KR20190052632A - Method for preparing Sodium Antimonate - Google Patents

Abstract

The present invention relates to a method of preparing sodium antimonate. More specifically, the method of the present invention comprises the steps of: forming a first solution by dissolving low-grade antimony trioxide with a purity of 99% or less in a potassium hydroxide solution; forming a sodium antimonate hydrate by adding sodium hydroxide and an oxidizer to the first solution to form a second solution and then, drying the second solution; and obtaining sodium antimonite by heating the sodium antimonate hydrate. According to the present invention, the method can remarkably reduce raw material costs and can minimize the generation of a yellowing phenomenon although low-grade antimony trioxide is used since low-grade antimony trioxide, a by-product, generated in a preparation process of high-grade antimony trioxide can be recycled during the preparation of sodium antimonite, and has an effect of enabling yield of sodium antimonite to be also increased by enabling a generation amount of insoluble material to be also minimized. Further, sodium antimonate with excellent high temperature stability can be obtained in the form of an anhydride through various thermoplasticity methods.

Description

TECHNICAL FIELD The present invention relates to a 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 in the form of a white powder, soluble in water and used as an oxidizing agent at high temperatures. The sodium antimonate has flame retardancy and can be used as a flame retardant adjuvant. It is also used as an opacifying agent for enamel, a glass fining agent for glass fibers and a decolorizer, Trend.

Conventional techniques for producing sodium antimonate are known in which antimony trioxide (Sb ₂ O ₃ ) is dissolved in a sodium hydroxide solution and heated to obtain antimony trioxide. The antimony trioxide is prepared by mixing high-quality antimony trioxide having a purity of 99.5% Grade antimony trioxide having a purity of 99% or less, which is a by-product generated during the process of manufacturing high-quality antimony trioxide.

However, the conventional technology for producing sodium antimonate has a problem of significantly reducing the quality of sodium antimonate produced due to yellowing when low-grade antimony trioxide having a purity of 99% or less is used as a raw material, and further, There is a problem in that the yield of sodium antimonate is lowered because the solubility is low because a large amount of antimony oxide is mixed with the oxidizing agent. For this reason, there is a limit to use a high quality antimony trioxide having a purity of 99.5% or more, which has a high raw material cost, as a raw material, and accordingly, it is difficult to supply sodium antimonate at low cost.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and it is an object of the present invention to provide an antimony trioxide which can recycle low-grade antimony trioxide, which is a byproduct produced during the production of high quality antimony trioxide, and that minimizes the occurrence of yellowing even when low- It is another object of the present invention to provide a method for producing sodium antimonate which can increase the yield of sodium antimonate.

It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. will be.

The present invention relates to a method for preparing sodium antimonate, and more particularly, to a method for producing sodium antimonate, which comprises dissolving a low-quality 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, followed by drying to form a sodium antimonate hydrate; And heating the sodium antimonate hydrate to obtain sodium antimonate.

According to the production process of the present invention, it is possible to recycle low-level antimony trioxide, which is a byproduct produced during the production of high-quality antimony trioxide, in the production of sodium antimonate, thereby remarkably reducing the cost of raw materials and using low-grade antimony trioxide The yellowing phenomenon can be minimized, and the amount of insolubles such as antimony oxide can be minimized, so that the yield of sodium antimonate can be increased.

In addition, according to the production method of the present invention, antimony acid hydrate can be obtained in the form of anhydride (anhydride), which is excellent in high-temperature stability through various thermosetting processes.

Fig. 1 shows the result of XRD analysis of the sodium antimonate hydrate (NaSb (OH) ₆ ) obtained by drying the second solution in Example 2 according to the present invention before heating in an electric furnace.
FIG. 2 shows XRD measurement results of sodium antimonate obtained by heating the sodium antimonate hydrate in an electric furnace in Example 2. FIG.
3 shows the XRD measurement results of the comparative example.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention is capable of various modifications and various embodiments, and specific embodiments are illustrated in the drawings and will be described in detail in the detailed description. It is to be understood, however, that the invention is not to be limited to the specific embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises" or "having" and the like are used to specify that there is a feature, a number, a step, an operation, an element, a component or a combination thereof described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

The terms first, second, etc. 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 process for preparing sodium antimonate, and more particularly, to a process for preparing a first solution by dissolving a low-quality antimony trioxide having a purity of 99% or less in a potassium hydroxide solution; Adding sodium hydroxide and an oxidizing agent to the first solution to form a second solution, followed by drying to form a 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 and is in the form of a white powder. Its molecular weight is 291.52, its specific gravity is 5.2 to 5.4, its melting point is 656 ° C, its boiling point is 1425 ° C and its density is 5.6. Antimony trioxide is a yellow liquid when heated, and when cooled, it becomes a white crystal. It dissolves in hydrochloric acid, soda lime, tartaric acid and the like, but does not dissolve in water or alcohol. Antimony trioxide is mainly used as a flame retardant, pigment, glass preparation, catalyst and the like.

In the present invention, the antimony trioxide is not a high-quality antimony trioxide having a purity of 99.5% or more but a low-grade antimony trioxide having a purity of 99% or less. That is, the present invention is characterized by recycling the low-grade antimony trioxide, which is a by-product generated during the production process of the high-quality antimony trioxide, so that the raw material cost can be remarkably reduced and the production cost of sodium antimonate There is an advantage.

In the present invention, the step of forming the first solution is a process of dissolving a low-quality 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 The present invention is characterized by dissolving the low-grade antimony trioxide in a potassium hydroxide solution before dissolving in a sodium hydroxide solution to suppress the yellowing phenomenon as described above. In addition, the present invention dissolves the low-grade antimony trioxide in a potassium hydroxide solution before dissolving the low-grade antimony trioxide in a sodium hydroxide solution, thereby significantly reducing the amount of insolubles produced, thereby increasing the yield of sodium antimonate.

The concentration of the potassium hydroxide solution is not particularly limited, but it is preferable that the molar concentration is 9 M to 10 M. This is because if the molar concentration of the potassium hydroxide solution is less than 9 M, there is a problem that the antimony trioxide does not dissolve. If the molar concentration exceeds 9 M, the remaining potassium hydroxide reacts with the oxidizing agent to lower the reaction efficiency .

On the other hand, the content of the low-level antimony trioxide is preferably 1 wt% to 1.5 wt% based on the total weight of the first solution, minimizes the occurrence of yellowing phenomenon, minimizes the amount of insolubles produced, and further improves the yield of sodium antimonate Do.

In the present invention, the step of forming the sodium antimonate hydrate may include forming a second solution by adding sodium hydroxide and an oxidizing agent to the first solution, and then drying the resultant to form sodium antimonate hydrate (NaSbO ₃ (H ₂ O) ₃ ) In particular, the present invention can further suppress the occurrence of yellowing on sodium antimonite by adding the above oxidizing agent.

The amount of the sodium hydroxide to be added is not particularly limited, but is preferably 20% by weight to 21% by weight based on the total weight of the second solution. If the added amount of sodium hydroxide is less than 20% by weight based on the total weight of the second solution, there is a problem that antimony trioxide reacted with potassium hydroxide in the first solution is not substituted with sodium hydroxide, %, There is a problem that the reaction efficiency is lowered due to the reaction of the remaining sodium hydroxide with the oxidizing agent.

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

The addition amount of the oxidizing agent is preferably 1.5% by weight to 2.0% by weight based on the total weight of the second solution. If the amount of the oxidizing agent added is less than 1.5 wt% based on the total weight of the second solution, the reaction with the oxidizing agent becomes less, If the concentration exceeds the above range, hydrogen peroxide may react with the remaining base or water, and the resulting material may inhibit the radical reaction of hydrogen peroxide.

In the present invention, the step of obtaining the sodium antimonate is a step of heating the sodium antimonate hydrate to obtain the desired sodium antimonate. In the case of the present invention, the heating step at a lower temperature than the conventional sodium antimonate- This has the advantage of reducing energy costs.

The heating conditions of the sodium hypochlorite monohydrate may vary depending on the type of the electric furnace used. In the case of using the batch electric furnace, the maximum temperature is maintained for 2 to 6 hours after reaching the maximum temperature, Is preferably 900 ° C to 1200 ° C, and in the case of using a continuous electric furnace, the heating zone is preferably heated at 900 ° C to 1300 ° C for a retention time of 6 hours to 12 hours. This is because, if the heating conditions are not satisfied, sodium hypochlorite hydrate (NaSb (OH) ₆ ) may partially remain and the yield of sodium antimonate may be lowered or yellowing may occur.

Sodium antimonate (NaSbO ₃ ) produced by the present invention is in the form of a white powder, is water-soluble and is used as an oxidizing agent at a high temperature. The sodium antimonate has flame retardancy and can be used as a flame retardant adjuvant, and can be used as an opacifier for enamel, a glass fining agent for glass fibers, and a decolorizer.

According to the method for producing sodium antimonate according to the present invention, it is possible to recycle low-level antimony trioxide, which is a by-product produced during the manufacturing process of high-quality antimony trioxide, so that the cost of raw materials can be remarkably reduced, and even if low-grade antimony trioxide is used, The generation of the phenomenon can be minimized, the amount of the insolubles produced can be minimized, and the yield of sodium antimonate can be increased.

Hereinafter, the present invention will be described by way of examples. The following examples are merely examples for helping understanding of the present invention, and thus 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, and magnetic bar was added thereto, followed by stirring 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 in the contents shown in Table 1 below and stirred for 6 hours to obtain a grayish first solution.

100 g (2.5 mol) of sodium hydroxide was added to the first solution prepared above and stirred for about 3 hours to obtain a transparent gray light solution. After the gray light solution synthesized in the above was transparent, After removing insolubles, 5 mL of hydrogen peroxide was added to obtain a second solution. Thereafter, the second solution was dried to obtain sodium antimonate hydrate.

The above sodium antimonate hydrate was heated in a batch type 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, magnetic bar was added, 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 filtration, 5 mL of hydrogen peroxide was added and then dried.

Thereafter, in a batch type electric furnace, heating was carried out under the heating conditions shown in Table 1 below to obtain sodium antimonate in crystalline form.

Example 1 Example 2 Example 3 Comparative Example Low-grade
Antimony trioxide
(Sb ₂ O ₃ ) content
4 g 5 g 5.5 g 5g Heating condition
(Batch type
Electric furnace) Maximum temperature
After reaching
Heating time 4 hr 4 hr 4 hr 4 hr Maximum temperature 1100 ℃ 1100 ℃ 1100 ℃ 1100 ℃

Experimental Example

(1) Yellowing phenomenon

For the above Examples 1 to 3 and Comparative Example, it was measured in accordance with JIS evaluation method Z8730 in order to confirm the occurrence of yellowing phenomenon, and 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, the color b values related to the yellowing phenomenon in the examples 1 to 3 according to the present invention are significantly lower than those of the comparative example, and it can be confirmed that the yellowing phenomenon hardly occurs.

(2) Yield test of sodium antimonate (amount of insolubles produced)

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

FIG. 1 shows the result of XRD analysis of the sodium antimonate hydrate (NaSb (OH) ₆ ) obtained by drying the second solution in Example 2 before heating in an electric furnace. FIG. 2 shows the results of XRD analysis As a result of XRD measurement on the sodium antimonate obtained by heating the sodium hydrate to an electric furnace, almost no insolubles exist in the resultant product, and the yield of sodium antimonate is almost 100%. On the other hand, FIG. 3 shows the result of XRD measurement of Comparative Example 2, and it was confirmed that a large amount of antimony oxide (Sb ₂ O ₅ ) as well as sodium antimonate was contained in the resultant product, and the yield of sodium antimonate 2 is significantly lower than that of Comparative Example 2.

(3) Changes in the quality of sodium antimonate according to the heating conditions:

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

Maximum temperature
(hr) Maximum temperature
Retention time
(hr)
Color L
Color a
Color b
Sodium antimonate
yield

800 ° C 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 the above Table 3, when heated using a batch type electric furnace, the yellowing of the sodium antimonite becomes much better when heated at the maximum temperature range of 900 to 1200 DEG C for 2 to 6 hours, The amount of sodium hydrate (NaSb (OH) ₆ ) is also minimized and ultimately the purity of sodium antimonate can be higher.

(4) Change in quality of sodium antimonate according to heating conditions: continuous electric furnace use

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

Heating zone temperature
(hr)
Heating time
(hr)
Color L
Color a
Color b
Sodium antimonate Yield


800 ° C 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 ° C 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 above, when heating is carried out using a continuous electric furnace at a heating zone temperature of 900 ° C. to 1300 ° C. for 6 to 12 hours, the yellowing of the sodium antimonite is much better and the remaining antimony The amount of sodium hydrate (NaSb (OH) ₆ ) is also minimized and ultimately the purity of sodium antimonate can be higher.

As described above, those skilled in the art will understand that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. It will be understood by those skilled in the art that the present invention may be embodied in many other specific forms without departing from the spirit or scope of the invention as defined by the appended claims and their equivalents. .

Claims (8)

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, followed by drying to form a sodium antimonate hydrate; And
And heating the sodium antimonate hydrate to obtain sodium antimonate.
The method according to claim 1,
Wherein the content of the low-grade antimony trioxide is 1 wt% to 1.5 wt% based on the total weight of the first solution.
The method according to claim 1,
Wherein the potassium hydroxide solution has a molar concentration of 9 to 10 M. 9. A process for producing sodium antimonate,
The method according to claim 1,
Wherein the sodium hydroxide is added in an amount of 20 to 30% by weight based on the total weight of the second solution.
The method according to claim 1,
Wherein the oxidizing agent is hydrogen peroxide.
The method according to claim 1,
Wherein the amount of the oxidizing agent added is 1.5 to 2.0 wt% based on the total weight of the second solution.
The method according to claim 1,
The sodium hypochromic acid hydrate is heated under a maximum temperature of 2 to 6 hours after the maximum temperature is reached when the batch type electric furnace is used, and then cooled. The maximum temperature is 900 to 1200 ° C. ≪ / RTI >
The method according to claim 1,
Wherein the sodium hypochlorite monohydrate is heated under a condition that the temperature of the heating zone is 900 ° C. to 1300 ° C. for a retention time of 6 hours to 12 hours when a continuous electric furnace is used.

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