Method for producing high purity phosphoric acid through quantum behavior control

Abstract

The present invention relates to a method for producing high-purity phosphoric acid through quantum behavior control, and more specifically, to a method for producing high-purity phosphoric acid that can economically and industrially obtain low-grade phosphoric acid as high-purity phosphoric acid by controlling the crystal growth position and speed of phosphoric acid crystals through changes in the molecular or quantum behavior of phosphoric acid and water molecules and impurities within the phosphoric acid raw material by utilizing the temperature difference between the inner and outer jackets of a cooling device and the rotation of the inner jacket, thereby suppressing the phenomenon of impurity trapping inside the phosphoric acid crystals and obtaining phosphoric acid crystals.

Description

Technology Field

[0001] The present invention relates to a method for producing high-purity phosphoric acid through quantum behavior control, and more specifically, to a method for producing high-purity phosphoric acid that can economically and industrially obtain low-grade phosphoric acid as high-purity phosphoric acid by controlling the crystal growth position and speed of phosphoric acid crystals through changes in the molecular or quantum behavior of phosphoric acid and water molecules and impurities within the phosphoric acid raw material by utilizing the temperature difference between the inner and outer jackets of a cooling device and the rotation of the inner jacket, thereby suppressing the phenomenon of impurity trapping inside the phosphoric acid crystals and obtaining phosphoric acid crystals. Background Technology

[0003] Phosphoric acid is the only material capable of wet-etching semiconductor silicon nitride films (Si3N4, SiN) and is an essential chemical material in the semiconductor manufacturing process. In this silicon nitride film etching process, impurities in the phosphoric acid etching solution have a direct impact on semiconductor yield and defect occurrence, so their concentration is strictly controlled.

[0004] High-purity phosphoric acid usable in such semiconductor manufacturing processes requires high process costs because it can only be produced by a dry method of extracting yellow phosphorus (P4) from high-quality phosphorite and oxidizing and burning it at a high temperature of 200°C or higher.

[0005] Furthermore, because the reserves of high-quality phosphate rock are limited, the price of high-purity phosphoric acid continues to rise due to accelerated mineral depletion, which economically leads to increased semiconductor manufacturing costs.

[0006] Various methods, such as membrane separation, ion exchange, or liquid extraction, have been proposed for the purification of phosphoric acid containing large amounts of metal ion impurities.

[0007] First, while membrane separation methods offer the advantage of high yield and purity of recovered phosphoric acid, they have the disadvantages of high process costs and highly complex operation. Additionally, the corrosiveness of phosphoric acid can lead to safety issues regarding the membranes used.

[0008] Ion exchange methods utilize ion exchange resins or calcium zeolites to remove acid, but the ion exchange resins used have a low ion exchange capacity, so they can only treat low concentrations of acid, and there are limitations in that process costs are continuously incurred because the ion exchange resins must be replaced after the ion exchange is completed.

[0009] The liquid extraction method has the advantages of continuous process operation and low equipment costs, but it has the disadvantage of being unable to obtain high-purity phosphoric acid at the level required for semiconductor processes.

[0010] Crystallization is a method of producing crystals from a saturated solution by controlling the crystal nucleation and crystal growth rates.

[0011] The above crystallization method can be divided into a crystallization method using a phosphate seed to promote crystal nucleation and a crystallization method that does not use a phosphate seed. In the case where a phosphate seed is not used, crystallization can proceed only if the crystallization conditions are controlled to a temperature of minus 40°C or lower, which results in a problem of high cost and time required to produce crystals.

[0012] Therefore, there is a need to develop a new method for manufacturing phosphoric acid that can economically and industrially obtain high-purity phosphoric acid free from unnecessary metals by separating impurities from phosphoric acid raw materials containing a large amount of impurities. The problem to be solved

[0014] The present invention aims to provide a method for producing high-purity phosphoric acid through quantum behavior control, which enables the economical and industrial production of phosphoric acid.

[0015] According to the present invention, the temperature difference between the inner and outer jackets of a cooling device and the rotation of the inner jacket control the crystal growth position and speed of the phosphoric acid crystal through changes in the molecular or quantum behavior of phosphoric acid and water molecules and impurities within the phosphoric acid raw material, thereby suppressing the phenomenon of impurity trapping inside the phosphoric acid crystal and obtaining the phosphoric acid crystal, thereby enabling the economical and industrial production of high-purity phosphoric acid from low-grade phosphoric acid. means of solving the problem

[0017] The present invention can provide a method for producing high-purity phosphoric acid, comprising the steps of: supplying a phosphoric acid raw material containing impurities to a cooling device including an inner jacket and an outer jacket (S1); introducing a phosphoric acid seed into the cooling device to form a phosphoric acid crystal (S2); and rotating the inner jacket within the cooling device to grow the phosphoric acid crystal (S3), wherein the temperature difference between the inner jacket and the outer jacket is 5°C or more.

[0018] In the above phosphoric acid crystal growth step (S3), the rotation speed of the inner jacket may be 1 to 150 RPM.

[0019] The method for producing high-purity phosphoric acid according to the present invention may further include a step (S4) of separating crystallized phosphoric acid and non-crystallized phosphoric acid by raising an internal jacket within the cooling device after the phosphoric acid crystal growth step (S3).

[0020] In the above crystallization phosphoric acid separation step (S4), the rising speed of the inner jacket may be 0.5 to 15 mm / min.

[0021] The method for producing high-purity phosphoric acid according to the present invention may further include a step (S5) of obtaining crystallized phosphoric acid by raising the temperature of the inner jacket to 40°C or higher after removing the uncrystallized phosphoric acid following the crystallized phosphoric acid separation step (S4).

[0022] The temperature difference between the inner jacket and the outer jacket may be 40℃ or less.

[0023] The temperature of the inner jacket above may be 0 to 30℃.

[0024] The temperature of the outer jacket above may be 5 to 50℃.

[0025] The concentration of the above phosphoric acid raw material may be 85 to 91.6%.

[0026] The above phosphoric acid raw material may have a total impurity content of 300 ppb or more, including Al, K and Cu.

[0027] The phosphoric acid obtained by the above method may contain Al, K, and Cu at 1 ppb or less each. Effects of the invention

[0029] When using the method for producing high-purity phosphoric acid through quantum behavior control provided by the present invention, it is possible to produce high-purity phosphoric acid economically and industrially. Specific details for implementing the invention

[0031] Unless otherwise defined in this specification, all technical and scientific terms have the same meaning as generally understood by those skilled in the art to which the invention pertains. The terms used in the description of the invention are merely for the purpose of effectively describing specific embodiments and are not intended to limit the invention.

[0032] The singular forms used in this specification include plural forms unless the phrases clearly indicate otherwise.

[0033] As used in this specification, the meaning of 'includes' specifies certain characteristics, regions, integers, steps, actions, elements, and / or components, and does not exclude the existence or addition of other specific characteristics, regions, integers, steps, actions, elements, components, and / or groups.

[0034] The present invention is capable of various modifications and may take various forms, and specific embodiments are illustrated and described in detail below. However, this is not intended to limit the invention to the specific disclosed forms, and it should be understood that the invention includes all modifications, equivalents, and substitutions that fall within the spirit and scope of the invention.

[0035] In this specification, where the positional relationship between two parts is described, for example, using expressions such as 'on', 'on the upper part', 'on the lower part', 'next to', etc., one or more other parts may be located between the two parts unless expressions such as 'immediately' or 'directly' are used.

[0036] In this specification, when temporal sequences are described, for example, using expressions such as ‘after,’ ‘following,’ ‘next,’ or ‘before,’ cases that are not continuous may be included unless expressions such as ‘immediately’ or ‘directly’ are used.

[0037] In this specification, the term 'at least one' should be understood to include all combinations that can be presented from one or more related items.

[0039] Hereinafter, a method for producing high-purity phosphoric acid according to a specific embodiment of the invention will be described in more detail.

[0040] According to one embodiment of the invention, a method for producing high-purity phosphoric acid is provided, comprising the steps of: supplying a phosphoric acid raw material containing impurities to a cooling device including an inner jacket and an outer jacket (S1); introducing a phosphoric acid seed into the cooling device to form a phosphoric acid crystal (S2); and rotating the inner jacket within the cooling device to grow the phosphoric acid crystal (S3), wherein the temperature difference between the inner jacket and the outer jacket is 5°C or more.

[0041] As mentioned above, conventionally, the method of crystallizing phosphoric acid through cooling is well known as a purification method. However, when a phosphoric acid seed is not used, crystallization can only proceed if the crystallization conditions are controlled to a temperature of minus 40°C or lower, which resulted in a problem of high cost and time required to produce crystals.

[0042] Accordingly, the present invention investigates a method to increase purification efficiency while carrying out crystallization at room temperature using a phosphoric acid seed. By using a cooling device including an inner jacket and an outer jacket to control the temperature difference between the inner jacket and the outer jacket to a certain level while growing phosphoric acid crystals formed by rotating the inner jacket, the crystal growth position and speed of the phosphoric acid crystals are controlled through changes in the molecular or quantum behavior of phosphoric acid and water molecules and impurities within the phosphoric acid raw material, thereby suppressing the phenomenon of impurity trapping within the phosphoric acid crystals. It was confirmed that high-purity phosphoric acid can be obtained on an economical and industrial scale by increasing purification efficiency.

[0043] According to the present invention, the method comprises the steps of: supplying a phosphoric acid raw material containing impurities to a cooling device including an inner jacket and an outer jacket (S1); introducing a phosphoric acid seed into the cooling device to form a phosphoric acid crystal (S2); and rotating the inner jacket within the cooling device to grow the phosphoric acid crystal (S3); wherein, when the temperature difference between the inner jacket and the outer jacket is controlled to be 5°C or more, the impurity purification efficiency is improved, and a higher purity phosphoric acid can be obtained.

[0044] First, regarding the aforementioned phosphoric acid raw material, commercially available low-purity (industrial grade) phosphoric acid may be purchased and used, or phosphoric acid used in the semiconductor etching process may be recovered and used; however, from the perspective of resource recycling, it is preferable to recover and use phosphoric acid containing impurities used in the semiconductor process.

[0045] The method for producing high-purity phosphoric acid according to the present invention supplies a phosphoric acid raw material containing a large amount of impurities to a cooling device including an inner jacket and an outer jacket, and then introduces a phosphoric acid seed into the cooling device to form phosphoric acid crystals, wherein the temperature difference between the inner jacket and the outer jacket is 5°C or more to increase the impurity purification efficiency.

[0046] Specifically, by creating a temperature difference between the inner jacket and the outer jacket of the cooling device, changes in the molecular or quantum behavior of phosphoric acid and water molecules and impurities within the phosphoric acid raw material can prevent the sporadic formation of crystals, and by inducing crystal growth to begin on the inner jacket surface, the trapping phenomenon in which metal impurities are trapped inside the phosphoric acid crystal can be prevented, thereby improving the efficiency of metal impurity purification.

[0047] When phosphoric acid crystals are formed by introducing a phosphoric acid seed, if there is no or minimal temperature difference between the inner jacket and the outer jacket, phosphoric acid crystallization occurs sporadically, and due to the trapping phenomenon in which impurities are trapped inside the phosphoric acid crystals, the phosphoric acid crystals produced contain a large amount of impurities, resulting in a decrease in the purity of the phosphoric acid obtained through crystallization.

[0048] In comparison, when crystallization is carried out by controlling the temperature difference between the inner jacket and the outer jacket to a level above a certain threshold and introducing a phosphate seed, a difference in the growth rate of phosphate crystals between the inside and outside is created through changes in the molecular and quantum behavior of phosphate and water molecules and impurities within the phosphate raw material, thereby preventing the sporadic formation of phosphate crystals and inducing the growth of phosphate crystals to begin on the surface of the inner jacket so that impurities are gathered toward the outer jacket, thereby increasing purification efficiency and enabling the acquisition of high-purity phosphate.

[0049] The above cooling device includes an inner jacket and an outer jacket formed spaced apart from the outer side of the inner jacket, and includes a reaction section in which a phosphoric acid raw material and a phosphoric acid seed are introduced with a certain space between the inner jacket and the outer jacket to proceed with the crystallization of phosphoric acid.

[0050] That is, when phosphoric acid raw materials and phosphoric acid seeds are introduced into the reaction section, which is the space between the inner jacket and the outer jacket, phosphoric acid crystals are formed and grown along the surface of the inner jacket in a form that wraps around the inner jacket due to the temperature difference between the inner jacket and the outer jacket.

[0051] At this time, the temperature difference between the inner jacket and the outer jacket may be 5°C or more, preferably 10°C or more. If the temperature difference between the inner jacket and the outer jacket is less than 5°C, there may be a problem in that the purification effect is reduced due to a trapping phenomenon in which metal impurities are trapped within the phosphoric acid crystals as phosphoric acid crystals are generated sporadically.

[0052] In addition, the temperature difference between the inner jacket and the outer jacket may be 40°C or less. If the temperature difference between the inner jacket and the outer jacket exceeds 40°C, there may be a problem in that the phosphoric acid crystals do not grow sufficiently.

[0053] Specifically, the temperature of the inner jacket may be 0 to 30°C, and the temperature of the outer jacket may be 5 to 50°C.

[0054] Within the above temperature range, the inner jacket has a lower temperature than the outer jacket.

[0055] After supplying a phosphoric acid raw material containing impurities to a cooling device including an inner jacket and an outer jacket, a phosphoric acid seed is introduced into the cooling device to form phosphoric acid crystals, wherein the amount of the phosphoric acid seed introduced can be 0.01 to 10 parts by weight based on 100 parts by weight of the phosphoric acid raw material.

[0056] If the amount of the phosphoric acid seed added is excessively small, there may be problems such as a slow phosphoric acid crystallization rate or failure of crystal growth; conversely, if the amount of the phosphoric acid seed added is excessively large, phosphoric acid crystals may be generated sporadically; therefore, it is desirable to add it at the aforementioned amount.

[0057] The method for producing high-purity phosphoric acid according to the present invention includes, after the phosphoric acid crystal formation step (S2), a step (S3) of growing phosphoric acid crystals by rotating an inner jacket within the cooling device.

[0058] As described above, phosphoric acid crystals are formed and grown along the surface of the inner jacket in a manner that wraps around the inner jacket. At this time, if the inner jacket of the cooling device is rotated at a constant speed, metal impurities that may be trapped within the phosphoric acid crystals can be discharged, thereby obtaining phosphoric acid of higher purity.

[0059] The rotational speed of the above phosphoric acid crystal may be 1 to 150 RPM, preferably 10 to 100 RPM.

[0060] When the rotational speed of the above phosphoric acid crystal is less than 1 RPM, the effect of discharging metal impurities is negligible, and when it exceeds 150 RPM, the crystallization yield of the final obtained phosphoric acid decreases, making it uneconomical.

[0061] The method for producing high-purity phosphoric acid according to the present invention may further include a step (S4) of separating crystallized phosphoric acid and non-crystallized phosphoric acid by raising an internal jacket within the cooling device after the phosphoric acid crystal growth step (S3).

[0062] According to the present invention, after growing phosphoric acid crystals by rotating the inner jacket of the cooling device at a constant speed, the inner jacket is raised to separate crystallized phosphoric acid and non-crystallized phosphoric acid, and at this time, the inner jacket is raised at a constant rising speed to separate the crystallized phosphoric acid.

[0063] The rising speed of the inner jacket may be 0.5 to 15 mm / min, preferably 1.0 to 10 mm / min.

[0064] By slowly raising the inner jacket at a constant speed, the pure phosphoric acid crystals grown within the inner jacket are separated from the uncrystallized phosphoric acid, thereby preventing the re-incorporation of impurities into the phosphoric acid crystals. Furthermore, by controlling the raising speed as described above, high-purity phosphoric acid can be obtained with excellent efficiency by separating the grown phosphoric acid crystals from the uncrystallized phosphoric acid while simultaneously continuously growing and crystallizing the phosphoric acid crystals in contact with the uncrystallized phosphoric acid.

[0065] At this time, the inner jacket can rise while rotating, for example, while rotating at a speed of 1 to 150 RPM, it can rise at a speed of 0.5 to 15 mm / min.

[0066] The method for producing high-purity phosphoric acid according to the present invention may further include a step (S5) of obtaining crystallized phosphoric acid by raising the temperature of the inner jacket to 40°C or higher after removing the uncrystallized phosphoric acid following the crystallized phosphoric acid separation step (S4).

[0067] The above-mentioned phosphoric acid raw material before purification contains a large amount of impurities, and specifically, the phosphoric acid raw material may have a total content of impurities including Al, K and Cu of 300 ppb or more.

[0068] As described above, high-purity phosphoric acid can be obtained economically and industrially through the method for producing high-purity phosphoric acid of the present invention, and specifically, the phosphoric acid obtained by the method may contain Al, K, and Cu at 1 ppb or less each.

[0070] Hereinafter, embodiments of the present invention will be described in more detail in the following examples. However, the following examples are merely illustrative of embodiments of the present invention, and the content of the present invention is not limited by the following examples.

[0072] (1) Example 1

[0073] 1,000 g of 91.6% phosphoric acid raw material containing impurities was supplied to a cooling device with the inner jacket set to 15℃ and the outer jacket to 25℃ (the temperature difference between the inner jacket and the outer jacket was 10℃).

[0074] After forming initial phosphoric acid crystals by introducing 1g of phosphoric acid seed into the cooling device, the phosphoric acid crystals were grown for 1 hour while rotating the inner jacket inside the cooling device at a speed of 10 RPM.

[0075] Afterwards, the inner jacket inside the cooling device was rotated at a speed of 10 RPM and raised at a speed of 1 mm / min to continuously grow phosphoric acid crystals while separating crystallized phosphoric acid and non-crystallized phosphoric acid.

[0076] After removing the uncrystallized phosphoric acid, the inner jacket was heated to 40°C or higher to obtain 808g of crystallized phosphoric acid.

[0078] (2) Example 2

[0079] 747g of crystallized phosphoric acid was obtained by proceeding in the same manner as in Example 1 above, except that the concentration of the phosphoric acid raw material was changed to 85%.

[0081] (3) Example 3

[0082] 775g of crystallized phosphoric acid was obtained by proceeding in the same manner as in Example 1 above, except that the rotation speed of the inner jacket was changed to 100 RPM.

[0084] (4) Example 4

[0085] 759 g of crystallized phosphoric acid was obtained by proceeding in the same manner as in Example 1 above, except that the rise speed of the inner jacket was changed to 10 mm / min.

[0087] (5) Comparative Example 1

[0088] 131g of crystallized phosphoric acid was obtained by proceeding in the same manner as in Example 1 above, except that the rotation speed of the inner jacket was changed to 200 RPM.

[0090] (6) Comparative Example 2

[0091] The procedure was carried out in the same manner as Example 1 above, except that the rise speed of the inner jacket was changed to 20 mm / min, but all of the crystallized phosphoric acid melted and crystallized phosphoric acid could not be obtained.

[0093] (7) Comparative Example 3

[0094] 1,000 g of 91.6% phosphoric acid raw material containing impurities was supplied to a cooling device with the inner jacket set to 15℃ and the outer jacket to 25℃ (the temperature difference between the inner jacket and the outer jacket was 10℃).

[0095] 1g of phosphoric acid seed was introduced into the above cooling device and phosphoric acid crystallization was carried out for 1 hour.

[0096] Afterwards, the inner jacket inside the cooling device was raised at a speed of 1 mm / min to separate crystallized phosphoric acid and non-crystallized phosphoric acid.

[0097] After removing the uncrystallized phosphoric acid, the inner jacket was heated to 40°C or higher to obtain 797g of crystallized phosphoric acid.

[0099] Analysis of Metal Impurity Content in Crystalline Phosphate

[0100] The metal impurity content in the phosphoric acid was analyzed for the phosphoric acid raw material, microcrystalline phosphoric acid, and obtained crystallized phosphoric acid, respectively, using ICP-MS.

[0101] Specifically, the metal impurity content in the sample was analyzed by diluting microcrystalline phosphoric acid and obtained crystallized phosphoric acid with DIW or 3% nitric acid using an Agilent ICP-MS 8900.

[0103] Phosphoric acid raw materials Example 1 Example 2 Example 3 Example 4 Microcrystalline phosphoric acid Crystallized phosphoric acid Microcrystalline phosphoric acid Crystallized phosphoric acid Microcrystalline phosphoric acid Crystallized phosphoric acid Microcrystalline phosphoric acid Crystallized phosphoric acid Al(ppb) 156 682 0.53 481 0.7 599 0.64 573 0.73 K(ppb) 221 914 0.71 733 0.64 722 0.81 726 0.75 Cu(ppb) 358 1326 0.74 1077 0.88 1112 0.75 1036 0.67

[0104] Phosphoric acid raw materials Comparative Example 1 Comparative Example 2 Comparative Example 3 Microcrystalline phosphoric acid Crystallized phosphoric acid Microcrystalline phosphoric acid Crystallized phosphoric acid Microcrystalline phosphoric acid Crystallized phosphoric acid Al(ppb) 156 153 0.89 152 - 615 3.4 K(ppb) 221 229 0.84 226 - 874 4.6 Cu(ppb) 358 319 0.61 338 - 1208 7.4

[0106] According to Tables 1 and 2 above, it was confirmed that in the case of phosphoric acid obtained according to the manufacturing method of the present invention, the metal content in the phosphoric acid is significantly reduced compared to the phosphoric acid raw material, so high-purity phosphoric acid can be obtained.

Claims

Claim 1 A method for producing high-purity phosphoric acid, comprising: a step of supplying a phosphoric acid raw material containing impurities to a cooling device (S1); a step of introducing a phosphoric acid seed into the cooling device to form a phosphoric acid crystal (S2); and a step of growing a phosphoric acid crystal by rotating an inner jacket within the cooling device (S3); wherein the cooling device comprises an inner jacket, an outer jacket formed spaced apart from the outer side of the inner jacket, and a reaction section having a certain space between the inner jacket and the outer jacket in which a phosphoric acid raw material and a phosphoric acid seed are introduced to proceed with the crystallization of phosphoric acid, and the temperature difference between the inner jacket and the outer jacket is 5°C or more. Claim 2 A method for producing high-purity phosphoric acid according to claim 1, wherein the rotation speed of the inner jacket in the phosphoric acid crystal growth step (S3) is 1 to 150 RPM. Claim 3 A method for producing high-purity phosphoric acid, further comprising, in claim 1, a step (S4) of separating crystallized phosphoric acid and non-crystallized phosphoric acid by raising an internal jacket in the cooling device after the phosphoric acid crystal growth step (S3). Claim 4 A method for producing high-purity phosphoric acid according to claim 3, wherein the rising speed of the inner jacket in the crystallization phosphoric acid separation step (S4) is 0.5 to 15 mm / min. Claim 5 A method for producing high-purity phosphoric acid according to claim 3, further comprising the step (S5) of removing uncrystallized phosphoric acid after the crystallized phosphoric acid separation step (S4) and raising the temperature of the inner jacket to 40°C or higher to obtain crystallized phosphoric acid. Claim 6 A method for producing high-purity phosphoric acid according to claim 1, wherein the temperature difference between the inner jacket and the outer jacket is 40℃ or less. Claim 7 A method for producing high-purity phosphoric acid according to claim 1, wherein the temperature of the inner jacket is 0 to 30℃. Claim 8 A method for producing high-purity phosphoric acid according to claim 1, wherein the temperature of the outer jacket is 5 to 50℃. Claim 9 A method for producing high-purity phosphoric acid according to claim 1, wherein the concentration of the phosphoric acid raw material is 85 to 91.6%. Claim 10 A method for producing high-purity phosphoric acid according to claim 1, wherein the phosphoric acid raw material has a total impurity content including Al, K and Cu of 300 ppb or more. Claim 11 A method for producing high-purity phosphoric acid according to claim 1, wherein the phosphoric acid obtained by the above method contains Al, K, and Cu at 1 ppb or less each.

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