa to form a sagger body green body; removing the sagger body green body from the mold cavity; and firing the sagger body green body to produce a fired sagger body.

[0024] During pressure casting of the slurry composition within the mold cavity, the filtrate may be removed from the mold cavity via an outlet configured to prevent the passage of solid components of the slurry composition.

[0025] The slurry composition may include one or more phyllosilicate minerals and water. The phyllosilicate minerals include calcined and uncalcined phyllosilicate minerals. Alternatively, the one or more phyllosilicate minerals may include: kaolin; montmorillonite; illite; chlorite; talc; vermiculite; palygorskite; sepiolite; silicoaluminous chamotte; and / or any combination thereof. Additionally, the slurry composition may optionally include: alumina, such as calcined alumina; corundum; magnesium carbonate, such as magnesite; mullite; kyanite; spinel; and / or any combination thereof. For example, the slurry composition includes kaolin, calcined kaolin, talc, calcined alumina, corundum, mullite and / or calcined clay, and any combination thereof.

[0026] The slurry composition may include a deflocculant and / or a binder, such as a polycarboxylic acid, a polysaccharide and / or a lignin sulfonate.

[0027] The slurry composition may have: a density of about 1500 g / L to about 3000 g / L, for example, about 1800 g / L to about 2800 g / L, or about 2000 g / L to about 2100 g / L, or about 2550 g / L to about 2650 g / L; a thixotropy of about 15°G to about 30°G (as measured by Gallenkamp universal torsional viscometry, with the first viscosity (i.e., over-swing) measurement being taken immediately after stirring and the second viscosity (i.e., over-swing) measurement being taken 5 minutes after stirring); and / or a water content of about 10 wt % to about 30 wt %, based on the total weight of the sagger.

[0028] The sagger may have a bottom plate and one or more side walls. The thickness of each of the bottom plate and the one or more side walls may be no greater than about 13 mm, e.g., no greater than about 12 mm, no greater than about 11 mm, no greater than about 10 mm, and the modulus of rupture of the sagger (i.e., the fired sagger body) is no less than about 15 MPa, e.g., no less than about 20 MPa, or no less than about 23 MPa.

[0029] The sagger can be used to hold powders during the calcination process. For example, the sagger can be used to hold battery electrode material powders, such as battery cathode material powders. For example, the sagger can be used to hold one or more oxides, hydroxides, carbonates, sulfates, and / or phosphates of lithium, titanium, vanadium, chromium, manganese, iron, cobalt, tungsten, and / or nickel.

[0030] It will be understood by those skilled in the art that, unless mutually exclusive, the features described in any one of the above aspects may be applied to any other aspects after modification as appropriate. In addition, unless mutually exclusive, any features described herein may be applied to any aspect and / or combined with any other features described herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Embodiments of the invention will now be described, by way of example only, with reference to the following drawings:

[0032] Figure 1 is a perspective view of a box sagger; and

[0033] Figure 2 Shown Figure 1 (a) Cross-sectional view and (b) plan view of the box-type sagger. DETAILED DESCRIPTION

[0034] sagger

[0035] A saggar, also known as a sag box, is a container suitable for holding and / or protecting a load in a kiln or furnace. More specifically, it is a box-shaped ceramic saggar used for firing or calcining powders, such as catalytic powders and / or battery electrode material powders that can be used in modern electric vehicles.

[0036] The sagger generally includes (eg, may be) a container for containing the load. The sagger may also include a lid (eg, a plate) for covering (eg, closing) an opening of the container.

[0037] A sagger (e.g., a container) typically has a body comprising a bottom plate and one or more side walls (e.g., formed of or consisting of the same). The body is typically box-shaped. Therefore, the sagger may be referred to as a box-type sagger.

[0038] It will be appreciated that the bottom plate and one or more side walls may have different shapes depending on the design of the sagger.

[0039] The base plate is generally flat or planar. The shape of the base plate can be polygonal (e.g., rectangular or square). It will be appreciated that the polygonal base plate does not necessarily have a sharp vertex and can also have a rounded vertex.

[0040] Each of the one or more side walls may be (eg substantially) flat (ie planar). Preferably, the bottom plate is generally rectangular and the sagger body may comprise four side walls, each of which is a generally flat panel connected to the generally rectangular bottom plate at a respective edge.

[0041] The one or more side walls may extend vertically upward from the base plate (i.e., when the sagger is arranged in use with the base plate substantially horizontal). Thus, each of the one or more side walls may be generally orthogonal to the base plate, but one or more side walls may also be slightly angled outward (i.e., away from the interior space enclosed by the sagger). For example, the angle at which each of the one or more side walls extends outward from the base plate may be from about 80° to about 100°, such as from about 85° to about 95°, or from about 87° to about 93°, or from about 88° to about 92°.

[0042] The thickness of the bottom plate and the one or more side walls can be substantially uniform throughout the sagger. Alternatively, the thickness can vary. For example, the thickness of the bottom plate and the one or more side walls can vary by no more than about 3 mm, or by no more than about 2 mm, or by no more than about 1 mm throughout the bottom plate and the one or more side walls.

[0043] The thickness of the bottom plate and one or more side walls (e.g., maximum thickness, such as the thickness at the maximum thickness point of the bottom plate) may be no greater than about 13 mm, such as no greater than about 12 mm, or no greater than about 11 mm, or no greater than about 10 mm. The thickness of the bottom plate and one or more side walls (e.g., minimum thickness, such as the thickness at the minimum thickness point of the bottom plate) may be no less than about 4 mm, such as no less than about 5 mm, or no less than about 6 mm, or no less than about 8 mm. The thickness of the bottom plate and one or more side walls (e.g., maximum thickness, minimum thickness, or average thickness as the average of the maximum thickness and minimum thickness) may be from about 4 mm to about 13 mm, such as from about 4 mm to about 12 mm, or from about 4 mm to about 10 mm, or from about 8 mm to about 12 mm, or from about 8 mm to about 10 mm.

[0044] The bottom plate may have a length and a width. The length and the width may be measured in directions at right angles to each other. The length and the width of the bottom plate may be the length and the width of the sagger body (i.e. the fired sagger body).

[0045] Each side wall may have a height. The height may be the straight-line distance between the lowermost edge of the side wall where it meets the base and the uppermost edge of the side wall. The height may be measured along a line perpendicular to the lowermost edge of the side wall where it meets the base.

[0046] The height of the sidewall can be substantially uniform. Alternatively, the height of the sidewall can vary according to the profile of the sidewall.

[0047] The height of each side wall (e.g., the minimum height, e.g., in an embodiment where the height is non-uniform, the height at which the side wall height is the minimum) may be about 50 mm, e.g., not less than about 60 mm, or not less than about 70 mm, or not less than about 80 mm, or not less than about 90 mm, or not less than about 100 mm. The height of each side wall (e.g., the maximum height, e.g., in an embodiment where the height is non-uniform, the height at which the side wall height is the maximum) may be about 200 mm, e.g., not more than about 190 mm, or not more than about 180 mm, or not more than about 170 mm, or not more than about 160 mm, or not more than about 160 mm, or not more than about 150 mm, or not more than about 140 mm, or not more than about 130 mm, or not more than about 120 mm.

[0048] The sagger, i.e., the fired sagger body, may have a mass of not less than about 2 kg, e.g., not less than about 3 kg, when unfilled. The mass of the sagger body when unfilled may not exceed about 4 kg. The mass of the sagger body when unfilled may be between about 2 kg and 4 kg, e.g., between about 3 kg and about 4 kg.

[0049] Figure 1An example box-type sagger 1 is shown. The sagger 1 has a box-shaped, fired sagger body 2. The body 2 has a bottom plate 3 and four side walls 4A, 4B, 4C, and 4D. The four side walls 4A, 4B, 4C, and 4B meet at rounded corners 5A, 5B, 5C, and 5D. The outer sides of the side walls 4A, 4B, 4C, and 4D are ridged near the rounded corners 5A, 5B, 5C, and 5D, as shown in Figure 6.

[0050] Figure 2 The sagger 1 is shown in (a) a cross-sectional view and (b) a plan view. The length of the bottom plate is represented by L. The width of the bottom plate is represented by W. The height of the side wall is represented by H. The thickness of the bottom plate is represented by T. B The thickness of the side wall is represented by T S The inner angle between the side wall and the bottom plate is denoted by α. The outer angle between the side wall and the bottom plate is denoted by β.

[0051] The sagger can be a sagger used to hold powder during the calcination process. The powder can be a battery electrode material powder, such as a battery cathode material powder. For example, the sagger can be used to hold one or more metal oxides, hydroxides, carbonates, sulfates, and / or phosphates. For example, the sagger can be used to hold one or more metal oxides, hydroxides, carbonates, sulfates, and / or phosphates of lithium, titanium, vanadium, chromium, manganese, iron, cobalt, tungsten, and / or nickel. Therefore, the sagger can be made of a material that is resistant to damage when in contact with these powders at high temperatures.

[0052] Manufacturing method

[0053] The method of manufacturing a sagger includes pressure-casting a slurry composition in a mold cavity to form a sagger body green body, removing the sagger body green body from the mold cavity, and firing the sagger body green body to produce a fired sagger body.

[0054] It is understood that pressure casting a component includes applying pressure (ie, pressurizing) to the slurry composition within the mold cavity during the molding process to form the component body green body. Therefore, pressure casting can be compared with non-pressurized slurry casting.

[0055] Because pressure casting involves forming a green component body from a slurry composition (ie, liquid slurry), pressure casting can also be compared to forming a green component body by pressing dry ceramic powder within a mold cavity.

[0056] Pressure casting

[0057] The method may include pressure casting the slurry composition within the mold cavity at a pressure of not less than about 200 kPa, for example, a pressure of not less than about 250 kPa, or not less than about 300 kPa, or not less than about 400 kPa, or not less than about 500 kPa, or not less than about 501 kPa, or not less than about 600 kPa, or not less than about 700 kPa, or not less than about 800 kPa, or not less than about 900 kPa, or not less than about 1000 kPa, or not less than about 1500 kPa, or not less than about 2000 kPa, or not less than about 2500 kPa, or not less than about 3000 kPa, or not less than about 3500 kPa. The method may include pressure casting the slurry composition within the mold cavity at a pressure of no more than about 4000 kPa, such as a pressure of no more than about 3500 kPa, or no more than about 3500 kPa, or no more than about 3000 kPa, or no more than about 2500 kPa, or no more than about 2000 kPa. The method can include pressure-casting the slurry composition within the mold cavity at a pressure of about 200 kPa to about 4000 kPa, for example, a pressure of about 200 kPa to about 3000 kPa, or about 200 kPa to about 2000 kPa, or about 200 kPa to about 1000 kPa, or about 200 kPa to about 500 kPa, or about 501 kPa to about 4000 kPa, or about 1000 kPa to about 4000 kPa, or about 2000 kPa to about 4000 kPa, or about 3000 kPa to about 4000 kPa, or about 2000 kPa to about 3000 kPa.

[0058] Pressure casting may be low pressure casting. Low pressure casting may be defined as pressure casting in which the slurry composition is cast at a pressure of about 200 kPa to about 5000 kPa.

[0059] Pressure casting can be high pressure casting. High pressure casting can be defined as wherein the slurry composition is cast at a pressure of about 501 kPa to about 4000 kPa, such as a pressure of about 1000 kPa to about 4000 kPa, or about 2000 kPa to about 4000 kPa.

[0060] It will be understood that the mold cavity refers to the interior space of the mold to be filled with the slurry composition. The mold cavity is usually surrounded by one or more mold walls. One or more mold walls usually define the internal shape of the mold cavity and, therefore, the shape of the sagger body green body.

[0061] The mold can be a multi-part mold. In other words, the entire mold can be composed of two or more independent mold parts, each of which defines a portion of the interior of one or more mold cavities. During use, the two or more mold parts can be secured together (to form the mold cavity) by, for example, a mechanical locking mechanism, pneumatic pressure, hydraulic pressure, or the like.

[0062] During the pressure casting process, a slurry composition is injected into a mold cavity under pressure through an inlet port. A filtrate is typically removed from the mold cavity (i.e., the slurry composition within the mold cavity), while the solids concentration (i.e., the solid components of the slurry composition) within the mold cavity (i.e., the slurry composition within the mold cavity) increases. Pressure casting is continued until the solids content within the mold cavity (i.e., compressed) is sufficiently high to produce a green sagger body that can be safely removed from the mold without significant damage or decomposition.

[0063] The filtrate can be removed through one or more mold walls of the mold cavity. The mold walls can include (e.g., be formed of or consist of) a porous or semi-porous material, such as gypsum or a porous or semi-porous resin. Thus, the mold walls can absorb the filtrate in the mold cavity and / or allow the filtrate to pass through the mold walls.

[0064] Additionally or alternatively, the filtrate may also be removed from the mold cavity via an outlet. The outlet may be formed on one or more mold walls, such as at one end (e.g., the lower end) of the mold cavity. The outlet may be configured to prevent the solid components of the slurry composition from passing through. Thus, the outlet may be configured to act as a filter, allowing the filtrate (i.e., liquid) to pass through but hindering the solid components from passing through.

[0065] In embodiments where the filtrate is removed from the mold cavity via an outlet, the mold walls may comprise (eg, be formed from or consist of) a non-porous material, such as a non-porous resin.

[0066] In some instances (e.g., using low pressure casting), compression casting can be carried out for no less than about 10 minutes, for example, no less than about 20 minutes, or no less than about 30 minutes, or no less than about 40 minutes. In some instances (e.g., using low pressure casting), compression casting can be carried out for no more than about 60 minutes, for example, no more than about 50 minutes, or no more than about 40 minutes, or no more than about 30 minutes. In some instances (e.g., using low pressure casting), compression casting can be carried out for about 10 minutes to about 60 minutes, for example, from about 20 minutes to about 60 minutes, or from about 30 minutes to about 60 minutes, or from about 20 minutes to about 40 minutes, or from about 20 minutes to about 30 minutes.

[0067] In some instances (for example, using high pressure casting), compression casting can be carried out for no less than about 30 seconds, for example, no less than about 1 minute, or no less than about 2 minutes, or no less than about 3 minutes. In some instances (for example, using high pressure casting), compression casting can be carried out for no more than about 10 minutes, for example, no more than about 8 minutes, or no more than about 6 minutes, or no more than about 5 minutes, or no more than about 4 minutes, or no more than about 3 minutes. In some instances (for example, using high pressure casting), compression casting can be carried out for about 30 seconds to about 10 minutes, for example, from about 1 minute to about 8 minutes, or from about 1 minute to about 6 minutes, or from about 1 minute to about 5 minutes, or from about 2 minutes to about 10 minutes, or from about 2 minutes to about 5 minutes, or from about 2 minutes to about 4 minutes, or from about 2 minutes to about 3 minutes.

[0068] The slurry composition can be pressurized using any suitable method known in the art. For example, mechanical, hydraulic, or pneumatic means can be used to apply pressure to the slurry composition. The slurry composition in the mold cavity can be directly pressurized, for example, by pumping the slurry composition into the mold cavity under pressure and maintaining the pressure of the slurry composition at the mold cavity entrance during casting. In addition, pressure (e.g., hydraulic pressure) can also be applied to the mold wall.

[0069] The method includes removing a green sagger body from a mold cavity after pressure casting. The green sagger body is also called a sagger preform. Removing the green sagger body may include separating the mold components from each other and / or from the green sagger body. The mold components may be separated from each other and / or from the green sagger body by applying pressure (e.g., air pressure or water pressure) and / or applying a vacuum.

[0070] After the green sagger body is removed from the mold cavity, one or more drying setters (eg, setting plates) may be applied.

[0071] The method may include drying the sagger body green body. The sagger body green body may be dried using any suitable method, for example, at room temperature, or at a temperature between 40°C and 100°C, for example, at a temperature of approximately 60°C. The drying time of the sagger body green body may be no less than 2 hours, or no less than 6 hours, or no less than 12 hours, or no less than 18 hours, or no less than 24 hours. The sagger body green body may be considered dried when its moisture content does not exceed 0.5% by weight based on the total weight of the sagger body green body.

[0072] Slurry composition

[0073] It will be appreciated that the slurry is a slurry used in ceramic production. Thus, the slurry composition used in the method may include one or more phyllosilicate minerals and water.

[0074] Phyllosilicate minerals include, but are not limited to, kaolin, calcined kaolin, montmorillonite, illite, clay, calcined clay, talc, vermiculite, palygorskite, and / or sepiolite.

[0075] Thus, the one or more phyllosilicate minerals in the slurry composition may include kaolin, calcined kaolin, montmorillonite, illite, clay, calcined clay, talc, vermiculite, palygorskite, sepiolite, and / or any combination thereof.

[0076] The one or more phyllosilicate minerals in the slurry composition may also comprise aluminosilicate fireclay, which is a mixture of aluminosilicate minerals fired at high temperatures (at least 1400° C.), such as a fired mixture of clay and kaolin.

[0077] In addition to the one or more phyllosilicate minerals and water, the slurry composition may include other components.

[0078] For example, the slurry composition may include one or more mineral components other than phyllosilicate minerals.

[0079] The slurry composition may include alumina (Al2O3). The slurry composition may include calcined alumina and / or uncalcined alumina.

[0080] The slurry composition may include corundum, a crystalline mineral form of aluminum oxide, which may also include trace amounts of iron, titanium, vanadium, and / or chromium.

[0081] The slurry composition may include magnesium carbonate (MgCO3). The slurry composition may include magnesite, a mineral form of magnesium carbonate, which may also include trace amounts of iron, manganese, cobalt and / or nickel.

[0082] The slurry composition may include mullite and / or kyanite. Mullite is also known as porcelainite and has a chemical formula of Al6Si2O 13 , occurs naturally, or can be manufactured, for example, by calcining kaolinite or kyanite. Kyanite is a high-pressure polycrystalline of andalusite and sillimanite.

[0083] The slurry composition may include spinel. Spinel defines a class of minerals with the general formula AB2X4 that crystallize in the cubic system, wherein the X anions are arranged in a cubic close-packed lattice and the A and B cations occupy octahedral and / or tetrahedral sites. Spinel includes a special mineral called "aluminum magnesium spinel", namely MgAl2O4. Therefore, the slurry composition may include aluminum magnesium spinel (MgAl2O4). Spinel may be naturally occurring or artificially produced. For example, the spinel may be a molten magnesium aluminate spinel.

[0084] Thus, the slurry composition may include one or more phyllosilicate minerals, water, and one or more of the following: alumina (eg, calcined alumina), corundum, magnesium carbonate (eg, magnesite), mullite, kyanite, spinel, and / or any combination thereof.

[0085] The slurry composition may include one or more phyllosilicate minerals, mullite, and water.

[0086] The slurry composition may include one or more phyllosilicate minerals, alumina and / or corundum, mullite, and water.

[0087] The slurry composition may include one or more of kaolin, talc, mullite, and water.

[0088] The slurry composition can be selected so that when fired it produces cordierite and mullite, which will provide the sagger with good chemical resistance at a reasonable cost.

[0089] The slurry composition may include one or more additives. For example, the slurry composition may include a deflocculant and / or a binder. For example, the slurry composition may include a polycarboxylic acid (e.g., DOLAPIX PC 67, available from Zschimmer & Schwarz GmbH Co., Germany), a polysaccharide (e.g., W-60 gellan gum, available from COLLTEC GmbH & Co., Germany) and / or lignin sulfonates (e.g. DD, available from Borregaard, Norway).

[0090] Alternatively, the slurry composition may comprise not less than about 70 wt %, such as not less than about 73 wt %, or not less than about 75 wt %, or not less than about 78 wt %, or not less than about 80 wt % of phyllosilicates, based on the total dry weight of the slurry composition. The slurry composition may comprise not more than about 90 wt %, such as not more than about 87 wt %, or not more than about 85 wt % of phyllosilicate minerals, based on the total dry weight of the slurry composition. The slurry composition may comprise from about 70 wt % to about 90 wt %, or from about 73 wt % to about 87 wt %, or from about 75 wt % to about 87 wt %, or from about 78 wt % to about 87 wt %, or from about 78 wt % to about 85 wt %, or from about 80 wt % to about 85 wt % of phyllosilicate minerals, based on the total dry weight of the slurry composition.

[0091] Advantageously, we have found that by casting using pressures between 200 kPa and 4000 kPa, the concentration of alumina in the slurry can be reduced without adversely affecting the mechanical properties of the fired sagger. As alumina contributes significantly to the weight of the sagger, this means that the weight of the sagger can be reduced.

[0092] The slurry composition may comprise not less than about 1 wt %, such as not less than about 2 wt %, or not less than about 3 wt %, or not less than about 4 wt %, or not less than about 5 wt %, or not less than about 10 wt %, or not less than about 12 wt % of alumina (e.g., calcined alumina), based on the total dry weight of the slurry composition. The slurry composition may comprise not more than about 30 wt %, or not more than about 25 wt %, or not more than about 20 wt %, or not more than about 15 wt %, or not more than about 10 wt %, or not more than about 5 wt % of alumina (e.g., calcined alumina), based on the total dry weight of the slurry composition. The slurry composition may comprise from about 1 wt % to about 30 wt %, such as from about 1 wt % to about 25 wt %, or from about 1 wt % to about 20 wt %, or from about 1 wt % to about 15 wt %, or from about 1 wt % to about 10 wt %, or from about 1 wt % to about 5 wt % of alumina (e.g., calcined alumina), based on the total dry weight of the slurry composition.

[0093] The slurry composition may not contain any corundum. Alternatively, the slurry composition may contain corundum.

[0094] The slurry composition may comprise not less than about 5 wt %, such as not less than about 10 wt %, or not less than about 15 wt % of corundum, based on the total dry weight of the slurry composition. The slurry composition may comprise not more than about 30 wt %, or not more than about 20 wt %, or not more than about 10 wt % of corundum, based on the total dry weight of the slurry composition. The slurry composition may comprise from about 5 wt % to about 30 wt %, such as from about 5 wt % to about 20 wt %, or from about 5 wt % to about 10 wt % of corundum, based on the total dry weight of the slurry composition.

[0095] The slurry composition may not contain any mullite. The slurry composition may not contain any kyanite. Alternatively, the slurry composition may contain mullite and / or kyanite. Based on the total dry weight of the slurry composition, the slurry composition may contain not less than about 5 weight %, for example, not less than about 8 weight %, or not less than about 10 weight %, or not less than about 12 weight % of mullite and / or kyanite. Based on the total dry weight of the slurry composition, the slurry composition may contain no more than about 30 weight %, or no more than about 25 weight %, or no more than about 20 weight %, or no more than about 17 weight %, or no more than about 15 weight % of mullite and / or kyanite. Based on the total dry weight of the slurry composition, the slurry composition may contain from about 5 weight % to about 30 weight %, or from about 5 weight % to about 25 weight %, from about 5 weight % to about 20 weight %, or from about 5 weight % to about 17 weight %, or from about 5 weight % to about 15 weight % of mullite and / or kyanite.

[0096] The slurry composition may be free of spinel. Alternatively, spinel may be included in the slurry composition. Based on the total dry weight of the slurry composition, the slurry composition may include not less than about 0.1 wt %, such as not less than about 1 wt %, or not less than about 1.5 wt % spinel. Based on the total dry weight of the slurry composition, the slurry composition may include no more than about 25 wt %, such as no more than about 10 wt %, or no more than about 5 wt %, or no more than about 4 wt % spinel. Based on the total dry weight of the slurry composition, the slurry composition may include from about 0 wt % to about 25 wt %, or from about 0 wt % to about 15 wt %, or from about 0 wt % to about 10 wt %, or from about 0 wt % to about 5 wt %, or from about 0.1 wt % to about 5 wt %, or from about 0 wt % to about 4 wt %, or from about 0 wt % to about 3 wt %, or from about 0.1 wt % to about 3 wt % spinel.

[0097] The slurry composition may comprise from about 0.01 wt % to about 1.5 wt %, for example from about 0.01 wt % to about 1.0 wt %, or from about 0.01 wt % to about 0.9 wt %, or from about 0.01 wt % to about 0.8 wt %, or from about 0.01 wt % to about 0.5 wt %, or from about 0.01 wt % to about 0.4 wt %, or from about 0.01 wt % to about 0.3 wt %, or from about 0.01 wt % to about 0.2 wt %, or from about 0.01 wt % to about 0.1 wt % of a deflocculant and / or binder, based on the total dry weight of the slurry composition.

[0098] The slurry composition may comprise from about 8 wt % to about 30 wt %, for example, from about 8 wt % to about 25 wt %, or from about 10 wt % to about 25 wt %, or from about 12 wt % to about 18 wt %, or from about 18 wt % to about 25 wt %, or from about 20 wt % to about 22 wt % water, based on the total dry weight of the slurry composition.

[0099] The levels of water and deflocculant and / or binder in the slurry composition can be adjusted to achieve a desired consistency (eg, as defined in terms of viscosity parameters such as thixotropy) suitable for pressure casting.

[0100] The slurry composition may comprise, based on the total dry weight of the slurry composition: about 70 wt % to about 90 wt %, for example, about 75 wt % to about 85 wt % of a phyllosilicate mineral; about 1 wt % to about 10 wt %, for example, about 2 wt % to about 8 wt % of alumina (e.g., calcined alumina); and about 5 wt % to about 20 wt %, for example, about 10 wt % to about 29 wt % of mullite.

[0101] The density of the slurry composition may be about 1500 g / L to about 3000 g / L, for example about 1800 g / L to about 3000 g / L, or about 2000 g / L to about 3000 g / L, or about 2000 g / L to about 2100 g / L, or about 2500 g / L to about 2700 g / L.

[0102] The thixotropy of the slurry composition (as measured by Gallenkamp universal torsional viscometry, with the first viscosity (i.e., over-swing) measurement taken immediately after stirring and the second viscosity (i.e., over-swing) measurement taken 5 minutes after stirring) can be from about 15°G to about 30°G, for example, from about 15°G to about 27.5°G, or from about 15°G to about 25°G, or from about 15°G to about 22.5°G, or from about 15°G to about 20°G, or from about 15°G to about 17.5°G, or from about 17.5°G to about 30°G, or from about 17.5°G to about 27.5°G. G, or about 17.5°G to about 25°G, or about 17.5°G to about 22.5°G, or about 17.5°G to about 20°G, or about 20°G to about 30°G, or about 20°G to about 27.5°G, or about 20°G to about 25°G, or about 20°G to about 22.5°G, or about 22.5°G to about 30°G, or about 22.5°G to about 27.5°G, or about 22.5°G to about 25°G, or about 25°G to about 30°G, or about 25°G to about 27.5°G, or about 27.5°G to about 30°G.

[0103] The slurry composition may have a water content of about 10 wt % to about 30 wt %, for example, about 10 wt % to about 25 wt %, or about 10 wt % to about 20 wt %, or about 10 wt % to about 15 wt %, or about 15 wt % to about 30 wt %, or about 15 wt % to about 25 wt %, or about 15 wt % to about 20 wt %, or about 20 wt % to about 30 wt %, or about 20 wt % to about 25 wt %, or about 25 wt % to about 30 wt %.

[0104] firing

[0105] The method includes firing a green sagger body (also referred to as a preform) to produce a fired sagger body.

[0106] The green sagger body may be fired in any suitable type of kiln or furnace known in the art.

[0107] The sagger body green body may be fired at a temperature of not less than about 1200° C., not less than about 1300° C., or not less than about 1325° C., or not less than about 1350° C. The sagger body green body may be fired at a temperature of not more than about 1500° C., for example, not more than about 1450° C., or not more than about 1400° C. The sagger body green body may be fired at a temperature of about 1200° C. to about 1500° C., for example, about 1200° C. to about 1400° C., or about 1300° C. to about 1400° C.

[0108] The firing time of the sagger body green body may be not less than about 12 hours, such as not less than about 15 hours, or not less than about 18 hours, or not less than about 21 hours, or not less than about 24 hours, or not less than about 27 hours, or not less than 30 hours.

[0109] Composition of fired sagger body

[0110] It will be appreciated that during the firing process, the slurry composition forming the green sagger body reacts to form a ceramic material, which is then cooled to form the fired sagger body.

[0111] The chemical composition of the fired sagger body can be determined by XRD.

[0112] The sagger may comprise from about 40 wt % to about 60 wt %, e.g., from about 45 wt % to about 60 wt %, or from about 45 wt % to about 55 wt %, or from about 45 wt % to about 52 wt %, or from about 47 wt % to about 52 wt % SiO 2 , based on the total weight of the sagger (i.e., the fired sagger body).

[0113] Based on the total weight of the sagger (i.e., the fired sagger body), the sagger may contain about 10 wt% to about 50 wt%, for example, about 10 wt% to about 45 wt%, or about 20 wt% to about 50 wt%, or about 20 wt% to about 45 wt%, or about 30 wt% to about 50 wt%, or about 30 wt% to about 45 wt%, or about 35 wt% to about 45 wt% Al2O3.

[0114] The sagger (ie the fired sagger body) usually contains SiO2 and Al2O3.

[0115] In addition to SiO2 and Al2O3, the sagger (ie, the fired sagger body) may contain one or more of Fe2O3, TiO2, CaO, MgO, K2O, and Na2O.

[0116] Based on the total weight of the sagger (i.e., the fired sagger body), the sagger may contain no more than about 2.0 wt%, such as no more than about 1.5 wt%, or no more than about 1.0 wt%, or no more than about 0.5 wt% Fe2O3. Based on the total weight of the sagger (i.e., the fired sagger body), the sagger may contain no less than about 0.1 wt% Fe2O3. Based on the total weight of the sagger (i.e., the fired sagger body), the sagger may contain from about 0.1 wt% to about 2.0 wt%, such as from about 0.1 wt% to about 1.5 wt%, or from about 0.1 wt% to about 1.0 wt%, or from about 0.1 wt% to about 0.5 wt% Fe2O3.

[0117] Based on the total weight of the sagger (i.e., the fired sagger body), the sagger may contain no more than about 1.0 wt%, such as no more than about 0.5 wt%, or no more than about 0.1 wt% TiO2. Based on the total weight of the sagger (i.e., the fired sagger body), the sagger may contain no less than about 0.05 wt% TiO2. Based on the total weight of the sagger (i.e., the fired sagger body), the sagger may contain from about 0.05 wt% to about 1.0 wt%, such as from about 0.05 wt% to about 0.5 wt%, or from about 0.05 wt% to about 0.1 wt% TiO2.

[0118] Based on the total weight of the sagger (i.e., the fired sagger body), the sagger may contain no more than about 1.0 wt%, such as no more than about 0.5 wt%, or no more than about 0.1 wt% CaO. Based on the total weight of the sagger (i.e., the fired sagger body), the sagger may contain from about 0.01 wt% to about 1.0 wt%, such as from about 0.01 wt% to about 0.5 wt%, or from about 0.01 wt% to about 0.1 wt%, or from about 0.05 wt% to about 1.0 wt%, or from about 0.05 wt% to about 0.5 wt%, or from about 0.05 wt% to about 0.1 wt% CaO.

[0119] Based on the total weight of the sagger (i.e., the fired sagger body), the sagger may contain not less than about 4 wt%, such as not less than about 5 wt%, or not less than about 6 wt%, or not less than about 7 wt%, or not less than about 8 wt%, or not more than about 9 wt% of MgO. Based on the total weight of the sagger (i.e., the fired sagger body), the sagger may contain not more than about 10 wt%, such as not more than about 9 wt%, or not more than about 8 wt%, or not more than about 7 wt%, or not more than about 6 wt%, or not more than about 5 wt% of MgO. Based on the total weight of the sagger (i.e., the fired sagger body), the sagger may contain from about 4 wt% to about 10 wt%, for example, from about 4 wt% to about 9 wt%, or from about 4 wt% to about 8 wt%, or from about 4 wt% to about 7 wt%, or from about 4 wt% to about 6 wt%, or from about 4 wt% to about 5 wt%, or from about 5 wt% to about 10 wt%, or from about 5 wt% to about 9 wt%, or from about 5 wt% to about 8 wt%, or from about 5 wt% to about 7 wt%, or from about 5 wt% to about 6 wt%, or from about 6 wt% to about 10 wt%, or from about 6 wt% to about 9 wt%, or from about 6 wt% to about 8 wt%, or from about 6 wt% to about 7 wt%, or from about 7 wt% to about 10 wt%, or from about 7 wt% to about 9 wt%, or from about 7 wt% to about 8 wt%, or from about 8 wt% to about 10 wt%, or from about 8 wt% to about 9 wt%, or from about 9 wt% to about 10 wt% MgO.

[0120] Based on the total weight of the sagger (i.e., the fired sagger body), the sagger may contain no more than about 2.0 wt%, such as no more than about 1.5 wt%, or no more than about 1.0 wt%, or no more than about 0.5 wt%, or no more than about 0.1 wt% of KO. Based on the total weight of the sagger (i.e., the fired sagger body), the sagger may contain no less than about 0.01 wt% of KO. Based on the total weight of the sagger (i.e., the fired sagger body), the sagger may contain from about 0.01 wt% to about 2.0 wt%, such as from about 0.01 wt% to about 1.5 wt%, or from about 0.01 wt% to about 1.0 wt%, or from about 0.01 wt% to about 0.5 wt%, or from about 0.01 wt% to about 0.1 wt% of KO.

[0121] Based on the total weight of the sagger (i.e., the fired sagger body), the sagger may contain no more than about 0.5 wt%, such as no more than about 0.1 wt%, or no more than about 0.05 wt% Na2O. Based on the total weight of the sagger (i.e., the fired sagger body), the sagger may contain no less than about 0.01 wt% Na2O. Based on the total weight of the sagger (i.e., the fired sagger body), the sagger may contain from about 0.01 wt% to about 0.5 wt%, such as from about 0.01 wt% to about 0.1 wt%, or from about 0.01 wt% to about 0.05 wt% Na2O.

[0122] The sagger may comprise about 20 wt% to about 55 wt% mullite, about 30 wt% to about 45 wt% cordierite, and about 0 wt% to about 25 wt% spinel, based on the total weight of the sagger (ie, the fired sagger body).

[0123] The sagger may include about 20 wt% to about 55 wt% mullite and about 30 wt% to about 45 wt% cordierite, and no spinel, based on the total weight of the sagger (ie, the fired sagger body).

[0124] The sagger may include about 20 wt% to about 55 wt% mullite, about 30 wt% to about 45 wt% cordierite, and about 0.1 wt% to about 4 wt% spinel, based on the total weight of the sagger (ie, the fired sagger body).

[0125] The sagger (i.e., the fired sagger body) can have a modulus of rupture (MOR) of not less than about 16 MPa, for example, not less than about 18 MPa, or not less than about 20 MPa, or not less than about 21 MPa, or not less than about 22 MPa, or not less than about 23 MPa, or not less than about 24 MPa, or not less than about 25 MPa, or not less than about 26 MPa, or not less than about 27 MPa. The modulus of rupture (MOR) of the sagger (i.e., the fired sagger body) can be from about 16 MPa to about 35 MPa, for example, from about 20 MPa to about 35 MPa, or from about 21 MPa to about 35 MPa, or from about 22 MPa to about 35 MPa, or from about 23 MPa to about 35 MPa, or from about 24 MPa to about 35 MPa, or from about 25 MPa to about 35 MPa. The MOR can be measured by a three-point bending test according to BS EN 993-6 1999 standard. Standard bars with dimensions of 125 x 20 x 20 mm were cut from the fired samples for testing. The measurements were carried out using an MTS QTEST / 10 apparatus.

[0126] The sagger may comprise about 5 wt % to about 30 wt %, eg, about 7 wt % to about 25 wt %, or about 10 wt % to about 20 wt % amorphous phase based on the total weight of the sagger (ie, the fired sagger body).

[0127] Based on the total weight of the sagger (i.e., the fired sagger body), the water absorption of the sagger may be from about 5% to about 20%, or from about 7% to about 20%, or from about 10% to about 20%, or from about 7% to about 16%, or from about 8% to about 15%, or from about 9% to about 11%, or from about 8% to about 10%, or from about 9% to about 10%, or from about 13% to about 16%, or from about 13% to about 15%, or from about 14% to about 15%. The water absorption can be measured according to BS EN 993-1.

[0128] The density of the sagger (i.e. the fired sagger body) can be about 1.6 g / cm 3 to about 3.0g / cm 3 , for example about 1.6 g / cm 3 to about 2.9g / cm 3 About 1.6g / cm 3 to about 2.8g / cm 3 , or about 1.6 g / cm 3 to about 2.7g / cm 3 , or about 1.6 g / cm 3 to about 2.6g / cm 3 , or about 1.6 g / cm 3 to about 2.5g / cm 3 , or about 1.6 g / cm 3 to about 2.4g / cm 3 , or about 1.6 g / cm 3 to about 2.3g / cm 3 , or about 1.6 g / cm 3 to about 2.2g / cm 3 , or about 1.6 g / cm 3 to about 2.1g / cm 3 , or about 1.6 g / cm 3 to about 2.0g / cm 3 , or about 1.7 g / cm 3 to about 3.0g / cm 3 , or about 1.8 g / cm 3 to about 3.0g / cm 3 , or about 1.9 g / cm 3 to about 3.0g / cm 3 , or about 2.0g / cm 3 to about 3.0g / cm 3 , or about 2.1 g / cm 3 to about 3.0g / cm 3 , or about 2.2 g / cm 3 to about 3.0g / cm 3 , or about 2.3g / cm 3 to about 3.0g / cm 3 , or about 2.4g / cm 3 to about 3.0g / cm 3 , or about 2.5g / cm 3 to about 3.0g / cm 3 , or about 1.8 g / cm 3 to about 2.8g / cm 3 , or about 1.8 g / cm 3 to about 2.0g / cm3 , or about 1.9 g / cm 3 to about 2.1g / cm 3 , or about 2.5g / cm 3 to about 2.7g / cm 3 , or about 2.6g / cm 3 to about 2.7g / cm 3 Density can be measured according to BS EN993-1.

[0129] For example, based on the total volume of the sagger (i.e., the fired sagger body), the porosity of the sagger may be from about 16% to about 35%, or from about 20% to about 35%, or from about 20% to about 30%, or from about 22% to about 30%, or from about 23% to about 30%, or from about 24% to about 30%, or from about 24% to about 29%. Porosity can be measured according to BS EN 993-1.

[0130] For example, the thermal expansion coefficient of the sagger (i.e., the fired sagger body) may be about 1.5×10 -6 K -1 to about 8.0×10 -6 K -1 , for example, about 1.5×10 -6 K -1 to about 7.5×10 -6 K -1 , or about 1.5×10 -6 K -1 to about 3.0×10 -6 K -1 , or about 1.5×10 -6 K -1 to about 2.5×10 -6 K -1 , or about 2.0×10 -6 K -1 to about 3.0×10 -6 K -1 , or about 2.0 × 10 -6 K -1 to about 2.5×10 -6 K -1 , or about 5.5×10 -6 K -1 to about 7.0×10 -6 K -1 , or about 6.0×10 -6 K -1 to about 7.5×10 -6 K -1 , or about 6.0×10 -6 K -1 to about 7.0×10 -6 K-1 , or about 6.0×10 -6 K -1 to about 6.5×10 -6 K -1 The coefficient of thermal expansion can be measured according to EN 821-11998 using a Netsch DIL 402PC / 4 dilatometer with a maximum operating temperature of 1600°C.

[0131] It will be understood that the present invention is not limited to the above-described embodiments and that various modifications and improvements may be made without departing from the concepts described herein. Unless mutually exclusive, any feature may be used alone or in combination with any other feature, and the present disclosure extends to and includes all combinations and subcombinations of one or more features described herein.

[0132] Example

[0133] Example 1

[0134] Two ceramic slurries, S1 and S2, were prepared, with compositions shown in Tables 1 and 2, respectively. A third (comparative) ceramic slurry, S3, containing a higher alumina content, was also prepared. These slurries were mixed in a conventional mixer equipped with a shear plunger. The water and deflocculant levels were determined to provide viscosity parameters suitable for casting.

[0135] In the table below,

[0136] Kaolin: kaoPearl CNL 30, available from Imerys

[0137] Clay: RR40, BS5 and Hymod excelsior, available from Imerys

[0138] Talc: Talc 2C, available from Imerys

[0139] Calcined alumina: Alo G4 4G, available from Mal

[0140] Mullite: Virgina Mullte-100, available from Kyanite Mining Corporation

[0141] Fire clay: Molochite-30, available from Imerys

[0142] Spinel: F27-100, available from Motim Fused cast refractories

[0143] Corundum: Korund ESK-A-1, available from Motim

[0144] The gellan gum was Collstab W-60 gellan gum, available from COLLTEC GmbH & Co. Lignin sulfate was Lignobond DD lignin sulfate, available from Borregaard Polycarboxylic acid was DOLAPIX PC 67, available from Zschimmer & Schwarz GmbH & Co.

[0145] Table 1-S1 composition

[0146] Kaolin 21.7 wt% talc 18.5 wt% Calcined alumina 4.6 wt% Silica-alumina fireclay 42.1% by weight Mullite 13.1 wt% total 100% by weight Polycarboxylic acid 0.2 wt% water 19.7 wt%

[0147] Water and polycarboxylic acid were added based on the total weight of dry matter.

[0148] Table 2-S2 composition

[0149] Kaolin 22.5 wt% talc 22.5 wt% Calcined alumina 4.0 wt% Silica-alumina fireclay 38.5 wt% Mullite 12.5 wt% total 100% by weight Polycarboxylic acid 0.1 wt% water 21.0 wt%

[0150] Water and polycarboxylic acid were added based on the total weight of dry matter.

[0151] Table 3-S 比较 Composition

[0152] Kaolin 15.2 wt% clay 3.8 wt% Calcined alumina 14.0 wt% spinel 25.0 wt% corundum 42.0 wt% total 100% by weight Gellan gum 1 0.01 wt% Polycarboxylic acid 0.8 wt% water 14.6 wt%

[0153] Water, gellan gum and polycarboxylic acid were added based on the total weight of dry matter.

[0154] The following properties were measured for each slurry composition: density; deflection angle at 0 and 5 minutes as measured by Gallenkamp Universal Torsional Viscometry; and thixotropy, which is the difference between the deflection angle at 0 and the deflection angle at 5 minutes. The results are shown in Table 4.

[0155] Table 4

[0156]

[0157] Three dry ceramic pressing compositions P1 to P3 were also prepared, and their compositions are shown in Tables 5 to 7, respectively.

[0158] Table 5-P1 composition

[0159]

[0160] Table 6-P2 composition

[0161] clay 21.0 wt% Calcined alumina 13.0 wt% spinel 27.0 wt% corundum 39.0 wt%

[0162] Table 7-P3 composition

[0163] clay 28.0 wt% talc 24.0 wt% Calcined alumina 5.0 wt% Mullite 5.0 wt% Silica-alumina fireclay 38.0 wt% Lignin sulfonate 0.40 wt%

[0164] The following properties were measured for each pressed composition: Water content. Details of the measurement methods are provided elsewhere in this specification. The measurement results are shown in Table 8.

[0165] Table 8

[0166] P1 P2 P3 Water content (%) 4.4 4.5 7.3

[0167] Two saggers were prepared using slurry compositions S1 and S2 by a high-pressure casting process. In each case, high-pressure casting was carried out using a resin mold mounted on a high-pressure casting machine having a movable top, a fixed bottom frame, and two movable side parts. The mold was closed by applying a maximum vertical hydraulic pressure of 240 bar and a maximum horizontal hydraulic pressure of 160 bar. Casting was carried out at a working pressure of 35 bar (3500 kPa). The casting time for each sagger was approximately 3 minutes. After casting, the green body was demoulded and dried at a temperature of 60°C for 24 hours, then fired in a kiln at 1350°C for 24 hours, and then cooled. A comparative sagger with an alumina content of approximately 80% by weight was also prepared under the same conditions.

[0168] The following properties were measured for each fired sagger: modulus of rupture (MOR); water absorption; density; porosity; coefficient of thermal expansion (CTE) as measured by a Netzsch DIL 402CD; and chemical composition. Detailed information on the measurement methods is provided elsewhere in this specification. The results are shown in Table 9.

[0169] Table 9

[0170] slurry S1 S2 <![CDATA[S 比较 ]]> MOR(MPa) 28 19 24 Water absorption (%) 15 16 9 <![CDATA[Density (g / cm 3 )]]> 1.90 1.87 2.66 Porosity (%) 28 29 25 <![CDATA[CTE(×10 -6 K -1 )]]> 3.2 2.6 6.42 <![CDATA[SiO2(%)]]> 50.1 48.3 9.3 <![CDATA[Al2O3(%)]]> 40.3 41.3 82 <![CDATA[Fe2O3(%)]]> 1.0 0.8 0.32 <![CDATA[TiO2(%)]]> 0.3 0.2 0.26 CaO (%) 0.3 0.1 0.1 MgO (%) 8.3 8.3 7.8 <![CDATA[K2O(%)]]> 1.0 0.9 0.11 <![CDATA[Na2O(%)]]> <0.1 <0.1 0.13 other(%) 0.1 0.1 0.01 thickness 11mm 11mm 11mm weight 4.5kg 4.4kg 5.4kg Mullite (weight %) 29 32 16 Cordierite (weight %) 43 51 4.5 Spinel (wt%) 2 0 26 Corundum (weight %) 2.0 0 53 Amorphous phase (wt%) 19 12.5 0

[0171] The comparison sagger has a similar MOR but weighs more than 5 kg and has a density of 2.66 g / cm 3 .

[0172] Two saggers were prepared using slurry compositions S1 and S2 by a low-pressure casting process. In each case, low-pressure casting was carried out using a plaster mold installed in a low-pressure casting machine having a steel frame, a movable top and bottom frame, and a fixed central frame. Vertical movement was mechanical, and horizontal movement was mechanical and pneumatic. In the vertical position, the mold was closed by mechanical locking and additional pneumatic pressure. In the horizontal position, the mold was closed hydraulically. Casting was carried out at a working pressure of 2 bar (200 kPa). The casting time for each sagger was about 20 to 30 minutes. After casting, the green body was demoulded and dried at a temperature of 60°C for 24 hours, then fired in a kiln at 1350°C for 24 hours, and then cooled.

[0173] Under the same conditions, S 比较Slurry Composition A comparative sagger was prepared having an alumina content of about 80 wt%.

[0174] The following properties were measured for each fired sagger: Modulus of rupture (MOR). Details of the measurement methods are provided elsewhere in this specification. The results are shown in Table 10.

[0175] Table 10

[0176] slurry S1 S2 <![CDATA[S 比较 ]]> MOR(MPa) 29 21 24

[0177] Three saggers were produced by a pressing process using pressing compositions P1, P2 and P3.

[0178] After casting, the green body was demoulded and dried at 60°C for 24 hours, then fired in a kiln at 1350°C for 24 hours and then cooled.

[0179] The following properties were measured for each fired sagger: modulus of rupture (MOR); water absorption; density; porosity; coefficient of thermal expansion (CTE); and chemical composition. Detailed information on the measurement methods is provided elsewhere in this specification. The results are shown in Table 11.

[0180] Table 11

[0181] Pressed composition P1 P2 P3 MOR(MPa) 8 8 17 Water absorption (%) 9 10 10 <![CDATA[Density (g / cm 3 )]]> 2.68 2.60 2.06 Porosity (%) 25 26 21 <![CDATA[CTE(×10 -6 K -1 )]]> 6.43 6.18 2.17 <![CDATA[SiO2(%)]]> 9.3 10.3 49.3 <![CDATA[Al2O3(%)]]> 82.0 80.5 39.1 <![CDATA[Fe2O3(%)]]> 0.3 0.3 1.3 <![CDATA[TiO2(%)]]> 0.3 0.3 0.6 CaO (%) 0.1 0.1 0.3 MgO (%) 7.8 8.2 8.2 <![CDATA[K2O(%)]]> 0.1 0.1 1.0 <![CDATA[Na2O(%)]]> 0.1 0.1 <0.1 other(%) <0.1 <0.1 0.1 thickness 13mm 13mm 13mm weight 6.1kg 6.0kg 6.5kg

[0182] Example 2:

[0183] The same ceramic slurry compositions S1 and S2 as well as comparative ceramic slurry compositions were prepared as described in Example 1.

[0184] These slurry compositions were used to prepare saggers by a high pressure casting process as described in Example 1. The difference in Example 2 was that the saggers prepared had a thickness of 9 mm.

[0185] The following properties were measured for each fired sagger: modulus of rupture (MOR); water absorption; density; porosity; coefficient of thermal expansion (CTE) as measured by a Netzsch DIL 402CD; and chemical composition. Detailed information on the measurement methods is provided elsewhere in this specification. The results are shown in Table 12.

[0186] Table 12

[0187] slurry S1 S2 <![CDATA[S 比较 ]]> MOR(MPa) 27.9 20.9 25.1 Water absorption (%) 14.4 15.8 10.1 <![CDATA[Density (g / cm 3 )]]> 1.92 1.87 2.6 Porosity (%) 27.7 29.6 26.2 <![CDATA[CTE(×10 -6 K -1 )]]> 3.25 2.61 6.71 thickness 9 mm 9mm 9mm weight 3.5kg 3.5kg 4.6kg

[0188] Using the same slurry compositions S1, S2 and S 比较 The sagger was produced by the low pressure casting process described in Example 1. The difference in Example 2 was that the sagger was produced with a thickness of 9 mm.

[0189] The modulus of rupture (MOR) was measured for each fired sagger. Details of the measurement method are provided in other parts of this specification. The results are shown in Table 13.

[0190] Table 13

[0191] slurry S1 S2 <![CDATA[S 比较 ]]> MOR(MPa) 24 18 29 thickness 9mm 9mm 9mm

Claims

1. A sagger having a body comprising a bottom plate and one or more side walls, wherein: The bottom plate and the one or more side walls have a thickness of no greater than about 13 mm, for example no greater than about 10 mm; and the sagger comprises no more than about 50 wt% Al2O3, preferably no more than about 45 wt% Al2O3, based on the total weight of the sagger; and: The density of the sagger is about 1.6 g / cm 3 to about 3.0g / cm 3 , for example about 1.6 g / cm 3 to about 2.3g / cm 3 and / or The thermal expansion coefficient of the sagger is about 1.5×10 -6 K -1 to about 5.0×10 -6 K -1 , for example, about 2.0×10 -6 K -1 to about 4.0×10 -6 K -1 and / or The sagger has a modulus of rupture of not less than about 15 MPa, such as not less than about 20 MPa, or not less than about 23 MPa, as measured in a three-point bend test according to BS EN 993-6 1999; and / or The ratio of the modulus of rupture to the thickness of the sagger is not less than about 1.5 MPa / mm, such as not less than about 2.0 MPa / mm, and preferably 1.5 MPa / mm to 4.0 MPa / mm.

2. The sagger according to claim 1, wherein The sagger comprises about 20 wt% to about 55 wt% mullite, about 30 wt% to about 45 wt% cordierite, and about 0 wt% to 25 wt% spinel, preferably about 0 wt% to about 5 wt% spinel, based on the total weight of the sagger.

3. The sagger according to claim 2 or 3, wherein: The sagger comprises from about 5 wt% to about 30 wt% of an amorphous phase, based on the total weight of the sagger.

4. A sagger according to any preceding claim, wherein: The water absorption of the sagger is about 5% to about 20%, such as about 8% to about 16%, based on the total weight of the sagger; and / or The sagger comprises: about 40 wt % to about 60 wt % of SiO 2 based on the total weight of the sagger; and about 30 wt % to about 50 wt % of Al 2 O 3 based on the total weight of the sagger, Optionally, the sagger comprises: no more than about 2.0 wt %, for example, about 0.1 wt % to about 2.0 wt %, of Fe2O3, based on the total weight of the sagger; no more than about 1.0 wt %, for example, about 0.05 wt % to about 1.0 wt % of TiO2, based on the total weight of the sagger; no more than about 1.0 wt %, for example, about 0.01 wt % to about 1.0 wt % of CaO, based on the total weight of the sagger; about 4 wt % to about 10 wt % of MgO, based on the total weight of the sagger; no more than about 2.0 wt %, for example, about 0.01 wt % to about 2.0 wt % of K2O, based on the total weight of the sagger; and / or no more than about 0.5 wt %, for example, about 0.01 wt % to about 0.5 wt % of Na2O, based on the total weight of the sagger.

5. The sagger according to any one of the preceding claims, wherein the sagger is used to hold powders during calcination, for example, wherein the sagger is used to hold battery electrode material powders, such as battery cathode material powders, for example, wherein the sagger is used to hold one or more oxides, hydroxides, carbonates, sulfates and / or phosphates of lithium, titanium, vanadium, chromium, manganese, iron, cobalt, tungsten and / or nickel.

6. A method for manufacturing a sagger for a kiln according to any one of claims 1 to 5, the method comprising: pressure-casting the slurry composition in a mold cavity at a pressure of about 200 kPa to about 4000 kPa to form a sagger body green body; Taking out the sagger body green body from the mold cavity; and The sagger body green body is fired to produce a fired sagger body.

7. The method according to claim 6, wherein: The pressure casting is low-pressure casting or high-pressure casting, preferably high-pressure casting.

8. The method according to claim 6 or 7, wherein: During pressure casting of the slurry composition within the mold cavity, filtrate is removed from the mold cavity via an outlet configured to prevent the passage of solid components of the slurry composition.

9. The method according to any one of claims 6 to 8, wherein The slurry composition comprises one or more phyllosilicate minerals and water; The one or more phyllosilicate minerals include: kaolin; calcined kaolin; montmorillonite; illite; clay; calcined clay; talc; vermiculite; palygorskite; sepiolite; and / or any combination thereof; Wherein, the slurry composition comprises: alumina, such as calcined alumina; corundum; magnesium carbonate, such as magnesite; mullite; kyanite; spinel; and / or any combination thereof; preferably, the slurry composition comprises kaolin, calcined kaolin, talc, calcined alumina, corundum, mullite and / or calcined clay, and / or any combination thereof.

10. The method according to claim 9, wherein the slurry composition comprises: About 70% to about 90% by weight, for example, about 75% to about 85% by weight, of phyllosilicate minerals; about 1% to about 10% by weight, for example, about 2% to about 8% by weight, of alumina (e.g., calcined alumina); and about 5% to about 20% by weight, for example, about 10% to about 29% by weight, of mullite.

11. The method according to any one of claims 6 to 10, wherein The sagger body green body is fired at a temperature of about 1300°C to about 1450°C.

12. A sagger obtainable by the method according to any one of claims 6 to 11.

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