WO2022017543A2 - 一种以稀土元素-铁氧化物制备胚体的方法 - Google Patents

一种以稀土元素-铁氧化物制备胚体的方法 Download PDF

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WO2022017543A2
WO2022017543A2 PCT/CN2021/118014 CN2021118014W WO2022017543A2 WO 2022017543 A2 WO2022017543 A2 WO 2022017543A2 CN 2021118014 W CN2021118014 W CN 2021118014W WO 2022017543 A2 WO2022017543 A2 WO 2022017543A2
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oxide
rare earth
earth element
reducing agent
sintering
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WO2022017543A3 (zh
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李笑天
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李笑天
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    • 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
    • C04B35/26—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 ferrites
    • C04B35/2675—Other ferrites containing rare earth metals, e.g. rare earth ferrite garnets
    • C—CHEMISTRY; METALLURGY
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    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/50—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on rare-earth 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
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/50—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on rare-earth compounds
    • C04B35/505—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on rare-earth compounds based on yttrium 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
    • 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
    • C04B35/6303—Inorganic additives
    • 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
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
    • C04B2235/3224—Rare earth oxide or oxide forming salts thereof, e.g. scandium 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
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
    • C04B2235/3224—Rare earth oxide or oxide forming salts thereof, e.g. scandium oxide
    • C04B2235/3225—Yttrium oxide or oxide-forming salts thereof

Definitions

  • the invention relates to the technical field of ceramic material synthesis, in particular, to a method for preparing embryo bodies by using rare earth element-iron oxide.
  • Rare earth-iron oxides are ceramic substances with reversible redox activity. In the process of preparing embryos from ceramic substances, high temperature is often used. Under high temperature conditions, in order to ensure the effect of embryos, it is necessary to make the active components in the product accurately reach the target oxidation value, but this requirement requires relatively harsh conditions. If there is no special means, the error of the tightness of the reaction vessel and the purity of the protective gas itself commonly used in the prior art make it difficult for the active components in the product to meet the requirements of the target oxidation value.
  • embryos are prepared from ceramic substances by using the following methods:
  • Solid-phase reaction method In this method, the powder of iron oxide, iron powder and rare earth oxide is directly mixed and pressed, and then heated and reacted to prepare the embryo body. Specifically, it is divided into reducing atmosphere method and closed container method.
  • the reducing atmosphere method means that in addition to the inert gas, a certain concentration of reducing gas is added to the reaction environment to make the iron component in the product reach the required oxidation value.
  • the reducing agent is generally hydrogen or carbon monoxide with a concentration of not more than 5%; the best accurate value of this concentration has been theoretically determined by a phase diagram, but there are few attempts to achieve an accurate value in practice.
  • the closed-vessel method refers to using stoichiometric ratios of ferric iron, reduced iron and rare earth oxides to heat and react in a closed vessel filled with an inert gas, such as a sealed tube, to prepare an embryo body. This method has a good effect of maintaining the purity of the product, but the sealing of the reaction vessel requires a relatively complicated operation, which is difficult to mass-produce.
  • the purpose of the present invention is to provide a method for preparing an embryo body by using rare earth element-iron oxide, which can make the active components in the rare earth element-iron oxide embryo body accurately reach the target oxidation value.
  • the present invention solves its technical problems by adopting the following technical solutions.
  • the embodiment of the present application provides a method for preparing an embryo body by using rare earth element-iron oxide, which includes the following steps: uniformly mixing ferric oxide, rare earth element oxide and an embryo body reducing agent to obtain a mixture, and pressing the mixture into a pre-preg
  • the embryo body is then placed in a sintering device for sintering to obtain an embryo body; a reducing agent or a deoxidizer is placed in the sintering device, and the reducing agent for the embryo body is iron powder or ferrous oxide;
  • the reducing activity is higher than that of the embryo body reducing agent.
  • the embodiments of the present invention at least have the following advantages or beneficial effects:
  • the method for preparing a green body from rare earth element-iron oxide provided by the present invention can effectively protect the raw material by adding a reducing agent or deoxidizer whose reducing activity is slightly higher than that of the reducing agent of the green body in the sintering equipment.
  • the residual oxidizing property of the environment is reduced to a level that just does not affect the raw materials, so that the active components in the rare earth element-iron oxide embryo can accurately reach the target oxidation value, avoiding the need to reduce the oxygen concentration in the environment in the traditional technology to protect the raw materials.
  • the above-mentioned existing technology cannot reduce the oxygen concentration to the required level, and at the same time, it is easy to scale up the production, and it is also convenient to prepare various large-sized or complex-shaped ceramic bodies.
  • the embodiments of the present application provide a method for a rare earth element-iron oxide embryonic body, which includes the following steps: uniformly mixing ferric oxide, rare earth element oxide and a reducing agent for the embryonic body to obtain a mixture, and pressing the mixture into a pre-preg
  • the embryo body is then placed in a sintering device for sintering to obtain an embryo body; a reducing agent or a deoxidizer is placed in the sintering device, and the reducing agent for the embryo body is iron powder or ferrous oxide;
  • the reducing activity is higher than that of the embryo body reducing agent.
  • the residual oxidizing property of the environment can be effectively reduced to the extent that it does not affect the raw material, so that the rare earth element-iron
  • the active ingredients in the oxide embryo body can accurately reach the target oxidation valence, avoiding the problem that the oxygen concentration in the environment needs to be reduced to protect the raw material in the traditional technology, but the existing technology cannot reduce the oxygen concentration to the required level.
  • the rare earth element oxide in the above method includes one or more of oxides of Yb, Y and Lu. At the same time, it can also be other rare earth element oxides with similar properties to Yb, Y and Lu besides the oxides of Yb, Y and Lu.
  • the molar ratio of ferric oxide, rare earth element oxide and iron powder in the above method is (4-6):(2-4):(1-3).
  • the active substance in the embryo body prepared from the raw materials in this ratio can reach the target oxidation value and the purity is high.
  • the molar ratio of ferric oxide, rare earth element oxide and iron powder in the above method is 5:3:2.
  • the percentage of active substances reaching the target oxidation price in the embryos prepared from the raw materials at this ratio is the highest.
  • the molar ratio of ferric oxide, rare earth element oxide and ferrous oxide in the above method is (0.5-1.5):(0.5-1.5):(1-3).
  • the active substance in the embryo body prepared from the raw materials in this ratio can reach the target oxidation value and the purity is high.
  • the molar ratio of ferric oxide, rare earth element oxide and ferrous oxide in the above method is 1:1:2.
  • the percentage of active substances reaching the target oxidation price in the embryos prepared from the raw materials at this ratio is the highest.
  • the sintering temperature is 1200-1500° C.
  • the sintering time is 15-26 h.
  • the sintering temperature and time in this range can obtain the green body of comparable quality.
  • the sintering temperature in the above method is 1300° C., and the sintering time is 24 hours.
  • the particle size of the iron powder in the above method is lower than 325 mesh.
  • the particle size and the iron powder smaller than the particle size can ensure that the raw material is fully reduced to reach the target oxidation value.
  • ferric oxide, rare earth element oxide and embryonic body reducing agent are mixed by grinding, and the liquid used for grinding is one or both of isopropanol or acetone.
  • the raw materials can also be added to a ball milling device for mixing.
  • the purpose of this embodiment is to provide a rare earth element-iron oxide embryo.
  • step (3) Put the preform body obtained in step (3) into a closed sintering device with a reducing agent or an oxygen scavenger placed in advance, and introduce an inert gas, such as nitrogen (the purity of nitrogen is the same as that in the prior art) sintered at 1300 °C for 24 h, the heating rate before sintering was 200 °C/h, and the cooling rate after sintering was -200 °C/h. After sintering, a ceramic body with YbFe2O4 as the main component was obtained. .
  • an inert gas such as nitrogen (the purity of nitrogen is the same as that in the prior art) sintered at 1300 °C for 24 h, the heating rate before sintering was 200 °C/h, and the cooling rate after sintering was -200 °C/h.
  • the purpose of this embodiment is to provide a rare earth element-iron oxide embryo.
  • step (3) Put the preform body obtained in step (3) into a closed sintering device with a reducing agent or an oxygen scavenger placed in advance, and introduce an inert gas, such as nitrogen (the purity of nitrogen is the same as that in the prior art) sintered at 1300 °C for 24 h, the heating rate before sintering was 200 °C/h, and the cooling rate after sintering was -200 °C/h. After sintering, a ceramic body with YbFe2O4 as the main component was obtained. .
  • an inert gas such as nitrogen (the purity of nitrogen is the same as that in the prior art) sintered at 1300 °C for 24 h, the heating rate before sintering was 200 °C/h, and the cooling rate after sintering was -200 °C/h.
  • the purpose of this embodiment is to provide a rare earth element-iron oxide embryo.
  • step (3) Put the preform body obtained in step (3) into a closed sintering device with a reducing agent or an oxygen scavenger placed in advance, and introduce an inert gas, such as nitrogen (the purity of nitrogen is the same as that in the prior art) sintered at 1200 °C for 22 h, the heating rate before sintering was 200 °C/h, and the cooling rate after sintering was -200 °C/h. After sintering, a ceramic body with YbFe2O4 as the main component was obtained. .
  • an inert gas such as nitrogen (the purity of nitrogen is the same as that in the prior art) sintered at 1200 °C for 22 h, the heating rate before sintering was 200 °C/h, and the cooling rate after sintering was -200 °C/h.
  • the purpose of this embodiment is to provide a rare earth element-iron oxide embryo.
  • step (3) Put the preform body obtained in step (3) into a closed sintering device with a reducing agent or an oxygen scavenger placed in advance, and introduce an inert gas, such as nitrogen (the purity of nitrogen is the same as that in the prior art) sintered at 1500 °C for 26 h, the heating rate before sintering was 200 °C/h, and the cooling rate after sintering was -200 °C/h. After sintering, a ceramic body with YbFe2O4 as the main component was obtained. .
  • an inert gas such as nitrogen (the purity of nitrogen is the same as that in the prior art) sintered at 1500 °C for 26 h, the heating rate before sintering was 200 °C/h, and the cooling rate after sintering was -200 °C/h.
  • the purpose of this embodiment is to provide a rare earth element-iron oxide embryo.
  • step (3) Put the preform body obtained in step (3) into a closed sintering device with a reducing agent or an oxygen scavenger placed in advance, and introduce an inert gas, such as nitrogen (the purity of nitrogen is the same as that in the prior art) sintered at 1300 °C for 24 h, the heating rate before sintering was 200 °C/h, and the cooling rate after sintering was -200 °C/h. After sintering, a ceramic body with YbFe2O4 as the main component was obtained. .
  • an inert gas such as nitrogen (the purity of nitrogen is the same as that in the prior art) sintered at 1300 °C for 24 h, the heating rate before sintering was 200 °C/h, and the cooling rate after sintering was -200 °C/h.
  • the purpose of this embodiment is to provide a rare earth element-iron oxide embryo.
  • step (3) Put the preform body obtained in step (3) into a closed sintering device with a reducing agent or an oxygen scavenger placed in advance, and introduce an inert gas, such as nitrogen (the purity of nitrogen is the same as that in the prior art) sintered at 1400 °C for 23 h, the heating rate before sintering was 200 °C/h, and the cooling rate after sintering was -200 °C/h. After sintering, a ceramic body with YbFe2O4 as the main component was obtained. .
  • an inert gas such as nitrogen (the purity of nitrogen is the same as that in the prior art) sintered at 1400 °C for 23 h, the heating rate before sintering was 200 °C/h, and the cooling rate after sintering was -200 °C/h.
  • the purpose of this embodiment is to provide a rare earth element-iron oxide embryo.
  • step (3) Put the preform body obtained in step (3) into a closed sintering device with a reducing agent or an oxygen scavenger placed in advance, and introduce an inert gas, such as nitrogen (the purity of nitrogen is the same as that in the prior art) sintered at 1200°C for 15h, the heating rate before sintering was 200°C/h, and the cooling rate after sintering was -200°C/h.
  • an inert gas such as nitrogen (the purity of nitrogen is the same as that in the prior art) sintered at 1200°C for 15h, the heating rate before sintering was 200°C/h, and the cooling rate after sintering was -200°C/h.
  • an inert gas such as nitrogen (the purity of nitrogen is the same as that in the prior art) sintered at 1200°C for 15h, the heating rate before sintering was 200°C/h, and the cooling rate after sintering was -200°C/h.
  • the purpose of this embodiment is to provide a rare earth element-iron oxide embryo.
  • step (3) Put the preform body obtained in step (3) into a closed sintering device with a reducing agent or an oxygen scavenger placed in advance, and introduce an inert gas, such as nitrogen (the purity of nitrogen is the same as that in the prior art) sintered at 1500 °C for 26 h, the heating rate before sintering was 200 °C/h, and the cooling rate after sintering was -200 °C/h. After sintering, a ceramic body with YbFe2O4 as the main component was obtained. .
  • an inert gas such as nitrogen (the purity of nitrogen is the same as that in the prior art) sintered at 1500 °C for 26 h, the heating rate before sintering was 200 °C/h, and the cooling rate after sintering was -200 °C/h.
  • the purpose of this embodiment is to provide a rare earth element-iron oxide embryo.
  • step (3) Put the preform body obtained in step (3) into a closed sintering device with a reducing agent or an oxygen scavenger placed in advance, and introduce an inert gas, such as nitrogen (the purity of nitrogen is the same as that in the prior art) sintered at 1300 °C for 24 h, the heating rate before sintering was 200 °C/h, and the cooling rate after sintering was -200 °C/h. After sintering, a ceramic body with LuFe2O4 as the main component was obtained .
  • an inert gas such as nitrogen (the purity of nitrogen is the same as that in the prior art) sintered at 1300 °C for 24 h, the heating rate before sintering was 200 °C/h, and the cooling rate after sintering was -200 °C/h.
  • the purpose of this embodiment is to provide a rare earth element-iron oxide embryo.
  • step (3) Put the preform body obtained in step (3) into a closed sintering device with a reducing agent or an oxygen scavenger placed in advance, and introduce an inert gas, such as nitrogen (the purity of nitrogen is the same as that in the prior art) sintered at 1300 °C for 24 h, the heating rate before sintering was 200 °C/h, and the cooling rate after sintering was -200 °C/h. After sintering, a ceramic body with YFe2O4 as the main component was obtained. .
  • an inert gas such as nitrogen (the purity of nitrogen is the same as that in the prior art) sintered at 1300 °C for 24 h, the heating rate before sintering was 200 °C/h, and the cooling rate after sintering was -200 °C/h.
  • the reducibility of the reducing agent or the oxygen scavenger is slightly higher than the reducing activity of the iron powder, which can effectively reduce the residual oxidizing property in the environment to a level that just does not affect the raw materials, that is, it is reduced to three.
  • the reducing agent or oxygen scavenger can be solid, or can be a solid or liquid substance coated on the screen, mesh or four walls in the pipeline, as long as its reducing activity meets the aforementioned requirements.
  • this method can also be used for re-sintering of sintered product powders, which can ensure that the components of these sintered product powders remain unchanged.
  • the method for preparing a green body from rare earth element-iron oxide is used to protect the raw material by adding a reducing agent or deoxidizer whose reducing activity is slightly higher than that of the green body reducing agent in the sintering equipment. , which can effectively reduce the residual oxidizing property of the environment to the level that just does not affect the raw materials, so that the active components in the rare earth element-iron oxide embryo can accurately reach the target oxidation value, that is, the raw materials Fe or Fe 2+ are unified to Fe 3+ , to avoid the problem that the oxygen concentration in the environment needs to be reduced in the traditional technology to protect the raw materials, but in fact the existing technology cannot reduce the oxygen concentration to the required level.
  • the fluidity of the gas in the environment will not be changed during heating, which will affect the target oxidation value of the active ingredient.
  • the purity of the gas or the oxidizing property in the environment is adjusted to a level that does not affect the reaction, that is, the requirements for the purity of the inert gas or the oxidizing property in the environment during the reaction are not as strict as those in the prior art. Therefore, the method is easy to scale up and more efficient. It is convenient to prepare ceramic embryos of various large sizes and complex shapes, and the working gas does not contain flammable components such as hydrogen, so it is also more convenient to operate and safer.

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Abstract

本发明提出了一种以稀土元素-铁氧化物制备胚体的方法，涉及陶瓷材料合成技术领域。该方法将三氧化二铁、稀土元素氧化物和胚体还原剂混合，得到混合物，将混合物压制成预胚体，再将预胚体置于烧结装置中烧结，得到胚体；烧结装置内放置有还原剂或除氧剂，胚体还原剂为铁粉或氧化亚铁；还原剂或除氧剂的还原活性高于胚体还原剂的活性。本发明的优点在于，可以有效将环境的残余氧化性降低到刚好不影响原料的程度，使稀土元素-铁氧化物胚体中的活性成分准确达到目标氧化价，同时易于放大生产，也便于制备各种大尺寸或者复杂形状的陶瓷胚体。

Description

一种以稀土元素-铁氧化物制备胚体的方法 技术领域
本发明涉及陶瓷材料合成技术领域，具体而言，涉及一种以稀土元素-铁氧化物制备胚体的方法。
背景技术
稀有土-铁氧化物是具有可逆氧化还原活性的陶瓷态物质。在利用陶瓷态物质制备胚体的过程中，常用到高温，在高温条件下，为保证胚体效果，需要使产物中的活性成分准确达到目标氧化价，但这一要求需要比较苛刻的条件。若无特殊手段，现有技术中常用的反应容器的密闭程度、保护气纯度本身的误差使得产物中活性成分很难达到目标氧化价的要求。
目前，人们通过使用以下几种方法利用陶瓷态物质制备胚体：
1、湿法：向铁和对应稀土元素的盐溶液中加入配位聚合剂，再蒸干溶液煅烧得到混合粉末。此方法本适用于原料无氧化还原活性且不需要由粉末成型的产物的制备，可直接得到成品，后续仍然需要和固相法类似的加热处理，但该方法由于复杂且没有增益效果现已基本淘汰。
2、固相反应法：该方法直接使用氧化铁、铁粉以及稀土氧化物的粉末混合压制成型后进行加热反应制备胚体。具体又分为还原性气氛法和密闭容器法。还原性气氛法是指除惰性气体外，在反应环境中加入一定浓度的还原性气体使产物中的铁成分达到需要的氧化价。此方法中还原剂一般为浓度不超过5％的氢气或一氧化碳；此浓度的最佳精确值理论上已有相图测 定，但实际少见试图达到精确值的尝试。此外，也有报告指明未使用还原剂，仅称将环境中的氧浓度降低到足够低的浓度，即可使活性成分达到目标氧化价，但该研究中指出的足够低的浓度是实际生产中难以达到的级别(～10 -14Pa)。此类方法难以精确控制反应环境还原性强度，进而难以稳定得到高纯度的产物。密闭容器法是指使用化学计量比的三价铁、还原性铁及稀土氧化物，在充入惰性气体的密闭容器例如封管中加热反应以制备胚体。此方法保持产物纯度的效果较好，但将反应容器密封需要比较复杂的操作，难以大批量生产。
因此，如果能研发一种方法，可以克服前述缺陷，将有利于稀有土-铁氧化物在陶瓷胚体制备中的广泛应用。
发明内容
本发明的目的在于提供一种以稀土元素-铁氧化物制备胚体的方法，该方法可以使稀土元素-铁氧化物胚体中的活性成分准确达到目标氧化价。
本发明解决其技术问题是采用以下技术方案来实现的。
本申请实施例提供一种以稀土元素-铁氧化物制备胚体的方法，包括如下步骤：将三氧化二铁、稀土元素氧化物和胚体还原剂混合均匀，得到混合物，将混合物压制成预胚体，再将预胚体置于烧结装置中烧结，得到胚体；烧结装置内放置有还原剂或除氧剂，胚体还原剂为铁粉或氧化亚铁；还原剂或除氧剂的还原活性高于胚体还原剂的活性。
综上，相对于现有技术，本发明的实施例至少具有如下优点或有益效果：
本发明提供的以稀土元素-铁氧化物制备胚体的方法，该方法通过在烧结设备内加入还原活性略高于胚体还原剂的还原剂或除氧剂，用于保护原料，可以有效将环境的残余氧化性降低到刚好不影响原料的程度，使稀土元素-铁氧化物胚体中的活性成分准确达到目标氧化价，避免传统技术中需要将环境中的氧浓度降低以便保护原料但实际上现有技术又无法将氧浓度下降到需要级别的问题，同时易于放大生产，也便于制备各种大尺寸或者复杂形状的陶瓷胚体。
具体实施方式
为使本发明实施例的目的、技术方案和优点更加清楚，下面将对本发明实施例中的技术方案进行清楚、完整地描述。实施例中未注明具体条件者，按照常规条件或制造商建议的条件进行。所用试剂或仪器未注明生产厂商者，均为可以通过市售购买获得的常规产品。
本申请实施例提供一种稀土元素-铁氧化物胚体胚体的方法，包括如下步骤：将三氧化二铁、稀土元素氧化物和胚体还原剂混合均匀，得到混合物，将混合物压制成预胚体，再将预胚体置于烧结装置中烧结，得到胚体；烧结装置内放置有还原剂或除氧剂，胚体还原剂为铁粉或氧化亚铁；还原剂或除氧剂的还原活性高于胚体还原剂的活性。通过在烧结设备内加入还原活性略高于胚体还原剂的还原剂或除氧剂，用于保护原料，可以有效将环境的残余氧化性降低到刚好不影响原料的程度，使稀土元素-铁氧化物胚体中的活性成分准确达到目标氧化价，避免传统技术中需要将环境中的氧浓度降低以便保护原料但实际上现有技术又无法将氧浓度下降到需要级别的问题。
在本发明的一些实施例中，上述方法中稀土元素氧化物包括Yb、Y和Lu的氧化物中的一种或多种。同时也可以是Yb、Y和Lu的氧化物以外与Yb、Y和Lu性质相近的其他稀土元素氧化物。
在本发明的一些实施例中，上述方法中三氧化二铁、稀土元素氧化物和铁粉的摩尔数量比为(4～6):(2～4):(1～3)。该比例下的原料制备的胚体中活性物质能达到目标氧化价，纯度较高。
在本发明的一些实施例中，上述方法中三氧化二铁、稀土元素氧化物和铁粉的摩尔数量比为5:3:2。该比例下的原料制备的胚体中活性物质达到目标氧化价的百分比最高。
在本发明的一些实施例中，上述方法中三氧化二铁、稀土元素氧化物和氧化亚铁的摩尔数量比为(0.5～1.5):(0.5～1.5):(1～3)。该比例下的原料制备的胚体中活性物质能达到目标氧化价，纯度较高。
在本发明的一些实施例中，上述方法中三氧化二铁、稀土元素氧化物和氧化亚铁的摩尔数量比为1:1:2。该比例下的原料制备的胚体中活性物质达到目标氧化价的百分比最高。
在本发明的一些实施例中，上述方法中烧结的温度为1200～1500℃，烧结的时间为15～26h。该范围下的烧结温度和时间均能得到质量相当的胚体。
在本发明的一些实施例中，上述方法中烧结的温度为1300℃，烧结的时间为24h。
在本发明的一些实施例中，上述方法中铁粉的粒度低于325目。该粒度以及小于该粒度的铁粉可以保证原料被充分还原，达到目标氧化价。
在本发明的一些实施例中，上述方法中三氧化二铁、稀土元素氧化物和胚体还原剂通过研磨混合，研磨所用液体为异丙醇或丙酮中的一种或两种。除了使用异丙醇或丙酮加入普通研钵对原料进行研磨，也可以将原料加入球磨装置中进行混合。
以下结合实施例对本发明的特征和性能作进一步的详细描述。
实施例1
本实施例的目的在于提供一种稀土元素-铁氧化物胚体。
本实施例提供的稀土-氧化物胚体的制备方法，包括如下步骤：
(1)按摩尔数量比5:3:2精准称量三氧化二铁、三氧化二Yb和铁粉；
(2)将称量好的三氧化二铁、三氧化二Yb和铁粉分别加入异丙醇中，研磨至适宜粒度，其中铁粉的粒度需要在325目以下(小于等于325目)，达到目标粒度后，蒸发异丙醇，得到三氧化二铁、三氧化二Yb和铁粉的目标粒度的粉末，将前述目标粒度的粉末混合后，得到混合物；
(3)将混合物压制成预胚体，可选用700MPa的单轴压片机压制成小块，或者选用更大尺寸的设备(如全向液压设备)压制成大尺寸的预胚体；
(4)将步骤(3)得到的预胚体放入密闭的且预先放置有还原剂或者除氧剂的烧结设备中，并通入惰性气体，如氮气(氮气纯度与现有技术中的单体纯度相当)，于1300℃烧结24h，烧结前升温的速率为200℃/h，烧结完成后降温的速率为-200℃/h，烧结完成后，即得到以YbFe2O4为主要成分的陶瓷胚体。
实施例2
本实施例的目的在于提供一种稀土元素-铁氧化物胚体。
本实施例提供的稀土-氧化物胚体的制备方法，包括如下步骤：
(1)按摩尔数量比5:3:2精准称量三氧化二铁、三氧化二Yb和铁粉；
(2)将称量好的三氧化二铁、三氧化二Yb和铁粉分别加入丙酮中，研磨至适宜粒度，其中铁粉的粒度需要在325目以下(小于等于325目)，达到目标粒度后，蒸发异丙醇，得到三氧化二铁、三氧化二Yb和铁粉的目标粒度的粉末，将前述目标粒度的粉末混合后，得到混合物；
(3)将混合物压制成预胚体，可选用700MPa的单轴压片机压制成小块，或者选用更大尺寸的设备(如全向液压设备)压制成大尺寸的预胚体；
(4)将步骤(3)得到的预胚体放入密闭的且预先放置有还原剂或者除氧剂的烧结设备中，并通入惰性气体，如氮气(氮气纯度与现有技术中的单体纯度相当)，于1300℃烧结24h，烧结前升温的速率为200℃/h，烧结完成后降温的速率为-200℃/h，烧结完成后，即得到以YbFe2O4为主要成分的陶瓷胚体。
实施例3
本实施例的目的在于提供一种稀土元素-铁氧化物胚体。
本实施例提供的稀土-氧化物胚体的制备方法，包括如下步骤：
(1)按摩尔数量比4:2:1精准称量三氧化二铁、三氧化二Yb和铁粉；
(2)将称量好的三氧化二铁、三氧化二Yb和铁粉分别加入异丙醇中，研磨至适宜粒度，其中铁粉的粒度需要在325目以下(小于等于325目)，达到目标粒度后，蒸发异丙醇，得到三氧化二铁、三氧化二Yb和铁粉的目标粒度的粉末，将前述目标粒度的粉末混合后，得到混合物；
(3)将混合物压制成预胚体，可选用700MPa的单轴压片机压制成小块，或者选用更大尺寸的设备(如全向液压设备)压制成大尺寸的预胚体；
(4)将步骤(3)得到的预胚体放入密闭的且预先放置有还原剂或者除氧剂的烧结设备中，并通入惰性气体，如氮气(氮气纯度与现有技术中的单体纯度相当)，于1200℃烧结22h，烧结前升温的速率为200℃/h，烧结完成后降温的速率为-200℃/h，烧结完成后，即得到以YbFe2O4为主要成分的陶瓷胚体。
实施例4
本实施例的目的在于提供一种稀土元素-铁氧化物胚体。
本实施例提供的稀土-氧化物胚体的制备方法，包括如下步骤：
(1)按摩尔数量比6:4:3精准称量三氧化二铁、三氧化二Yb和铁粉；
(2)将称量好的三氧化二铁、三氧化二Yb和铁粉分别加入异丙醇中，研磨至适宜粒度，其中铁粉的粒度需要在325目以下(小于等于325目)，达到目标粒度后，蒸发异丙醇，得到三氧化二铁、三氧化二Yb和铁粉的目标粒度的粉末，将前述目标粒度的粉末混合后，得到混合物；
(3)将混合物压制成预胚体，可选用700MPa的单轴压片机压制成小块，或者选用更大尺寸的设备(如全向液压设备)压制成大尺寸的预胚体；
(4)将步骤(3)得到的预胚体放入密闭的且预先放置有还原剂或者除氧剂的烧结设备中，并通入惰性气体，如氮气(氮气纯度与现有技术中的单体纯度相当)，于1500℃烧结26h，烧结前升温的速率为200℃/h，烧结完成后降温的速率为-200℃/h，烧结完成后，即得到以YbFe2O4为主要成分的陶瓷胚体。
实施例5
本实施例的目的在于提供一种稀土元素-铁氧化物胚体。
本实施例提供的稀土-氧化物胚体的制备方法，包括如下步骤：
(1)按摩尔数量比1:1:2精准称量三氧化二铁、三氧化二Yb和氧化亚铁；
(2)将称量好的三氧化二铁、三氧化二Yb和氧化亚铁分别加入异丙醇中，研磨至适宜粒度，其中铁粉的粒度需要在325目以下(小于等于325目)，达到目标粒度后，蒸发异丙醇，得到三氧化二铁、三氧化二Yb和氧化亚铁的目标粒度的粉末，将前述目标粒度的粉末混合后，得到混合物；
(3)将混合物压制成预胚体，可选用700MPa的单轴压片机压制成小块，或者选用更大尺寸的设备(如全向液压设备)压制成大尺寸的预胚体；
(4)将步骤(3)得到的预胚体放入密闭的且预先放置有还原剂或者除氧剂的烧结设备中，并通入惰性气体，如氮气(氮气纯度与现有技术中的单体纯度相当)，于1300℃烧结24h，烧结前升温的速率为200℃/h，烧结完成后降温的速率为-200℃/h，烧结完成后，即得到以YbFe2O4为主要成分的陶瓷胚体。
实施例6
本实施例的目的在于提供一种稀土元素-铁氧化物胚体。
本实施例提供的稀土-氧化物胚体的制备方法，包括如下步骤：
(1)按摩尔数量比0.5:0.5:2精准称量三氧化二铁、三氧化二Yb和氧化亚铁；
(2)将称量好的三氧化二铁、三氧化二Yb和氧化亚铁分别加入异丙醇中，研磨至适宜粒度，其中铁粉的粒度需要在325目以下(小于等于325目)，达到目标粒度后，蒸发异丙醇，得到三氧化二铁、三氧化二Yb和氧化亚铁的目标粒度的粉末，将前述目标粒度的粉末混合后，得到混合物；
(3)将混合物压制成预胚体，可选用700MPa的单轴压片机压制成小块，或者选用更大尺寸的设备(如全向液压设备)压制成大尺寸的预胚体；
(4)将步骤(3)得到的预胚体放入密闭的且预先放置有还原剂或者除氧剂的烧结设备中，并通入惰性气体，如氮气(氮气纯度与现有技术中的单体纯度相当)，于1400℃烧结23h，烧结前升温的速率为200℃/h，烧结完成后降温的速率为-200℃/h，烧结完成后，即得到以YbFe2O4为主要成分的陶瓷胚体。
实施例7
本实施例的目的在于提供一种稀土元素-铁氧化物胚体。
本实施例提供的稀土-氧化物胚体的制备方法，包括如下步骤：
(1)按摩尔数量比1.5:1.5:1精准称量三氧化二铁、三氧化二Yb和氧化亚铁；
(2)将称量好的三氧化二铁、三氧化二Yb和氧化亚铁分别加入异丙醇中，研磨至适宜粒度，其中铁粉的粒度需要在325目以下(小于等于325目)，达到目标粒度后，蒸发异丙醇，得到三氧化二铁、三氧化二Yb和铁粉的目标粒度的粉末，将前述目标粒度的粉末混合后，得到混合物；
(3)将混合物压制成预胚体，可选用700MPa的单轴压片机压制成小块，或者选用更大尺寸的设备(如全向液压设备)压制成大尺寸的预胚体；
(4)将步骤(3)得到的预胚体放入密闭的且预先放置有还原剂或者除氧剂的烧结设备中，并通入惰性气体，如氮气(氮气纯度与现有技术中的单体纯度相当)，于1200℃烧结15h，烧结前升温的速率为200℃/h，烧结完成后降温的速率为-200℃/h，烧结完成后，即得到以YbFe2O4为主要成分的陶瓷胚体。
实施例8
本实施例的目的在于提供一种稀土元素-铁氧化物胚体。
本实施例提供的稀土-氧化物胚体的制备方法，包括如下步骤：
(1)按摩尔数量比1:1:2精准称量三氧化二铁、三氧化二Yb和氧化亚铁；
(2)将称量好的三氧化二铁、三氧化二Yb和氧化亚铁分别加入丙酮中，研磨至适宜粒度，其中铁粉的粒度需要在325目以下(小于等于325 目)，达到目标粒度后，蒸发异丙醇，得到三氧化二铁、三氧化二Yb和氧化亚铁的目标粒度的粉末，将前述目标粒度的粉末混合后，得到混合物；
(3)将混合物压制成预胚体，可选用700MPa的单轴压片机压制成小块，或者选用更大尺寸的设备(如全向液压设备)压制成大尺寸的预胚体；
(4)将步骤(3)得到的预胚体放入密闭的且预先放置有还原剂或者除氧剂的烧结设备中，并通入惰性气体，如氮气(氮气纯度与现有技术中的单体纯度相当)，于1500℃烧结26h，烧结前升温的速率为200℃/h，烧结完成后降温的速率为-200℃/h，烧结完成后，即得到以YbFe2O4为主要成分的陶瓷胚体。
实施例9
本实施例的目的在于提供一种稀土元素-铁氧化物胚体。
本实施例提供的稀土-氧化物胚体的制备方法，包括如下步骤：
(1)按摩尔数量比5:3:2精准称量三氧化二铁、三氧化二Lu和铁粉；
(2)将称量好的三氧化二铁、三氧化二Lu和铁粉分别加入异丙醇中，研磨至适宜粒度，其中铁粉的粒度需要在325目以下(小于等于325目)，达到目标粒度后，蒸发异丙醇，得到三氧化二铁、三氧化二Lu和铁粉的目标粒度的粉末，将前述目标粒度的粉末混合后，得到混合物；
(3)将混合物压制成预胚体，可选用700MPa的单轴压片机压制成小块，或者选用更大尺寸的设备(如全向液压设备)压制成大尺寸的预胚体；
(4)将步骤(3)得到的预胚体放入密闭的且预先放置有还原剂或者除氧剂的烧结设备中，并通入惰性气体，如氮气(氮气纯度与现有技术中的单体纯度相当)，于1300℃烧结24h，烧结前升温的速率为200℃/h，烧结完成后降温的速率为-200℃/h，烧结完成后，即得到以LuFe2O4为主要成分的陶瓷胚体。
实施例10
本实施例的目的在于提供一种稀土元素-铁氧化物胚体。
本实施例提供的稀土-氧化物胚体的制备方法，包括如下步骤：
(1)按摩尔数量比5:3:2精准称量三氧化二铁、Y2O3和铁粉；
(2)将称量好的三氧化二铁、Y2O3和铁粉分别加入异丙醇中，研磨至适宜粒度，其中铁粉的粒度需要在325目以下(小于等于325目)，达到目标粒度后，蒸发异丙醇，得到三氧化二铁、Y2O3和铁粉的目标粒度的粉末，将前述目标粒度的粉末混合后，得到混合物；
(3)将混合物压制成预胚体，可选用700MPa的单轴压片机压制成小块，或者选用更大尺寸的设备(如全向液压设备)压制成大尺寸的预胚体；
(4)将步骤(3)得到的预胚体放入密闭的且预先放置有还原剂或者除氧剂的烧结设备中，并通入惰性气体，如氮气(氮气纯度与现有技术中的单体纯度相当)，于1300℃烧结24h，烧结前升温的速率为200℃/h，烧结完成后降温的速率为-200℃/h，烧结完成后，即得到以YFe2O4为主要成分的陶瓷胚体。
实施例1～10步骤(4)中还原剂或者除氧剂的还原性略高于铁粉的还原活性，可以有效将环境中的残余氧化性降低到刚好不影响原料的程度，即降低到三价铁可以自行分解的水平。还原剂或者除氧剂可以是固态的，也可以是涂覆在管道内的筛、网或四壁上的固态或液态物质，只要其还原活性达到前述要求即可。同时，虽然实施例中给出的原料是从头烧结，但也可以将该方法用于烧结后的产物粉末重新烧结，可以保证这些烧结后的产物粉末的成分不变。
综上所述，本发明实施例的以稀土元素-铁氧化物制备胚体的方法，通过在烧结设备内加入还原活性略高于胚体还原剂的还原剂或除氧剂，用于保护原料，可以有效将环境的残余氧化性降低到刚好不影响原料的程度，使稀土元素-铁氧化物胚体中的活性成分准确达到目标氧化价，即将原料Fe或Fe 2+都统一到Fe 3+，避免传统技术中需要将环境中的氧浓度降低以便保护原料但实际上现有技术又无法将氧浓度下降到需要级别的问题。同时，由于本发明提供的方法是在固相原料中配制而成，在加热时就不会因为环境中的气体的流动性发生改变，影响活性成分达到目标氧化价，由于无需将烧结时的惰性气体的纯度或环境中的氧化性调至不影响反应的级别，即反应时惰性气体的纯度或环境中氧化性的要求不会像现有技术中那么严格，因此，该方法易于放大，也更加便于制备各种大尺寸和复杂形状的陶瓷胚体，工作气体中不含氢气等可燃成分，因此也更方便操作，更加安全。
以上所描述的实施例是本发明一部分实施例，而不是全部的实施例。本发明的实施例的详细描述并非旨在限制要求保护的本发明的范围，而是仅仅表示本发明的选定实施例。基于本发明中的实施例，本领域普通技术人员在没有作出创造性劳动前提下所获得的所有其他实施例，都属于本发明保护的范围。

Claims (10)

  1. 一种以稀土元素-铁氧化物制备胚体的方法，其特征在于，包括如下步骤：将三氧化二铁、稀土元素氧化物和胚体还原剂混合，得到混合物，将混合物压制成预胚体，再将预胚体置于烧结装置中烧结，得到胚体；所述烧结装置内放置有还原剂或除氧剂，所述胚体还原剂为铁粉或氧化亚铁；所述还原剂或除氧剂的还原活性高于所述胚体还原剂的活性。
  2. 根据权利要求1所述的方法，其特征在于，所述稀土元素氧化物包括Yb、Y和Lu的氧化物的一种或多种。
  3. 根据权利要求1所述的方法，其特征在于，所述三氧化二铁、稀土元素氧化物和铁粉的摩尔数量比为(4～6):(2～4):(1～3)。
  4. 根据权利要求3所述的方法，其特征在于，所述三氧化二铁、稀土元素氧化物和铁粉的摩尔数量比为5:3:2。
  5. 根据权利要求1所述的方法，其特征在于，所述三氧化二铁、稀土元素氧化物和氧化亚铁的摩尔数量比为(0.5～1.5):(0.5～1.5):(1～3)。
  6. 根据权利要求5所述的方法，其特征在于，所述三氧化二铁、稀土元素氧化物和氧化亚铁的摩尔数量比为1:1:2。
  7. 根据权利要求1-6任意一项所述的方法，其特征在于，所述烧结的温度为1200～1500℃，所述烧结的时间为15～26h。
  8. 根据权利要求7所述的方法，其特征在于，所述烧结的温度为1300℃，所述烧结的时间为24h。
  9. 根据权利要求1-6任意一项所述的方法，其特征在于，所述铁粉的粒度低于325目。
  10. 根据权利要求1-6任意一项所述的方法，其特征在于，三氧化二铁、稀土元素氧化物和胚体还原剂通过研磨混合，研磨所用液体为异丙醇或丙酮中的一种或两种。
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