Method for producing antimony trisulfide

Abstract

To provide a production method capable of stably producing antimony trioxide with good purity.SOLUTION: A method for producing antimony trisulfide includes: a mixing step of mixing antimony metal powders, antimony trioxide powders, and sulfur powders to obtain a mixture thereof; and a heating step of heating the mixture.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for producing antimony trisulfide. [Background technology]

[0002] Antimony trisulfide is in demand in the fields of, for example, explosives, solid lubricants, etc. Such antimony trisulfide exhibits favorable properties suited to each field, and there is a demand in the market for a stable, inexpensive supply of antimony trisulfide.

[0003] For example, Patent Document 1 discloses a method for producing antimony trisulfide, which comprises charging antimony trioxide powder and sulfur into a reaction vessel and heating the vessel to 250 to 700°C to react the antimony trioxide with the sulfur. Also, a method for producing antimony trisulfide is widely known in which metallic antimony powder and sulfur are mixed and heated to react with each other. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2014 / 054112 Summary of the Invention [Problem to be solved by the invention]

[0005] The method for producing antimony trisulfide disclosed in Patent Document 1 requires a large amount of heat and generates a large amount of sulfur dioxide due to the reaction between oxygen in antimony trioxide and sulfur. Furthermore, in the method for producing antimony trisulfide in which metallic antimony powder and sulfur are mixed and heated to react, the heat of reaction can cause unreacted sulfur to rapidly vaporize, resulting in an explosion and a decrease in the reaction rate.

[0006] Therefore, one object of some aspects of the present invention is to provide a method for producing antimony trisulfide safely, which requires less energy and generates less sulfur dioxide, and can stably produce antimony trisulfide with good purity. [Means for solving the problem]

[0007] The present invention has been made to solve at least some of the above-mentioned problems, and can be realized in the following aspects or application examples.

[0008] One aspect of the method for producing antimony trisulfide according to the present invention is to a mixing step of mixing metallic antimony powder, antimony trioxide powder, and sulfur powder to obtain a mixture; a heating step of heating the mixture; Equipped with.

[0009] According to this production method, since the raw material contains metallic antimony powder, antimony trisulfide with good purity can be stably produced.

[0010] In the above aspect, The mass of Sb in the antimony trioxide powder in the mixture (M O ) and the Sb mass (M M ) ratio (M O :M M ) may be in the range of 1:2 to 2:1.

[0011] In the above aspect, The maximum temperature reached in the heating step may be 300°C or higher and 800°C or lower.

[0012] In the above aspect, The metallic antimony powder may have an average particle size of 120 μm or less.

[0013] In the above aspect, The antimony trioxide may have an average particle size of 8 μm or less.

[0014] In the above aspect, The total mass of the mixture may be 1 kg or more. DETAILED DESCRIPTION OF THE INVENTION

[0015] Several embodiments of the present invention will be described below. The embodiments described below are merely examples of the present invention. The present invention is not limited to the following embodiments, and includes various modified forms that are implemented within the scope of the present invention. Note that not all of the configurations described below are necessarily essential configurations of the present invention.

[0016] 1. Method for producing antimony trisulfide The method for producing antimony trisulfide according to this embodiment includes a mixing step of mixing metallic antimony powder, antimony trioxide powder, and sulfur powder to obtain a mixture, and a heating step of heating the mixture.

[0017] 1.1.Mixing process In the mixing step, metallic antimony powder, antimony trioxide powder, and sulfur powder are mixed to obtain a mixture. The mixing is carried out by introducing metallic antimony powder, antimony trioxide powder, and sulfur powder into an appropriate container described below. The order of introduction is not particularly limited.

[0018] 1.1.1. Metallic antimony powder Metallic antimony can be produced by, for example, the method described in JP-A-6-322455. Metallic antimony powder can be obtained by pulverizing metallic antimony by a known method.

[0019] The particle size and particle size distribution of the metallic antimony powder can also be adjusted using known techniques. The particle size and particle size distribution of the metallic antimony powder are not particularly limited. However, it is preferable that the average particle size of the metallic antimony powder is 120 μm or less. Furthermore, a smaller average particle size of the metallic antimony powder tends to improve reactivity, so it is more preferable that the average particle size is 80 μm or less, and even more preferably 60 μm or less.

[0020] In this specification, the average particle size of a powder is measured by a laser diffraction / scattering method and is defined as the particle size at cumulative 50% (D50) determined by volume frequency particle size distribution measurement. An example of a commercially available laser diffraction particle size distribution analyzer capable of such measurements is the MT3300EXII manufactured by Microtrac.

[0021] 1.1.2. Antimony trioxide powder Antimony trioxide can be produced, for example, by the method described in JP-A-6-329417. Antimony trioxide powder can be obtained by pulverizing antimony trioxide by a known method.

[0022] The particle size and particle size distribution of the antimony trioxide powder can also be adjusted using known techniques. The particle size and particle size distribution of the antimony trioxide powder are not particularly limited. However, the average particle size of the antimony trioxide powder is preferably 8 μm or less. If the average particle size exceeds 8 μm, reactivity and energy costs tend to deteriorate. This tends to result in unreacted antimony trioxide remaining in the produced antimony trisulfide. To avoid this tendency, the average particle size of the antimony trioxide powder is preferably smaller, more preferably 1.5 μm or less, and even more preferably 1 μm or less.

[0023] Antimony trioxide powder is obtained by volatile oxidation smelting, etc., and therefore has a small particle size, a large specific surface area, and good reactivity. Furthermore, high-purity antimony trioxide with low impurities such as lead, arsenic, and crystalline silica is easily available, and by using high-purity antimony trioxide powder as a raw material, it is possible to produce antimony trisulfide with fewer impurities.

[0024] 1.1.3. Sulfur powder Sulfur can be obtained commercially in the form of powder or lumps, for example. Sulfur powder can be obtained by pulverizing sulfur by a known method as needed.

[0025] The particle size and particle size distribution of the sulfur powder particles can also be adjusted using known techniques. The particle size and particle size distribution of the sulfur powder particles are not particularly limited. However, the average particle size of the sulfur powder is preferably 500 μm or less. The average particle size of the sulfur powder is preferably smaller, more preferably 250 μm or less, and even more preferably 100 μm or less.

[0026] The shape of the sulfur particles in the sulfur powder is not particularly limited and may be, for example, spherical, scaly, acicular, irregular, or a mixture of these shapes. The particle size and shape of the sulfur particles contained in the powder do not need to be uniform.

[0027] The sulfur powder used in the mixing step is in the form of powder or lumps, and can maintain its powdery properties by being handled at a temperature of 119° C. or less, preferably 112° C. or less, more preferably 106° C. or less. Note that the sulfur powder may be partially or entirely melted in the mixing step.

[0028] 1.1.4. Container The container used in the mixing step is not particularly limited, and for example, a container appropriately equipped with a raw material inlet, a product outlet, a gas inlet, a gas outlet, etc. can be used. The container may or may not be sealed. Furthermore, the container may be equipped with a heating mechanism, a stirring mechanism, a safety mechanism, etc.

[0029] The scale of the vessel is not limited, but a vessel with an appropriate volume is used depending on the amount of antimony trisulfide to be produced. In the method for producing antimony trisulfide of this embodiment, it is more preferable that the total mass of the mixture obtained in this mixing step is 1 kg or more. By using such a scale, productivity can be further improved.

[0030] The vessel may be of a batch type or a continuous type, and the mixture can be introduced into the vessel in a manner that suits the type of vessel.

[0031] 1.1.5.Mixing ratio The mixing ratio of the metallic antimony powder, antimony trioxide powder, and sulfur powder is not particularly limited as long as it is close to the stoichiometric ratio.

[0032] However, the mass of Sb in the antimony trioxide powder (M O ) and the Sb mass (M M ) ratio (M O :M M ) is more preferably within the range of 1:2 to 2:1.

[0033] It is more preferable to mix sulfur powder in an amount greater than the stoichiometric amount in antimony trisulfide, which will almost completely eliminate the risk of unreacted metallic antimony or antimony trioxide remaining in the antimony trisulfide produced.

[0034] Furthermore, the higher the purity of the sulfur used in the mixing step, the better. However, impurities such as other elements and sulfur compounds may be contained in a certain amount or less. Such impurities include, for example, those contained in the sulfur raw material or those mixed in during handling of the powder or lumps. The amount of such impurities is preferably 2% by mass or less, more preferably 1% by mass or less, even more preferably 0.5% by mass or less, particularly preferably 0.1% by mass or less, and particularly preferably 0.01% by mass or less. It is preferable that the impurities are substantially absent.

[0035] 1.2.Heating process In the heating step, the mixture obtained in the mixing step is heated. Heating can be performed by contact heating using a heater or the like, or radiant heating using an infrared lamp or the like.

[0036] While the inside of the vessel is being heated to produce antimony trisulfide, an inert gas may be continuously introduced into the vessel to purge it, thereby preventing the antimony metal from reacting with oxygen in the air.

[0037] When metallic antimony powder, antimony trioxide powder, and sulfur powder are heated in a container, the metallic antimony combines with sulfur to form antimony trisulfide, and the antimony trioxide loses oxygen to the sulfur, generating SO2 gas. The antimony is then reduced by the sulfur and combines with the sulfur to form antimony trisulfide. The reaction formulas are as follows: 2Sb2O3+ 9S → 2Sb2S3+ 3SO2···(I) 2Sb + 3S → 2Sb2S3 (II)

[0038] When antimony trioxide alone is used as in the above formula (I), a large amount of sulfur dioxide gas is generated, but by replacing a portion of it with metallic antimony as in the above formula (II), the generation of sulfur dioxide gas can be reduced.

[0039] The maximum temperature reached in the heating step may be 300°C or higher and 800°C or lower. Here, the maximum temperature reached refers to the temperature of the mixture, and is the highest temperature reached in the heating step. Therefore, the maximum temperature reached does not refer to the temperature of the heater used for heating.

[0040] After the heating step, antimony trisulfide is produced. The produced antimony trisulfide may be heated to or above its melting point to melt it and discharged as a liquid from the container. In this case, the discharged liquid antimony sulfide may be cooled and solidified. The melting point of antimony trisulfide is 550°C. This allows for efficient production of antimony trisulfide. This also makes it easy to produce antimony trisulfide in a continuous manner.

[0041] 1.3.Effects According to the method for producing antimony trisulfide of this embodiment, it is possible to stably produce antimony trisulfide with good purity, and it is also possible to suppress the generation of sulfur dioxide.

[0042] 2. Examples and Comparative Examples The present invention will be explained in more detail below with reference to examples and comparative examples. The present invention is not limited to the above examples.

[0043] 2.1. Experimental content Metallic antimony powder, antimony trioxide powder, and sulfur powder were prepared. Metallic antimony powder was METAL-P manufactured by Nippon Seiko Co., Ltd. Antimony trioxide powder was PATOX-M, PATOX-C, and PATOX-L manufactured by Nippon Seiko Co., Ltd. Sulfur powder was fine sulfur 200 mesh manufactured by Hosoi Chemical Industry Co., Ltd.

[0044] The average particle size of metallic antimony was adjusted by the vibration ball mill grinding time.

[0045] The mixtures of each example were placed in crucibles according to the formulations shown in Tables 1 and 2, and heated to the temperatures shown in Tables 1 and 2. The heating rate was about 6.7°C / min, except for Example 5, in which the heating rate was about 3.0°C / min, and Examples 21 and 22, in which the heating rate was about 6.4°C / min.

[0046] Tables 1 and 2 show the scale, formulation, average particle size (D50) of metallic antimony powder and antimony trioxide powder, reaction temperature, and evaluation results of the examples and comparative examples.

[0047] [Table 1]

[0048] [Table 2]

[0049] The items in Tables 1 and 2 are explained below. Scale (kg): The raw materials were mixed so that this mass would be obtained when 100% synthesis was completed. Sb mass ratio (%) "metallic antimony": Indicates the mass ratio of Sb contained in metallic antimony when the total mass of metallic antimony and Sb contained in antimony trioxide in the mixture is taken as 100. Sb mass ratio (%) "antimony trioxide": Indicates the mass ratio of Sb contained in antimony trioxide when the total mass of metal antimony and Sb contained in antimony trioxide in the mixture is taken as 100. Sulfur addition ratio "mol ratio relative to metallic antimony": This indicates the ratio of the number of moles of sulfur added as a raw material to the number of moles obtained by multiplying the number of moles of metallic antimony in the raw material by 1.5, according to the above formula (II). Sulfur addition ratio "mol ratio relative to antimony trioxide": This indicates the ratio of the number of moles of sulfur added as a raw material to the number of moles of antimony trioxide multiplied by 4.5, according to the above formula (I). Excess sulfur content (g): This refers to the mass of sulfur added in excess of the stoichiometric amount (see formulas (I) and (II) above) required to obtain antimony trisulfide. Average particle size (D50) (μm) of metallic antimony: The results are shown as measured using a laser diffraction particle size distribution analyzer, "Microtrac MT3300EXII." Average particle size of antimony trioxide (μm): The average particle size (BET equivalent particle size) calculated from the specific surface area determined using a specific surface area measuring device, Macsorb 1210. However, in Example 16, the measurement was performed using the laser diffraction particle size distribution measuring device. · Temperature during reaction (℃): Indicates the maximum temperature reached by the material inside the crucible.

[0050] 2.2. Evaluation Contents (1) Quality evaluation The products obtained in each example were subjected to XRD Rietveld analysis using a PANalytical X'Pert PRO MPD to determine the antimony trisulfide content. A higher antimony trisulfide content indicates higher purity. Evaluation was performed using the following evaluation criteria (3 levels), and the results are shown in Tables 1 and 2. Evaluation criteria: The content of antimony trisulfide is A: 95% or more B: 90% or more but less than 95% C: Less than 90%

[0051] (2) Safety evaluation In each example, the crucible was observed with a monitor during the reaction. Evaluation was performed according to the following evaluation criteria (3 levels), and the results are shown in Tables 1 and 2. Evaluation criteria: A: Maximum flame length 15cm B: Maximum flame length is 15cm or more and the eruption is intense C: Explosion

[0052] (3) Evaluation of sulfur dioxide emissions In each example, the theoretical amount of sulfur dioxide (SO2) generated was calculated. The results were evaluated using the following criteria (3 levels), and are shown in Tables 1 and 2. Evaluation criteria: Theoretical SO2 generation amount (mol / kg generated Sb2S3) A: Less than 3.5 B: 3.5 or more and less than 7.0 C:7.0 or higher

[0053] 2.3.Evaluation Results As can be seen from Tables 1 and 2, in all of the Examples, which were obtained through a mixing step of mixing metallic antimony powder, antimony trioxide powder, and sulfur powder to obtain a mixture, and a heating step of heating the mixture, it was found that the generation of sulfur dioxide was suppressed and the produced antimony trisulfide had good purity and could be produced stably. In contrast, it was found that the products of the Comparative Examples, which lacked any of metallic antimony powder, antimony trioxide powder, and sulfur powder as raw materials, were insufficient in at least one of sulfur dioxide generation, quality, and safety.

[0054] The present invention is not limited to the above-described embodiments, and various modifications are possible. For example, the present invention includes substantially the same configurations as those described in the embodiments (for example, configurations with the same functions, methods, and results, or configurations with the same purpose and effects). The present invention includes configurations in which non-essential parts of the configurations described in the embodiments are replaced. The present invention also includes configurations that have the same effects as the configurations described in the embodiments or that can achieve the same purpose. The present invention also includes configurations in which publicly known technology is added to the configurations described in the embodiments.

Claims

1. a mixing step of mixing metallic antimony powder, antimony trioxide powder, and sulfur powder to obtain a mixture; a heating step of heating the mixture; A method for producing antimony trisulfide, comprising:

2. In claim 1, The mass of Sb in the antimony trioxide powder in the mixture (M Ｏ ) and the Sb mass (M Ｍ ) ratio (M Ｏ : M Ｍ ) is in the range of 1:2 to 2:

1.

3. In claim 1 or claim 2, The method for producing antimony trisulfide, wherein the maximum temperature reached in the heating step is 300°C or higher and 800°C or lower.

4. In any one of claims 1 to 3, The method for producing antimony trisulfide, wherein the average particle size of the metallic antimony powder is 120 μm or less.

5. In any one of claims 1 to 4, The antimony trisulfide manufacturing method, wherein the antimony trioxide powder has an average particle size of 8 μm or less.

6. In any one of claims 1 to 5, The method for producing antimony trisulfide, wherein the total mass of the mixture is 1 kg or more.

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