WO1991014659A1 - Process for manufacturing fibrous magnesium oxide - Google Patents
Process for manufacturing fibrous magnesium oxide Download PDFInfo
- Publication number
- WO1991014659A1 WO1991014659A1 PCT/AT1991/000041 AT9100041W WO9114659A1 WO 1991014659 A1 WO1991014659 A1 WO 1991014659A1 AT 9100041 W AT9100041 W AT 9100041W WO 9114659 A1 WO9114659 A1 WO 9114659A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- magnesium oxide
- magnesium
- fibrous
- calcined
- fibrous magnesium
- Prior art date
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
- C01F5/00—Compounds of magnesium
- C01F5/02—Magnesia
- C01F5/06—Magnesia by thermal decomposition of magnesium compounds
- C01F5/08—Magnesia by thermal decomposition of magnesium compounds by calcining magnesium hydroxide
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
- C01F5/00—Compounds of magnesium
- C01F5/02—Magnesia
- C01F5/06—Magnesia by thermal decomposition of magnesium compounds
-
- 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
- C04B2/00—Lime, magnesia or dolomite
- C04B2/10—Preheating, burning calcining or cooling
- C04B2/102—Preheating, burning calcining or cooling of magnesia, e.g. dead burning
-
- 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
- C04B35/03—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 magnesium oxide, calcium oxide or oxide mixtures derived from dolomite
- C04B35/04—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 magnesium oxide, calcium oxide or oxide mixtures derived from dolomite based on magnesium oxide
- C04B35/053—Fine ceramics
-
- 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
- C04B35/62227—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products obtaining fibres
- C04B35/62231—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products obtaining fibres based on oxide ceramics
- C04B35/62263—Fibres based on magnesium oxide
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/10—Particle morphology extending in one dimension, e.g. needle-like
Definitions
- the invention relates to a process for the production of fibrous magnesium oxide, in which a material present in the form of needle-shaped particles and containing magnesium and water of crystallization is converted into the fibrous magnesium oxide by calcination.
- Magnesium oxide has a very high melting point and has good chemical resistance to basic systems and furthermore has good electrical insulation ability and also a relatively good thermal conductivity. As a result of these properties, it is widely used in various fields, in particular as a material for refractory bodies or stones which are used in the iron and steel industry and as a filler for synthetic resins which can increase the thermal conductivity of the synthetic resin material.
- the magnesium oxide usually consists of particles of granular shape, ie of particles which, like cubes and spheres, have approximately the same dimensions in different directions.
- Fibrous magnesium oxide is also known, ie a magnesium oxide, the particles of which have an elongated shape, the length of these particles relating to their largest mean transverse dimension being at least 10: 1, the cross-sectional area of the particles being less than 0.05 mm 2 and the particle width is less than 0.25 mm (see also ASTM D 3878).
- Such fibrous magnesium oxide particles have a comparatively high strength and, as a result, bodies or stones which consist of magnesium oxide and are used, for example, to form refractory linings, and in particular bodies made of plastics which contain magnesium oxide as a filler significantly higher strength can be achieved than when using the usual magnesium oxide with granular particles.
- the known processes for the production of fibrous magnesium oxide have a number of disadvantages, such as, for example, low performance, the production costs being burdened at the same time by a large expenditure of energy, and a relatively complicated process procedure for intermediates which result from slow-running reactions. stand, and the additional serious disadvantage that the conversion of these intermediates to the fibrous Magnesium ⁇ oxide corrosive or toxic gases, the disposal of which is difficult and burdens the process costs.
- One such known method provides for the deposition of magnesium oxide from the vapor phase, in which magnesium metal vapor is first reacted with oxygen to form magnesium oxide, and when the magnesium oxide is deposited, fibrous magnesium oxide particles are formed from the vapor phase. This method has a relatively low performance and requires a large amount of energy.
- Another known process provides for the intermediate product to be made from acicular basic magnesium compounds in which a mono- to tetravalent anion is present and which contain water of crystallization, and to convert this intermediate product to fibrous magnesium oxide by calcining, or to initially produce magnesium hydroxide from such an intermediate product and from this to form the fibrous magnesium oxide.
- the production of the basic magnesium compounds mentioned is cumbersome and corrosive or toxic gases are released when the latter are calcined, as a result of which the process is further complicated with regard to the necessary disposal of these gases.
- the process of the type mentioned at the outset is characterized in that one or more magnesium neutral carbonates containing water of crystallization, which correspond to the formula MgC0 3 .xH 2 0, where 1 ⁇ x ⁇ 5, in particular magnesium carbonate trihydrate, are used as the material to be calcined.
- Magnesium-neutral carbonates containing water of crystallization are relatively easily accessible, for example by precipitation of magnesium salt solutions with ammonia and carbon dioxide. oxide, ammonium carbonate or ammonium bicarbonate, or by carbonizing precipitated magnesium hydroxide.
- magnesium carbonate trihydrate in the form of acicular crystals can be precipitated simply and quickly from an aqueous solution, the size of the crystals being able to be influenced by the choice of the temperature in the reactor. These are temperatures which are only slightly above the ambient temperature and do not cause any special structural measures or energy expenditure.
- the magnesium neutral carbonates containing water of crystallization can be calcined in a simple manner with largely maintaining the particle shape to give fibrous magnesium oxide. This calcining process does not produce any toxic or corrosive products.
- the calcining temperature can be selected within wide limits, and good results can be achieved at calcining temperatures between 350 and 2000 ° C. Calcination temperatures between 800 and 1600 ° C. are preferably used. Depending on the equipment used for the calcination, very short calcination times, e.g. a few seconds, up to long calcining times of a few hours. It is advantageous if the material to be calcined is dried in a vacuum or partially dewatered at a temperature below 100 ° C. before calcining.
- the particles of the fibrous magnesium oxide produced by the process according to the invention have a high strength, and higher strength values can be achieved than they are present with particles of fibrous magnesium oxide which has been produced in a known manner from basic magnesium compounds. If fibrous magnesium oxide, which has been produced by the process according to the invention, is used as a filler for synthetic resins, a considerable increase in the strength values of the filled plastic can be achieved even with relatively small amounts of filler. aims to be.
- Example 1 500 ml of distilled water were placed in a thermostatted stirring vessel, 500 ml of a magnesium chloride solution with 298 g / 1 MgCl 2 were added and the mixture was heated to 35 ° C. The solution was mixed vigorously with the aid of a stirrer and 213 g of a 25% strength ammonia solution were added dropwise over a period of 30 minutes and 35 l of CO 2 were introduced into the solution. The reaction mixture was kept at a temperature of 40 ° C. using a heat exchanger. After the reaction was complete, the suspension was filtered, the filter cake was washed with water and the product obtained was dried in vacuo at low temperatures of less than 40 ° C. The product was identified as nesquehonite, MgC0 3 .3H 2 0, with acicular crystal habit.
- the product produced in this way was calcined at 1100 ° C. for 3 hours, fibrous magnesium oxide being obtained. Similar to the Nesquehonit primary fibers used, the synthesized fibers had a length of approximately 150 ⁇ m and an average diameter of approximately 5 ⁇ m. The product was identified as magnesium oxide by means of X-ray diffractometry.
- Example 2 The procedure was analogous to Example 1, but the filter cake obtained after the reaction and filtration of the suspension had been washed and washed with water was dried in vacuo at a temperature of 70 ° C. for 2 h.
- the chemical analysis showed that a magnesium neutral carbonate with the product composition MgC0 3 .2.4H 2 0 had formed.
- Scanning electron micrographs showed that the product thus obtained was composed of fibers with a length of approximately 150 ⁇ m and an average diameter of approximately 5 ⁇ m.
- the product manufactured in this way was treated with a Heating rate of 3 ° C / min brought to a temperature of 850 ° C and cooled uncontrolled after a holding time of 1 h.
- a fibrous substance with fiber lengths of approximately 150 ⁇ m and average fiber diameters of approximately 5 ⁇ m was obtained.
- X-ray diffractometric images confirmed that the material was magnesium oxide.
- Example 3 The product from Example 1, identified as nesquehonite, MgC0 3 .3H 2 0, with acicular crystal halus was brought to a temperature of 1600 ° C. at a heating rate of 5 ° C./min a holding time of 1 h cooled in an uncontrolled manner.
- the fibrous product could be identified as magnesium oxide by X-ray diffractometric images. Similar to the nesquehonite used, the fiber lengths were 50-150 ⁇ m, with average fiber diameters of 2-5 ⁇ m.
- Example 4 The magnesium neutral carbonate from Example 2 with the product composition MgC0 3 .2.4H 2 0 was brought to a temperature of 400 ° C at a heating rate of 10 ° C / min. After a holding time of 3 hours, fibrous magnesium oxide was obtained. The fibers synthesized did not differ morphologically from the magnesium neutral carbonate used and showed fiber lengths of up to 150 ⁇ m and average fiber diameter of about 3-5 ⁇ m. X-ray diffractometric images confirmed that the material was magnesium oxide.
- EXAMPLE 5 Use of the MgO Fibers to Increase the Strengths of Composites:
- the results of the tests are summarized in Table I. It can be seen that with the MgO fibers according to the invention there is a significant increase in the bending strength of the composite materials even with the small amounts added.
- the intrinsic strength of the MgO fibers according to the invention is calculated on the basis of the mixing rule and assuming an isotropic distribution of the fibers in the matrix.
- Epoxy resin MgO-62 according to the invention
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Organic Chemistry (AREA)
- Ceramic Engineering (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Inorganic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
- Compositions Of Macromolecular Compounds (AREA)
- Paper (AREA)
Abstract
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP3506244A JPH0723216B2 (en) | 1990-03-22 | 1991-03-07 | Method for producing fibrous magnesium oxide |
KR1019910701362A KR920701045A (en) | 1990-03-22 | 1991-03-07 | Fibrous Magnesium Oxide Manufacturing Method |
NO914560A NO914560D0 (en) | 1990-03-22 | 1991-11-21 | PROCEDURE FOR THE PREPARATION OF FIBER-MAGNESIUM OXIDE |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AT0068290A AT393677B (en) | 1990-03-22 | 1990-03-22 | METHOD FOR PRODUCING FIBROUS MAGNESIUM OXIDE |
ATA682/90 | 1990-03-22 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1991014659A1 true WO1991014659A1 (en) | 1991-10-03 |
Family
ID=3497042
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/AT1991/000041 WO1991014659A1 (en) | 1990-03-22 | 1991-03-07 | Process for manufacturing fibrous magnesium oxide |
Country Status (9)
Country | Link |
---|---|
EP (1) | EP0473762A1 (en) |
JP (1) | JPH0723216B2 (en) |
KR (1) | KR920701045A (en) |
AT (1) | AT393677B (en) |
AU (1) | AU7546991A (en) |
BR (1) | BR9105100A (en) |
CA (1) | CA2056992A1 (en) |
HU (1) | HUT60223A (en) |
WO (1) | WO1991014659A1 (en) |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP2418241B1 (en) | 2010-08-12 | 2016-02-17 | Bene_fit Systems GmbH & Co. KG | Filling material for compound materials containing magnesium carbonate, method for its production and application |
JP6284099B2 (en) * | 2014-03-05 | 2018-02-28 | 国立研究開発法人産業技術総合研究所 | Resin composition for dielectric and high frequency dielectric device |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3371993A (en) * | 1964-12-21 | 1968-03-05 | Corning Glass Works | Method of making magnesium oxide fibers |
EP0132610A1 (en) * | 1983-06-27 | 1985-02-13 | Kyowa Chemical Industry Co., Ltd. | Fibrous magnesium oxide and process for production thereof |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS63162560A (en) * | 1986-12-25 | 1988-07-06 | 三菱マテリアル株式会社 | Magnesia whisker reinforced inorganic material |
-
1990
- 1990-03-22 AT AT0068290A patent/AT393677B/en not_active IP Right Cessation
-
1991
- 1991-03-07 JP JP3506244A patent/JPH0723216B2/en not_active Expired - Lifetime
- 1991-03-07 EP EP91906525A patent/EP0473762A1/en not_active Withdrawn
- 1991-03-07 CA CA002056992A patent/CA2056992A1/en not_active Abandoned
- 1991-03-07 KR KR1019910701362A patent/KR920701045A/en not_active Application Discontinuation
- 1991-03-07 WO PCT/AT1991/000041 patent/WO1991014659A1/en not_active Application Discontinuation
- 1991-03-07 BR BR919105100A patent/BR9105100A/en not_active Application Discontinuation
- 1991-03-07 HU HU914085A patent/HUT60223A/en unknown
- 1991-03-07 AU AU75469/91A patent/AU7546991A/en not_active Abandoned
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3371993A (en) * | 1964-12-21 | 1968-03-05 | Corning Glass Works | Method of making magnesium oxide fibers |
EP0132610A1 (en) * | 1983-06-27 | 1985-02-13 | Kyowa Chemical Industry Co., Ltd. | Fibrous magnesium oxide and process for production thereof |
Also Published As
Publication number | Publication date |
---|---|
AT393677B (en) | 1991-11-25 |
HUT60223A (en) | 1992-08-28 |
BR9105100A (en) | 1992-06-02 |
KR920701045A (en) | 1992-08-11 |
CA2056992A1 (en) | 1991-09-23 |
AU7546991A (en) | 1991-10-21 |
JPH0723216B2 (en) | 1995-03-15 |
JPH04503797A (en) | 1992-07-09 |
HU914085D0 (en) | 1992-07-28 |
ATA68290A (en) | 1991-05-15 |
EP0473762A1 (en) | 1992-03-11 |
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