阅读说明：本技术 一种多组分粉体原料的预处理方法 (Pretreatment method of multi-component powder raw material ) 是由 毛召召 李志涛 周游 陈刚 杜立华 熊良明 于 2021-01-05 设计创作，主要内容包括：本发明公开了一种多组分粉体原料的预处理方法,包括以下步骤：将包含敏感组分的多组分粉体原料加热升温直至粉体原料中敏感组分与其他粉体原料反应为更稳定的化合物粉体,获得含有更稳定的化合物粉体的多组分粉体原料；所述敏感组分为挥发性或不稳定的组成物。本发明提供包含敏感组分的多组分粉体原料的预处理方法,通过预升温的手段,将易挥发或不稳定的敏感组分转换为更加稳定的粉体组分,有效减少易挥发或不稳定组分在烧结工艺中含量减少带来的组分偏移,避免由于组分偏移导致的最终产品性能不佳,或者产品批次间一致性不好的问题。(The invention discloses a pretreatment method of a multi-component powder raw material, which comprises the following steps: heating a multi-component powder raw material containing a sensitive component until the sensitive component in the powder raw material reacts with other powder raw materials to form more stable compound powder, and obtaining the multi-component powder raw material containing the more stable compound powder; the sensitive component is a volatile or unstable composition. The invention provides a pretreatment method of a multi-component powder raw material containing sensitive components, which converts volatile or unstable sensitive components into more stable powder components by means of preheating, effectively reduces component deviation caused by content reduction of the volatile or unstable components in a sintering process, and avoids the problems of poor performance of final products or poor consistency among product batches due to component deviation.)

1. A pretreatment method of multi-component powder raw materials containing sensitive components is characterized by comprising the following steps:

heating a multi-component powder raw material containing a sensitive component until the sensitive component in the powder raw material reacts with other powder raw materials to form more stable compound powder, and obtaining the multi-component powder raw material containing the more stable compound powder;

the sensitive component is a volatile or unstable composition.

2. The pretreatment method of the multicomponent powder raw material containing the sensitive component according to claim 1, wherein the multicomponent powder raw material containing the sensitive component is heated to raise a temperature until the sensitive component in the powder raw material reacts with other powder raw materials to form more stable compound powder, and specifically comprises:

heating a multi-component powder raw material containing a sensitive component, and keeping the temperature within a preset temperature range until the sensitive component in the powder raw material reacts with other powder raw materials to form more stable compound powder.

3. The method according to claim 1, wherein the upper limit of the temperature range is not higher than the lowest melting point of each component in all powder raw materials and is not higher than the lowest melting point of each component in all powder raw materials combined in pairs;

the lower limit of the temperature range is preferably 0-150 ℃ lower than the maximum value of the upper limit of the temperature range.

4. The method according to claim 1, wherein when the melting point of the sensitive component is higher than the melting points of at least one other group of components, the multi-component powder raw material containing the sensitive component is heated and kept in a first temperature range until the temperature is lower than the melting point of the sensitive component, and the components of the sensitive component completely react to form a eutectic to obtain an intermediate material; the temperature is then raised to a second temperature range until the sensitive components in the intermediate react with the other constituents to form more stable compounds.

5. The method of claim 4, wherein the upper limit of the first temperature range is not higher than the lowest melting point of the composition and the melting points of the composition combined in pairs; the upper limit of the second temperature range is not higher than the lowest melting point value of each composition in the intermediate material and not higher than the lowest melting point value of each composition in every two compositions in all the intermediate materials according to the proportion.

6. The method for pretreating a multicomponent powder raw material containing a sensitive component according to claim 1, wherein when the number of sensitive components of the powder raw material is not less than two, the temperature is gradually maintained within a preset temperature range from low to high according to the sequence of the melting points of the sensitive components until the sensitive components react with other powder raw materials in sequence to form a more stable compound.

7. The method of claim 6, wherein the upper limit of the predetermined temperature range for each segment is not higher than the lowest melting point of all the components at the beginning of the segment and not higher than the lowest melting point of all the components at the beginning of the segment.

8. The pretreatment method of the multicomponent powder raw material containing the sensitive component as claimed in any one of claims 1 to 7, characterized in that the heat preservation time is 5-20 h; the heating rate is controlled within 10 ℃/min.

9. The method for pretreating a multicomponent powder raw material containing a sensitive component according to claim 1, wherein when the weight ratio of at least one sensitive component in the multicomponent powder raw material containing a sensitive component is less than or equal to a preset threshold, the preset threshold is preferably 5%, the multicomponent powder raw material containing a sensitive component is heated to increase the temperature so that the sensitive component reacts with other powder raw materials to form a more stable compound powder, and the temperature increase rate is less than or equal to 10 ℃/min. Preferably, when the melting point temperature value of the sensitive component is less than the melting point temperature of the reaction of the sensitive component and other powder raw materials, the heating rate is less than or equal to Ty/Tx 10 ℃/min; and when the melting point temperature value of the sensitive component is greater than the melting point temperature of the reaction of the sensitive component and other powder raw materials, the heating rate is less than or equal to (Ty-Tx)/Ty 10 ℃/min, wherein Ty is the melting point temperature value of the sensitive component, and Tx is the melting point temperature of the reaction of the sensitive component and other powder raw materials. The heating rate is not lower than 0.5 ℃/min.

10. The method of pretreating a multicomponent powder feedstock containing sensitive components of claim 1, further comprising ball milling the multicomponent powder feedstock containing the more stable compound powder to achieve comparable levels of particle size for each component.

Technical Field

The invention belongs to the field of material preparation, and particularly relates to a pretreatment method of a multi-component powder raw material containing a sensitive component.

Background

The powder raw material treatment is an important stage in the material preparation process, the pretreatment of the powder raw materials is involved in the preparation of materials such as glass, ceramics, crystals and the like, the pretreatment of the powder raw materials only comprises the processes of mixing and drying, the powder raw materials are directly put into a high-temperature furnace for preparing glass, stirring equipment is used for enabling glass liquid to be uniform, and the prepared ceramics are placed into the high-temperature furnace for sintering after being formed.

If the melting points of the raw material compositions are greatly different, or B is contained₂O₃、P₂O₅、TeO₂、Bi₂O₃、CaCO₃And the like are volatile, unstable and easily decomposed, and are volatilized at the high-temperature stages of material sintering and glass melting, so that component deviation is caused, and the final performance and the consistency among product batches are influenced.

Disclosure of Invention

Aiming at the defects or the improvement requirements of the prior art, the invention provides a pretreatment method of a multi-component powder raw material containing a sensitive component, which aims to ensure that the sensitive component in the powder raw material reacts with other powder raw materials to form more stable compound powder by accurately controlling the temperature of the multi-component powder raw material, and avoid component deviation caused by volatilization or instability of the sensitive component in the subsequent sintering step, thereby solving the technical problems of poor performance of the final product or poor consistency among product batches caused by the existing deviation of the addition amount of volatile and unstable components.

To achieve the above object, according to one aspect of the present invention, there is provided a method for pretreating a multicomponent powder raw material containing a sensitive component, comprising the steps of:

heating a multi-component powder raw material containing a sensitive component until the sensitive component in the powder raw material reacts with other powder raw materials to form more stable compound powder, and obtaining the multi-component powder raw material containing the more stable compound powder;

the sensitive component is a volatile or unstable composition.

Preferably, the method for pretreating a multicomponent powder raw material containing a sensitive component heats the multicomponent powder raw material containing the sensitive component until the sensitive component in the powder raw material reacts with other powder raw materials to form a more stable compound powder, and specifically comprises the following steps:

heating a multi-component powder raw material containing a sensitive component, and keeping the temperature within a preset temperature range until the sensitive component in the powder raw material reacts with other powder raw materials to form more stable compound powder.

Preferably, the upper limit of the temperature range of the pretreatment method for the multi-component powder raw material containing the sensitive component is not higher than the lowest melting point value of each component in all the powder raw materials and is not higher than the lowest melting point value of each component in all the powder raw materials combined pairwise according to the ratio;

the lower limit of the temperature range is preferably 0-150 ℃ lower than the maximum value of the upper limit of the temperature range.

Preferably, when the melting point of the sensitive component is higher than the melting point of at least one other group of components, the method for pretreating the multicomponent powder raw material containing the sensitive component heats the multicomponent powder raw material containing the sensitive component and keeps the temperature in a first temperature range until the temperature is lower than the melting point of the sensitive component and the components completely react to form a eutectic substance, so as to obtain an intermediate material; the temperature is then raised to a second temperature range until the sensitive components in the intermediate react with the other constituents to form more stable compounds.

Preferably, in the pretreatment method of the multicomponent powder raw material containing the sensitive component, the upper limit of the first temperature range is not higher than the lowest value of the melting point of the composition and the melting point of the composition combined pairwise according to the proportion; the upper limit of the second temperature range is not higher than the lowest melting point value of each composition in the intermediate material and not higher than the lowest melting point value of each composition in every two compositions in all the intermediate materials according to the proportion.

Preferably, in the pretreatment method of the multi-component powder raw material containing the sensitive components, when the number of the sensitive components of the powder raw material is not less than two, the temperature is kept in a preset temperature range in a segmented manner according to the sequence of the melting points of the sensitive components from low to high until the sensitive components react with other powder raw materials in sequence to form a more stable compound.

Preferably, for each section, the upper limit of the preset temperature range of the pretreatment method for the multi-component powder raw material containing the sensitive component is not higher than the lowest melting point value of all the components at the beginning of the section and not higher than the lowest melting point value of all the components at the beginning of the section, wherein the melting points of all the components are combined in pairs.

Preferably, the heat preservation time of the pretreatment method for the multi-component powder raw material containing the sensitive component is 5-20 h; the heating rate is controlled within 10 ℃/min.

Preferably, in the method for pretreating a multi-component powder raw material containing a sensitive component, when the weight ratio of at least one sensitive component in the multi-component powder raw material containing a sensitive component is lower than or equal to a preset threshold, the preset threshold is preferably 5%, the multi-component powder raw material containing a sensitive component is heated to increase the temperature so that the sensitive component reacts with other powder raw materials to form more stable compound powder, and the temperature increase rate is less than or equal to 10 ℃/min. Preferably, when the melting point temperature value of the sensitive component is less than the melting point temperature of the reaction of the sensitive component and other powder raw materials, the heating rate is less than or equal to Ty/Tx 10 ℃/min; and when the melting point temperature value of the sensitive component is greater than the melting point temperature of the reaction of the sensitive component and other powder raw materials, the heating rate is less than or equal to (Ty-Tx)/Ty 10 ℃/min, wherein Ty is the melting point temperature value of the sensitive component, and Tx is the melting point temperature of the reaction of the sensitive component and other powder raw materials. The heating rate is not lower than 0.5 ℃/min.

Preferably, the method for pretreating a multicomponent powder raw material containing sensitive components further comprises ball milling the multicomponent powder raw material containing more stable compound powder so that the particle size of each component reaches a comparable level.

In general, compared with the prior art, the above technical solution contemplated by the present invention can achieve the following beneficial effects:

the invention provides a pretreatment method of a multi-component powder raw material containing sensitive components, which converts volatile or unstable sensitive components into more stable powder components by means of preheating, effectively reduces component deviation caused by content reduction of the volatile or unstable components in a sintering process, and avoids the problems of poor performance of final products or poor consistency among product batches due to component deviation. Meanwhile, the final sintering temperature of the powder raw material is reduced, and the energy consumption of powder treatment in the later stage process is reduced.

Drawings

FIG. 1 is a binary phase diagram having a melting point lower than the melting points of the components;

FIG. 2 is a binary phase diagram with a melting point higher than the melting points of the components.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

The invention provides a pretreatment method of a multi-component powder raw material containing sensitive components, which comprises the following steps:

heating a multi-component powder raw material containing a sensitive component until the sensitive component in the powder raw material reacts with other powder raw materials to form more stable compound powder, and obtaining the multi-component powder raw material containing the more stable compound powder;

the sensitive component is a volatile or unstable composition.

Generally, the weight ratio of the sensitive components exceeds a preset threshold value, for example, 5%, and heat preservation is needed to ensure complete reaction; heating a multi-component powder raw material containing a sensitive component, and keeping the temperature within a preset temperature range until the sensitive component in the powder raw material reacts with other powder raw materials to form more stable compound powder, so as to obtain the multi-component powder raw material containing more stable compound powder; the sensitive component is a volatile or unstable composition. Preferably, the heat preservation time is 5-20 h.

The upper limit of the temperature range is not higher than the lowest melting point value of each composition in all the powder raw materials and is not higher than the lowest melting point value of each composition in all the powder raw materials in pairwise combination according to the proportion;

the lower limit of the temperature range is preferably 0-150 ℃ lower than the maximum value of the upper limit of the temperature range; experiments have confirmed that in this range, the sensitive component reacts more rapidly and completely to a more stable compound powder. In a preferable scheme, when the melting point of the sensitive component is higher than the melting points of at least one group of other components, heating a multi-component powder raw material containing the sensitive component, and keeping the temperature in a first temperature range until the temperature is lower than the melting point of the sensitive component, and enabling the components to completely react to form a eutectic substance to obtain an intermediate material; the temperature is then raised to a second temperature range until the sensitive components in the intermediate react with the other constituents to form more stable compounds. The upper limit of the first temperature range is not higher than the melting point of the sensitive component and not higher than the lowest value of the melting point of each composition which is combined pairwise according to the proportion, and the upper limit of the second temperature range is not higher than the lowest value of the melting point of each composition in the intermediate material and not higher than the lowest value of the melting point of each composition which is combined pairwise according to the proportion in all the intermediate materials.

According to the preferable scheme, when the sensitive components of the powder raw material are not less than two, the temperature is kept in a preset temperature range in a segmented manner according to the sequence of the melting points of the sensitive components from low to high until the sensitive components react with other powder raw materials in sequence to form a more stable compound; for each section, the upper limit of the preset temperature range is not higher than the lowest melting point value of all the compositions at the beginning of the section and not higher than the lowest melting point value of all the compositions at the beginning of the section, which are combined in pairs according to the proportion.

The first temperature range, the second temperature range, or the temperature range of each section is a special case of the preset temperature range, and the lower limit of the temperature range is preferably 0-150 ℃ lower than the maximum value of the upper limit of the temperature range.

As shown in fig. 1, the dotted line indicates the melting point of component T1, the melting point of component A, B is TA or TB, the upper limit of the preset temperature is not higher than TA or Tm, and the component a melts and the powder morphology changes. In fig. 2, component B has the lowest melting point, and the predetermined temperature should be lower than component B melting point TB.

The components are preferably the parts with the maximum content, the total mass of the components is more than 80 percent, and the single mass of the components is more than 5 percent, and the whole components of the powder raw materials can be better controlled by processing the components according to the method, so that the consistency of the product is higher.

When the weight ratio of at least one sensitive component in the multi-component powder raw materials containing the sensitive components is lower than or equal to a preset threshold, the preset threshold is preferably 5%, the multi-component powder raw materials containing the sensitive components are heated to increase the temperature, so that the sensitive components and other powder raw materials react to form more stable compound powder, and the temperature increase rate is less than or equal to 10 ℃/min. Preferably, when the melting point temperature value of the sensitive component is less than the melting point temperature of the reaction of the sensitive component and other powder raw materials, the heating rate is less than or equal to Ty/Tx 10 ℃/min; and when the melting point temperature value of the sensitive component is greater than the melting point temperature of the reaction of the sensitive component and other powder raw materials, the heating rate is less than or equal to (Ty-Tx)/Ty 10 ℃/min, wherein Ty is the melting point temperature value of the sensitive component, and Tx is the melting point temperature of the reaction of the sensitive component and other powder raw materials. The heating rate is not lower than 0.5 ℃/min.

The multi-component powder raw material and the intermediate material are uniformly mixed powder raw materials, the uniformity degree of the multi-component powder raw material and the intermediate material is analyzed by a particle size analysis method, an image method or a regional element quantitative method, the dispersion degree of different sample components is tested to meet normal distribution, and the ratio of standard deviation to average value is below 2%, preferably below 1%.

When the particle size analysis method is used for evaluation, the particle size distribution after ball milling, the median particle size D50 value in more than 10 sample tests is taken as the particle size, and the ratio of the standard deviation of the particle size to the average particle size is less than 2 percent, preferably 1 percent, namely the particles are considered to be uniform.

When an image analysis method is adopted for evaluation, the method specifically comprises the following steps: the method comprises the steps of taking pictures of different powder components with different colors, particle sizes or other morphological differences by using a microscope or a high-definition camera, and analyzing the distribution states of at least 10 different selected areas according to the powder differences, wherein the distribution states comprise the internal dispersion uniformity of the selected areas and the dispersion consistency among the different selected areas. The different powder components in the selected area are uniformly dispersed and distributed, the proportion of the same powder component in different selected areas is tested, and the proportion of the standard deviation of the proportion to the average proportion is calculated to be less than 2 percent, preferably less than 1 percent, namely the powder components are considered to be uniform.

When the quantitative analysis method of the regional elements is adopted, the method specifically comprises the following steps: testing the component element content of the unit sample, calculating the content ratio of the same powder component among different samples, and calculating the ratio of the ratio standard deviation to the average ratio, wherein the ratio is less than 2 percent, preferably less than 1 percent, and the sample is considered to be uniform.

When the multi-component powder raw material is heated, the heating rate is controlled within 10 ℃/min; the multi-component powder raw material is kept within a preset temperature range, and the heat preservation time is 5-20 hours. The efficiency and the pretreatment effect are considered, the heating rate is not too slow, and the production efficiency is too low. When the content of the sensitive component is less than 5%, the temperature rising speed is not too fast, the reaction is easy to be insufficient, and the heat preservation time is the same.

Preferably, the method also comprises the step of performing ball milling on the multi-component powder raw material containing the more stable compound powder to enable the particle size of each component to reach a considerable level so as to be beneficial to sintering and forming.

According to the pretreatment method of the multi-component powder raw material, volatile or unstable components are considered firstly, the raw material is treated into a more stable intermediate product at a lower temperature, and component deviation caused by reduction of the content of the volatile or unstable components is reduced. The heat preservation range of the multi-component powder raw material is the key for reducing component deviation, the loss of the adding amount of volatile or unstable components can be caused by too high temperature, the more stable intermediate product can not be fully reacted by the volatile or unstable components due to too low temperature, and the larger component deviation still exists in the sintering treatment process. The invention selects proper temperature to reduce the component deviation caused by volatilization in the material preparation process, and the sintering or melting temperature can be obviously reduced.

In addition, the components which are fully mixed can be fully contacted with each other, so that the reaction is better.

The following are examples:

example 1A 0.2Na₂O-0.2B₂O₃-0.6SiO₂Multicomponent glass powder with Na as raw material₂CO₃、B₂O₃、SiO₂。

Wherein Na₂CO₃Melting point lower than decomposition temperature, glass will decompose to generate bubbles as sensitive component, B₂O₃Is volatile and is a sensitive component, and adopts multi-section heat preservation.

The pretreatment steps are specifically as follows:

accurately weighed in proportion by Na₂CO₃、B₂O₃、SiO₂Ball milling three kinds of powder to homogeneous.

Heating the multi-component powder raw material, wherein the heating rate is as follows: 10 ℃/min, maintaining at 800-850 ℃, and keeping the temperature for 8 h.

Determination of the upper limit of the temperature range, due to B₂O₃The melting point is lower, is 450 ℃, and is Na₂CO₃Will eventually decompose due to Na₂CO₃The melting point is about 850 ℃, and the bubbles generated during glass melting can be reduced by forming intermediate components by pre-burning. Inquiring a phase diagram according to the melting points of the components, wherein the melting point temperatures of the components are all higher than B₂O₃The melting point is set so that the first predetermined temperature range is 400-450 ℃. The second preset temperature is not more than 850 ℃ and is made of Na₂O-B₂O₃，Na₂O-SiO₂And obtaining a phase diagram, wherein the lowest melting points of the components are higher than 850 ℃ under the proportioning composition, so that the second preset temperature range is set to be 800-850 ℃. And after secondary ball milling, finishing treatment, testing, wherein the three components are not volatilized at the heat preservation temperature, if the powder is not hardened or melted, indicating that the temperature does not exceed the upper limit, and detecting whether the sensitive components have reacted or not and whether the reaction is complete or not through XRD and differential thermal analysis.

The results of the measurements show that the components are almost free from deviation and the reaction of the sensitive components is complete after the pretreatment according to the method provided in this example.

Example 2

Bi_0.5Na_0.5TiO₃Ceramic powder with Na as raw material₂CO₃、Bi₂O₃、TiO₂。

Wherein Na₂CO₃、Bi₂O₃Is a sensitive component.

The pretreatment steps are specifically as follows:

accurately weighed in proportion by Na₂CO₃、Bi₂O₃、TiO₂Ball milling three kinds of powder to homogeneous.

Heating the multi-component powder raw material, wherein the heating rate is as follows: 5 ℃/min and 750 ℃ and the holding time is 12 h.

Determination of the upper limit of the temperature range, Bi₂O₃Melting point 825 deg.C, Na₂CO₃Melting Point about 850 ℃ and query for Bi₂O₃-TiO₂And phase diagram, under the condition of obtaining the original components, the melting point temperature of the system is about 1200 ℃, the lowest melting point of any proportion is about 820 ℃, and the melting point of the tested components is about 800 ℃, so that the pre-sintering temperature is set to be within the range of 750-800 ℃. Due to the fact that two sensitive components with low melting points are adopted, in order to fully react, the heating rate is properly reduced and is not more than 6 ℃/min, the heat preservation time is prolonged, and the range of 10-15 h is achieved. After secondary ball milling, testing after finishing treatment, and evaluating by adopting a high-definition camera by an image method if Bi is present₂O₃The introduced yellow-green color completely disappears, and the powder turns to pure white, which indicates that the reaction is complete. Whether the sensitive components have reacted and whether the reaction is complete is detected by XRD and differential thermal analysis.

The results of the measurements show that the components are almost free from deviation and the reaction of the sensitive components is complete after the pretreatment according to the method provided in this example.

Example 3

0.3SiO₂-0.2B₂O₃-0.2La₂O₃-0.3TeO₂The multi-component glass powder is prepared from SiO₂、B₂O₃、La₂O₃、TeO₂。

Wherein B is₂O₃、TeO₂Is a volatile sensitive component.

The pretreatment steps are specifically as follows:

accurately weighed by SiO in proportion₂、B₂O₃、La₂O₃、TeO₂And ball-milling the four kinds of powder until the powder is uniform.

Due to B₂O₃Melting point 450 ℃ and TeO₂The melting point is 733 ℃, and two-stage heat preservation temperature needs to be set. Heating the multi-component powder raw material, keeping the temperature at a first preset temperature of 420 ℃, heating at a rate of 5 ℃/min, and keeping the temperature for 12 h. Determining the upper limit of the first preset temperature range in combination with B₂O₃The melting points of the components are higher than those of B₂O₃Melting point, i.e. upper temperature limit, of B₂O₃The melting point temperature is within the optimal heat preservation range of 400-450 ℃; then the temperature is increased to a second preset temperature of 650 ℃, the heating rate is 10 ℃/min, the heat preservation time is 6h, the second temperature range is determined, B₂O₃With SiO₂、La₂O₃Solid phase reaction to form a more stable composition, phase diagram B₂O₃With SiO₂The melting point is lowest at the mixture ratio and is about 1000 ℃, so the second temperature cannot exceed 1000 ℃. TeO₂The melting point of the components is higher than that of TeO when the components are mixed with other components₂Melting Point, B₂O₃-TeO₂The minimum melting point temperature is about 680 ℃, so the second predetermined temperature range can be set to 600-680 ℃.

After secondary ball milling, the treatment is finished and a test is carried out, and whether the sensitive components have reacted or not and whether the reaction is complete or not are detected through XRD and differential thermal analysis.

The results of the measurements show that the components are almost free from deviation and the reaction of the sensitive components is complete after the pretreatment according to the method provided in this example.

It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.