WO1990015661A1 - Membrane ceramique poreuse et procede - Google Patents

Membrane ceramique poreuse et procede Download PDF

Info

Publication number
WO1990015661A1
WO1990015661A1 PCT/GB1990/000945 GB9000945W WO9015661A1 WO 1990015661 A1 WO1990015661 A1 WO 1990015661A1 GB 9000945 W GB9000945 W GB 9000945W WO 9015661 A1 WO9015661 A1 WO 9015661A1
Authority
WO
WIPO (PCT)
Prior art keywords
dispersion
membrane
particles
layer
ceramic
Prior art date
Application number
PCT/GB1990/000945
Other languages
English (en)
Inventor
Rowena Roshanthi Landham
Original Assignee
Alcan International Limited
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Alcan International Limited filed Critical Alcan International Limited
Publication of WO1990015661A1 publication Critical patent/WO1990015661A1/fr

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/626—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B
    • C04B35/63—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B using additives specially adapted for forming the products, e.g.. binder binders
    • C04B35/632—Organic additives
    • C04B35/634—Polymers
    • C04B35/63404—Polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • C04B35/63416—Polyvinylalcohols [PVA]; Polyvinylacetates
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D67/00—Processes specially adapted for manufacturing semi-permeable membranes for separation processes or apparatus
    • B01D67/0039—Inorganic membrane manufacture
    • B01D67/0046—Inorganic membrane manufacture by slurry techniques, e.g. die or slip-casting
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
    • B01D69/12—Composite membranes; Ultra-thin membranes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
    • B01D71/02—Inorganic material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J35/00—Catalysts, in general, characterised by their form or physical properties
    • B01J35/50—Catalysts, in general, characterised by their form or physical properties characterised by their shape or configuration
    • B01J35/58—Fabrics or filaments
    • B01J35/59—Membranes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B18/00—Layered products essentially comprising ceramics, e.g. refractory products
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
    • C04B35/48—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on zirconium or hafnium oxides, zirconates, zircon or hafnates
    • C04B35/486—Fine ceramics
    • C04B35/488—Composites
    • C04B35/4885—Composites with aluminium oxide
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/626—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B
    • C04B35/63—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B using additives specially adapted for forming the products, e.g.. binder binders
    • C04B35/632—Organic additives
    • C04B35/634—Polymers
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/626—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B
    • C04B35/63—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B using additives specially adapted for forming the products, e.g.. binder binders
    • C04B35/632—Organic additives
    • C04B35/634—Polymers
    • C04B35/63404—Polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • C04B35/6342—Polyvinylacetals, e.g. polyvinylbutyral [PVB]
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/626—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B
    • C04B35/63—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B using additives specially adapted for forming the products, e.g.. binder binders
    • C04B35/632—Organic additives
    • C04B35/634—Polymers
    • C04B35/63404—Polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • C04B35/63424—Polyacrylates; Polymethacrylates
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/626—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B
    • C04B35/63—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B using additives specially adapted for forming the products, e.g.. binder binders
    • C04B35/632—Organic additives
    • C04B35/634—Polymers
    • C04B35/63404—Polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • C04B35/63444—Nitrogen-containing polymers, e.g. polyacrylamides, polyacrylonitriles, polyvinylpyrrolidone [PVP], polyethylenimine [PEI]
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/626—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B
    • C04B35/63—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B using additives specially adapted for forming the products, e.g.. binder binders
    • C04B35/632—Organic additives
    • C04B35/636—Polysaccharides or derivatives thereof
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/626—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B
    • C04B35/63—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B using additives specially adapted for forming the products, e.g.. binder binders
    • C04B35/632—Organic additives
    • C04B35/636—Polysaccharides or derivatives thereof
    • C04B35/6365—Cellulose or derivatives thereof
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B38/00—Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2323/00—Details relating to membrane preparation
    • B01D2323/12—Specific ratios of components used
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
    • C04B2111/00474—Uses not provided for elsewhere in C04B2111/00
    • C04B2111/00793—Uses not provided for elsewhere in C04B2111/00 as filters or diaphragms
    • C04B2111/00801—Membranes; Diaphragms
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2237/00—Aspects relating to ceramic laminates or to joining of ceramic articles with other articles by heating
    • C04B2237/02—Aspects relating to interlayers, e.g. used to join ceramic articles with other articles by heating
    • C04B2237/12—Metallic interlayers
    • C04B2237/126—Metallic interlayers wherein the active component for bonding is not the largest fraction of the interlayer
    • C04B2237/127—The active component for bonding being a refractory metal
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2237/00—Aspects relating to ceramic laminates or to joining of ceramic articles with other articles by heating
    • C04B2237/30—Composition of layers of ceramic laminates or of ceramic or metallic articles to be joined by heating, e.g. Si substrates
    • C04B2237/32—Ceramic
    • C04B2237/34—Oxidic
    • C04B2237/343—Alumina or aluminates

Definitions

  • This invention relates to porous ceramic membranes and methods of making them.
  • Such membranes are increasingly being used as filters, as catalyst supports and in diagnostic applications, for they have
  • the membranes are all characterised by having a particularly uniform pore size and narrow pore size distribution.
  • the membranes are all characterised by having a particularly uniform pore size and narrow pore size distribution.
  • ⁇ J5 membrane is a composite membrane.
  • Composite ceramic membranes comprising a layer of partly sintered ceramic particles and an overlying film of partly sintered ceramic particles, are well known, and are described for example in EPA 0 242208 (Alcan International), GB 1605275 (CEA), US 4738874 (CEA), and Canadian 1196873 (Geceral).
  • the overlying film is arranged to have narrower pores than the support layer. It is possible to make the overlying film very thin, with the result that the 5 composite membrane combines good selectivity on the basis of particle size with high flux.
  • a dispersion of ceramic particles is applied to form a thin film on a pre-formed porous support layer.
  • US Patent 4652441 describes a technique of slurrying ceramic particle agglomerates with binder and volatile solvent to form a slip, and tape-casting the slip on a smooth substrate at room temperature.
  • a plurality of slip layers of the same composition and particle size may be cast to provide a laminated porous tape with enhanced strength.
  • Each of GB 1605248 and FR 2587026 and DE 3149796 describes the preparation of a porous body by heating a mass of refractory particulate material to 5 partly sinter the particles, in which the refractory material is a mixture of particles of different sizes.
  • this invention provides a free-standing ceramic membrane having pores of substantially uniform size, formed by partly sintering Q a cast layer of ceramic particles consisting of 60 - 99% by weight of relatively larger particles and correspondingly from 40 - 1.0% of relatively smaller particles having an average diameter of from 4 n up to 10% of the average diameter of the larger particles.
  • the membrane may be made by providing a dispersion of ceramic particles in a solution of a polymeric binder in a volatile organic solvent, casting the dispersion to form a layer on a flat impervious surface, removing volatile solvent and heating the layer to partly sinter Q the particles.
  • this invention provides a composite porous ceramic membrane comprising a support layer which is a free-standing ceramic membrane as described, and an overlying film of partly sintered ceramic particles.
  • These composite membranes may be made by various methods:- i)
  • the first method involves the use of a first dispersion of ceramic particles in a solution of a first polymeric binder in a volatile solvent, and of a second dispersion of ceramic particles in a volatile liquid which is a non-solvent for the first polymeric binder.
  • the first dispersion is formed into a layer, preferably by tape-casting on a flat surface.
  • the second dispersion is formed into a film of desired thickness overlying the layer.
  • the composite After removal of volatile materials, the composite is heated to partly sinter the ceramic particles and form the desired porous membrane. Formulation of the first and second dispersions need to be performed in conjunction with one another.
  • the granulometry of the first dispersion is preferably as described above.
  • the second method involves providing a first dispersion of ceramic particles in a solution of a polymeric binder in a volatile solvent, and a second dispersion of ceramic particles in a volatile liquid which is a solvent for the polymeric binder, casting the first dispersion to form a layer, casting the second dispersion to form a film overlying the layer, removing the volatile solvent and heating to partly sinter the ceramic particles and form the desired porous membrane.
  • This method has the advantage over i) that selection of volatile liquids is not so critical. Provided that the overlying film is dried quickly, dissolution or disintegration of the support layer can be avoided. This may be achieved by casting the overlying film at high speed and at low film thickness.
  • the granulometry of the first dispersion is preferably as described above.
  • the third method involves providing a first dispersion of ceramic particles in a solution of a polymeric binder in a volatile solvent, providing a second dispersion of ceramic particles in a solution of a polymeric binder in a volatile solvent, casting the first dispersion to form a layer, separately casting the second dispersion to form a film, placing the film on the layer, and heating the layer and the overlying film to partly sinter the ceramic particles and form the desired composite porous membrane.
  • the granulometry of the first dispersion is preferably as described above.
  • the preferably tape- cast layer and overlying films are laminated under pressure and mild heat (to soften the binder) to produce a flexible laminate which is cut or punched to size prior to sintering.
  • This method has the advantages over i) and ii) that there are fewer limitations on the two formulations and on the casting conditions. It is possible to select a support layer and an overlying film to produce a range of pore sizes and chemistries.
  • the ceramic particles in the first dispersion comprise 60 to 99%, preferably 80 to 95% by weight of relatively larger particles and correspondingly from 40 to 1.0%, preferably 20 to 5%, of relatively smaller particles.
  • the larger particles may have an average size in the range 0.5 to 60 microns, particularly 1 to 20 microns, chosen to generate films with pores of desired size.
  • the smaller particles may have an average size in the range 4 nm up to 2 micron, but not more than 0.1 times the average size of the larger particles.
  • the smaller particles act as a sintering aid, permitting the layer to be sintered at lower temperatures than would otherwise be possible. It is generally preferable that the relatively larger particles be of substantially uniform size, but the same is not true of the relatively smaller particles. The proportion of smaller particles should not be so great as to substantially block the pores between the larger particles.
  • the smaller particles improve adhesion between the support and the overlying films. They also help to ensure that the composite membrane can be sintered in a single heating operation. If the smaller particles are absent, then the temperatures required to sinter the support layer and the overlying films may be so different that production of a porous composite membrane in a single heating step is impossible.
  • other kinds of sintering aids may be provided in the support layer, in an amount to approximate the sintering temperature of that layer to that of the overlying film.
  • a glassy material may be included in the first dispersion.
  • the first dispersion may comprise a proportion of particles that soften at a relatively lower temperature than the remainder.
  • a proportion of silica particles may be included in a dispersion of zirconia and/or alumina particles. In this case, the relative sizes of the low-temperature-softening particles and of the remaining particles is not critical .
  • the ceramic particles may be for example oxides, nitrides, borides or carbides, for example titania, alumina, ceria, zirconia, lead zirconate titanate (PZT), silica, mullite, refractory metal oxides generally, and mixtures thereof.
  • the ceramic particles are preferably of a refractory metal oxide.
  • alumina it may be useful to add a minor proportion of zirconia to increase the mechanical properties of the fired membrane.
  • a preferred feature of the invention is that, when the ceramic particles are of zirconia, particles of alumina are also present in a minor proportion sufficient to increase the strength of the fired membrane.
  • the binder is a polymeric material with a molecular weight high enough to provide strength and toughness to the green tape.
  • the binder preferably has a glass transition temperature below ambient, in order that the green tape may be sufficiently flexible to be bent or punched at ambient temperature.
  • a plasticizer may be added to the tape casting formulation to improve flexibility.
  • the binder should preferably be compatible with any dispersant used in the formulation, in order to avoid any possibility of phase separation. The binder should burn out cleanly during firing.
  • Suitable polymeric binders include polyvinylbutyral , polyvinylalcohol , polyvinylpyrol lidone, polyacrylates and poylmeth- acrylates including the methyl and higher esters, and cellulose and starch derivatives.
  • the binder is dissolved in a volatile solvent, which should preferably be inexpensive, non- toxic under the conditions of use, and have a vapour pressure sufficiently high that it is removed during drying without boiling.
  • Suitable solvents are organic solvents such as trichloroethylene or methylethyl- ketone or a mixture of one of them with ethanol.
  • the formulation may contain a dispersant to aid dispersion of the ceramic particles.
  • Useful dispersants include fish oil (predominantly derivatives of glyceryl trioleate) and corn oil.
  • a preferred solvent is methylethylketone plus ethanol.
  • a preferred solvent is trichloroethylene plus ethanol.
  • the porosity of the support layer, and if desired also of the overlying film, can be greatly increased by creating many isolated cavities within the membrane which are larger than the average pore size but not big enough to penetrate through to both surfaces of the membrane.
  • Such cavities can be provided by incorporating in the formulation a pyrolysable particulate material which is coarser than the ceramic. These particles burn out during firing leaving cavities.
  • a suitable pyrolysable material is carbon. Hollow carbon spheres are especially suitable because they burn out without disrupting the surrounding ceramic particles. Hollow spheres 21 microns in diameter and with a wall thickness of 1.5 microns have been found to work well. The quantity of pyrolysable material that can be added is limited by the effect of the cavities on strength and the need to avoid creating so many cavities that they join up and penetrate through the thickness of the membrane.
  • the solvent concentration is preferably the minimum, or just slightly more than the minimum, required to make the viscosity suitable for casting.
  • the binder concentration is sufficient to provide a green tape or membrane of adequate strength.
  • An upper limit on binder concentration is set by the need to avoid "mud cracking" of the membrane during firing. Within these limits, it is surprisingly found that an increase in binder concentration tends to lead to an increase in the overall porosity (though not to any significant extent the pore size) of the membrane after firing. It is therefore generally preferred to use a rather high binder concentration.
  • the formulation is cast in a uniform layer, thick enough to provide the desired strength both before and after firing, but thin enough to retain an adequate flux. Layers will typically be 0.01 to 2.0 mm thick after firing. Preferably casting is effected by the. use of a doctor blade onto a flat impermeable substrate s-uch as glass.
  • the formulation comprised a sintering aid as described above, and the cast layer is heated to remove volatile solvent and organic material and partly sinter the ceramic particles together, there results a ceramic membrane having good strength and freedom from warping.
  • These membranes also have pores of substantially uniform pore size. For example, at least 75% of the pores are generally within 25% greater or less than the mean pore size. In preferred embodiments, at least 90% of the pores have a size within 10% of the mean.
  • the cast layer may be used as the support layer of a composite membrane.
  • Method i) above is the preferred method of making such a composite membrane.
  • the second dispersion comprises ceramic particles in a volatile liquid which preferably also contains a polymeric binder.
  • the ceramic particles may be chemically the same as or different from those in the first dispersion.
  • the average size of particles in the second dispersion is generally chosen to be smaller than that of particles in the first dispersion, so that the overlying film has a smaller average pore size.
  • pore size after sintering is related to original particle size. Large particles, above about 1 micron in diameter result in a pore size of approximately 10% of the particle diameter. Sub-micron particles may tend to give a pore size which is about 50% of the particle diameter.
  • the ceramic particles in the second dispersion preferably have an average particle size of from 0.1 to 50 microns.
  • the volatile liquid may conveniently be water.
  • a water-soluble polymeric binder is preferably present, as this is found to reduce the tendency to cracking as the film is dried on the support layer.
  • Suitable binders include cellulosic and vinyl derivatives and starches, methyl cellulose derivatives being particularly suitable.
  • the formulation of the second dispersion needs to match that of the first dispersion, in particular so that:- a) Complete wetting of the layer occurs on application. This may be achieved by the use of a viscous second dispersion with a high content of ceramic particles. Viscosity also depends on other factors including particle size and agglomeration and organic binder content. b) No delamination of the film occurs on drying.
  • the second dispersion is cast, preferably by tape-casting using a doctor blade as before, on to the support layer.
  • This support layer has preferably been dried before receiving the second dispersion, although this is not absolutely necessary particularly where some intermingling of the two is acceptable.
  • the volatile liquid of the second dispersion is a non- solvent for the polymeric binder of the first layer, and as a result there is no significant migration of the first polymeric binder from the layer into the film. Because the support layer is flat and non- porous, it is easy to cast the second dispersion as a smooth coating of uniform thickness on it, without any interpenetration of the two.
  • the film needs to be continuous, i.e. a complete skin, but thin enough to provide an adequate flux.
  • Casting by doctor blade can be used to form a flexible uniform tape of substantial area. Using another doctor blade, it is easy to cast the second dispersion over the entire surface of the first one.
  • the resulting simple or composite membrane is then dried until it becomes self-supporting and removed from its support.
  • the green membrane is flexible and can be formed into spirals, tubes or corrugated membranes, which is useful for increasing the specific surface area of a filter. Surprisingly, the membrane in the green state can be embossed and retain its embossed pattern after firing. It is possible to emboss channels for liquid flow in filters or diagnostic devices.
  • the green membrane is then heated to a temperature in the range 600 to 1600°C sufficient to burn off organic material and partly sinter the ceramic particles together.
  • a stack of pieces of the composite membrane may be subjected to pressure to reduce buckling. It is an advantage of the invention that both layer and film are fired at the same time, so that only a single heating step is required.
  • the pore size is determined essentially by the size of the particles used to form the overlying fi lm.
  • the porosity is determined by several factors, including ceramic particle size of support layer and film; thickness of support layer and film; the amount of binder used in formulating the support layer and overlying film; and the possible presence of pyrolysable particles, e.g. hollow carbon spheres, in the formulation for the support layer.
  • 150g of alumina (1.5 ⁇ m particle size) and 12.2g zirconia (24 ⁇ 8 crystallite size) were slurried in a liquid system composed of 82g trichloroethylene, 33g ethanol, 4.2g corn oil, 12g polyvinyl butyral and 16g polyethyleneglycol .
  • the ball milled slurry was tape cast on a glass substrate into a film of width 173mm, which was dried to yield a flexible tape of thickness 0.17mm.
  • Discs of diameter 26.5mm were cut from the tape and partially sintered at 1475°C for 1 hour, to produce a 25mm diameter ceramic membrane with a porosity of 53% and an average pore size of 0.48 ⁇ m.
  • the pore size distribution of the membrane was surprisingly sharp with >80% of the pores within _+10% of the average diameter.
  • an aqueous suspension of 0.5 ⁇ m polystyrene beads was filtered through the membrane it retained 100% of the beads.
  • the permeability of the membrane to pure water was 19 ml/minute/cm at 70 kPa.
  • the chemical resistance of the membrane was excellent. No weight loss was 5 experienced when the porous ceramic discs were immersed in pH 1 (buffer HC1) and pH 10 (alkaline phosphatase) solution for 100 hours at 20°C.
  • EXAMPLE 2 o Fabrication of a double layer membrane by tape casting 70g of coarse zirconia (14 ⁇ m particle size), and 7g of fine zirconia (240A 0 crystallite size), 3.5g yttria and 9g (1.5 ⁇ m particle size) alumina were slurried in a liquid system composed of 2.5g Menhaden 5 fish oil, 22g methyl ethyl ketone, 13g ethanol, 7g polyvinylbutyral and 9g poly-ethyleneglycol . The slurry was tape cast on a glass substrate into a film of width 173 mm, which was dried in air to yield a flexible tape of thickness 0.31 mm.
  • a second slurry 0 composed of 25g of zirconia (2.5 ⁇ m particle size) and 1.25g yttria was dispersed in a solution of 3.5g methocel polymer in 100 ml water, and then cast as a thin layer on top of the first tape and allowed to dry at RT.
  • the double layer green tape was punched into 5 discs of diameter 27 mm and partially sintered at
  • EXAMPLE 3 a) 70 g of zirconia with an average particle size of 1 ⁇ m, 14 g of zirconia with a crystallite size of 240 Angstroms and 3.5 g yttria were slurried in a liquid system composed of 23 g methylethylketone, 11 g ethanol, 4 g fish oil, 5 g polyvinylbutyral and 3 g polyethlyeneglycol . The slurry was cast into a tape, cut into discs and fired at 1500°C for 1 hour. The partially sintered ceramic had poor mechanical strength and could not be used as a membrane filter in a stirred cell.
  • Average pore size was 0.48 ⁇ m
  • the resulting membrane had an average flow 2 rate of 3.5ml/min/cm at 70 kPa on a membrane 320 ⁇ m thick. Examination of the membrane in the SEM revealed the presence of large discrete spherical voids within the membrane, which contributed to an increased porosity without increasing the effective pore size of the filter.
  • 140 g of coarse unstabilised zirconia (14 ⁇ m particle size), 4 g of fine stabilised zirconia (240 8 crystallite size), 7 g yttria (sub micron particle size) and 15 g alumina (1.5 ⁇ m particle size) were slurried in a liquid system composed of 0.5 g Mazola (Trade Mark) corn oil, 40 g trichloroethylene and 16g anhydrous ethanol. The slurry was ball milled for 3 hours. 8 g polyvinylbutyral and 9 g polyethyleneglycol were added to this slurry which was then ball milled for a further 18 hours.
  • Mazola Trade Mark
  • the resultant slurry was tape cast on to a clean glass substrate into a film of width 173 mm which was dried in air to yield a flexible tape.
  • a doctor blade height of 850 ⁇ m resulted in a green tape that was 350 ⁇ m thick.
  • aqueous slurry composed of 35 g of 5 zirconia (2.5 ⁇ m particle size) and 2.1 g yttria dispersed in a solution of 0.1 g of Darvan C surfactant (an ammonium salt of a polyelectrolyte from R. T. Vanderbilt Co. , CT, USA) in 25 ml of water, was ball milled for 17 hours. 80 ml of a 5% solution of 0 Methocel polymer (Dow Chemicals) was then added and the resultant slurry ball milled again for a further 1 hour. This slurry was then cast as a thin layer on top of the support tape and allowed to dry at room temperature.
  • Darvan C surfactant an ammonium salt of a polyelectrolyte from R. T. Vanderbilt Co. , CT, USA
  • a blade height of 425 ⁇ m (of which a 5 height of 350 ⁇ m is to allow for the thickness of the base layer) resulted in a top coat that was about 75 ⁇ m thick.
  • the double layer green tape was punched into discs of diameter 26 mm and partially sintered at 1475°C to produce a porous composite membrane which was o 400 ⁇ m thick and 25 mm in diameter.
  • the pore diameters of the support and top coat were 3.6 ⁇ m and 0.40 ⁇ m respectively.
  • the permeability of the composite p membrane to pure water was 30 ml/min/cm at 70 kPa. The membrane gave a 100% retention of 0.45 ⁇ m 5 polystryrene beads when an aqueous suspension of beads were filtered through the membrane.
  • the second tape was prepared by casting a slurry composed of 70 g zirconia (2.4 ⁇ m particle size), 7 g fine zirconia (240 ft crystallite size), 3.5 g yttria (submicron particle size) and 9 g alumina (1.5 ⁇ m particle size) in 28 g methylethylketone, 17 g ethanol, 6 g Menhaden fish oil, 9 g polyvinylbutyral and 13 g polyethyleneglycol .
  • the ball milled slurry was cast using a blade height of 50 ⁇ m, dried in air and then stripped from the glass substrate.
  • the tape was then placed on top of the support tape and pressed together at a pressure of 5 bar for a period of 2 minutes between heated metal plates maintained at 80°C.
  • the laminated tape was then punched and fired to produce a composite porous ceramic membrane.
  • the support layer was 180 ⁇ m thick and had an average pore size of 3.5 ⁇ m whilst the separation layer was 10 ⁇ m thick and had an average pore size of 0.40 ⁇ m.
  • the pore size distribution of the separation layer was narrow with 85% of the pores within +25% of the average diameter.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Inorganic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Structural Engineering (AREA)
  • Composite Materials (AREA)
  • Separation Using Semi-Permeable Membranes (AREA)

Abstract

On peut former une membrane céramique libre comportant des pores de taille sensiblement uniforme, par frittage partiel d'une couche coulée de particules céramiques comprenant plus de 60 % de grosses particules et jusqu'à 40 % de petites particules à titre d'auxiliaire de frittage. Une membrane composite comprend à titre de couche de support ladite membrane céramique libre, ainsi qu'un film de couverture de particules céramiques partiellement frittées. On peut former à la fois la couche de support et les films de couverture par coulage en bandes de dispersions des particules en solutions de liant polymère, de préférence dans des liquides volatils différents.
PCT/GB1990/000945 1989-06-19 1990-06-19 Membrane ceramique poreuse et procede WO1990015661A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB898914023A GB8914023D0 (en) 1989-06-19 1989-06-19 Porous ceramic membrane method
GB8914023.0 1989-06-19

Publications (1)

Publication Number Publication Date
WO1990015661A1 true WO1990015661A1 (fr) 1990-12-27

Family

ID=10658665

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB1990/000945 WO1990015661A1 (fr) 1989-06-19 1990-06-19 Membrane ceramique poreuse et procede

Country Status (3)

Country Link
AU (1) AU5828490A (fr)
GB (1) GB8914023D0 (fr)
WO (1) WO1990015661A1 (fr)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19857591A1 (de) * 1998-12-14 2000-06-15 Fraunhofer Ges Forschung Keramische Mehrschichtenfilter und Verfahren zu deren Herstellung
EP1063005A2 (fr) * 1999-06-22 2000-12-27 Sterilox Medical (Europe) Limited Membrane céramique
FR2805807A1 (fr) * 2000-03-02 2001-09-07 Murata Manufacturing Co Composition en film epais isolante et dispositif electronique en ceramique et appareil electronique l'utilisant
US6551369B1 (en) 1998-12-14 2003-04-22 Fraunhofer-Gesellschaft Zur Forderung Der Angewandten Forschung E.V. Ceramic flat membrane and method for producing the same
WO2004071630A1 (fr) * 2003-02-13 2004-08-26 Itn Nanovation Gmbh Couche inorganique
WO2008043781A1 (fr) 2006-10-10 2008-04-17 Robert Bosch Gmbh ProcÉdÉ de fabrication d'au moins une couche poreuse
WO2010148051A3 (fr) * 2009-06-18 2011-04-21 Entegris, Inc. Matériau poreux fritté comprenant des particules ayant différentes granulométries moyennes
DE102010035637A1 (de) * 2010-08-27 2012-03-01 Fachhochschule Koblenz Keramischer Filter sowie Verfahren zur Erstellung eines keramischen Filters
EP3372327A1 (fr) * 2017-03-06 2018-09-12 Seiko Epson Corporation Pâte et procédé de fabrication d'un article moulé en trois dimensions
CN110330358A (zh) * 2019-07-04 2019-10-15 南充三环电子有限公司 一种多孔氧化铝陶瓷板及其制备方法
CN114247304A (zh) * 2020-09-25 2022-03-29 三达膜科技（厦门）有限公司 一种内部多通道圆盘式陶瓷膜的制备方法

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2502508A1 (fr) * 1981-03-30 1982-10-01 Geceral Grpt Etu Ceramiques Al Structure de filtration, procede de realisation de telles structures et dispositif d'ultrafiltration en comportant
DE3149796A1 (de) * 1981-12-16 1983-06-23 Elektroschmelzwerk Kempten GmbH, 8000 München Verfahren zur herstellung von poroesen formkoerpern aus polykristallinem borcarbid mit eigenbindung durch drucklose sinterung
GB1605248A (en) * 1943-12-10 1986-03-05 Mond Nickel Co Ltd Production of articles from powdered metals
FR2587026A1 (fr) * 1985-09-09 1987-03-13 Centre Nat Rech Scient Utilisation de poudres frittables de granulometrie particuliere dans la realisation d'elements de filtration en ceramique poreuse, et ceramiques ainsi obtenues

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1605248A (en) * 1943-12-10 1986-03-05 Mond Nickel Co Ltd Production of articles from powdered metals
FR2502508A1 (fr) * 1981-03-30 1982-10-01 Geceral Grpt Etu Ceramiques Al Structure de filtration, procede de realisation de telles structures et dispositif d'ultrafiltration en comportant
DE3149796A1 (de) * 1981-12-16 1983-06-23 Elektroschmelzwerk Kempten GmbH, 8000 München Verfahren zur herstellung von poroesen formkoerpern aus polykristallinem borcarbid mit eigenbindung durch drucklose sinterung
FR2587026A1 (fr) * 1985-09-09 1987-03-13 Centre Nat Rech Scient Utilisation de poudres frittables de granulometrie particuliere dans la realisation d'elements de filtration en ceramique poreuse, et ceramiques ainsi obtenues

Cited By (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19857591A1 (de) * 1998-12-14 2000-06-15 Fraunhofer Ges Forschung Keramische Mehrschichtenfilter und Verfahren zu deren Herstellung
US6978901B1 (en) 1998-12-14 2005-12-27 Fraunhofer-Gesellschaft Zur Forderung Der Angewandten Forschung E.V. Ceramic multilayer filters and method for producing the same
DE19857591B4 (de) * 1998-12-14 2005-04-07 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Keramische Mehrschichtenfilter und Verfahren zu deren Herstellung
US6551369B1 (en) 1998-12-14 2003-04-22 Fraunhofer-Gesellschaft Zur Forderung Der Angewandten Forschung E.V. Ceramic flat membrane and method for producing the same
GB2354478B (en) * 1999-06-22 2003-01-15 Sterilox Medical Ceramic membrane
US6528214B1 (en) 1999-06-22 2003-03-04 Sterilox Medical (Europe) Limited Ceramic membrane
EP1063005A3 (fr) * 1999-06-22 2001-07-18 Sterilox Medical (Europe) Limited Membrane céramique
GB2354478A (en) * 1999-06-22 2001-03-28 Sterilox Medical Moulding ceramic membranes
EP1063005A2 (fr) * 1999-06-22 2000-12-27 Sterilox Medical (Europe) Limited Membrane céramique
FR2805807A1 (fr) * 2000-03-02 2001-09-07 Murata Manufacturing Co Composition en film epais isolante et dispositif electronique en ceramique et appareil electronique l'utilisant
WO2004071630A1 (fr) * 2003-02-13 2004-08-26 Itn Nanovation Gmbh Couche inorganique
DE10305866B4 (de) * 2003-02-13 2007-02-08 Itn Nanovation Gmbh Anorganische Schicht
WO2008043781A1 (fr) 2006-10-10 2008-04-17 Robert Bosch Gmbh ProcÉdÉ de fabrication d'au moins une couche poreuse
WO2010148051A3 (fr) * 2009-06-18 2011-04-21 Entegris, Inc. Matériau poreux fritté comprenant des particules ayant différentes granulométries moyennes
US8932381B2 (en) 2009-06-18 2015-01-13 Entegris, Inc. Sintered porous material comprising particles of different average sizes
DE102010035637A1 (de) * 2010-08-27 2012-03-01 Fachhochschule Koblenz Keramischer Filter sowie Verfahren zur Erstellung eines keramischen Filters
EP3372327A1 (fr) * 2017-03-06 2018-09-12 Seiko Epson Corporation Pâte et procédé de fabrication d'un article moulé en trois dimensions
CN108527854A (zh) * 2017-03-06 2018-09-14 精工爱普生株式会社 膏剂以及三维造型物的制造方法
US10730235B2 (en) 2017-03-06 2020-08-04 Seiko Epson Corporation Paste and method for producing three-dimensional shaped article
CN108527854B (zh) * 2017-03-06 2020-09-29 精工爱普生株式会社 膏剂以及三维造型物的制造方法
CN110330358A (zh) * 2019-07-04 2019-10-15 南充三环电子有限公司 一种多孔氧化铝陶瓷板及其制备方法
CN114247304A (zh) * 2020-09-25 2022-03-29 三达膜科技（厦门）有限公司 一种内部多通道圆盘式陶瓷膜的制备方法

Also Published As

Publication number Publication date
GB8914023D0 (en) 1989-08-09
AU5828490A (en) 1991-01-08

Similar Documents

Publication Publication Date Title
US6592787B2 (en) Porous articles and method for the manufacture thereof
US7223356B2 (en) Method for preparing a thin ceramic material with controlled surface porosity gradient, and resulting ceramic material
US20100233009A2 (en) Process for producing sintered porous materials
WO1990015661A1 (fr) Membrane ceramique poreuse et procede
JPH0667460B2 (ja) 熱反応性無機結合剤を有する多孔質で無機質の膜体の製法
CA1325327C (fr) Procede de fabrication de produits de ceramique poreux
US5073689A (en) Zirconia refractory heating element
JPS61268314A (ja) フイルタおよびその製造方法
WO2005081800A2 (fr) Supports de membrane céramique liée par réaction avec un coefficient d’expansion thermique élevé
WO2007025152A1 (fr) Procede de realisation d'un modele colloidal pour la fabrication de ceramiques hautement poreuses
US10183242B2 (en) Porous inorganic membranes and method of manufacture
Das et al. Formatation of pore structure in tape-cast alumina membranes–effects of binder content and firing temperature
CN110193292A (zh) 复合陶瓷膜及其制备方法和应用
EP1063005B1 (fr) Membrane céramique
KR100239892B1 (ko) 상온 압출 성형 공정에 의한 섬유상 세라믹스의 제조방법 및 이를 이용한 섬유상 단체 세라믹스의 제조방법
JPH0295423A (ja) 無機膜
JP2002066280A (ja) ガス分離フィルタおよびその製造方法
JP2004089838A (ja) 分離膜モジュール及びその製造方法
EP2098348A1 (fr) Procédé permettant de produire une structure de nid d'abeilles obstruée
JPH01133988A (ja) 網目状シリカウィスカー・セラミックス多孔質体複合体の製造方法
JP4024704B2 (ja) 複層構造セラミックスフィルターの製造方法
Larbot Ceramic processing techniques of support systems for membranes synthesis
JP4155650B2 (ja) セラミックフィルタの製造方法
JP2005255439A (ja) ナノ・ミクロおよびマクロ多重構造多孔体およびその製法
JP2003220319A (ja) 分離膜モジュール及びその製造方法

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): AT AU BB BG BR CA CH DE DK ES FI GB HU JP KP KR LK LU MC MG MW NL NO RO SD SE SU US

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): AT BE BF BJ CF CG CH CM DE DK ES FR GA GB IT LU ML MR NL SE SN TD TG

REG Reference to national code

Ref country code: DE

Ref legal event code: 8642

NENP Non-entry into the national phase

Ref country code: CA