KR20230133491A - Titanium powder manufacturing method - Google Patents

Abstract

The present invention relates to a method for producing titanium-based powder, comprising the steps of charging a mixture of titanium-based powder and agglomeration inhibitor powder into a heating furnace; A deoxidation step of heating the heating furnace to deoxidize the titanium-based powder; and a recovery step of recovering the titanium-based powder from the mixture, wherein the agglomeration inhibitor powder has a particle size smaller than that of the titanium-based powder.
According to the present invention, it is possible to increase the recovery rate of deoxidized titanium-based powder.

Description

Titanium powder manufacturing method}

The present invention relates to a method for producing titanium-based powder, and more specifically, to a method for producing titanium-based powder capable of increasing the recovery rate of deoxidized titanium-based powder.

Spherical titanium powder and titanium alloy powder for 3D printing (hereinafter referred to as 'titanium-based powder') can be manufactured by two methods.

The first is a method of producing square powder from titanium sponge or scrap through a hydrogenation process, grinding/powdering process, and dehydrogenation process, and then sphericalizing it using a plasma heat source. This method produces square powder by grinding/powdering process. The oxygen content increases to about 3,000 ppm or more, and it is not easy to lower the oxygen content below 2,000 ppm even by spheronizing this square powder.

Another method is the Gas Atomization method, which produces spherical powder by melting a titanium ingot in an Ar atmosphere. Previously, this method was widely used to produce low-oxygen titanium-based powder. However, gas atomization requires an expensive low-oxygen titanium ingot, and even if a low-oxygen titanium ingot is used, hundreds of ppm of oxygen increases with powderization, making it difficult to manufacture titanium-based powder with an oxygen content of less than 800 ppm.

Therefore, in order to economically produce low-oxygen titanium-based powder, a method of deoxidizing commercially available spherical titanium-based powder can be considered. However, deoxidation of titanium proceeds at a high temperature, and in particular, as the size of the titanium-based powder becomes smaller, agglomeration occurs between the powders, so there is a problem that the recovery rate of the titanium-based powder in powder form after deoxidation is low.

KR 10-2019-007474 A

Therefore, the purpose of the present invention is to solve such conventional problems and provide a method for producing titanium-based powder that can increase the recovery rate of deoxidized titanium-based powder.

The problem to be solved by the present invention is not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the description below.

The above object is, according to the present invention, a charging step of charging a mixture of titanium-based powder and agglomeration inhibitor powder into a heating furnace; A deoxidation step of heating the heating furnace to deoxidize the titanium-based powder; and a recovery step of recovering the titanium-based powder from the mixture, wherein the aggregation inhibitor powder is achieved by a titanium-based powder manufacturing method, wherein the agglomeration inhibitor powder has a smaller particle size than the titanium-based powder.

The aggregation inhibitor powder may be a calcium-based powder.

The method for producing titanium-based powder according to the present invention is performed after the recovery step, and includes a washing step of washing the recovered titanium-based powder; And a drying step of drying the washed titanium-based powder.

In the charging step, the deoxidizer powder is mixed with the mixture so that contact deoxidation can proceed during charging.

The agglomeration inhibitor powder preferably has a smaller particle size than the deoxidizer powder.

In the mixture, the weight of the aggregation inhibitor powder may be 1 to 5% based on the weight of the titanium-based powder.

In the charging step, the deoxidizing agent powder is charged separately from the mixture, so that non-contact deoxidation can proceed at a high temperature higher than the melting point of the deoxidizing agent. In this case, since the agglomeration phenomenon of the titanium-based powder intensifies, the weight of the agglomeration inhibitor powder in the mixture may be 8 to 12% compared to the weight of the titanium-based alloy powder.

According to the titanium-based powder manufacturing method according to the present invention, when deoxidizing at high temperature, the titanium-based powders are positioned apart from each other due to the agglomeration inhibitor located between the titanium-based powders, thereby reducing the agglomeration phenomenon between the titanium-based powders. , the recovery rate of titanium-based powder can be increased.

The above effect can be increased by specifying the ingredients of the agglomeration inhibitor powder and its weight compared to the titanium-based powder.

1 is an explanatory diagram of a method for producing titanium-based powder according to the present invention.
Figure 2 is an explanatory diagram of the principle of improving the recovery rate of the titanium-based powder production method according to the present invention;
Figure 3 is an explanatory diagram for the case where deoxidation is performed by contact in the titanium-based powder production method according to the present invention.

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.

Figure 1 shows an explanatory diagram of the method for producing titanium-based powder according to the present invention.

The method for producing titanium-based powder according to the present invention basically includes a charging step (S10), a deoxidation step (S20), and a recovery step (S30).

In the charging step (S10), a mixture of titanium-based powder and agglomeration inhibitor powder is charged into the heating furnace. Titanium-based powder may be a powder made of pure titanium or a powder made of titanium alloy. And the titanium alloy may include, for example, TiAl-based powder, and the TiAl-based powder may be Ti-48Al-2Nb-2Cr powder.

A flocculation inhibitor powder that satisfies the following three conditions is used. Firstly, it must not react with the titanium-based powder in the deoxidation step (S20) that follows the charging step (S10), secondly, it must not melt in the deoxidation step (S20), and thirdly, the particle size must be smaller than that of the titanium-based powder. Must have. For example, powders that satisfy these conditions may be made of calcium-based materials and have a particle size smaller than that of titanium-based powders.

In the charging step (S10), the deoxidizer powder along with the mixture may be charged into the heating furnace. The deoxidizer powder may be mixed with the mixture and charged, or may be charged separately from the mixture powder. For example, calcium powder may be used as the deoxidizing agent powder.

In the deoxidation step (S20), the titanium-based powder is deoxidized by heating the furnace. The heated deoxidizer powder can cause the titanium-based powder to be reduced, resulting in deoxidation of the titanium-based powder. In order to prevent oxygen from entering the heating furnace during deoxidation, the interior of the heating furnace may be formed in a vacuum atmosphere or an Ar atmosphere.

In the recovery step (S30), titanium-based powder is recovered from the mixture. Since the agglomeration inhibitor powder constituting the mixture is easily dissolved by washing, it is possible to recover the titanium-based powder.

Since the titanium-based powder and the agglomeration inhibitor powder that make up the mixture have different particle sizes, it is also possible to recover the titanium-based powder by filtering the mixture through a sieve.

According to the method for producing titanium-based powder of the present invention, it is possible to increase the recovery rate of titanium-based powder after deoxidation. That is, as a principle of improving the recovery rate of titanium-based powder, if the agglomeration inhibitor powder is not mixed, agglomeration phenomenon occurs between titanium-based powders (particles marked with 'Ti') due to heat during deoxidation, as shown in (a) of Figure 2. This occurs and the recovery rate of titanium in complete powder form decreases, but when the titanium-based powder is mixed with the agglomeration inhibitor powder, there is a gap between the titanium-based powders (particles marked 'Ti') as shown in (b) of Figure 2. The agglomeration inhibitor (particles marked with 'CaO') located in causes each titanium-based powder to be positioned away from each other, thereby reducing the agglomeration phenomenon between the titanium-based powders, thereby increasing the recovery rate of titanium in complete powder form.

Since the agglomeration inhibitor does not melt due to heat during deoxidation, the titanium-based powders do not agglomerate with each other due to the agglomeration inhibitor.

As mentioned above, the agglomeration inhibitor powder may be a calcium-based powder.

When deoxidizing titanium-based powders, a problem may arise in which aggregation between the powders becomes more severe due to lowering of the surface melting point due to powder refinement. The contact between the titanium-based powders is reduced by the high-melting-point calcium-based powder located between the titanium-based powders, thereby reducing the titanium-based powders. It can suppress the agglomeration of system powders.

The method for producing titanium-based powder according to the present invention may further include a washing step (S40) and a drying step (S50). The washing step (S40) and drying step (S50) are performed in order after the recovery step (S30).

In the washing step (S40), the titanium-based powder recovered in the recovery step (S30) can be washed to remove the deoxidizing agent or agglomeration inhibitor attached to the surface of the titanium-based powder. Accordingly, the recovery rate of titanium-based powder can be further increased.

The washing step (S40) may be performed, for example, in distilled water for about 5 minutes or in 10% dilute hydrochloric acid for about 5 minutes.

In the drying step (S50), the titanium-based powder washed in the washing step (S40) is dried to remove moisture, etc. from the surface of the titanium-based powder. The drying step (S50) can be performed, for example, at about 70°C for about 2 hours using a vacuum oven.

More specifically, the calcium-based powder as an aggregation inhibitor powder may include, for example, calcium oxide (CaO), calcium carbonate (CaCO ₃ ), and calcium hydroxide (Ca(OH) ₂ ).

These calcium-based compounds are dissolved in water and can be easily removed from the surface of the titanium-based powder in the washing step (S40).

In particular, calcium oxide has a melting point of about 2,600°C, and calcium carbonate has a melting point of about 1,340°C. Since it does not melt in the deoxidation step (S20), it is located between titanium-based powders and reduces contact between titanium-based powders. It is possible to increase the recovery rate.

In the charging step (S10), the deoxidizer powder may be mixed and charged with a mixture of titanium-based powder and agglomeration inhibitor powder. That is, a contact deoxidation method can be used for titanium-based powder. Figure 3 shows an explanatory diagram for this case.

In the non-contact deoxidation method, compared to the contact deoxidation method, the deoxidation step (S20) is performed at a relatively high temperature and the titanium-based powder and deoxidizer powder must be charged separately, making it difficult to deoxidize a large amount of titanium-based powder at once. There is.

Therefore, for deoxidation of titanium-based powder, it is more advantageous to use a contact deoxidation method in which deoxidation is performed by mixing the mixture and deoxidizer powder together, in terms of saving energy required for deoxidation and enabling deoxidation in large quantities.

When using the contact deoxidation method in the present invention, deoxidation may be performed at about 750°C to prevent the calcium powder as a deoxidizer in contact with the titanium-based powder from melting during deoxidation. Even in this case, since the deoxidizer powder and the titanium-based powder are in contact, deoxidation of the titanium-based powder can proceed efficiently.

When using a contact deoxidation method, as shown in Figure 3 (b), agglomeration inhibitor powder (particles marked with 'CaO') with a smaller particle size than the deoxidizing agent powder (particles marked with 'Ca') is used. , the agglomeration inhibitor powder can cause gaps to be formed between the titanium-based powders (particles marked 'Ti') and between the titanium-based powder and the deoxidizer powder.

When deoxidizing titanium-based powder using a contact deoxidation method, the weight of the agglomeration inhibitor powder in the mixture may be 1 to 5%, more preferably about 3%, relative to the weight of the titanium-based powder.

If the weight of the agglomeration inhibitor powder is less than 1% of the weight of the titanium-based powder, the effect of the agglomeration inhibitor powder to disperse the titanium-based powder is reduced, and the recovery rate of the titanium-based powder is low. In addition, if the weight of the agglomeration inhibitor powder is more than 5% of the weight of the titanium-based powder, the recovery rate of the titanium-based powder will not increase further even if the weight ratio of the agglomeration inhibitor powder is increased, and the washing step (S40) and drying step (S50) In the case of further processing, the washing time increases to wash a large amount of agglomeration inhibitor powder, and the titanium-based powder is lost, which may lower the recovery rate.

As mentioned above, the deoxidizer powder may be charged separately from the mixture. That is, a non-contact deoxidation method may be used.

The non-contact deoxidation method has the advantage of reducing the deoxidation time over the contact deoxidation method because it uses calcium vapor at a higher temperature than the melting point of calcium (842°C). When the aluminum content in the titanium alloy powder is high, a TiAl intermetallic compound is formed, so the diffusion rate of oxygen in the TiAl intermetallic compound is slow, reducing the deoxidation effect by the contact method. Therefore, when titanium-based powder forms a TiAl-based intermetallic compound, using a non-contact deoxidation method can increase the deoxidation effect, but agglomeration between powders intensifies at high temperatures, so more agglomeration inhibitor powder is needed.

In non-contact deoxidation of titanium-based powder, the agglomeration phenomenon of the titanium-based powder due to high-temperature deoxidation intensifies, so the weight of the agglomeration inhibitor powder in the mixture may be 8 to 12% of the weight of the titanium-based powder.

If the weight of the agglomeration inhibitor powder is less than 8% of the weight of the titanium-based powder, the effect of the agglomeration inhibitor powder in suppressing the agglomeration of the titanium-based powder will be reduced, so the recovery rate of the titanium-based powder will be low, and the weight of the agglomeration inhibitor powder will be less than that of the titanium-based powder. If it is more than 12% by weight, the recovery rate of titanium-based powder does not significantly increase even if the weight ratio of the agglomeration inhibitor powder is increased.

Hereinafter, examples of the titanium-based powder manufacturing method according to the present invention will be described.

Example 1

Deoxidation of titanium-based powder made of pure titanium (Ti) was performed through a charging step (S10), a deoxidation step (S20), a recovery step (S30), a washing step (S40), and a drying step (S50).

Calcium oxide (CaO) was used as an agglomeration inhibitor powder, calcium was used as a deoxidizing agent, and a contact deoxidation method was used. The titanium-based powder was spherical and had a particle size of 15 to 53㎛, and the titanium-based powder and deoxidizer powder were charged in a ratio of 2:1. Then, deoxidation was performed while changing the weight of the agglomeration inhibitor powder to 0%, 0.1%, 1%, 3%, 5%, and 10% of the weight of the titanium-based powder.

The deoxidation step (S20) was performed in an Ar atmosphere and at 750°C for 5 hours.

The first recovery rate was measured after the recovery step (S30), and the final recovery rate was measured after the washing step (S40) and drying step (S50). The primary recovery rate refers to the rate recovered excluding titanium-based powders that agglomerated in the recovery step (S30) after deoxidation, and the final recovery rate refers to the rate finally recovered as powder through the washing step (S40) and drying step (S50). means.

[Table 1] shows the first recovery rate, final recovery rate, and oxygen content of the finally recovered titanium-based powder by ratio of agglomeration inhibitor powder and titanium-based powder during deoxidation according to Example 1.

When more than 1% of calcium oxide agglomeration inhibitor powder is added, the recovery rate of deoxidized titanium-based powder increases significantly, and when more than 3% of aggregation inhibitor powder is added, the first recovery rate is 99% and the final recovery rate is 96%, which is the highest recovery rate. You can see this appearing.

When more than 5% of agglomeration inhibitor powder is added, the final recovery rate can be seen to decrease. This is because titanium-based fine powders are lost as the washing time increases in the process of washing a large amount of agglomeration inhibitor powder.

When more than 10% of the agglomeration inhibitor powder is added, the oxygen content of the final titanium-based powder is judged to increase somewhat because the large amount of calcium oxide deoxidation product is not completely washed away.

In conclusion, it can be judged that adding 3% of the agglomeration inhibitor powder compared to the titanium-based mass is the optimal process, as the first and final recovery rates are the highest.

Example 2

Deoxidation was performed on titanium-based powder made of pure titanium under the same conditions as in Example 1, but using calcium carbonate (CaCO ₃ ) and calcium hydroxide (Ca(OH) ₂ ) as agglomeration inhibitor powders, respectively. The weight of the agglomeration inhibitor powder was set at 3% compared to the weight of the titanium-based powder. And it was compared with the case where agglomeration inhibitor powder was not used.

[Table 2] shows the presence or absence of agglomeration inhibitor powder, the first recovery rate by type of aggregation inhibitor, the final recovery rate, and the oxygen content of the finally recovered titanium-based powder during deoxidation according to Example 2.

When calcium carbonate and calcium hydroxide were used as the agglomeration inhibitor powder, the recovery rate increased compared to the case where the aggregation inhibitor powder was not used, and the oxygen content was within the error range compared to the case where the aggregation inhibitor powder was not used.

Through this, it can be confirmed that calcium carbonate and calcium hydroxide can also be used as agglomeration inhibitor powder.

Example 3

Deoxidation of titanium alloy (Ti-48Al-2Nb-2Cr) powder was performed through the charging step (S10), deoxidation step (S20), recovery step (S30), washing step (S40), and drying step (S50). .

Calcium oxide (CaO) was used as an agglomeration inhibitor powder, calcium was used as a deoxidizing agent, and a non-contact deoxidation method was used. Titanium-based powder was used with particle sizes of ~45㎛, 45~75㎛, 75~100㎛, 100~125㎛, and 125~150㎛, respectively. Titanium-based powder and deoxidizer powder were charged at a ratio of 10:1. And deoxidation was performed by setting the weight of the agglomeration inhibitor powder to 10% of the weight of the titanium-based powder.

The deoxidation step (S20) was performed in a vacuum atmosphere and at 900°C for 2 hours.

The first recovery rate was measured after the recovery step (S30), and the final recovery rate was measured after the drying step (S50).

[Table 3] and [Table 4] show the first recovery rate, final recovery rate, and oxygen content of the finally recovered titanium-based powder by particle size during deoxidation according to Example 3. [Table 3] is a case where agglomeration inhibitor powder was not used, and [Table 4] is a case where aggregation inhibitor powder was used.

When deoxidation was carried out without using an agglomeration inhibitor powder, as the particle size of the titanium-based powder became smaller, agglomeration occurred severely and the recovery rate sharply decreased.

On the other hand, when 10% of the agglomeration inhibitor powder was added compared to the titanium-based powder, it can be seen that the smaller the particle size of the powder, the greater the recovery rate compared to the case where the agglomeration inhibitor powder was not used.

In this example, the oxygen content after deoxidation appears to be lower when deoxidation is performed using an aggregation inhibitor powder than when deoxidation is performed without using an aggregation inhibitor powder. This is because in the case where an aggregation inhibitor powder is not used, the titanium-based It is believed that this is because complete washing is difficult due to the agglomeration of the powder, which increases the oxygen content, but this problem does not occur when an agglomeration inhibitor powder is used.

The scope of the present invention is not limited to the above-described embodiments, but may be implemented in various forms of embodiments within the scope of the appended claims. It is considered to be within the scope of the claims of the present invention to the extent that anyone skilled in the art can make modifications without departing from the gist of the invention as claimed in the claims.

Claims (8)

A charging step of charging a mixture of titanium-based powder and agglomeration inhibitor powder into a heating furnace;
A deoxidation step of heating the heating furnace to deoxidize the titanium-based powder; and
It includes a recovery step of recovering the titanium-based powder from the mixture,
A method for producing a titanium-based powder, characterized in that the agglomeration inhibitor powder has a particle size smaller than the titanium-based powder.
According to paragraph 1,
A method for producing a titanium-based powder, wherein the agglomeration inhibitor powder is a calcium-based powder.
According to paragraph 1,
As it proceeds after the recovery step,
A washing step of washing the recovered titanium-based powder; and
A method for producing titanium-based powder, further comprising a drying step of drying the washed titanium-based powder.
According to paragraph 1,
In the charging step, a titanium-based powder manufacturing method characterized in that the deoxidizing agent powder is mixed with the mixture and charged.
According to paragraph 4,
A method for producing a titanium-based powder, wherein the agglomeration inhibitor powder has a particle size smaller than the deoxidizer powder.
According to paragraph 4,
In the mixture, the weight of the aggregation inhibitor powder is 1 to 5% of the weight of the titanium-based powder.
According to paragraph 1,
A method for producing titanium-based powder, characterized in that in the charging step, the deoxidizing agent powder is charged separately from the mixture.
In clause 7,
In the mixture, the weight of the agglomeration inhibitor powder is 8 to 12% of the weight of the TiAl-based alloy powder.