CN108557856A - A kind of calcium oxide particle and preparation method thereof based on vacuum-sintering - Google Patents
A kind of calcium oxide particle and preparation method thereof based on vacuum-sintering Download PDFInfo
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- CN108557856A CN108557856A CN201810433525.2A CN201810433525A CN108557856A CN 108557856 A CN108557856 A CN 108557856A CN 201810433525 A CN201810433525 A CN 201810433525A CN 108557856 A CN108557856 A CN 108557856A
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- 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
- C01F11/00—Compounds of calcium, strontium, or barium
- C01F11/02—Oxides or hydroxides
- C01F11/04—Oxides or hydroxides by thermal decomposition
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/60—Particles characterised by their size
- C01P2004/61—Micrometer sized, i.e. from 1-100 micrometer
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/10—Solid density
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/80—Compositional purity
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Abstract
The present invention relates to a kind of calcium oxide particle and preparation method thereof based on vacuum-sintering.Its technical solution is:By calcium hydroxide powder: the mass ratio of additive is 1: (0.002~0.05) is filtered first by calcium hydroxide powder and additive wet-milling 1~5 hour, and drying, grinding to grain size is 1~300 μm, obtains mixed powder.Mixed powder is placed in Granulation Equipments, is granulated, calcium hydroxide particle, drying is made.Calcium hydroxide particle after drying is placed in heating furnace, 1100 DEG C are warming up under the conditions of vacuum degree is 50~2000Pa, then 1300~1700 DEG C is continuously heating under the conditions of vacuum degree is 0.1~50Pa, keeps the temperature 1~5 hour, cooling is to get the calcium oxide particle based on vacuum-sintering.Present invention process is simple, and the crystallite dimension of calcium oxide is larger in the calcium oxide particle based on vacuum-sintering of preparation, and it is good with hydration resistance that made product has stable high-temperature performance, and can be used as the raw material for preparing the advanced materials such as calcium oxide refractory material and ceramics.
Description
Technical field
The invention belongs to calcium oxide particle technical fields.More particularly to a kind of calcium oxide particle based on vacuum-sintering and its
Preparation method.
Background technology
It is special type fire material made from essential mineral (CaO is main component) that calcium oxide products, which are using calcium oxide (square calcium stone),
Material.The real density of square calcium stone (CaO) is 3.75g/cm3, and fusing point is 2570 DEG C, belongs to basic refractory;Square calcium stone (main component
For CaO) Mohs' hardness be 6 degree, 0~1700 DEG C of average linear expansion coefficient is 13.8 × 10-6/ DEG C, 1000 DEG C of thermal conductivity is
7.71W/ (mK), 930 DEG C of resistivity are 4.175 × 106 Ω cm and 1460 DEG C of resistivity are 91 Ω cm.Calcium oxide products
Have many advantages, such as that high-temperature behavior is good, alkali resistance slag action is strong and can cleaning high-temp melt, in metallurgy industries such as precious metal smeltings
It is widely applied.
Calcia linker is the primary raw material for preparing calcium oxide products.The preparation method of calcia linker include sintering process and
Electric smelting method, sintering process are first to calcine lime stone under the conditions of 1200~1300 DEG C, it is cooling after briquet, then by block in
It is burnt under the conditions of 1700 DEG C or so, calcium oxide particle material is broken into after cooling.Electric smelting method is directly by marble blocks in three-phase electricity
Electrically smelting needs before electric smelting by marble, at particulate material or balling-up, then can just be put into electric furnace for calcia linker in arc
Electric smelting.In the technology path of sintering process also it has been proposed that:It is first that lime stone is light-burned, active calcium oxide is made, then by active oxygen
Change calcium digestion (adding water) and calcium hydroxide slurry is made, the calcium hydroxide green body that will be obtained after slurry by filtration, drying;Then it is added each
After kind additive and calcium hydroxide green body are ground altogether, it is pressed into base;High temperature under the conditions of by obtained green body in 1600~1800 DEG C
Calcium oxide green body is made in calcining, is finally crushed calcium oxide green body and obtains calcium oxide particle.
As can be seen that the preparation method cost and high energy consumption of existing calcium oxide particle, and complex process, it is important to existing
In some technology paths, the sinter layer of the calcium oxide billet surface after high-temperature process is destroyed in shattering process, after being crushed
New surface is exposed, so as to cause calcium oxide particle easily aquation, the deposit and calcium oxide-based material of oxidizing calcium raw material
Production bring extreme difficulties.
Invention content
The present invention is directed to overcome the shortage of prior art, it is therefore an objective to provide a kind of oxidation simple for process based on vacuum-sintering
The preparation method of calcium particle, with this method prepare the calcium oxide particle based on vacuum-sintering in calcium oxide crystallite dimension compared with
Greatly, the calcium oxide particle based on vacuum-sintering of preparation have stable high-temperature performance it is good with hydration resistance.
To achieve the above object, the technical solution adopted in the present invention is:
By calcium hydroxide powder: the mass ratio of additive is 1: (0.002~0.05), first by the calcium hydroxide powder and
The additive wet-milling 1~5 hour is filtered, drying, and grinding to grain size is 1~300 μm to get mixed powder.
The mixed powder is placed in Granulation Equipments, is granulated, calcium hydroxide particle, drying is made;By the hydrogen after drying
Calcium oxide particle is placed in heating furnace, is warming up to 1100 DEG C under the conditions of vacuum degree is 50~2000Pa, is then in vacuum degree
It is continuously heating to 1300~1700 DEG C under the conditions of 0.1~50Pa, keeps the temperature 1~5 hour, it is cooling to get the oxygen based on vacuum-sintering
Change calcium particle.
Ca (OH) in the calcium hydroxide powder2Content >=95wt%;Grain size is 1~300 μm.
The additive is one kind in zirconium hydroxide powder, Zirconium oxide powder, yttrium oxide, lanthanum oxide powder, described to add
It is 1~300 μm to add the grain size of agent.
Due to the adoption of the above technical scheme, the present invention has following good effect compared with prior art:
1) present invention is directly granulated calcium hydroxide powder, simple for process up to calcium oxide particle after high-temperature process.
2) granularity for the feed particles that the present invention is prepared due to Granulation Equipments is small, in high-temperature process, contains additive
Calcium hydroxide complete decomposition;Meanwhile under vacuum, calcium oxide particle sintering degree is high, and crystallite dimension is big.Additive
The hydration resistance for being conducive to improve the calcium oxide particle based on vacuum-sintering is added.
3) present invention will not destroy oxidation without carrying out being crushed processing again to the calcia material obtained after high-temperature process
The sinter layer that calcium particle surface is formed in high-temperature process, thus, the obtained calcium oxide particle based on vacuum-sintering
Hydration resistance it is good, convenient for storage and production, the particle that can be prepared directly as calcium oxide-based refractory material and refractory ceramics
Material uses.
4) temperature in use of the calcium oxide particle based on vacuum-sintering prepared by the present invention is up to 2000 DEG C or more, vacuum item
Part has stable high-temperature performance, bulk density is big and hydration resistance is good, can be used as that prepare calcium oxide refractory material and ceramics etc. advanced
The raw material of material.
Calcium oxide particle based on vacuum-sintering prepared by the present invention is after testing:CaO content >=93wt%;Bulk density >=
2.9g/cm3;Crystallite dimension >=50 μm;Under 50 DEG C and 90% damp condition, 10h is kept, after 110 DEG C of drying, calcium oxide is former
Aquation rate of body weight gain≤2% of material base body.
Present invention process is simply and low energy consumption, the crystal grain ruler of calcium oxide in the calcium oxide particle based on vacuum-sintering of preparation
Very little larger, having stable high-temperature performance for the calcium oxide particle based on vacuum-sintering is good with hydration resistance, can be used as and prepares calcium oxide
The raw material of the advanced materials such as refractory material and ceramics.
Specific implementation mode
The present invention will be further described With reference to embodiment, not to the limitation of its protection domain.
It is now that the technical parameter Unify legislation involved by present embodiment is as follows to avoid repeating, in embodiment not
It repeats again:
Ca (OH) in the calcium hydroxide powder2Content >=95wt%;Grain size is 1~300 μm.
The grain size of the additive is 1~300 μm.
Embodiment 1
A kind of calcium oxide particle and preparation method thereof based on vacuum-sintering.Preparation method described in the present embodiment is:
By calcium hydroxide powder: the mass ratio of additive is 1: (0.002~0.01), first by the calcium hydroxide powder and
The additive wet-milling 1~2 hour is filtered, drying, and grinding to grain size is 1~300 μm to get mixed powder.
The mixed powder is placed in Granulation Equipments, is granulated, calcium hydroxide particle, drying is made;By the hydrogen after drying
Calcium oxide particle is placed in heating furnace, is warming up to 1100 DEG C under the conditions of vacuum degree is 50~200Pa, is then in vacuum degree
It is continuously heating to 1300~1400 DEG C under the conditions of 0.1~10Pa, keeps the temperature 4~5 hours, it is cooling to get the oxygen based on vacuum-sintering
Change calcium particle.
The additive is zirconium hydroxide powder.
Calcium oxide particle manufactured in the present embodiment based on vacuum-sintering is after testing:96~98wt% of CaO content;Volume is close
Spend 2.9~2.98g/cm3;50~58 μm of the crystallite dimension of calcium oxide;Under 50 DEG C and 90% damp condition, 10h is kept, in
After 110 DEG C of drying, 1.4~2wt% of aquation rate of body weight gain of calcium oxide particle.
Embodiment 2
A kind of calcium oxide particle and preparation method thereof based on vacuum-sintering.Preparation method described in the present embodiment is:
By calcium hydroxide powder: the mass ratio of additive is 1: (0.01~0.02), first by the calcium hydroxide powder and
The additive wet-milling 2~3 hours is filtered, drying, and grinding to grain size is 1~300 μm to get mixed powder.
The mixed powder is placed in Granulation Equipments, is granulated, calcium hydroxide particle, drying is made;By the hydrogen after drying
Calcium oxide particle is placed in heating furnace, is warming up to 1100 DEG C under the conditions of vacuum degree is 200~800Pa, is then in vacuum degree
It is continuously heating to 1400~1500 DEG C under the conditions of 10~20Pa, keeps the temperature 3~4 hours, it is cooling to get the oxidation based on vacuum-sintering
Calcium particle.
The additive is yttrium oxide.
Calcium oxide particle manufactured in the present embodiment based on vacuum-sintering is after testing:CaO content 95-97wt%;Volume is close
Spend 2.95~3.02g/cm3;55~63 μm of the crystallite dimension of calcium oxide;Under 50 DEG C and 90% damp condition, 10h is kept, in
After 110 DEG C of drying, 0.9~1.5wt% of aquation rate of body weight gain of calcium oxide raw material green body.
Embodiment 3
A kind of calcium oxide particle and preparation method thereof based on vacuum-sintering.Preparation method described in the present embodiment is:
By calcium hydroxide powder: the mass ratio of additive is 1: (0.02~0.03), first by the calcium hydroxide powder and
The additive wet-milling 3~5 hours is filtered, drying, and grinding to grain size is 1~300 μm to get mixed powder.
The mixed powder is placed in Granulation Equipments, is granulated, calcium hydroxide particle, drying is made;By the hydrogen after drying
Calcium oxide particle is placed in heating furnace, is warming up to 1100 DEG C under the conditions of vacuum degree is 800~1200Pa, is then in vacuum degree
It is continuously heating to 1500~1600 DEG C under the conditions of 20~30Pa, keeps the temperature 1~2 hour, it is cooling to get the oxidation based on vacuum-sintering
Calcium particle.
The additive is Zirconium oxide powder.
Calcium oxide particle manufactured in the present embodiment based on vacuum-sintering is after testing:94~96wt% of CaO content;Volume is close
Spend 3.04~3.1g/cm3;60~67 μm of the crystallite dimension of calcium oxide;Under 50 DEG C and 90% damp condition, 10h is kept, in
After 110 DEG C of drying, 0.7~1.0wt% of aquation rate of body weight gain of calcium oxide raw material green body.
Embodiment 4
A kind of calcium oxide particle and preparation method thereof based on vacuum-sintering.Preparation method described in the present embodiment is:
By calcium hydroxide powder: the mass ratio of additive is 1: (0.03~0.05), first by the calcium hydroxide powder and
The additive wet-milling 1~2 hour is filtered, drying, and grinding to grain size is 1~300 μm to get mixed powder.
The mixed powder is placed in Granulation Equipments, is granulated, calcium hydroxide particle, drying is made;By the hydrogen after drying
Calcium oxide particle is placed in heating furnace, 1100 DEG C is warming up under the conditions of vacuum degree is 1200~2000Pa, then in vacuum degree
To be continuously heating to 1600~1700 DEG C under the conditions of 30~50Pa, 2~3 hours are kept the temperature, cooling is to get the oxygen based on vacuum-sintering
Change calcium particle.
The additive is lanthanum oxide powder.
Calcium oxide particle manufactured in the present embodiment based on vacuum-sintering is after testing:93~95wt% of CaO content;Volume is close
Spend 3.0~3.06g/cm3;64~70 μm of the crystallite dimension of calcium oxide;Under 50 DEG C and 90% damp condition, 10h is kept, in
After 110 DEG C of drying, 0.5~0.8wt% of aquation rate of body weight gain of calcium oxide particle.
Present embodiment has following good effect compared with prior art:
1) present embodiment is directly granulated calcium hydroxide powder, up to calcium oxide particle, technique after high-temperature process
Simply.
2) granularity for the feed particles that present embodiment is prepared due to Granulation Equipments is small, in high-temperature process, contains
There is the calcium hydroxide complete decomposition of additive;Meanwhile under vacuum, calcium oxide particle sintering degree is high, and crystallite dimension is big.
The addition of additive is conducive to improve the hydration resistance of the calcium oxide particle based on vacuum-sintering.
3) present embodiment is not necessarily to carry out being crushed processing again to the calcia material obtained after high-temperature process, will not
The sinter layer that calcium oxide particle surface is formed in high-temperature process is destroyed, thus, the obtained oxygen based on vacuum-sintering
The hydration resistance for changing calcium particle is good, can be directly as calcium oxide-based refractory material and refractory ceramics system convenient for storage and production
Standby particulate material uses.
4) present embodiment prepare the calcium oxide particle based on vacuum-sintering temperature in use be up to 2000 DEG C with
Above, vacuum condition has stable high-temperature performance, bulk density is big and hydration resistance is good, can be used as and prepares calcium oxide refractory material and pottery
The raw material of the advanced materials such as porcelain.
Calcium oxide particle based on vacuum-sintering prepared by present embodiment is after testing:CaO content >=93wt%;Body
Product density >=2.9g/cm3;Crystallite dimension >=50 μm;Under 50 DEG C and 90% damp condition, 10h is kept, after 110 DEG C of drying,
Aquation rate of body weight gain≤2% of calcium oxide raw material green body.
Present embodiment is simple for process and low energy consumption, calcium oxide in the calcium oxide particle based on vacuum-sintering of preparation
Crystallite dimension it is larger, having stable high-temperature performance for the calcium oxide particle based on vacuum-sintering is good with hydration resistance, can be used as system
The raw material of the advanced materials such as standby calcium oxide refractory material and ceramics.
Claims (4)
1. a kind of preparation method of the calcium oxide particle based on vacuum-sintering, it is characterised in that:By calcium hydroxide powder: additive
Mass ratio be 1: (0.002~0.05), first by the calcium hydroxide powder and the additive wet-milling 1~5 hour, filtering,
Drying, grinding to grain size are 1~300 μm to get mixed powder;
The mixed powder is placed in Granulation Equipments, is granulated, calcium hydroxide particle, drying is made;By the hydroxide after drying
Calcium particle is placed in heating furnace, vacuum degree be 50~2000Pa under the conditions of be warming up to 1100 DEG C, then in vacuum degree be 0.1~
It is continuously heating to 1300~1700 DEG C under the conditions of 50Pa, keeps the temperature 1~5 hour, it is cooling to get the calcium oxide based on vacuum-sintering
Grain.
2. the preparation method of the calcium oxide particle based on vacuum-sintering according to claim 1, it is characterised in that the hydrogen-oxygen
Change Ca (OH) in calcium powder body2Content >=95wt%;Grain size is 1~300 μm.
3. the preparation method of the calcium oxide particle based on vacuum-sintering according to claim 1, it is characterised in that the addition
Agent is zirconium hydroxide powder, Zirconium oxide powder, yttrium oxide, one kind in lanthanum oxide powder, the grain size of the additive is 1~
300μm。
4. a kind of calcium oxide particle based on vacuum-sintering, it is characterised in that the calcium oxide particle based on vacuum-sintering is root
Prepared by preparation method according to the calcium oxide particle based on vacuum-sintering described in any one of claims 1 to 3 item based on true
The calcium oxide particle of sky sintering.
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Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN109179470A (en) * | 2018-09-30 | 2019-01-11 | 武汉科技大学 | A kind of passive oxidation calcium particle and preparation method thereof |
CN109384255A (en) * | 2018-11-30 | 2019-02-26 | 武汉科技大学 | A kind of calcium oxide spherolite and preparation method thereof |
CN109678190A (en) * | 2019-02-22 | 2019-04-26 | 武汉科技大学 | A kind of core-shell structure calcium oxide particle and preparation method thereof |
CN111268711A (en) * | 2020-02-17 | 2020-06-12 | 武汉科技大学 | Coated anti-hydration calcium oxide material and preparation method thereof |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN104261448A (en) * | 2014-10-16 | 2015-01-07 | 武汉科技大学 | Nano calcium oxide and preparation method thereof |
CN106219585A (en) * | 2016-07-08 | 2016-12-14 | 武汉科技大学 | A kind of dense granule calcia material and preparation method thereof |
-
2018
- 2018-05-08 CN CN201810433525.2A patent/CN108557856A/en active Pending
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN104261448A (en) * | 2014-10-16 | 2015-01-07 | 武汉科技大学 | Nano calcium oxide and preparation method thereof |
CN106219585A (en) * | 2016-07-08 | 2016-12-14 | 武汉科技大学 | A kind of dense granule calcia material and preparation method thereof |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN109179470A (en) * | 2018-09-30 | 2019-01-11 | 武汉科技大学 | A kind of passive oxidation calcium particle and preparation method thereof |
CN109384255A (en) * | 2018-11-30 | 2019-02-26 | 武汉科技大学 | A kind of calcium oxide spherolite and preparation method thereof |
CN109678190A (en) * | 2019-02-22 | 2019-04-26 | 武汉科技大学 | A kind of core-shell structure calcium oxide particle and preparation method thereof |
CN111268711A (en) * | 2020-02-17 | 2020-06-12 | 武汉科技大学 | Coated anti-hydration calcium oxide material and preparation method thereof |
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