KR102028184B1 - Method for preparing titanium metal powder or titanium alloy powder - Google Patents

Abstract

The present invention relates to a method for preparing high purity titanium metal powder or titanium alloy powder that can be used in various fields. The method comprises the following steps of: partially reducing each of at least one metal oxide and titanium oxide; mixing the partially reduced metal oxide with the titanium oxide to prepare a first mixture; preparing a second mixture by mixing the first mixture and calcium hydride; and d) completely reducing the second mixture to prepare titanium metal or a titanium alloy.

Description

Method for producing titanium metal powder or titanium alloy powder {METHOD FOR PREPARING TITANIUM METAL POWDER OR TITANIUM ALLOY POWDER}

The present invention relates to a method for producing high purity titanium metal powder or titanium alloy powder that can be used in various fields. Specifically, the present invention relates to a method for producing titanium metal powder or titanium alloy powder that can be mass-produced and reduced in cost using a multistage reduction process.

Titanium metals and titanium alloys have been regarded as materials suitable for aerospace applications where they are light, have good mechanical properties, have high temperature and corrosion resistance and are difficult to use with other traditional alloys. However, the titanium-based material has a problem that not only the raw material is expensive but also the manufacturing cost is high.

Despite the excellent properties of titanium, due to the high cost, various manufacturing methods have been developed for cost reduction since the 1950s.

As a known method of manufacturing titanium, a sponge titanium is produced by using a Kroll process, and a method of manufacturing a processed material through extrusion, rolling, etc. by manufacturing an ingot by using a VAR (Vacuum Arc Remelting) method. have.

The Kroll process is currently most commonly used for the production of titanium metals, with the final product not in powder but in sponge form. In the crawl process, the pure titanium ore is charged to a sponge in a special electric furnace. This process takes place in a chlorinator where chlorine gas passes through an electric charge to form titanium tetrachloride (TiCl ₄ ) in liquid form. The titanium tetrachloride thus formed is purified through a complex distillation process. After the distillation process, magnesium or sodium is added to the purified titanium tetrachloride and reacted to produce a metal titanium sponge and magnesium or sodium chloride. Then the titanium sponge is crushed and pressed. The pulverized titanium sponge is dissolved by vacuum arc melting (VAR). The crawl process is problematic in that the process is complicated, difficult to handle and uses unsafe materials.

Powder metallurgy (PM) technology is drawing attention as it can provide titanium in complex shapes at low cost without compromising mechanical properties compared to ingot technology. Powder metallurgy (PM) technology has great potential in that titanium can be manufactured at low cost, but the physical properties of titanium products produced by conventional powder metallurgy processes are not satisfactory, and there is no expected cost savings. It is not used much for such reasons. Therefore, in order to manufacture titanium using powder metallurgy technology, a method for not only reducing costs but also improving physical properties of the final product is required.

International Publication WO2014 / 187867 discloses a process for producing a wide range of metal powders, metal alloy powders, intermetallic compound powders and / or hydride powders thereof, wherein calcium hydride powders or granules are used to reduce the metal powders to metals. Calcium hydride is directly used, with or without the presence of another metal, in one or more metal oxides to produce metal alloy powder.

US Pat. No. 6,264,719 discloses a process for producing titanium alumina suspended with a small amount of aluminum oxide as a metal matrix composite powder when a small amount of titanium dioxide is reacted with aluminum metal powders.

Various methods of producing titanium metal powder or titanium alloy powder have been tried, but there is still insufficient development of a method capable of producing high quality titanium metal powder or titanium alloy powder at low cost and mass production on an industrial scale. to be.

The present invention provides a method for producing titanium metal powder or titanium alloy powder of good quality at low cost, which can be easily carried out on an industrial scale, and can be produced on an industrial scale. The purpose.

The above task includes the steps of: a) partially reducing each of at least one metal oxide and titanium oxide; b) mixing the partially reduced metal oxide with titanium oxide to produce a first mixture; c) mixing the first mixture with calcium hydride to produce a second mixture; And d) completely reducing the second mixture to produce a titanium metal or a titanium alloy.

In addition, the object of the present invention is a step of partially reducing one of at least one metal oxide and titanium oxide; b) preparing a first mixture by mixing the metal oxide and titanium oxide of which one is partially reduced; c) mixing the first mixture with calcium hydride to produce a second mixture; And d) completely reducing the second mixture to produce a titanium metal or a titanium alloy.

Preferably, after step b), before the step c) may comprise the step of partially reducing the first mixture.

Preferably, the partial reduction of step a) and complete reduction of step d) may be carried out by heat treatment for 1 to 10 hours at a temperature of 1,000 ° C to 1,500 ° C and a hydrogen atmosphere.

Also preferably, the partial reduction of step a) and the complete reduction of step d) may be performed by heat treatment for 1 to 10 hours at a temperature of 1,000 ° C to 1,500 ° C and a hydrogen atmosphere.

Preferably, the metal oxide in the group consisting of CaO, V ₂ O ₅ , Cr ₂ O ₃ , B ₂ O ₃ , SiO ₂ , Nb ₂ O ₅ , MoO ₃ , WO ₃ , Y ₂ O ₃ and ZrO ₂ Can be selected.

Also preferably, the stoichiometric ratio of the first mixture and the calcium hydride may be 1: 1.1 to 1.25.

Also preferably, the second mixture may further include aluminum and vanadium oxide (V ₂ O ₅ ) powder.

Also preferably, the titanium alloy powder may be Ti-6Al-4V powder.

Also preferably, the titanium metal powder and the titanium alloy powder may have an oxygen content of less than 0.3 wt% and a particle size distribution of less than 50 μm.

The present invention can provide a low cost method of manufacturing high quality titanium metal powder and titanium alloy powder that can be used in more applications. Through the present invention, the use of titanium and its alloy powders can be extended not only to general industry but also to fields requiring high quality titanium metal powders such as aerospace, medical or military use.

1 is a scanning electron micrograph showing the Morphology of a titanium metal powder prepared according to the present invention.
2 is an X-ray diffraction pattern showing the material phase of a titanium metal powder prepared according to the present invention.
3 is a view showing a particle size distribution of titanium metal powder prepared according to the present invention.
Figure 4 is a scanning electron micrograph showing the Morphology of the titanium alloy (Ti-6Al-4V) powder prepared according to the present invention.
5 is a view showing a particle size distribution of a titanium alloy (Ti-6Al-4V) powder product prepared according to the present invention.

All technical terms used in the present invention, unless defined otherwise, have the following definitions and conform to the meanings commonly understood by those skilled in the art in the relevant field of the present invention. In addition, although a preferred method or sample is described herein, similar or equivalent things are included in the scope of the present invention.

The term "about" means 30, 25, 20, 15, 10, 9, 8, 7, 6, 5, by reference quantity, level, value, number, frequency, percentage, dimension, size, amount, weight, or length. By amount, level, value, number, frequency, percentage, dimension, size, amount, weight or length, varying by 4, 3, 2 or 1%.

Throughout this specification, the terms “comprises” and “comprising”, unless otherwise indicated in the context, include a given step or component, or group of steps or components, but any other step or component, or It is to be understood that it does not exclude a step or group of components.

The process for producing titanium metal powder or titanium alloy powder of any form according to the invention is characterized in that it comprises a multistage reduction step. Preferably, it comprises a reduction step of two steps. More preferably it comprises the following steps:

a) partially reducing each of the at least one metal oxide and the titanium oxide (first reduction step);

b) mixing the partially reduced metal oxide and titanium oxide to produce a first mixture (first mixing step);

c) mixing the first mixture and calcium hydride to produce a second mixture (second mixing step);

d) thermally treating the second mixture to reduce the second mixture to produce a titanium metal or a titanium alloy (second reduction step).

According to one embodiment of the present invention, the method further comprises e) pulverizing and powdering the manufactured titanium metal or titanium alloy (powdering step).

Hereinafter, each step will be described in detail.

First, at least one of the at least one metal oxide and titanium oxide is partially reduced (first reduction step).

The first reduction step may be performed by heat treating the metal oxide and the titanium oxide for 1 to 10 hours at a temperature of 1,000 ° C. to 1,500 ° C. and a hydrogen atmosphere, respectively. The heat treatment temperature is preferably 1,100 ℃ to 1,300 ℃, more preferably, may be 1,100 ℃ to 1,200 ℃. The treatment time may preferably be 2 to 4 hours. The hydrogen atmosphere may be a hydrogen gas flow of 1.5 l / min or more, preferably 1.5 l / min to 5 l / min, which may vary depending on the size of the heat treatment furnace and the amount of raw material.

In the first reduction step, a metal oxide or titanium oxide is placed in a semi-circular cross-section crucible made of stainless steel and heated in a heat treatment region of the furnace. The heat treatment furnace can be a tube furnace. The heat treatment furnace used in the present invention may have two separate heat treatment zones for the first reduction step and the second reduction step. Preferably all types of furnaces operating under a gas atmosphere capable of promoting a reduction reaction operating at temperatures up to 1,500 ° C. can be used. The heat treatment furnace should be suitable for working with a gas such as hydrogen or argon.

Each heat treatment zone may individually form a hydrogen gas stream.

In this step, the oxygen content of the metal oxide and the titanium oxide, which are raw materials, may be reduced by heat treatment, and an oxide which may be easily reduced in the second reduction step may be formed.

The metal oxide may be at least one selected from the group consisting of CaO, V ₂ O ₅ , Cr ₂ O ₃ , B ₂ O ₃ , SiO ₂ , Nb ₂ O ₅ , MoO ₃ , WO ₃ , Y ₂ O ₃ and ZrO ₂ . And more preferably CaO. The titanium oxide may be TiO ₂ or TiO, more preferably TiO ₂ .

According to one embodiment of the present invention, when producing a titanium alloy powder, the metal oxide may be CaO and V ₂ O ₅ , and further, aluminum or aluminum oxide may be used together with the metal oxide. In this case, the titanium alloy powder may be Ti-6Al-4V.

The metal oxide and titanium oxide are preferably in powder form.

According to an embodiment of the present invention, the first reduction step includes: a1) a first partial reduction step of partially reducing each of calcium oxide and titanium oxide; And a2) a second partial reduction step of partially reducing the first mixture of the partially reduced calcium oxide and titanium oxide again.

By dividing the first reduction step into two steps as described above, a mixture of calcium oxide and titanium oxide that is uniformly reduced and mixed can be obtained.

According to another embodiment of the present invention, only one of the metal oxide and the titanium oxide may be partially reduced in the first reduction step.

Next, a first mixture is prepared by mixing the partially reduced metal oxide and titanium oxide (first mixing step), and a second mixture is prepared by mixing the first mixture and calcium hydride (second mixture). step).

In this step, the first mixture and calcium hydride are preferably mixed in a stoichiometric ratio of 1: 1.1 to 1.25.

Calcium hydride may be used in the form of a powder or granule, the particle size may be preferably 0.02 ~ 2mm. Calcium hydride used in the present invention may use a commercially available product, but preferably, the calcium hydride used in the present invention may be used for Calcium Metal Shaving or Calcium Metal Granules under a hydrogen gas atmosphere of 550 to 750. Calcium hydride flakes or granules converted by heating to a temperature of 1 hour to 10 hours.

Next, the second mixture is heat-treated and completely reduced to prepare a titanium metal or a titanium alloy (second reduction step).

The heat treatment may be performed for 1 to 10 hours under a temperature and hydrogen atmosphere of 1,000 ℃ to 1,500 ℃. The heat treatment temperature is preferably 1,100 ℃ to 1,300 ℃, more preferably, may be 1,100 ℃ to 1,200 ℃. The treatment time may preferably be 2 to 4 hours. The hydrogen atmosphere may be a hydrogen gas flow of 1.5 l / min or more, preferably 1.5 l / min to 5 l / min, depending on the size of the heat treatment furnace and the amount of the mixture. The heat treatment furnace used in the second reduction step is the same as described in the first reduction step.

In this step, a mixture of a partially reduced metal oxide and titanium oxide and calcium hydride as a reducing agent may react under a hydrogen atmosphere to form a titanium metal or a titanium alloy. The titanium metal or titanium alloy thus formed is recovered.

Finally, e) the powder produced in the recovery step can be powdered by washing and drying. According to one embodiment of the invention, since the recovered titanium metal or titanium alloy is in bulk form, it can be ground using a high energy ball milling device prior to the washing and drying steps.

In the washing and drying step, the ground powder may be mixed with water to form a slurry, and washed with stirring. In order to enhance the washing effect, a solvent such as acetic acid may be added to the slurry.

In the drying step after washing, the powder may be dried at a temperature of 80 ~ 90 ℃ in an open low temperature oven.

The titanium metal or titanium alloy produced in the present invention is in powder form, has a particle size distribution of 50 μm or less, preferably 10 to 50 μm, and an oxygen content of less than 0.3 wt%.

As used herein, the term "powder" indicates that the particle size is less than 1 mm.

As used herein, "X50" refers to the particle size distribution of the final powder, which represents the median diameter or median value of the particle size distribution. Preferably X50 indicates a particle size distribution of 50 μm or less, or 40 μm or less, more preferably 20 μm or less.

Hereinafter, the present invention will be described in detail with reference to Examples, but the scope of the present invention is not limited by these Examples.

Example

Starting materials used in the examples of the present invention are shown in Table 1 below.

division water
manufacturer TiO ₂ (Rutile) Powder 99% 325 mesh or less Beijing Toodudu ltd- China Aluminum powder 99.5% 325 mesh or less Xinkang Advanced Materials Co. ltd- China Calcium oxide powder 99.5% 325 mesh or less Ganzhou Wanfeng Advanced Materials Tech Co. ltd- China CaH ₂ Powder 99% 325 mesh or less NAP V ₂ O ₅ 99.6% 325 mesh or less Ganzhou Wanfeng Advanced Materials Tech. Co. ltd- China

The apparatus used to analyze the titanium metal powder and titanium alloy powder finally prepared in the present invention is shown in Table 2 below.

Equipment name Manufacturer and model name Remarks Inductively Coupled Plasma Atomic Emission Spectrometry (ICP) Perkin Elmer, Optima 3300DV Chemical composition analysis X Ray Diffraction Machine Rigaku, DMAX 2200 X-ray Diffraction Test Particle Size Analyzer Beckman Coulter, LS230 Particle size distribution analysis ONH Analyzer ELTRA GmbH, ELTRA ONH-2000 Gas analysis SEM JEOL, JSM-6380 Scanning electron microscope

Example  1: titanium metal powder manufacturer

50 g of CaO powder having a purity of 99.5% and 50 g of TiO ₂ powder having a purity of 99% were placed in a SUS310S crucible, respectively, and partially reduced at 1,100 ° C. for 2 hours in a hydrogen gas atmosphere of 2-3 L / min in a heat treatment region of a tubular tube. A second mixture was prepared by thoroughly mixing 100 g of the first mixture of partially reduced CaO and TiO ₂ and 130 g of calcium hydride powder (particle size of 0.02-2 mm). The stoichiometric ratio of calcium hydride to the first mixture is 1.1 to 1.25x. The second mixture was then placed in a SUS310S crucible and fully reduced at 1,100 ° C. for 2 hours in a hydrogen gas atmosphere of 2-3 l / min in the heat treatment zone to the tubular tube. The bulk material obtained was placed in a ball milling apparatus, ground, mixed with water and acetic acid, washed with stirring and dried completely at 90 ° C. The physical properties of the metal powder were measured using the apparatus of Table 2 above. A scanning electron micrograph of the prepared powder is shown in FIG. 1. In addition, the X-ray diffraction pattern was measured in order to confirm the substance of the prepared powder and is shown in FIG. 2, and the particle size distribution of the powder was measured and shown in FIGS. 2, it can be seen that the prepared powder is a titanium (Ti) metal. In addition, looking at Figure 3 and Table 3, it can be seen that the particle size distribution range of the prepared powder is 10 ~ 50μm. In addition, it was 0.19 wt% when the residual oxygen content of the prepared powder was confirmed. The residual oxygen content of the titanium metal powder produced in the present invention is significantly lower than that of the titanium metal powder produced by a known method.

division diameter Particle size One Diameter at X10 2.86 μm 2 Diameter at X50 9.07 μm 3 Diameter at X90 20.20 μm 4 Average diameter 10.45 μm

Example 2: Titanium Alloy (Ti-6Al-4V) Powder Preparation

150 g of a mixture of 99.5% pure CaO powder and 99% pure TiO ₂ powder was placed in a SUS310S crucible and partially reduced at 1,100 ° C. for 2 hours in a hydrogen gas atmosphere of 2 to 3 l / min in a heat treatment zone to a tubular tube. I was. Completely mixed the first mixture of CaO and TiO ₂ partially reduced, 7.13g of V ₂ O ₅ powder of 99.6% purity and 6g of aluminum metal powder of 99.5% purity, and 207g of calcium hydride powder (particle size 0.02 ~ 2mm) Mixing gave a second mixture. The stoichiometric ratio of calcium hydride to the first mixture is 1.1 to 1.25x. The second mixture was then placed in a SUS310S crucible and fully reduced at 1,100 ° C. for 2 hours in a hydrogen gas atmosphere of 2-3 l / min in the heat treatment zone to the tubular tube. The bulk material obtained was placed in a ball milling apparatus, ground, mixed with water and acetic acid, washed with stirring and dried completely at 90 ° C. The physical properties of the metal powder were measured using the apparatus of Table 2 above. A scanning electron micrograph of the prepared powder is shown in FIG. 4. In addition, the particle size distribution of the prepared powder was measured and shown in FIG. 5 and Table 4. FIG. 5 and Table 4, it can be seen that the particle size distribution range of the prepared powder is 10 ~ 50μm. In addition, it was 0.28 wt% when the residual oxygen content of the prepared powder was confirmed. The residual oxygen content of the titanium alloy powder produced in the present invention is significantly lower than the titanium metal powder produced by the known method.

division diameter Particle size One Diameter at X10 3.69 μm 2 Diameter at X50 13.48 μm 3 Diameter at X90 39.48 μm 4 Average diameter 17.95 μm

Example 3: Titanium Alloy (Ti-6Al-4V) Powder Preparation

150 g of a mixture of 99.5% pure CaO powder and 99% pure TiO ₂ powder was placed in a SUS310S crucible and partially reduced at 1,100 ° C. for 2 hours in a hydrogen gas atmosphere of 2 to 3 l / min in a heat treatment zone to a tubular tube. I was. 207 g of calcium hydride powder (particle size 0.02 to 2 mm) and a first mixture of CaO and TiO ₂ partially reduced, 7.13 g of V ₂ O ₅ powder having a purity of 99.6%, and 7.1 g of aluminum oxide powder having a purity of 99.5% were mixed. Mix thoroughly to prepare a second mixture. The stoichiometric ratio of calcium hydride to the first mixture is 1.1 to 1.25x. The second mixture was then placed in a SUS310S crucible and fully reduced at 1,100 ° C. for 2 hours in a hydrogen gas atmosphere of 2-3 l / min in the heat treatment zone to the tubular tube. The obtained bulk material was placed in a ball milling apparatus, pulverized, mixed with water and acetic acid, washed with stirring, and dried completely at 90 ° C. to obtain a titanium alloy (Ti-6Al-4V) powder.

Having described the specific part of the present invention in detail, it is apparent to those skilled in the art that the specific technology is merely a preferred embodiment, and the scope of the present invention is not limited thereto. Therefore, the substantial scope of the present invention will be defined by the appended claims and equivalents thereof.

delete

delete

Claims (13)

a) partially reducing each of at least one metal oxide and titanium oxide;
b) mixing the partially reduced metal oxide with titanium oxide to produce a first mixture;
c) mixing the first mixture with calcium hydride to produce a second mixture; And
d) completely reducing the second mixture to produce a titanium metal or a titanium alloy,
The metal oxide is CaO, characterized in that the titanium metal powder or titanium alloy powder production method. a) partially reducing one of at least one metal oxide and titanium oxide;
b) preparing a first mixture by mixing the metal oxide and titanium oxide of which one is partially reduced;
c) mixing the first mixture with calcium hydride to produce a second mixture; And
d) completely reducing the second mixture to produce a titanium metal or a titanium alloy,
The metal oxide is CaO, characterized in that the titanium metal powder or titanium alloy powder production method. The method according to claim 1 or 2,
After said step b), before said step c), partially reducing said first mixture. The method according to claim 1 or 2,
The partial reduction of step a) and the complete reduction of step d) are performed by heat treatment for 1 to 10 hours at a temperature of 1,000 ° C. to 1,500 ° C. and a hydrogen atmosphere, to produce titanium metal powder or titanium alloy powder. Way. The method of claim 3,
The partial reduction of step a) and the complete reduction of step d) are performed by heat treatment for 1 to 10 hours at a temperature of 1,000 ° C. to 1,500 ° C. and a hydrogen atmosphere, to produce titanium metal powder or titanium alloy powder. Way. The method according to claim 1 or 2,
e) a method of producing titanium metal powder or titanium alloy powder, further comprising the step of pulverizing the powdered titanium metal or titanium alloy. delete delete The method according to claim 1 or 2,
A stoichiometric ratio of the first mixture and the calcium hydride is 1: 1.1 to 1.25, characterized in that the titanium metal powder or titanium alloy powder production method. The method according to claim 1 or 2,
Method for producing a titanium metal powder or titanium alloy powder, characterized in that it further comprises aluminum and vanadium oxide (V ₂ O ₅ ) powder in the second mixture. The method of claim 10,
The titanium alloy is Ti-6Al-4V, characterized in that the titanium metal powder or titanium alloy powder production method. The method according to claim 1 or 2,
The titanium metal and titanium alloy is characterized in that the oxygen content is less than 0.3% by weight and the particle size distribution is less than 50μm, titanium metal powder or titanium alloy powder production method. delete

Images