KR102021997B1 - Method for preparing Sodium Antimonate - Google Patents

Abstract

The present invention relates to a method for preparing sodium antimonate, more specifically, the step of dissolving low-grade antimony trioxide having a purity of 99% or less in a potassium hydroxide solution to form a first solution; Adding sodium hydroxide and an oxidizing agent to the first solution to form a second solution and then drying to form sodium antimonate hydrate; And heating the sodium antimonate hydrate to obtain sodium antimonate. According to the production method according to the present invention, in the production of sodium antimonate, it is possible to recycle the low-grade antimony trioxide, which is a by-product generated during the production of high-quality antimony trioxide, can significantly reduce the raw material cost, and lower-grade antimony trioxide Even when used, it is possible to minimize the occurrence of yellowing, it is also possible to minimize the amount of insolubles, there is an effect that can increase the yield of sodium antimonate. In addition, antimony acid hydrate can be obtained in the form of anhydride (sodium hydride), which has excellent high temperature stability through various thermal calcining methods.

Description

Method for preparing sodium antimonate {Method for preparing Sodium Antimonate}

The present invention relates to a method for producing sodium antimonate by recycling low-grade antimony trioxide.

Sodium Antimonate (NaSbO ₃ ) is a white powder that is water soluble and used as an oxidant at high temperatures. In addition, the sodium antimonate may be used as a flame retardant adjuvant because it has a flame retardancy, and is also used as an opaque agent for enamel or as a glass fining agent and a decolorizer of glass fiber, and its demand has recently increased. It is a trend.

Conventional antimony trioxide manufacturing technology is known to obtain a technique obtained by dissolving antimony trioxide (Sb ₂ O ₃ ) in sodium hydroxide solution and heating, the antimony trioxide is a high-quality antimony trioxide with a purity of 99.5% or more It is divided into low-grade antimony trioxide with less than 99% purity, which is a by-product generated during the manufacture of high-quality antimony trioxide.

However, the existing manufacturing technology of sodium antimonate has a problem of significantly lowering the quality of the sodium antimonate produced by the yellowing phenomenon when using a low-grade antimony trioxide with a purity of 99% or less, and further, the low-grade antimony trioxide Polyoxidation has a problem in that the antimony oxide is mixed with a large amount of solubility, so that the yield of sodium antimonate is lowered. For this reason, there is a limit to using high-quality antimony trioxide of 99.5% or more with high raw material cost as a raw material. Accordingly, the demand is increasing, and it is difficult for the industry to supply sodium antimonate at a low price.

The present invention was derived to solve the above problems, it is possible to recycle the low-grade antimony trioxide, which is a by-product generated during the production of high-quality antimony trioxide, and to minimize the occurrence of yellowing even when using a low-grade antimony trioxide It can be, and the object of the present invention is to provide a method for producing sodium antimonate which can also increase the yield of sodium antimonate.

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

The present invention for solving the above problems relates to a method for producing sodium antimonate, more specifically, the step of dissolving low-grade antimony trioxide of 99% or less purity in a potassium hydroxide solution to form a first solution; Adding sodium hydroxide and an oxidizing agent to the first solution to form a second solution and then drying to form sodium antimonate hydrate; And heating the sodium antimonate hydrate to obtain sodium antimonate.

According to the production method according to the present invention, in the production of sodium antimonate can recycle the low-grade antimony trioxide, which is a by-product generated during the production of high-quality antimony trioxide, can significantly reduce the raw material cost, use low-grade antimony trioxide Even if the yellowing phenomenon can be minimized, the polyoxidation can also minimize the amount of insolubles, such as antimony oxide, it is possible to increase the yield of sodium antimonate.

In addition, according to the production method according to the invention there is an effect that the antimony acid hydrate can be obtained in the form of an anhydride (unhydrated) of sodium antimonate excellent in high temperature stability through various thermal calcining methods.

FIG. 1 shows XRD analysis of sodium antimonate hydrate (NaSb (OH) ₆ ) obtained by drying a second solution in Example 2 before heating in an electric furnace.
Figure 2 shows the XRD measurement results for sodium antimonate obtained by heating the sodium antimonate hydrate in an electric furnace in Example 2.
Figure 3 shows the XRD measurement results of the comparative example.

As the inventive concept allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the written description. However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all transformations, equivalents, and substitutes included in the spirit and scope of the present invention. In the following description of the present invention, if it is determined that the detailed description of the related known technology may obscure the gist of the present invention, the detailed description thereof will be omitted.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "have" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination thereof.

Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

The present invention relates to a method for preparing sodium antimonate, more specifically, the step of dissolving low-grade antimony trioxide having a purity of 99% or less in a potassium hydroxide solution to form a first solution; Adding sodium hydroxide and an oxidizing agent to the first solution to form a second solution and then drying to form sodium antimonate hydrate; And heating the sodium antimonate hydrate to obtain sodium antimonate.

Antimony trioxide (Sb ₂ O ₃ ) is a kind of antimony oxide, which is in the form of white powder, has a molecular weight of 291.52, specific gravity of 5.2 to 5.4, melting point of 656 ° C, boiling point of 1425 ° C, and density of 5.6. Antimony trioxide becomes a yellow liquid when heated, and becomes white crystal when cooled. It dissolves in hydrochloric acid, caustic, tartaric acid, etc., but does not dissolve in water or alcohol. Antimony trioxide is mainly used for flame retardants, pigments, glass preparation, catalysts, and the like.

In the present invention, the antimony trioxide is not high-quality antimony trioxide of 99.5% or more purity, it is characterized by low-grade antimony trioxide of 99% or less purity. That is, the present invention is characterized by recycling the low-grade antimony trioxide, which is a by-product generated during the production of high-quality antimony trioxide, can significantly reduce the raw material cost, thereby reducing the production cost of sodium antimonate There is an advantage.

In the present invention, the forming of the first solution is a process of dissolving low-grade antimony trioxide having a purity of 99% or less in a potassium hydroxide solution, which causes yellowing when the low-grade antimony trioxide is immediately dissolved in a sodium hydroxide solution. In addition, the present invention is characterized in that the low-grade antimony trioxide is dissolved in potassium hydroxide solution before dissolving in the sodium hydroxide solution in order to suppress the occurrence of such a yellowing phenomenon. In addition, the present invention can significantly reduce the amount of insolubles produced by dissolving the low-grade antimony trioxide in the potassium hydroxide solution before dissolving it in the sodium hydroxide solution, it is also possible to increase the yield of sodium antimonate.

The concentration of the potassium hydroxide solution is not particularly limited, but the molar concentration is preferably 9 M to 10 M. This is because when the molar concentration of the potassium hydroxide solution is less than 9 M, there is a problem that antimony trioxide is not dissolved, and when it exceeds 9 M, potassium hydroxide remaining after the reaction reacts with the oxidizing agent to decrease the reaction efficiency. .

On the other hand, the content of the low-grade antimony trioxide is preferably 1% to 1.5% by weight relative to the total weight of the first solution to minimize the occurrence of yellowing, and to minimize the amount of insolubles to further increase the yield of sodium antimonate. Do.

Forming the sodium antimonate hydrate in the present invention is the addition of sodium hydroxide and an oxidizing agent to the first solution to form a second solution and dried to form sodium antimonate hydrate (NaSbO ₃ (H ₂ 0) ₃ ) In particular, the present invention may further suppress the yellowing of sodium antimonate by adding the oxidizing agent.

The amount of the sodium hydroxide added is not particularly limited, but is preferably 20% to 21% by weight based on the total weight of the second solution. This is a problem because when the amount of the sodium hydroxide added is less than 20% by weight relative to the total weight of the second solution, it is not replaced by sodium hydroxide in the antimony trioxide reacted with potassium hydroxide in the first solution. This is because when the amount is exceeded, the remaining sodium hydroxide reacts with the oxidizing agent, resulting in a decrease in the reaction efficiency.

The oxidizing agent is not particularly limited, but in order to maximize the yellowing inhibitory effect of sodium antimonate, the present invention is preferably any one selected from the group consisting of peroxides such as hydrogen peroxide and di-tert-butyl peroxide. Among them, it is most preferable to use hydrogen peroxide.

In addition, the amount of the oxidizing agent is preferably 1.5% to 2.0% by weight based on the total weight of the second solution. This is because when the addition amount of the oxidizing agent is less than 1.5% by weight relative to the total weight of the second solution, the reaction with the oxidizing agent is small, so that the efficiency is lowered because the reaction does not proceed as a whole to the desired final substance. If the weight percentage is exceeded, a problem may occur in that the substance produced by reacting with hydrogen peroxide and the remaining base or water may inhibit the radical reaction of hydrogen peroxide.

The step of obtaining the sodium antimonate in the present invention is a step of obtaining the sodium antimonate of the target by heating the sodium antimonate hydrate, in the case of the present invention heating process at a lower temperature than conventional sodium antimonate production technology This is possible, which has the advantage of reducing energy costs.

Heating conditions of the sodium antimonate hydrate may vary depending on the type of electric furnace used, ① When using a batch type electric furnace to maintain the maximum temperature range for 2 to 6 hours after reaching the maximum temperature, the maximum temperature Is preferably from 900 ℃ to 1200 ℃, ② When using a continuous electric furnace is preferably heated for 6 to 12 hours the retention time of the heating section at 900 ℃ to 1300 ℃. This is because if the heating conditions are not satisfied, some of the anti-monate sodium hydrate (NaSb (OH) ₆ ) may remain, resulting in a low yield of sodium antimonate or a yellowing phenomenon.

Sodium antimonate (NaSbO ₃ ) prepared by the present invention is in the form of a white powder, water-soluble and used as an oxidizing agent at high temperatures. In addition, the sodium antimonate may be used as a flame retardant adjuvant because it has a flame retardancy, and may be used as an enamel opacifying agent or glass fining agent and decolorizer for glass fibers.

According to the method for producing sodium antimonate according to the present invention, it is possible to recycle the low-grade antimony trioxide, which is a by-product generated during the production of high-quality antimony trioxide, can significantly reduce the raw material cost, yellowing even when using a low-grade antimony trioxide The phenomenon can be minimized, and the amount of insoluble matter can be minimized, so that the yield of sodium antimonate can be increased.

Hereinafter, the present invention will be described through examples. The following examples are merely examples to aid the understanding of the present invention, and the scope of the present invention is not limited thereto.

Example

140.27 g (2.5 mol) of potassium hydroxide was added to 250 mL of water, a magnetic bar was added, and stirred for 30 minutes to obtain a potassium hydroxide solution. Low-grade antimony trioxide (Sb ₂ O ₃ ) having a purity of 99% was added to the potassium hydroxide solution as shown in the following Table 1, and stirred for 6 hours to obtain a grayish first solution.

After adding 100 g (2.5 mol) of sodium hydroxide to the first solution synthesized above, the mixture was stirred for about 3 hours to obtain a transparent gray solution, and then filtered when the gray solution synthesized above became transparent. After removing the insoluble matter through 5 mL of hydrogen peroxide (Hydrogen peroxide) was added to obtain a second solution. The second solution was then dried to give sodium antimonate hydrate.

The sodium antimonate hydrate was heated in a batch electric furnace under the heating conditions shown in Table 1 below to obtain sodium antimonate in crystalline form.

Comparative example

200 g (5 mol) of sodium hydroxide was added to 250 mL of water, a magnetic bar was added thereto, and stirred for 30 minutes to obtain a sodium hydroxide solution. 5 g of low-grade antimony trioxide (Sb ₂ O ₃ ) having a purity of 99% was added to the sodium hydroxide solution, and stirred for 6 hours to obtain a grayish solution. When the grayish solution became transparent, the insoluble matter was removed by filtering. 5 mL of hydrogen peroxide was added and then dried.

After heating in a batch electric furnace in the heating conditions shown in Table 1 below to obtain the sodium antimonate in the form of a crystal.

Example 1 Example 2 Example 3 Comparative example Low grade
Antimony trioxide
(Sb ₂ O ₃ ) content
4 g 5 g 5.5 g 5 g Heating condition
(Placement type
Furnace) Temperature
After reaching
Heating time 4 hr 4 hr 4 hr 4 hr Highest temperature 1100 ℃ 1100 ℃ 1100 ℃ 1100 ℃

Experimental Example

(1) yellowing

In order to confirm whether the yellowing phenomenon occurs in Examples 1 to 3 and Comparative Examples was measured according to JIS evaluation method Z8730, the results are shown in Table 2 below.

Example 1 Example 2 Example 3 Comparative example Color l 99.41 99.58 99.49 99.15 Color a 0.49 0.52 0.56 0.61 Color b 0.28 0.29 0.20 2.07

As shown in Table 2, in Examples 1 to 3 according to the present invention, the value of Color b related to the yellowing phenomenon was significantly lower than that of the comparative example, and thus it was confirmed that the yellowing phenomenon hardly occurred.

(2) Yield test of sodium antimonate (amount of insoluble matter)

The yield of sodium antimonate was confirmed by X-ray diffraction (XRD) on the results of Example 2 and Comparative Example, and the results are shown in FIGS. 1 to 3.

1 is a result of XRD analysis before heating with an electric furnace for sodium antimonate hydrate (NaSb (OH) ₆ ) obtained by drying the second solution in Example 2, Figure 2 is the antimonic acid in Example 2 As a result of XRD measurement about the sodium antimonate obtained by heating sodium hydrate with an electric furnace, it turns out that there is almost no insoluble thing in the result, and the yield of sodium antimonate is almost 100%. On the contrary, FIG. 3 is a XRD measurement result of Comparative Example 2, and it was confirmed that a large amount of not only sodium antimonate but also polyhydric oxide (Sb ₂ O ₅ ) was mixed in the result, so that the yield of sodium antimonate was obtained in the above Example. It can be seen that it is significantly lower than 2.

(3) Changes in the quality of sodium antimonate according to heating conditions: batch type electric furnace

For Example 2, when the heating conditions of the batch-type electric furnace was changed, the yield change and yellowing of the resulting sodium antimonate was confirmed, the results are shown in Table 3 below.

Temperature
(hr) Temperature range
Retention time
(hr)
Color l
Color a
Color b
Sodium antimonate
yield

800 ℃ 3 98.54 -0.38 1.80 123.32 4 98.79 -0.25 1.72 118.01 5 98.93 -0.11 1.67 114.32 6 99.07 -0.03 1.59 109.38 7 99.13 0.09 1.36 105.85

900 ℃ 4 99.14 0.08 1.34 105.89 5 99.19 0.13 0.98 102.34 6 99.49 0.29 0.52 99.97 7 99.32 0.34 0.79 99.85 8 99.29 0.56 1.12 99.32


1000 ℃ 2 99.18 0.12 1.20 110.06 3 99.09 0.22 0.86 103.05 4 99.51 0.61 0.32 99.82 5 99.53 0.69 0.35 99.68 6 99.51 0.76 0.42 99.34 7 99.42 0.80 0.69 99.29

1100 ℃ 2 99.13 0.19 0.99 102.41 3 99.50 0.65 0.75 99.92 4 99.44 0.69 0.89 99.71 5 99.51 0.56 0.92 99.55 6 99.31 0.64 1.10 99.03
1200 ℃ One 99.04 0.23 0.86 101.05 2 99.39 0.32 0.69 99.78 3 99.29 0.78 1.20 99.61 4 99.10 0.99 1.90 99.35

As shown in Table 3 above, when heated using a batch electric furnace, yellowing of sodium antimonate becomes even better when heated for 2 to 6 hours at a maximum temperature of 900 ° C. to 1200 ° C., while antimony remaining at the same time. The amount of acid sodium hydrate (NaSb (OH) ₆ ) can also be minimized, resulting in a higher purity of sodium antimonate.

(4) Changes in the quality of sodium antimonate depending on heating conditions: continuous electric furnace

For Example 2, when the heating conditions of the continuous electric furnace was changed, the yield change and yellowing of the resulting sodium antimonate was confirmed, the results are shown in Table 4 below.

Heating section temperature
(hr)
Heating time
(hr)
Color l
Color a
Color b
Sodium antimonate yield


800 ℃ 4 98.25 -0.46 1.78 130.33 6 98.36 -0.39 1.62 118.03 8 98.31 -0.35 1.58 111.25 10 98.68 -0.34 1.48 107.32 12 98.73 -0.28 1.44 102.57 14 98.98 -0.12 1.42 101.39


900 ℃ 6 98.68 -0.34 1.48 107.07 8 98.77 -0.04 1.18 104.95 10 99.04 0.04 0.97 101.78 12 99.42 0.66 0.24 99.88 14 99.38 0.69 0.69 99.51 16 99.23 0.32 0.78 99.42


1000 ℃ 4 99.01 -0.25 1.44 107.12 6 99.02 0.07 1.13 102.17 8 99.15 0.15 0.78 100.37 10 99.49 0.35 0.26 99.81 12 99.50 0.39 0.47 99.75 14 99.23 0.42 0.97 99.29

1100 ℃ 4 99.12 -0.17 1.13 104.18 6 99.69 0.18 0.81 100.93 8 99.66 0.45 0.79 99.90 10 99.41 0.58 0.54 99.76 12 99.13 0.72 0.97 99.29

1200 ℃ 5 99.22 -0.06 0.92 101.18 7 99.51 0.22 0.61 99.97 8 99.66 0.35 0.69 99.81 10 99.43 0.58 0.54 99.76 12 99.07 0.68 0.98 99.19

1300 ℃ 4 99.08 -0.19 1.10 102.18 6 99.46 0.25 0.63 99.90 8 99.52 0.34 0.79 99.73 10 99.01 0.88 0.94 99.76
1400 ℃ 3 98.67 0.98 1.91 97.89 4 98.09 1.20 2.15 95.82 6 97.21 1.48 3.54 93.78

As shown in Table 4, when heated using a continuous electric furnace, when heated for 6 to 12 hours at a heating zone temperature of 900 ℃ to 1300 ℃ 6, the anti-yellowing of sodium antimonate is better, at the same time remaining antimony The amount of acid sodium hydrate (NaSb (OH) ₆ ) can also be minimized, resulting in a higher purity of sodium antimonate.

As described above, those skilled in the art will understand that the present invention can be implemented in other specific forms without changing the technical spirit or essential features. The scope of the present invention is shown by the claims to be described later rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts are included in the scope of the present invention. Should be.

Claims (8)

Dissolving low-grade antimony trioxide of 99% or less in purity in a potassium hydroxide solution to form a first solution;
Adding sodium hydroxide and an oxidizing agent to the first solution to form a second solution and then drying to form sodium antimonate hydrate; And
To include the step of heating the sodium antimonate hydrate to obtain sodium antimonate;
The heating conditions of the sodium antimonate hydrate is cooled after maintaining the maximum temperature range for 2 to 6 hours after reaching the maximum temperature of 900 ℃ to 1200 ℃ in a batch electric furnace, or 900 ℃ temperature of the heating section in a continuous electric furnace Method of preparing sodium antimonate will be heated for 1 to 12 hours at a residence time of 6 to 12 hours.
The method of claim 1,
The low-grade antimony trioxide content is a method for producing sodium antimonate, characterized in that 1% to 1.5% by weight relative to the total weight of the first solution.
The method of claim 1,
The potassium hydroxide solution is a method for producing sodium antimonate, characterized in that the molar concentration of 9 to 10 M.
The method of claim 1,
The amount of the sodium hydroxide added is 20 to 30% by weight relative to the total weight of the second solution, the method for producing sodium antimonate.
The method of claim 1,
The oxidizing agent is a method for producing sodium antimonate, characterized in that the hydrogen peroxide.
The method of claim 1,
The amount of the oxidizing agent is a method of producing sodium antimonate, characterized in that 1.5 to 2.0% by weight relative to the total weight of the second solution.
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