Indium powder and preparation method thereof

Abstract

The invention belongs to the technical field of high-purity indium powder, and discloses indium powder and a preparation method thereof.The preparation method of the indium powder comprises the steps that indium liquid is subjected to spray granulation in a nitrogen environment to obtain the indium powder; the atomization pressure of the spray granulation is 8-15 Bar, the atomization amount is 2-3 kg / min, and the atomization temperature is 280-320 DEG C. According to the indium powder preparation method provided by the invention, the indium liquid is subjected to spray granulation under the conditions that the atomization pressure is 8-15 Bar, the atomization amount is 2-3 kg / min and the atomization temperature is 280-320 DEG C to obtain the indium powder of which the most particles have the particle size of 60-200 meshes, and the particle size of the indium powder is effectively controlled, so that the requirements of downstream products are met.

Description

Technical Field

[0001] The present invention relates to the technical field of high-purity indium powder, and in particular to indium powder and a preparation method thereof. Background Art

[0002] Indium powder has good electrical and thermal conductivity, so it is widely used in the electronics industry. It is also used as an alloy additive to improve the strength and hardness of the alloy. In addition, it is also used in the manufacture of semiconductor materials and high-temperature lubricants.

[0003] At present, traditional methods for preparing indium powder mainly include electrolysis, vacuum distillation, etc.

[0004] For example, prior art 1: the invention of Chinese patent application 201310038246.3 discloses a method for preparing high-purity indium. The method first prepares an indium sulfate electrolyte with pure water, analytical grade concentrated sulfuric acid, 4N metallic indium, high-purity sodium chloride and analytical grade gelatin, obtains electrolytic indium by two electrolysis steps under ultra-clean conditions, and then purifies the electrolytic indium by vacuum distillation (above 750°C) to obtain 5N-7N high-purity indium. Although this method can produce high-purity indium.

[0005] Prior art 1 uses a combination of electrolysis and vacuum distillation to prepare high-purity indium powder, but its production conditions are extremely complex, and the equipment cost is high and the output is low, making it difficult to carry out large-scale industrial production.

[0006] Prior art 2 has improved this defect. Prior art 2: Chinese patent application 202310957900.4 discloses a method for preparing high-purity indium powder. First, an electrolyte is prepared. The pH value of the electrolyte is 0.5-1. The electrolyte includes the following components: 30-70 g / L of In 3+ , 50-70g / L sodium chloride, and the rest is ultrapure water, and then the electrolyte is electrolyzed to obtain electrolytic indium, and then the electrolytic indium is washed, dried, and calcined in sequence to obtain micron-sized indium powder. The calcination is specifically as follows: the electrolytic indium is placed in a graphite crucible and fired to obtain indium powder, and the graphite crucible is filled with a mixed gas of nitrogen and oxygen.

[0007] Prior art 2 provides a method for preparing indium powder by combining electrolysis and calcination to prepare indium powder, which effectively reduces equipment costs and increases output.

[0008] However, the preparation methods of the prior art 1 and the prior art 2 cannot control the particle size of the indium powder, and the particle size of the indium powder will affect the performance of the semiconductor material.

[0009] Therefore, the technical problem to be solved by the present invention is: how to develop a method for preparing indium powder with controllable indium powder particle size. Summary of the invention

[0010] One of the purposes of the present invention is to provide a method for preparing indium powder, which controls the particle size of indium powder by spray granulation under specific process conditions, thereby achieving controllable particle size of indium powder while also having the advantages of low oxygen content, low agglomeration and good stability of indium powder. In addition, the preparation method is simple and controllable and is suitable for industrial application.

[0011] Another object of the present invention is to provide an indium powder prepared by the indium powder preparation method of the present invention, the particle size of which can fully meet the high requirements of semiconductor material preparation.

[0012] To achieve the above purpose, the present invention provides a method for preparing indium powder, wherein indium liquid is spray-granulated in a nitrogen environment to obtain indium powder; the atomization pressure of the spray granulation is 8-15 Bar, the atomization amount is 2-3 kg / min, and the atomization temperature is 280-320°C.

[0013] Specifically, the method for preparing indium powder of the present invention comprises the following steps:

[0014] Step 1: Melting the indium block to obtain indium liquid;

[0015] Step 2: spraying and granulating the indium liquid under a nitrogen environment to obtain a first indium powder;

[0016] Step 3: Screen the first indium powder through a sieve to obtain a second indium powder.

[0017] Furthermore, the step 1 is specifically as follows: heating the indium block to 250-300° C. in a low oxygen environment to obtain an indium liquid.

[0018] Furthermore, the specific operation of step 1 is: placing the indium block into a crucible of a heating furnace; then evacuating the heating furnace to a pressure of 5-10 Pa, introducing nitrogen to a pressure of 3000-3500 Pa, and cyclically evacuating and introducing nitrogen for gas replacement 3 times to place the indium block in a low-oxygen environment; heating to 250-300°C to melt the indium block into indium liquid.

[0019] It should be noted that in order to prevent the indium liquid from coming into contact with oxygen and being oxidized during the transfer process to the spray granulation equipment, a spray granulation equipment with a heating device can be used to heat the indium block to obtain the melted indium liquid, so that the indium liquid will not come into contact with external oxygen during the transfer process.

[0020] Preferably, the step 3 specifically includes:

[0021] Step 31: sieving the first indium powder through a 200-mesh sieve to obtain indium powder of 200 mesh and below;

[0022] Step 32: Screen the indium powder of 200 mesh and below through a 60-mesh sieve, select the part remaining on the 60-mesh sieve, and obtain the second indium powder with a particle size of 60-200 mesh.

[0023] The invention also discloses an indium powder, which is prepared by adopting the indium powder preparation method.

[0024] Beneficial Effects

[0025] Compared with the prior art, the present invention provides a method for preparing indium powder, by spraying and granulating indium liquid under the conditions of an atomization pressure of 8-15 Bar, an atomization amount of 2-3 kg / min, and an atomization temperature of 280-320°C to obtain indium powder with a particle size of 60-200 meshes, thereby effectively controlling the particle size of the indium powder to meet the needs of downstream products. DETAILED DESCRIPTION

[0026] The present invention will be further described below in conjunction with the embodiments, but it does not constitute any limitation to the present invention. Any limited number of modifications made within the scope of the claims of the present invention are still within the scope of the claims of the present invention.

[0027] In order to explain the technical content of the present invention in detail, further description is given below in conjunction with the implementation modes.

[0028] Example 1

[0029] An indium powder is prepared by the following steps:

[0030] Step 1: Place the indium block in a crucible of a heating furnace; then evacuate the heating furnace to a pressure of 10 Pa, introduce nitrogen to a pressure of 3500 Pa, cycle the evacuation and introduction of nitrogen for gas replacement 3 times to place the indium block in a low-oxygen environment; heat to 300°C to melt the indium block into indium liquid;

[0031] Step 2: spraying and granulating the indium liquid in a spray granulator in a nitrogen atmosphere at an atomization pressure of 15 Bar, an atomization volume of 2 kg / min, and an atomization temperature of 320° C. to obtain a first indium powder;

[0032] Step 3: Sieve the first indium powder through a 200-mesh sieve to obtain indium powder of 200 mesh and below;

[0033] Step 4: Screen the indium powder of 200 mesh and below through a 60-mesh sieve, select the part remaining on the 60-mesh sieve, and obtain the second indium powder with a particle size of 60-200 mesh.

[0034] Example 2

[0035] An indium powder is prepared by the following steps:

[0036] Step 1: Place the indium block in a crucible of a heating furnace; then evacuate the heating furnace to a pressure of 5 Pa, introduce nitrogen to a pressure of 3000 Pa, cycle the evacuation and introduction of nitrogen for gas replacement 3 times to place the indium block in a low-oxygen environment; heat to 250°C to melt the indium block into indium liquid;

[0037] Step 2: spraying and granulating the indium liquid in a spray granulator in a nitrogen atmosphere at an atomization pressure of 8 Bar, an atomization volume of 3 kg / min, and an atomization temperature of 280° C. to obtain a first indium powder;

[0038] Step 3: Sieve the first indium powder through a 200-mesh sieve to obtain indium powder of 200 mesh and below;

[0039] Step 4: Screen the indium powder of 200 mesh and below through a 60-mesh sieve, select the part remaining on the 60-mesh sieve, and obtain the second indium powder with a particle size of 60-200 mesh.

[0040] Example 3

[0041] An indium powder is prepared by the following steps:

[0042] Step 1: Place the indium block in a crucible of a heating furnace; then evacuate the heating furnace to a pressure of 10 Pa, introduce nitrogen to a pressure of 3500 Pa, cycle the evacuation and introduction of nitrogen for gas replacement 3 times to place the indium block in a low-oxygen environment; heat to 300°C to melt the indium block into indium liquid;

[0043] Step 2: spraying and granulating the indium liquid in a spray granulator in a nitrogen atmosphere at an atomization pressure of 11 Bar, an atomization volume of 3 kg / min, and an atomization temperature of 300° C. to obtain a first indium powder;

[0044] Step 3: Sieve the first indium powder through a 200-mesh sieve to obtain indium powder of 200 mesh and below;

[0045] Step 4: Screen the indium powder of 200 mesh and below through a 60-mesh sieve, select the part remaining on the 60-mesh sieve, and obtain the second indium powder with a particle size of 60-200 mesh.

[0046] Comparative Example 1

[0047] An indium powder is prepared by the following steps:

[0048] Step 1: Place the indium block in a crucible of a heating furnace; then evacuate the heating furnace to a pressure of 10 Pa, introduce nitrogen to a pressure of 3500 Pa, cycle the evacuation and introduction of nitrogen for gas replacement 3 times to place the indium block in a low-oxygen environment; heat to 300°C to melt the indium block into indium liquid;

[0049] Step 2: spraying and granulating the indium liquid in a spray granulator in a nitrogen atmosphere at an atomization pressure of 15 Bar, an atomization volume of 5 kg / min, and an atomization temperature of 320° C. to obtain a first indium powder;

[0050] Step 3: Sieve the first indium powder through a 200-mesh sieve to obtain indium powder of 200 mesh and below;

[0051] Step 4: Screen the indium powder of 200 mesh and below through a 60-mesh sieve, select the part remaining on the 60-mesh sieve, and obtain the second indium powder with a particle size of 60-200 mesh.

[0052] Comparative Example 2

[0053] An indium powder is prepared by the following steps:

[0054] Step 1: Place the indium block in a crucible of a heating furnace; then evacuate the heating furnace to a pressure of 10 Pa, introduce nitrogen to a pressure of 3500 Pa, cycle the evacuation and introduction of nitrogen for gas replacement 3 times to place the indium block in a low-oxygen environment; heat to 300°C to melt the indium block into indium liquid;

[0055] Step 2: spraying and granulating the indium liquid in a spray granulator in a nitrogen atmosphere at an atomization pressure of 6 Bar, an atomization volume of 2 kg / min, and an atomization temperature of 320° C. to obtain a first indium powder;

[0056] Step 3: Sieve the first indium powder through a 200-mesh sieve to obtain indium powder of 200 mesh and below;

[0057] Step 4: Screen the indium powder of 200 mesh and below through a 60-mesh sieve, select the part remaining on the 60-mesh sieve, and obtain the second indium powder with a particle size of 60-200 mesh.

[0058] Comparative Example 3

[0059] An indium powder is prepared by the following steps:

[0060] Step 1: Place the indium block in a crucible of a heating furnace; then evacuate the heating furnace to a pressure of 10 Pa, introduce nitrogen to a pressure of 3500 Pa, cycle the evacuation and introduction of nitrogen for gas replacement 3 times to place the indium block in a low-oxygen environment; heat to 300°C to melt the indium block into indium liquid;

[0061] Step 2: spraying and granulating the indium liquid in a spray granulator in a nitrogen atmosphere at an atomization pressure of 18 Bar, an atomization volume of 2 kg / min, and an atomization temperature of 320° C. to obtain a first indium powder;

[0062] Step 3: Sieve the first indium powder through a 200-mesh sieve to obtain indium powder of 200 mesh and below;

[0063] Step 4: Screen the indium powder of 200 mesh and below through a 60-mesh sieve, select the part remaining on the 60-mesh sieve, and obtain the second indium powder with a particle size of 60-200 mesh.

[0064] Product Testing

[0065] 1. The oxygen content of the second indium powder obtained in Example 1-3 and Comparative Example 1-3 was tested by an oxygen tester;

[0066] 2. The indium blocks and the second indium powder of Examples 1-3 and Comparative Examples 1-3 were weighed to obtain the weights of the indium blocks and the indium powder, respectively, and then the yield of 60-200 mesh indium powder was calculated by the following formula:

[0067]

[0068] The second indium powder obtained in Examples 1-3 and Comparative Examples 1-3 was tested by the above method, and the results are shown in Table 1;

[0069] Table 1 Oxygen content and yield of the second indium powder of Examples 1-3 and Comparative Examples 1-3

[0070] Oxygen content (ppm) 60-200 mesh indium powder yield (%) Example 1 159 55 Example 2 172 53 Example 3 185 56 Comparative Example 1 182 43 Comparative Example 2 178 40 Comparative Example 3 169 46

[0071] According to the results in Table 1, we can see that:

[0072] According to the data comparison between Example 1 and Comparative Example 1, the specific atomization process of the present invention can effectively improve the yield of 60-200 mesh indium powder and achieve controllable indium powder particle size. Excessive atomization amount will seriously affect the controllability of the indium powder particle size.

[0073] According to the data comparison between Example 1 and Comparative Examples 2 and 3, it can be seen that excessive atomization pressure or too low atomization pressure will affect the controllability of the particle size of the indium powder, and the yield of 60-200 mesh indium powder is significantly reduced.

[0074] The embodiments presented herein are only embodiments selected according to the combination of all possible embodiments. The appended claims should not be limited by the embodiments describing the present invention. Some numerical ranges used in the claims include sub-ranges therein, and the changes in these ranges should also be covered by the appended claims.

Claims

1. A method for preparing indium powder, characterized in that: Indium liquid is sprayed and granulated in a nitrogen environment to obtain indium powder; the atomization pressure of the spray granulation is 8-15 Bar, the atomization amount is 2-3 kg / min, and the atomization temperature is 280-320°C.

2. The method for preparing indium powder according to claim 1, characterized in that: The steps include: Step 1: Melting the indium block to obtain indium liquid; Step 2: spraying and granulating the indium liquid under a nitrogen environment to obtain a first indium powder; Step 3: Screen the first indium powder through a sieve to obtain a second indium powder.

3. The method for preparing indium powder according to claim 2, characterized in that: The specific step 1 is: heating the indium block to 250-300° C. in a low oxygen environment to obtain indium liquid.

4. The method for preparing indium powder according to claim 3, characterized in that: The specific operation of step 1 is: placing the indium block into the crucible of the heating furnace; then evacuating the heating furnace to a pressure of 5-10 Pa, introducing nitrogen to a pressure of 3000-3500 Pa, cyclically evacuating and introducing nitrogen for gas replacement 3 times to place the indium block in a low-oxygen environment; heating to 250-300° C. to melt the indium block into indium liquid.

5. The method for preparing indium powder according to claim 2, characterized in that: The step 3 specifically includes: Step 31: sieving the first indium powder through a 200-mesh sieve to obtain indium powder of 200 mesh and below; Step 32: Screen the indium powder of 200 mesh and below through a 60-mesh sieve, select the part remaining on the 60-mesh sieve, and obtain the second indium powder with a particle size of 60-200 mesh.

6. An indium powder, characterized in that: The indium powder is prepared by the indium powder preparation method according to any one of claims 1 to 6.

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