EP-3190089-B1 - METHOD FOR MANUFACTURING PRODUCT INORGANIC COMPOUND AND PRODUCT INORGANIC COMPOUND

EP3190089B1EP 3190089 B1EP3190089 B1EP 3190089B1EP-3190089-B1

Inventors

ISHIKAWA, KUNIO
TSURU, KANJI
TOITA, RIKI
ISHIKAWA, MAHO
KAWACHI, GIICHIRO
NAKASHIMA, YASUHARU

Dates

Publication Date: 20260513
Application Date: 20150831

Claims (10)

A method of producing a product inorganic compound comprising: a step A in which a raw material inorganic compound having a volume of 10 -13 m 3 or more is immersed in an electrolyte aqueous solution or an electrolyte suspension; a step B1 in which anions in the raw material inorganic compound are exchanged with anions in the electrolyte aqueous solution or the electrolyte suspension; a step B2 in which cations in the raw material inorganic compound are exchanged with cations in the electrolyte aqueous solution or the electrolyte suspension; or a step B3 in which a component (provided that it excludes water, hydrogen, and oxygen) in the electrolyte aqueous solution or the electrolyte suspension that is not included in the raw material inorganic compound is made to be included in the raw material inorganic compound; and a process C in which a product inorganic compound having a volume of 10 -13 m 3 or more is obtained from the raw material inorganic compound, wherein the raw material inorganic compound has a solubility in g of solute per 100 g of solvent that is greater than 0 and that is 5 or less with respect to distilled water or the electrolyte aqueous solution at 20 °C, and wherein, in the electrolyte aqueous solution or the electrolyte suspension in which the raw material inorganic compound is immersed, at least, elements other than hydrogen and oxygen, which are included in the product inorganic compound but not included in the raw material inorganic compound are included, wherein the raw material inorganic compound is an artificial material comprising at least one of calcium carbonate and calcium phosphate, wherein the raw material inorganic compound is an interconnected porous body, wherein the product inorganic compound comprises a core portion which is unreacted raw material inorganic compound, and a surface layer portion which is the precipitated inorganic compound covering the core portion, and wherein, in the process C, a product inorganic compound which is a porous body including pores having an aspect ratio of at least 2 or more is obtained.
The method of producing a product inorganic compound according to claim 1, wherein a porosity of the raw material inorganic compound is 30% or more.
The method of producing a product inorganic compound according to claim 1 or 2, wherein the surface layer portion comprises at least one selected from the group consisting of calcium hydrogen phosphate, calcium carbonate, and apatite.
The method of producing a product inorganic compound according to any one of claims 1 to 3, wherein, in the step C, a precipitated inorganic compound layer formed in the steps B1 to B3 forms a porous body according to a curing reaction in which the plurality of raw material inorganic compounds are bridged.
The method of producing a product inorganic compound according to claim 1 to 4, wherein a support is included in the core portion.
The method of producing a product inorganic compound according to claim 5, wherein the support comprises at least one selected from the group consisting of a metal, a polymer, and a ceramic.
A product inorganic compound having a volume of 10 -13 m 3 or more, comprising: at least a core portion and a surface layer portion that covers the core portion, wherein the core portion and the surface layer portion have different compositions, wherein an inorganic compound of the surface layer portion comprises at least grain boundaries other than sinterable grain boundaries and preserves a form without disintegrating even if it is immersed in water for 24 hours, and wherein an inorganic compound of the surface layer portion comprises at least one element included in a composition of the core portion, wherein the core portion is an artificial material including at least one of calcium carbonate and calcium phosphate, wherein the core portion is an interconnected porous body, wherein the product inorganic compound is a porous body including pores having an aspect ratio of at least 2 or more.
The product inorganic compound according to claim 7, wherein a support is included in the core portion.
The product inorganic compound according to claim 8, wherein the support comprises at least one selected from the group consisting of a metal, a polymer, and a ceramic.
The product inorganic compound according to any one of claims 7 to 9, wherein a mass ratio between the core portion and the surface layer portion (core portion:surface layer portion) is 97:3 to 50:50.

Description

[Technical Field] The present invention relates to a method of producing a product inorganic compound and to a product inorganic compound. [Background Art] Forms of a product inorganic compound in the present invention are granules or a block having a volume of a certain value or more. In general, inorganic compounds in the form of granules or a block having a volume of a certain value or more are produced from powders using a sintering or curing reaction. Sintering is a process in which inorganic compound powder is pressed and molded to impart a shape and is sometimes called calcination, and when a powder compacted body is heated at a lower temperature than a melting point, inorganic compound elements diffuse through grain boundaries between particles and the powder solidifies. As a result of sintering, sinterable grain boundaries are formed between particles. However, the sintering process is not applicable in some inorganic compounds because thermal decomposition occurs at a much lower temperature than a melting point. In addition, the sintering process is a mass energy consumption type production process which requires a high temperature of about 1000 °C or more. A low energy consumption type production process is desired in consideration of reducing an environmental load. Further, the obtained inorganic compound sintered body may have low functionality because a surface area of a material decreases and a crystallite size increases during sintering. A curing reaction is a reaction in which a powder is cured and is known for gypsum, zinc phosphate cement, apatite cement, calcium hydrogen phosphate cement and the like. When calcium sulfate hemihydrate powder is mixed with water, gypsum is cured and is compositionally converted into calcium sulfate dihydrate. When zinc oxide powder is mixed in phosphoric acid, zinc phosphate cement is cured to zinc phosphate. Apatite cement is, for example, a powder in which calcium hydrogen phosphate and tetracalcium phosphate, is cured to apatite when mixed with water. Calcium hydrogen phosphate cement is, for example, a powder in which β-type tricalcium phosphate and calcium dihydrogen phosphate, is cured to calcium hydrogen phosphate when mixed with water or phosphoric acid. Inorganic compounds are also used for medical treatment. For example, there are many cases in which bone defect emerged due to pathological causes or external injuries need to be reconstructed. In reconstruction therapy of bone defects, it is preferable to densely fill the bone defect with an artificial bone reconstruction material represented by an apatite or β-type tricalcium phosphate having excellent tissue compatibility and osteoconductivity. Artificial bone reconstruction materials in the form of a block or granules are currently being clinically applied, but such artificial bone reconstruction materials are generally produced through sintering. Also, since the bone is hard tissue, bone reconstruction materials are sometimes called hard tissue reconstruction materials and hard tissue reconstruction materials are sometimes called bone prosthetic materials because they fill and reconstruct bone defects, but they have basically the same meaning. Calcium carbonate may be used as a bone reconstruction material in addition to an apatite and β-type tricalcium phosphate. Calcium carbonate is a skeletal tissue composition of an invertebrate animal and is produced from corals, shells, marble and the like. Corals are clinically applied as bone prosthetic materials also due to the presence of interconnected porous structure. However, the harvest of corals causes damage to the environment and problems such as a cost in finding appropriate corals, a cost for collection, a cleaning cost, impurity problems, and uniformity problems are unavoidable in order to use corals as materials for medical treatment. Therefore, artificial production is preferable. As can be seen in plaster, calcium carbonate can be produced when calcium hydroxide is exposed to carbon dioxide for curing. However, there is a problem of the likelihood of there being remaining calcium hydroxide. In addition, it is necessary to prepare a mold for molding. An apatite and tricalcium phosphate which are bone reconstruction materials are produced by sintering an apatite powder (Patent Literature 1 and Patent Literature 2). Recently, it has been found that, when a calcium compound such as a calcium carbonate block is immersed in a phosphoric acid aqueous solution, an apatite block can be produced without sintering (Patent Literature 3). In addition, as a recycling method for gypsum board, it is known that potassium hydroxide and calcium sulfate dihydrate react in water and calcium hydroxide having an average particle size of 0.5 to 5 µm is produced (Patent Literature 4). Similarly, as a recycling method for gypsum board and the like, it is known that, when gypsum is immersed in ammonia water or a sodium hydroxide aqueous solution and carbon dioxid