TWI485003B - Method for producing tetraalkylammonium salt solution - Google Patents

Description

Method for producing tetraalkylammonium salt aqueous solution

The present invention relates to a novel process for the production of an aqueous solution of a tetraalkylammonium salt using a cation exchange resin. Specifically, it is a method for producing a tetraalkylammonium (hereinafter, a tetraalkylammonium abbreviated as TAA) salt aqueous solution: a developing waste containing TAA hydroxide is introduced into a packed column packed with a cation exchange resin. The liquid is caused to adsorb TAA ions to the cation exchange resin, and then the cation exchange resin is contacted with the acid to dissolve the TAA ions adsorbed by the cation exchange resin to obtain a high concentration of the TAA salt aqueous solution. At this time, the TAA ions are prevented from being exchanged for the cations. The resin leaks from the packed column during adsorption and effectively adsorbs TAA ions to the cation exchange resin in the packed column.

In a semiconductor and liquid crystal manufacturing process, a development process is performed in which a pattern formed on a substrate such as a wafer or a glass is coated with a negative type composed of a phenol resin, a polystyrene resin, or the like on a metal layer formed on the surface of the substrate (negative Type) or a positive type resist, which is exposed by a photomask for forming the pattern, and the unhardened portion or the hardened portion is performed using a developer containing TAA as a main component Development is then performed by etching to form a pattern on the above metal layer. In this project, the development engineering waste liquid containing TAA hydroxide is discharged.

Further, after development by the developer, in order to remove the developer remaining on the substrate, it is washed with ultrapure water, and after the washing process, the washing waste liquid containing TAA of hydroxide is discharged. These developing waste liquids and washing engineering waste liquids are usually discharged as development waste liquid containing TAA after each being mixed. In recent years, as the production amount of semiconductors and liquid crystals has increased, the consumption of the developer has increased, and the amount of development waste liquid containing TAA has also increased. Recently, a method for recovering TAA from which TAA is recovered and purified from the developing waste liquid containing TAA is proposed.

The TAA concentration in the developing waste liquid containing TAA discharged by mixing the development engineering waste liquid and the washing engineering waste liquid is usually a low concentration of about 100 to 10,000 ppm.

Therefore, in order to efficiently recover and purify the TAA from the developing waste liquid containing TAA, a solution of a high concentration of TAA hydroxide is obtained, and a concentration means for increasing the concentration of the hydroxide TAA in the waste liquid is indispensable. Less.

As the above-mentioned concentration means, for example, a method is proposed in which a TAA of a developing waste liquid is brought into contact with a cation exchanger such as a cation exchange resin, and TAA ions are adsorbed to the cation exchanger, and then the aqueous acid solution is brought into contact with the cation exchanger. TAA ions are eluted from the resin to obtain a TAA salt aqueous solution (see Patent Document 1).

Alternatively, a method is also proposed in which a photoresist waste liquid containing TAA hydroxide is passed through a plurality of adsorption tanks filled with an ion exchange resin in series, TAA ions are adsorbed to the resin, and then the regeneration liquid is connected in parallel. The TAA ions are eluted from the ion exchange resin by flowing through the plurality of adsorption grooves (see Patent Document 2).

The methods described in the above Patent Documents 1 and 2 utilize the case where the solubility of the TAA salt in water is higher than that of the hydroxide TAA. That is, the elution of the TAA ions by the acid can be carried out in an amount less than the above-mentioned developing waste liquid which is in contact with the cation exchange resin, and as a result, a TAA salt aqueous solution containing TAA ions having a higher concentration than the developing waste liquid can be obtained.

Further, the obtained TAA salt aqueous solution can be converted into an aqueous solution of TAA hydroxide by electrolysis or the like.

[Previous Technical Literature] [Patent Literature]

Patent Document 1: Japanese Patent Laid-Open No. Hei 6-142649

Patent Document 2: Japanese Patent Laid-Open Publication No. 2004-066102

However, the inventors of the present invention conducted a verification test on the method described in Patent Document 1, and as a result, it was found that sufficient adsorption of TAA ions was not performed with respect to the total exchange capacity of the cation exchange resin filled in the packed column, and it was effective. There is a problem in the recovery of TAA ions from the developing waste liquid containing TAA hydroxide.

That is, a developing waste liquid containing TAA hydroxide is introduced into a packed column packed with a cation exchange resin, and changes in TAA ions in the discharged liquid discharged from the packed column are tracked with time, and as a result, exchanged cations are exchanged. When about half of the total exchange capacity of the resin is exchanged for TAA ions, TAA ions are detected in the discharge liquid, and leakage of TAA ions into the discharge liquid occurs.

Further, it was found that when the developing waste liquid containing TAA was continuously supplied, a part of the TAA ions in the developed developing waste liquid were adsorbed by the cation exchange resin in the packed column, but the amount of TAA ions leaking into the discharged liquid was also Increasing, as the exchange rate of the cation exchange resin (the ratio of the amount of the adsorbed TAA ions to the total exchange capacity of the cation exchange resin) increases, the adsorption rate of the TAA ions in the developed waste liquid (ie, The ratio of the amount of adsorbed TAA ions to the amount of total TAA ions in the developed developing waste liquid is greatly reduced.

As can be seen from the above verification test, although the development waste liquid containing TAA ions is stopped and the acid aqueous solution is supplied when the TAA ions leak to the discharge liquid discharged from the packed column, the development waste can be omitted. The TAA salt solution is recovered from the TAA ion in the liquid, but the amount of the TAA salt aqueous solution that can be recovered by one adsorption treatment is reduced.

Alternatively, the developing waste liquid containing TAA may be continuously passed until the adsorption amount of the TAA ions reaches about 80 to 90% of the total exchange capacity of the filled cation exchange resin. In this case, it can be recovered by one adsorption treatment. The amount of the TAA brine solution is increased, but the amount of TAA ions leaking into the discharge liquid is also increased, and the recovery rate of recovering TAA ions from the developed development waste liquid containing TAA is greatly reduced.

As described above, it has been found that the TAA salt aqueous solution having a higher concentration of TAA ions in the developing waste liquid containing TAA ions can be obtained by the method described in Patent Document 1, but is effectively used from the development waste containing TAA ions. There is a problem in the recovery of TAA ions in the liquid.

Further, in the method described in Patent Document 2, the developing waste liquid containing TAA hydroxide is passed through a plurality of adsorption tanks in series, but the elution of the adsorbed TAA ions is simultaneously performed on the plurality of adsorption tanks. Therefore, although the exchange rate of the cation exchange resin in the adsorption tank initially contacting the development waste liquid is increased, the exchange rate of the cation exchange resin in the second and subsequent adsorption tanks is still low, effectively from the TAA containing hydroxide. There is a problem in the recovery of TAA ions in the developing waste liquid.

Accordingly, an object of the present invention is to provide a method for producing a TAA salt aqueous solution in which a developing waste liquid containing TAA hydroxide is introduced into a packed column filled with a cation exchange resin, and TAA ions are adsorbed to the resin, followed by resin and The acid is contacted to dissolve the TAA ions adsorbed by the resin to obtain a high concentration of the TAA salt aqueous solution. At this time, a high concentration of the TAA salt aqueous solution can be efficiently produced without leaking the TAA ions in the developing waste liquid.

The inventors conducted intensive studies in view of the above problems. First, the present inventors introduced a developing waste liquid containing TAA into the packed column until the packed column filled with the cation exchange resin for adsorbing TAA ions reached a target exchange rate (the amount of TAA ions adsorbed relative to the cation) The ratio of the total exchange capacity of the exchange resin). At this time, it is confirmed that the amount of TAA ions ("penetration capacity") adsorbed by the packed column until the TAA ion leaks from the packed column, and the "TAA ion from the packed column until the packed column reaches the target exchange rate" The amount of leakage leaked."

Next, a plurality of packed columns identical or substantially identical to the packed column filled with the cation exchange resin described above are prepared, and they are connected in series to form a packed column production line, even if the adsorption process is performed until the most upstream filling on the side of the developing waste liquid. The tower reaches the target exchange rate, and the TAA ions do not leak from the most downstream packed tower. The number of such packed towers is studied.

As a result, it was found that the adsorption tower can be subjected to the adsorption processing up to the most upstream filling by the packed column production line composed of the above-mentioned "Tail amount of leakage of TAA ions from the packed column" / "penetration capacity" + 1 (in which the decimal point is followed) The tower reaches the target exchange rate without leaking TAA ions from the most downstream packed column.

Further, it has been found that the dissolution of TAA ions is carried out by using one packed column, introducing a developing waste liquid into the packed column, and stopping the passage of the developing waste liquid (stopping at the breakthrough capacity) when TAA ion leakage occurs. In the case of setting the target exchange rate to a level exceeding the penetration capacity of the packed column, the most upstream packed column that has reached the target exchange rate from the packed column production line, and the packed tower that has been disconnected When the acid aqueous solution is passed through to dissolve the TAA ions, the amount of the TAA salt aqueous solution per packed column is greatly increased, and the TAA salt aqueous solution can be efficiently obtained.

Next, the packed column after dissolving the TAA ions is connected to the packed tower which is directly connected to the downstream side of the most upstream packed column as the most upstream of the packed tower production line (the remaining packed column production line), thereby forming a new filling. Tower production line. It has been found that by using the new packed column production line, the adsorption process of the TAA ions and the elution of the adsorbed TAA ions are repeated, and the TAA salt aqueous solution can be efficiently produced by the above-mentioned number of packed columns, thereby completing the following invention.

That is, the present invention is a method for producing a TAA salt aqueous solution, which comprises the following works:

In the adsorption engineering (S1), an aqueous solution of the raw material containing TAA hydroxide is introduced into the initial packed column production line to adsorb the TAA ions to the cation exchange resin until the first packed column at the most upstream of the initial packed column production line is over-pierced. a target exchange rate of the permeate capacity, wherein the aforementioned initial packed column production line is connected in series by a plurality of packed columns of the same or substantially the same filled with a cation exchange resin;

In the dissolution regeneration project (S2), the first packed column which adsorbs the TAA ions by the foregoing adsorption process to reach the target exchange rate is disconnected from the initial packed column production line, and the acid is introduced into the disconnected first packed column. An aqueous solution such that the adsorbed TAA ions are dissolved as an aqueous solution of the TAA salt, and the cation exchange resin filled in the aforementioned first packed column is regenerated;

The number of packed columns connected in series in the above-mentioned initial packed column production line is an integer n or more obtained by the following formula (1), so that the TAA ion adsorption of the packed column at the most downstream of the aforementioned initial packed column production line in the aforementioned adsorption process is performed. The amount is lower than the penetration capacity,

n={1+ (TAA ion leakage amount (mol) until the first packed column reaches the target exchange rate) / (penetration capacity (mol) of the first packed column)} (1)

Wherein the decimal point is post-received, and the first packed column which is regenerated after the foregoing dissolution regeneration process (S2) is connected to the most downstream of the remaining packed column production line remaining after the first packed column is disconnected, and is formed to start at the foregoing adsorption process. The second packed column directly connected to the downstream side of the first packed column is the new packed column production line of the most upstream packed column, and the adsorption process (S3) and the aforementioned dissolution regeneration are repeated using the new packed column production line. Engineering (S4).

"Multiple packed columns of the same or substantially the same" means a packed column in which the total exchange capacity of TAA ions is the same or substantially the same (the difference of the total exchange capacity ± 10%, preferably ± 5%). Further, it is preferable that the plurality of packed columns forming the packed column production line of the present invention are filled with the same cation exchange resin and the same packed column of L/D, and preferably all of the same packed columns (types of cation exchange resins, filling) The amount and the filled column are the same).

In the above invention, the packed tower which is the most upstream of the initial packed column production line is referred to as a first packed column, and the packed column directly connected to the downstream side thereof is referred to as a second packed column, and in the subsequent adsorption process (S3) In the new packed column production line, the most upstream packed column is the second packed column, and in the new packed column production line in the subsequent adsorption process (S4), the most upstream packed column is the further downstream side of the second packed column. The packed tower. That is, the present invention is a method of repeating the process of once the packed tower of the most upstream of the packed column production line reaches the target exchange rate, and is broken to form a packed tower having the most upstream packed side of the downstream side as the most upstream. The remaining packed tower production line, after the broken packed tower is regenerated, is placed on the most downstream side of the above remaining packed tower production line to form a new packed tower production line for adsorption engineering.

The "exchange rate" of the packed column means the ratio of the amount of TAA ions (mol) adsorbed by the packed column to the total exchange capacity (mol) of the cation exchange resin filled in the packed column, and the "target exchange rate" means Its target value.

The "penetration capacity" of the packed column means that the raw material aqueous solution is supplied only to the packed column, and the amount of TAA ions adsorbed by the cation exchange resin in the packed column from the start of the supply until the TAA ion starts to leak from the packed column ( Mol).

The target exchange rate of the packed column exceeds the breakthrough capacity, which means that the target exchange rate is set higher than the exchange rate of the packed column when the packed column reaches the breakthrough capacity.

Further, in the method for producing a TAA salt aqueous solution, the number of packed columns constituting the initial packed column production line is the integer n+1, and the separation is performed during the dissolution regeneration process of the first upstream packed column. a raw material solution is introduced into the remaining packed column production line of the first packed column, and the first amount of regeneration is obtained before the adsorption amount of the tetraalkylammonium ion of the packed column at the most downstream of the remaining packed column production line reaches the breakthrough capacity. The packed column is connected to the most downstream of the remaining packed column production line, whereby the packed column eluted TAA ions from the adsorption to the predetermined target exchange rate and the TATA developing waste liquid supplied to the packed column production line can be simultaneously performed, It is particularly preferable to continuously produce a TAA salt aqueous solution from a developing waste liquid containing TAA hydroxide.

Further, in the method for producing a TAA salt aqueous solution, it is preferred that the target exchange rate of the adsorption process is 70 to 90%. When the target exchange rate is less than 70%, the concentration of the TAA salt solution recovered in the dissolution process becomes thin, so it is not good, and when the target exchange rate exceeds 90%, it is feared that it is required to reach the target exchange rate. The supply amount of the raw material aqueous solution is increased, the treatment cost is increased, and the number of packed columns that form the initial packed column production line is increased, and the initial cost is increased.

Further, in the method for producing a TAA salt aqueous solution, it is preferred that the dissolution and regeneration process is performed by a first dissolution regeneration process until the acid of the acid aqueous solution that has been introduced, and a second dissolution regeneration after the acid is discharged. The engineering composition is obtained by using the aqueous solution obtained in the first dissolution regeneration project as the target TAA salt solution. If the obtained TAA salt aqueous solution contains an acid, the process of neutralizing the acid is required, and the treatment efficiency is deteriorated. Therefore, the TAA salt aqueous solution can be more efficiently produced by passing the acid-free TAA salt aqueous solution obtained by the first dissolution regeneration project as a target.

Further, in the method for producing a TAA salt aqueous solution described above, the switching from the first dissolution regeneration process to the second dissolution regeneration process in the above-described dissolution regeneration process can be performed by monitoring the conductivity of the discharge liquid.

According to the present invention, by using a packing tower based on the breakthrough capacity of the packed column and the amount of leakage of TAA ions leaking from the packed column, the adsorption of TAA ions to the packed column can be performed at a high exchange rate without The TAA ions are leaked into the effluent discharged from the packed column at the most downstream of the packed column production line. Thereby, the production amount of the TAA salt aqueous solution per packed column can be increased, and a high concentration TAA salt aqueous solution can be efficiently produced.

Further, in the method for producing a TAA salt aqueous solution of the present invention, by using the above-described number of +1 packed columns, it is possible to simultaneously elute TAA ions from the adsorption tower to a packed column having a predetermined target exchange rate, and The TATA developing waste liquid is supplied to the packed column production line, and the TAA salt aqueous solution can be continuously produced, and the TAA salt aqueous solution can be efficiently produced.

Further, in the production method of the present invention, the TAA ions are adsorbed until they reach the same target exchange rate for all the packed columns connected in series, and the cation exchange resin in each packed column can be uniformly used. Therefore, it is expected that the life of the cation exchange resin in the packed column will be prolonged.

<aqueous raw material solution>

In the method for producing a TAA salt aqueous solution of the present invention, a raw material aqueous solution containing TAA hydroxide (hereinafter sometimes referred to simply as "raw material aqueous solution") is introduced into a packed column production line, and TAA ions are adsorbed to the packed column. Cation exchange resin in the production line.

The TAA of the above-mentioned raw material aqueous solution means a compound in which the counter ion of the TAA ion is a hydroxide ion, and the hydroxide TAA is dissociated in the raw material aqueous solution to exist in the state of TAA ion and hydroxide ion. The above-mentioned hydroxide TAA is not particularly limited as long as it can be industrially obtained, and various kinds of hydroxide TAA can be used. Examples of the hydroxide TAA include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, and tetrabutylammonium hydroxide. Among the above-mentioned hydroxide TAA, tetramethylammonium hydroxide can be suitably used from the viewpoint of being widely used as a developer in a semiconductor manufacturing process.

Further, the raw material aqueous solution is not particularly limited as long as it is composed of an aqueous solution of TAA hydroxide. Specific examples of the raw material aqueous solution include a TAA aqueous solution obtained by a known production method, and a development process in a manufacturing process of an electronic component such as a semiconductor device (LSI, VLSI, etc.), a printed circuit board, or a liquid crystal display (LCD). The waste liquid discharged from the washing process (hereinafter, referred to as development waste liquid, washing waste liquid, etc., respectively). The development engineering waste liquid and the washing engineering waste liquid are usually mixed and discharged as development waste liquid (hereinafter, the mixed waste liquid of the development engineering waste liquid and the washing engineering waste liquid is sometimes referred to as "developing waste liquid"). In the aqueous solution of the raw material, the waste liquid can be developed from the viewpoint of recovering and recycling the TAA ions in the waste liquid by the method for producing a TAA salt of the present invention.

The concentration of the hydroxide TAA in the aqueous solution of the raw material is not particularly limited, and various aqueous raw material solutions having a TAA concentration of hydroxide can be used. For example, the concentration of TAA in the development waste liquid discharged from the development project is usually about 1.0 to 5.0% by mass, and the amount of pure water in the washing process is 5 to 100 times that of the developer, so that a large amount of Since the washing waste liquid is mixed with the development engineering waste liquid, the concentration of the TAA in the developing waste liquid discharged from the semiconductor and liquid crystal manufacturing engineering is usually about 100 to 10,000 ppm. Among them, the developing waste liquid discharged from the liquid crystal display manufacturing process has a TAA concentration of usually 100 to 5000 ppm, and the production method of the present invention is particularly suitable for producing a TAA salt aqueous solution from the developing waste liquid having a low TAA concentration.

The developing waste liquid contains a trace amount of a metal component eluted from a metal layer, a pipe material, or the like from a semiconductor/liquid crystal manufacturing process. The concentration of the metal component is, for example, 0.1 to 50 ppb of the developing waste liquid containing TAA discharged in the semiconductor manufacturing process, and the developing waste liquid containing TAAA discharged by the liquid crystal manufacturing process is about 1 to 100 ppb.

In addition, as described above, an organic substance derived from a photoresist such as a phenol resin or a polystyrene resin, and a trace amount of an organic substance such as an organic solvent or a surfactant are dissolved in the developing waste liquid (hereinafter, these may be used) Organic matter is collectively referred to as "organic matter."). The concentration of the organic substance dissolved in the developing waste liquid having a TAA concentration of 1% by mass or less is usually in the range of several ppm to several hundreds ppm in terms of COD (chemical oxygen demand).

<Cation exchange resin>

In the method for producing a TAA salt aqueous solution of the present invention, the cation exchange resin to be used is not particularly limited as long as it can adsorb TAA ions present in the raw material aqueous solution, and an industrially obtainable cation exchange resin can be used. Examples of the cation exchange resin include a sulfonic acid group introduced into a matrix such as a styrene-divinylbenzene copolymer, an acrylic-divinylbenzene copolymer, or a methacrylic acid-divinylbenzene copolymer. A strongly acidic cation exchange resin of a strong acid group, and a weakly acidic cation exchange resin in which a weak acid group such as a carboxyl group or a phenolic hydroxyl group is introduced into the above matrix. Among these cation exchange resins, those which use a weakly acidic cation exchange resin are preferred from the viewpoint that the adsorbed TAA ions can be easily desorbed.

Specific examples of the strongly acidic cation exchange resin include Amberlite IR120B manufactured by Rohm and Haas Co., Ltd., Amberlite IR124, DIAION SK1B manufactured by Mitsubishi Chemical Corporation, DIAION PK228, Duolite C255LFH manufactured by Sumika Chemtex Co., Ltd., and LANXESS Co., Ltd. LEWATIT MonoPlus S100, Purolite's Purolite C160 and so on. In addition, as a specific example of the weakly acidic cation exchange resin, Amberlite IRC76 manufactured by Rohm and Haas Co., Ltd., DIAION WK40L manufactured by Mitsubishi Chemical Corporation, Duolite C433LF manufactured by Sumika Chemtex Co., Ltd., Duolite C476, and LANXESS Co., Ltd. LEWATIT CNP80WS, Purolite C104 from Purolite.

In addition, the structure of the cation exchange resin is not particularly limited, and any of the cation exchange resins of any of a gel type, a porous type, and a highly porous type can be suitably used. In particular, from the viewpoint of excellent swelling shrinkage strength, it is preferably a highly porous type.

The above cation exchange resin is generally marketed as a counter ion in the form of a hydrogen ion (H type) or a sodium ion (Na type), but when a Na type cation exchange resin is used, it is discharged by ion exchange with TAA ions. The Na ion tends to increase in Na ions in the discharge liquid containing TAA ions. Therefore, as the cation exchange resin, H type is preferably used. Further, in the case of using a cation exchange resin which is commercially available as a Na type, an acid such as hydrochloric acid or sulfuric acid may be introduced into the cation exchange resin in advance to convert the counter ion into an H form and then used.

Further, the above-mentioned H-type cation exchange resin and the cation exchange resin which converts the Na type to the H type by an acid are preferably washed in advance with ultrapure water before being brought into contact with the development waste liquid containing TAA ions.

From the viewpoint of preventing the incorporation of Na ions into the treatment waste liquid, it is preferred that the amount of sodium eluted from the water discharged from the cation exchange resin is 100 ppb or less when washing with ultrapure water. When the sodium elution amount in the water exceeds 100 ppb, the H-type substitution by the introduction of the above-mentioned acid and the washing with ultrapure water may be performed until the amount of sodium elution in the water is 100 ppb or less.

<TAA ion adsorption tower adsorption project>

In the method for producing a TAA salt aqueous solution of the present invention, the cation exchange resin is used by being packed in a packed column. Regarding the ratio (L/D) of the height (L) of the cation exchange resin converted to H-type filled in the packed column to the diameter (D) of the resin column, and the rate of introduction of the aqueous solution of the raw material, consider the cation exchange resin. The exchange capacity of the exchange group, the TAA concentration of the hydroxide in the raw material aqueous solution, or the production amount of the TAA salt aqueous solution may be appropriately determined. For example, in the case of the developing waste liquid having a TAA concentration of 0.001 to 1% by mass of the aqueous solution of the raw material, the ratio of the height (L) of the cation exchange resin filled in the packed column to the diameter (D) of the resin column (L) /D) In 0.5 to 30, the space velocity (SV) of the developing waste liquid may be appropriately set in the range of 1 to 150 h ^-1 .

Further, as the adsorption of TAA ions to the cation exchange resin filled in the packed column proceeds, the volume of the cation exchange resin swells, and the height of the cation exchange resin in the packed column increases. Therefore, it is sufficient to carry out the filling of the cation exchange resin into the packed column in consideration of the volume of the cation exchange resin when the TAA ions are adsorbed to the target adsorption rate.

Further, when the raw material aqueous solution is the development waste liquid, as described above, the development waste liquid contains an organic substance such as a resin derived from a resist. As the TAA ions in the developing waste liquid are adsorbed by the cation exchange resin, the pH of the developing waste liquid passing through the packed column is near neutral, and as the pH changes, the solubility of the organic substance is lowered, and sometimes the organic substance is precipitated in the cation. Remains in the surface of the resin and in the pores.

In this case, in order to elute the organic waste after bringing the development waste liquid into contact with the packed column filled with the cation exchange resin, the precipitated organic matter can be dissolved and washed by bringing the rhodium into contact therewith. If the organic substance precipitated to the cation exchange resin is preliminarily washed before the dissolution regeneration process, the content of the organic substance in the aqueous solution of the TAA salt obtained by dissolving the TAA ion from the cation exchange resin is reduced, and the TAA salt having high purity is obtained. It is particularly preferred in terms of an aqueous solution.

Further, as the above-mentioned crucible for washing the packed column, from the viewpoint of avoiding the incorporation of metal ions, it is preferred to use a TAA solution of hydroxide, particularly from the viewpoint of avoiding the incorporation of impurities, using the same TIA ion as that adsorbed by the cation exchange resin. The TAA ion of the aqueous solution of TAA is preferred.

<Dissolution regeneration of adsorbed TAA ions>

The TAA ion adsorbed by the cation exchange resin can be dissolved by bringing the resin into contact with an acid. The acid to be contacted with the cation exchange resin is not particularly limited as long as it generates hydrogen ions in an aqueous solution, and examples thereof include inorganic acid aqueous solutions such as hydrochloric acid and sulfuric acid. Among the above acids, an aqueous hydrochloric acid solution is most suitable from the viewpoint of being industrially inexpensive to obtain and easy to adjust the concentration. The concentration and amount of the above hydrochloric acid are not particularly limited as long as it is sufficient to dissolve the adsorbed TAA ions. Usually, the cation exchange resin and the 1 to 20% by mass aqueous hydrochloric acid solution are 1 to 10 (L/). L-resin) contact is sufficient.

Further, the counter ion of the cation exchange resin in the packed column contacting the acid becomes H-type, and the regenerated packed column can be supplied to the adsorption process of the TAA ion without particularly washing the resin.

<Determining the number of initial packed tower production lines>

The method for producing a TAA salt aqueous solution of the present invention is characterized in that an initial packed column production line in which a plurality of packed columns of the same or substantially the same filled with a cation exchange resin are connected in series is formed, and the initial packed column production line and the aforementioned raw material aqueous solution are formed. contact.

Further, "a plurality of packed columns which are the same or substantially the same" means a packed column in which the total exchange capacity of TAA ions is the same or substantially the same (the difference of the total exchange capacity ± 10%, preferably ± 5%). Further, it is preferable that a plurality of packed columns forming the packed column production line of the present invention are filled with the same cation exchange resin and a packed column having the same L/D, and it is more preferable from the viewpoint of simple management of the packed column production line. All the same packed columns (the type of cation exchange resin, the amount of the cation exchange, and the packed column are the same).

In addition, as described later, when the adsorption and detachment of TAA ions in the raw material aqueous solution are repeated as described later, the cation exchange resin in the packed column is deteriorated, and sometimes in each filling. There is a difference in the total exchange capacity between the towers (depending on the situation, sometimes a difference of ±10% or more is generated.) In this case, each packed tower is also considered to be substantially the same.

Here, the exchange rate of the TAA ions of the packed column indicates the ratio of the counter ion of the resin converted from the H type to the TAA type with respect to the total exchange capacity of the cation exchange resin filled in the packed column, and can be expressed by the following formula (2) Find.

{(Total amount of hydroxide TAA in contact with the packed column) - (Amount of TAA ion (mol) discharged from the packed column)} / (Total exchange capacity of the cation exchange resin filled in the packed column (mol ))…(2)

In the formula (2), the total amount of the TAA in contact with the packed column can be calculated from the molar concentration of the hydroxide TAA in the raw material aqueous solution and the supply amount of the solution to the packed column. Further, the amount of TAA ions discharged from the packed column can be determined by analyzing the concentration of TAA ions in the discharged liquid discharged from the packed column by ion chromatography.

Next, in the manufacturing method of the present invention, the target exchange rate of the first packed column in the most upstream packed column of the packed column production line, that is, the first packed column in the initial packed column production line is set to exceed the breakthrough capacity of the first packed column. To the extent that the raw material aqueous solution is passed into the above-mentioned packed column production line until the target exchange rate is reached. In the case where the raw material aqueous solution is introduced into the packed column until the breakthrough capacity of the packed column is exceeded, the TAA ions flow out into the discharged liquid. In the present invention, as described below, by forming a packed column production line by serially transporting a predetermined number n of packed columns, it is possible to prevent TAA ions from flowing out into the discharge liquid, effectively adsorbing TAA ions, and efficiently producing TAA salt aqueous solution. .

In addition, it is preferable that the above target exchange rate is set to 70 to 90%. When the target exchange rate is less than 70%, the concentration of the TAA salt aqueous solution recovered in the dissolution process becomes thin. In addition, as the exchange rate of TAA ions increases, the adsorption efficiency of the cation exchange resin, that is, the ratio of the TAA ions supplied to the raw material aqueous solution of the packed column to the cation exchange resin decreases, and the amount of leakage of TAA ions tends to increase rapidly. Therefore, when the target exchange rate exceeds 90%, not only the supply amount of the raw material aqueous solution required to reach the target exchange rate is increased, the treatment cost of the raw material aqueous solution is increased, but also the TAA ion is prevented from leaking from the most downstream packed column. The number of packed towers that form the initial packed tower production line will increase and the original cost will increase. In particular, from the viewpoint of the treatment cost of the raw material aqueous solution and the original cost for forming the initial packed column production line, it is preferable to set the above target exchange rate in the range of 80 to 90%.

The effluent from the most upstream packed column of the initial packed column line is passed sequentially into a second and subsequent packed column connected in series to the packed column. Therefore, when TAA ions are contained in the discharged liquid from the most upstream packed column, the TAA ions in the discharged liquid are sequentially adsorbed by the cation exchange resin filled in the second and subsequent packed columns. In the production method of the present invention, the number of the packed columns forming the initial packed column production line is an integer n or more obtained by the following formula (1) (wherein, when the value obtained by the formula is not an integer) The decimal point is rounded up after the decimal point.).

n={1+ (amount (mol) of TAA ions leaking from the first packed column until the first packed column reaches the target exchange rate) / (penetration capacity (mol) of the first packed column)}... 1)

By setting the number of the packed columns forming the initial packed column production line to the above number (n or more), the adsorption treatment of the TAA ions can be performed until the exchange rate of the TAA ions of the most upstream packed column reaches the above target exchange rate and the TAA ions are not It will leak from the most downstream packed tower.

The number of the packed columns forming the initial packed column production line is not particularly limited as long as it is the above-described integer n or more, and may be appropriately determined in consideration of the size of the production apparatus and the like. However, if the number of packed columns is too large, the packed column which does not participate in the adsorption of TAA ions in the adsorption process of the primary TAA ions will increase, which is not industrially effective, and thus forms the root of the packed column of the packed column production line. The number is preferably set as appropriate in the range of the above integer n~n+2.

In particular, when the number of the packed column production lines is n+1, as described later, the dissolution regeneration process of the packed column which has reached the predetermined target exchange rate and the supply of the raw material aqueous solution to the remaining packed column production line can be simultaneously performed. Adsorption engineering. Therefore, the treatment of the raw material aqueous solution can be continuously performed, and the TAA salt aqueous solution can be continuously produced, which is particularly preferable.

Here, the "penetration capacity" of the packed column means that the raw material aqueous solution is supplied to the packed column, and the TAA ion adsorbed by the cation exchange resin in the packed column from the start of the supply until the TAA ion starts to leak from the packed column. Amount (mol).

The penetration capacity (mol) of the first packed column and the amount (mol) of TAA ions leaking from the first packed column until the first packed column reaches the target exchange rate can be obtained by the following method.

Initially, a packed column identical or substantially identical to the packed column forming the initial packed column production line is prepared, and an aqueous raw material solution is supplied to the packed column. The aqueous raw material solution used herein can be used without any particular limitation.

Further, when the above-mentioned developing waste liquid is used as the raw material aqueous solution, there is a fear that the above-mentioned penetration capacity and TAA ion leakage amount cannot be accurately obtained due to the presence of metal ions contained in the development waste liquid. However, as described above, the ratio of the metal ions in the developing waste liquid to the TAA hydroxide is not more than 1%, and the presence of metal ions in the developing waste liquid can be ignored. Therefore, as the raw material aqueous solution for determining the above-described penetration capacity and TAA ion leakage amount, there is no problem even if the development waste liquid is used.

The raw material aqueous solution was supplied to the packed column, and the discharged liquid discharged from the packed column was sampled over time, and the concentration of TAA ions in the discharged liquid was analyzed by ion chromatography. The penetration capacity can be calculated from the amount of the raw material aqueous solution supplied to the packed column and the molar concentration of the TAA ion in the raw material aqueous solution up to the time when the TAA ion is detected in the discharged liquid for the first time. Further, the exchange rate of the cation exchange resin in the packed column can also be determined by the above formula (2). Further, the introduction of the raw material aqueous solution and the analysis of the discharged liquid are continued until the exchange rate of the cation exchange resin in the packed column reaches the target exchange rate, and the TAA ion leakage amount can be obtained by analyzing the discharge liquid at the time when the target exchange rate is reached.

<Method for Producing TAA Salt Aqueous Solution>

The method for producing a TAA salt aqueous solution of the present invention comprises the following steps: adsorption engineering, introducing an aqueous solution of the raw material into an initial packed column production line formed by the number obtained by the above method, and adsorbing TAA ions in the packed tower. a first packed column upstream of the production line until the target exchange rate is reached; and a dissolution regeneration process, the first packed column in which a predetermined amount of TAA ions are adsorbed by the adsorption process is disconnected from the initial packed column production line, to the first An acid aqueous solution is introduced into a packed column to dissolve the adsorbed TAA ions in the form of an aqueous solution of the TAA salt, and to regenerate the cation exchange resin filled in the first packed column; the method enables the aforementioned adsorption engineering The TAA ion adsorption amount of the packed column at the most downstream of the initial packed column production line is lower than the breakthrough capacity, and the first packed column which is regenerated after the foregoing dissolution regeneration process is connected to the first packed column which is disconnected from the initial packed column production line. The most downstream of the remaining packed column production line, forming a second packed column directly connected to the downstream side of the first packed column Upstream of the packed column, packed column new production line, works are repeated adsorption and regeneration engineering eluting the new packed column lines.

Hereinafter, a preferred embodiment will be described with reference to Fig. 2 for the manufacturing method of the present invention, but the manufacturing method of the present invention is not limited to the embodiment of Fig. 2 . 2 is a flow chart when the initial packed column production line is formed by using two packed columns in the case where the target exchange rate of each packed column is 80% and the integer n obtained by the above formula (1) is 2.

In Figure 2, the first packed column of the initial packed column line is (A) and the second packed column is (B). First, an aqueous raw material solution was passed from the (A) column side of the initial packed column production line, and the liquid was continuously supplied until the adsorption of the TAA ions of the (A) column reached the target exchange rate (TAA ion adsorption engineering). The discharged liquid discharged from the (A) column is passed to the (B) column downstream of the series connection. At this time, since the exchange amount of the TAA ions in the (B) column is equal to or less than the breakthrough capacity, the TAA ions do not leak into the discharged liquid discharged from the (B) column (step 1).

Next, the (A) column was disconnected from the initial packed column production line, and an aqueous acid solution was introduced into the (A) column to elute the TAA ions, and the TAA ions were recovered as a TAA chloride aqueous solution. At this time, the (B) column is standby as the remaining packed column production line (step 2).

The counter ion of the cation exchange resin of the (A) column in which the TAA ion is dissolved is changed to the H type, and the regeneration process of the (A) column is completed together with the dissolution of the TAA ion. Here, the (A) column after the completion of the dissolution regeneration process is connected to the most downstream of the (B) column which is the remaining packed column production line, and a new packed column production line in which the (B) column is the first packed column is formed. Next, the raw material aqueous solution is introduced into the (B) column until the adsorption of the TAA ions in the (B) column reaches the target exchange rate, and the adsorption process of the TAA ions by the new packed column production line is performed (step 3).

After the adsorption process of the step 3, the (B) column is disconnected from the packed column production line, and an aqueous acid solution is introduced into the (B) column to elute the TAA ions, and the TAA chloride aqueous solution is recovered. At this time, the (A) column is standby as the remaining packed column production line (step 4).

Thus, by repeating the above steps 1 to 4, it is possible to efficiently produce a TAA salt aqueous solution using two packed columns.

<Other Ways of Manufacturing Method of the Present Invention>

Further, in the method for producing a TAA salt aqueous solution of the present invention, the number of the packed columns forming the packed column production line is n+1, and the raw material can be introduced into the remaining packed column production line during the above-described dissolution regeneration process. a solution, and connecting the regenerated packed column to the most downstream of the remaining packed column line before the TAA ion adsorption amount of the packed column at the most downstream of the remaining packed column production line reaches the breakthrough capacity of the most downstream packed column In this way, the dissolution regeneration process of the most upstream packed column that has reached the target exchange rate and the adsorption process based on the supply of the raw material aqueous solution to the remaining packed column production line can be performed simultaneously, and the TAA salt aqueous solution can be continuously produced.

Hereinafter, a method for producing a TAA salt aqueous solution of the present invention in which an initial packed column production line is formed by n+1 packed columns will be described based on Fig. 3, but Fig. 3 is merely an illustration of one embodiment of the present invention, and the present invention It is not limited to the mode of FIG.

3 is a flowchart in the case where the target exchange rate of each packed column is 80% and the integer n obtained by the above formula (1) is 2, which is 2+1, that is, 3 The packed tower forms a packed tower production line.

In Fig. 3, the first packed column in the initial packed column production line is the (A) column, and the subsequent packed columns are the (B) column and the (C) column, respectively. In the same manner as in the above-mentioned FIG. 2, the raw material aqueous solution was introduced into the (A) column of the initial packed column production line, and the TAA ion adsorption process was performed until the adsorption of the TAA ions of the (A) column reached the target exchange rate. The discharged liquid discharged from the (A) column is passed to the (B) column connected in series. At this time, the exchange amount of the TAA ions in the (B) column is equal to or less than the breakthrough capacity, and the TAA ions are not leaked into the discharge liquid discharged from the (B) column. Therefore, the (C) tower is on standby (step 1). Further, there is no problem even if the discharge liquid from the (B) column is introduced into the C column.

Next, the (A) column was disconnected from the initial packed column production line, and an aqueous acid solution was introduced into the (A) column to remove the TAA ions, and the TAA ions were recovered as a TAA chloride aqueous solution. At the same time, a raw material aqueous solution is introduced into the new packed column production line formed by the (B) column-(C) column and the (B) column is the most upstream, and the TAA ion adsorption process is performed until the (TA) TAA of the column (B) The adsorption of ions reaches the target exchange rate. At this time, the exchange amount of the TAA ions in the (C) column is equal to or less than the breakthrough capacity, and the TAA ions are not leaked into the discharge liquid discharged from the (C) column. Further, the counter ion of the cation exchange resin of the (A) column in which the TAA ion is dissolved is changed to the H type, and the regeneration process of the (A) column is completed together with the dissolution of the TAA ion (step 2).

After the completion of the step 2, the (B) column is disconnected from the packed column production line, and an acid aqueous solution is introduced into the (B) column to elute the TAA ions, and the TAA ions are recovered as a TAA chloride aqueous solution. At the same time, a raw material aqueous solution is introduced into the new packed column production line formed by the (C) column-(A) column and the (C) column is the most upstream, and the TAA ion adsorption process is performed until the (C) tower TAA The adsorption of ions reaches the target exchange rate. At this time, the exchange amount of the TAA ions in the (A) column is equal to or less than the breakthrough capacity, and the TAA ions are not leaked into the discharge liquid discharged from the (A) column. Further, the counter ion of the cation exchange resin of the (B) column in which the TAA ion is dissolved is changed to the H type, and the regeneration process of the (B) column is completed together with the dissolution of the TAA ion (step 3).

After the end of step 3, the (C) column is disconnected from the packed column production line, and an acid aqueous solution is introduced into the (C) column to elute the TAA ions, and the TAA ions are recovered as a TAA chloride aqueous solution. At the same time, a raw material aqueous solution is introduced into the new packed column production line formed by the (A) column-(B) column and the (A) column is the most upstream, and the TAA ion adsorption process is performed until the TAA of the (A) column. The adsorption of ions reaches the target exchange rate (step 4).

In the following, by repeating steps 2 to 4, it is possible to simultaneously perform an elution regeneration process in which TAA ions are eluted from each of the packed towers that have reached a predetermined target exchange rate, and an adsorption process in which a raw material aqueous solution is supplied to each packed column production line. The TAA salt aqueous solution can be continuously produced.

<Dissolution regeneration project>

In the method for producing a tetraalkylammonium salt aqueous solution of the present invention, the dissolution regeneration process can be carried out in two stages. As described above, the dissolution regeneration process is a process in which, when the packed column on the upstream side of the packed column production line adsorbs TAA ions until the target exchange rate is reached, the packed column on the upstream side is disconnected from the packed column production line, and the disconnection is performed. An aqueous acid solution is introduced into the packed column to dissolve the TAA ions adsorbed by the packed column in the form of an aqueous TAA salt solution.

Figure 4 is a graph showing the HCl concentration in the effluent and the TAA salt (tetramethylammonium chloride: TMACl) measured in the dissolution regeneration process with the target exchange rate of the packed column at 80%. ) The chart of concentration. According to Fig. 4, only TMACl was first dissolved, and then, HCl was started to flow out and a mixed solution of TMACl and HCl was flowed out.

When HCl is contained in the effluent, it is necessary to neutralize the effluent, and the engineering will increase, which is not preferable. Therefore, in a preferred embodiment of the present invention, the dissolution regeneration process is divided into a first dissolution regeneration process until the start of the acid of the introduced acid aqueous solution, and a second dissolution regeneration process after the start of the discharge of the acid. The acid-free effluent obtained by the first dissolution regeneration project was used as a target, that is, a TAA salt aqueous solution. Further, the aqueous solution containing the acid and the TAA salt discharged from the second dissolution regeneration project can be used as the aqueous acid solution used in the subsequent dissolution regeneration process, whereby the regenerated TAA salt can be obtained without waste.

Whether or not the acid is contained in the discharge liquid can be grasped by measuring the pH, conductivity, and the like of the discharge liquid.

The conductivity of the discharge liquid is shown in Fig. 4. First, as the TAMCl is eluted, the conductivity of the discharge liquid rises, and as the concentration of the TMACl in the discharge liquid becomes stable, the conductivity of the discharge liquid is also stabilized, and thereafter, once HCl When it flows out, the conductivity of the discharge liquid rises sharply. By using this phenomenon, by monitoring the conductivity of the discharge liquid, switching from the first dissolution regeneration process to the second dissolution regeneration process can be performed.

At this time, by providing a buffer tank (not shown) on the discharge line of the discharge liquid or providing a flow path switching device at a position sufficiently downstream from the measurement position of the conductivity meter, the discharge liquid of the first dissolution regeneration project can be prevented. It contains HCl which is contained when the conductivity is sharply increased (a TAA salt solution containing no acid can be obtained).

<Subsequent processing>

According to the method for producing a TAA salt aqueous solution of the present invention described above, a TAA salt aqueous solution having a high concentration and a high purity can be obtained. The TAA ion concentration in the TAA salt aqueous solution obtained by the production method of the present invention depends on the concentration of the aqueous acid solution or the performance of the cation exchange resin, and in the case of using an aqueous solution of a raw material having a TAA concentration of 0.001 to 1% by mass. Next, a 2 to 40% by mass aqueous solution of TAA salt can be usually obtained.

Further, the obtained TAA salt aqueous solution can be made into a TAA hydroxide by a known method. Examples of the method include electrodialysis, electrolysis, and the like.

Further, before the electrodialysis and electrolysis, the TAA salt aqueous solution can be purified and concentrated. The method for purifying the TAA salt aqueous solution may be a method of removing the metal ion component in the TAA salt aqueous solution by contacting the aqueous solution with a cation exchange resin and/or a chelating resin; and making the TAA salt aqueous solution and activated carbon A method in which an adsorbent or an anion exchange resin is contacted to remove an organic substance such as a photoresist.

In addition, as a method of concentrating the TAA salt aqueous solution, specifically, a method of concentrating by electrodialysis, an evaporation can, or a reverse osmosis membrane may be mentioned.

[Examples]

In order to specifically describe the present invention, the following examples are described, but the present invention is not limited to these examples.

Further, a waste liquid containing tetramethylammonium hydroxide (hereinafter abbreviated as TMAH) discharged from a liquid crystal factory is used as a sample liquid.

In addition, the pH was measured and converted by a pH electrode method (measurement apparatus: HM-30R (manufactured by DKK-TOA CORPORATION)), and the TMAC1 concentration was measured by ion chromatography (measurement apparatus: DX120 (Dionex)) to determine the TMA ion concentration. And converted to get. With respect to the HCl concentration, the Cl concentration was measured by ion chromatography (measurement apparatus: DX320 (Dionex)), and excess Cl ions other than Cl ions paired with TMA ions were converted into HCl concentration.

<Example 1> (Determining the number of packed towers)

1000 ml of a weakly acidic cation exchange resin DIAION WK40L (manufactured by Mitsubishi Chemical Corporation) having an exchange capacity of 4.4 mol/L was packed in a column having a diameter of 50 mm to have a total exchange capacity of 4.4 mol and a resin height of 500 mm.

A sample liquid (TMAH concentration: 0.045 mass%) of BV = 2000 (L/L-resin) was introduced into the above-mentioned packed column at SV (space velocity) = 100 h ^-1 to carry out adsorption of TMA ions.

At this time, the point at which the TMA ion was detected in the discharged liquid was BV = 430 (L/L-resin), and the breakthrough capacity was 2.12 mol. At this time, the exchange rate at the breakthrough point was 48.2%. Next, when the target adsorption rate was 80%, the liquid passing amount was BV = 1000 (L/L-resin), and the total amount of TMA ions (TMA ion leakage amount) contained in the treated wastewater at this time was 1.48 mol. Thus, n obtained by the formula (1) is 2, and the number of required packed columns is determined to be 2 columns.

(Adsorption engineering (first packed tower → second packed tower))

A packed column identical to the above packed column was prepared, and two columns were placed in series to form an initial packed column production line. The upstream side is the first packed column and the downstream side is the second packed column. The target exchange rate of the first packed column was set to 80%, and 0.045% by mass of TMAH developing waste liquid was introduced into the packed column production line at BV = 1000 (L/L-resin). At this time, no leakage of TMA ions was observed in the discharged liquid from the second packed column.

(Dissolution regeneration project of the first packed tower)

Next, the first packed column was opened, and 6000 ml of 1N-HCl as a solution was introduced into the first packed column at SV = 3 h ^-1 to elute the adsorbed TMA ions as TMAC1. The effluent is fractionated to separate into two parts of the liquid. The first 1000 ml was taken as the first fraction. The first fractionation solution does not contain TCAM1 and is treated as a waste liquid. The next 5000 ml was taken as the second fraction. The second fraction contained 7.3% by mass (0.67 mol/l) of TCAMl and 0.02% by mass (0.01 mol/l) of HCl. The second fraction is the desired TCAMCl solution.

(Adsorption engineering (second packed tower → first packed tower))

After the dissolution and regeneration of the first packed column is completed, a packed column production line having a second packed column on the upstream side and a first packed column on the downstream side is formed so that the first packed column can be passed through the second packed column. When 0.045 mass% of TMAH developing waste liquid was passed at BV = 700 (L/L-resin), the exchange rate of the second packed column was 80%. At this time, no leakage of TMA ions was observed in the discharged liquid from the first packed column.

(Separation regeneration project of the second packed tower)

Next, the second packed column was opened, and 6000 ml of 1N-HCl as a solution was introduced into the second packed column at SV = 3 h ^-1 to elute the adsorbed TMA ions in the form of TMACl. The effluent is fractionated to separate into two parts of the liquid. The first 1000 ml was taken as the first fraction. The first fractionation solution does not contain TCAM1 and is treated as a waste liquid. The next 5000 ml was taken as the second fraction. The second fraction contained 7.3% by mass (0.67 mol/l) of TMACl and 0.02% by mass (0.01 mol/l) of HCl. The second fraction is the desired TCAMCl solution.

The recovery rate (%) of each packed column was determined from "the amount (mol) of TMACl in the fractionating liquid / the amount of TMA (mol) adsorbed by the cation exchange resin in the packed column". Both the first packed column and the second packed column were 94.6%.

<Examples 2 to 11>

In the examples 2 to 11, as shown in Table 1, the target exchange rate was changed to 50 to 95, and in the same manner as in the first embodiment, n was calculated, and the number of towers in the packed column production line was determined, and TMAH was introduced. The sample solution adsorbs TMA ions to produce TMACl. The results are shown in Table 1.

<Comparative Example 1> (adsorption engineering)

Under the same conditions as in Example 1, the target adsorption rate was set to 45%, and 0.045% by mass of TMAH developing waste liquid was introduced at BV = 400 (L/L-resin).

(Dissolution regeneration project of the first packed tower)

6000 ml of 1N-HCl as a solution was introduced into the first packed column at SV = 3 h ^-1 to elute the adsorbed TMA ions in the form of TMACl. The eluate is fractionated to separate into two parts of the liquid. The first 1000 ml was taken as the first fraction. The first fractionation solution does not contain TCAM1 and is treated as a waste liquid. The next 5000 ml was taken as the second fraction. The second fraction contained 3.4% by mass (0.37 mol/l) of TCAMCl and 2.21% by mass (0.61 mol/l) of HCl.

Comparative Example 1 is an example in which the target adsorption ratio of Example 1 was changed from 80% to 45%, and the concentration of the finally obtained TMACl solution was low and contained a large amount of HCl.

<Example 12 (merry-go-round operation)> (Determining the number of resin towers)

When the packed column and the sample liquid are used in the same manner as in the above-described first embodiment, and the target adsorption rate is set to 80%, the number of required packed columns n is two, and in order to continuously perform the adsorption treatment, n + is formed. A packed tower production line consisting of 1 of 3 towers.

(Adsorption engineering (first packed tower → second packed tower))

In the same manner as in the first embodiment, a first packed column was provided on the upstream side and a second packed column was provided on the downstream side to form a packed column production line. The adsorption treatment was carried out by using a resin tower in which two columns were connected in series. At this time, the third packed tower is on standby.

(Adsorption engineering (second packed tower → third packed tower))

After the adsorption of the first packed column is completed, the first packed column is disconnected so as to be able to be connected in series from the second packed column to the third packed column to form a new packed column production line. 0.045% by mass of TMAH developing waste liquid was introduced into the new packed column production line at BV = 700 (L/L-resin), and as a result, the exchange rate of the second packed column reached 80%. At this time, no leakage of TMA ions was observed in the discharged liquid from the third packed column.

(Dissolution regeneration project of the first packed tower)

The dissolution and regeneration of the first packed column is performed simultaneously with the above adsorption process (second packed column → third packed column). 6000 ml of 1N-HCl as a solution was introduced into the first packed column at SV = 3 h ^-1 to elute the adsorbed TMA ions in the form of TMACl. The eluate is fractionated to separate into two parts of the liquid. The first 1000 ml was taken as the first fraction. The first fractionation solution does not contain TCAM1 and is treated as a waste liquid. The next 5000 ml was taken as the second fraction. The second fraction contained 7.3% by mass (0.67 mol/l) of TMACl and 0.02% by mass (0.01 mol/l) of HCl. The second fraction is the desired TCAMCl solution.

In the present embodiment, the dissolution regeneration process of the first packed column ends before the second packed column in the adsorption process (second packed column → third packed column) reaches the target exchange rate. Therefore, it is possible to connect the regenerated first packed column to the downstream side of the third packed column immediately after the second packed column reaches the target exchange rate and the adsorption process (second packed column → third packed column) ends. Forming a new packed tower production line (third packed tower → first packed tower), immediately performing adsorption engineering using the packed tower production line (third packed tower → first packed tower), and simultaneously achieving the target exchange rate In the dissolution regeneration process of the two packed columns, the production of the TMACl solution can be continuously performed.

[figure 1]

Fig. 1 is a block diagram showing an outline of a method for producing a TAA salt aqueous solution of the present invention.

[figure 2]

Fig. 2 is a flow chart showing a preferred embodiment of the method for producing a TAA salt aqueous solution of the present invention.

[image 3]

Fig. 3 is a flow chart showing another preferred embodiment of the method for producing a TAA salt aqueous solution of the present invention.

[Figure 4]

4 is a graph showing the concentration of TAA salt (TMACl) and hydrogen chloride (HCl) in the discharge liquid, and the conductivity of the discharge liquid.

Claims (7)

A method for producing a tetraalkylammonium salt aqueous solution, comprising the following steps: adsorption engineering, introducing an aqueous solution of a raw material containing tetraalkylammonium hydroxide into an initial packed column production line to adsorb tetraalkylammonium ions to cation exchange Resin until the first packed column upstream of the initial packed column line reaches a target exchange rate exceeding the breakthrough capacity, wherein the aforementioned initial packed column line is connected in series by a plurality of packed columns of the same or substantially the same filled with a cation exchange resin And the dissolution regeneration project, disconnecting the first packed column that has passed the adsorption process to adsorb the tetraalkylammonium ion to reach the target exchange rate from the initial packed column production line, to the first packed tower that is disconnected Passing an aqueous acid solution to dissolve the adsorbed tetraalkylammonium ion as an aqueous solution of a tetraalkylammonium salt, and regenerating the cation exchange resin filled in the aforementioned first packed column; The number of packed towers connected in series in the production line is an integer n or more obtained by the following formula, thereby making the aforementioned adsorption engineering The adsorption capacity of the tetraalkylammonium ion in the packed column of the most downstream of the aforementioned initial packed column production line is lower than the breakthrough capacity, n={1+ (the amount of tetraalkylammonium ion leakage until the first packed column reaches the target exchange rate) (mol)) / (penetration capacity (mol) of the first packed column)} (1) wherein the decimal point is post-received, and the first packed column which is regenerated after the aforementioned dissolution regeneration process is connected to Forming the most downstream of the remaining packed column production line remaining after the first packed column is disconnected, forming a second packed column directly connected to the downstream side of the first packed column at the beginning of the adsorption process as the most upstream packed column The new packed tower production line is repeatedly subjected to the aforementioned adsorption engineering and the aforementioned dissolution regeneration project using the new packed tower production line. The method for producing an aqueous solution of a tetraalkylammonium salt according to the first aspect of the invention, wherein the number of the packed columns constituting the initial packed column production line is the aforementioned integer n+1, and the first filling of the most upstream is performed. During the dissolution and regeneration of the column, the raw material solution is introduced into the remaining packed column production line in which the first packed column is disconnected, and the amount of tetraalkylammonium ions adsorbed in the packed column at the most downstream of the remaining packed column production line is reached. Prior to the capacity, the regenerated first packed column is connected to the most downstream of the remaining packed column line. The method for producing a tetraalkylammonium salt aqueous solution according to claim 1 or 2, wherein the target exchange rate of the adsorption engineering is 70 to 90%. The method for producing a tetraalkylammonium salt aqueous solution according to the first or second aspect of the invention, wherein the dissolution and regeneration process is performed by a first dissolution regeneration process until the acid of the introduced acid aqueous solution is discharged, and the discharge is performed. A second dissolution regeneration engineering composition after the acid, wherein the aqueous solution obtained in the first dissolution regeneration process is used as a target, that is, a tetraalkylammonium salt aqueous solution. The method for producing a tetraalkylammonium salt aqueous solution according to the fourth aspect of the invention, wherein the conductivity of the effluent is monitored to perform the dissolution regeneration process. Switching from the first dissolution regeneration project to the second dissolution regeneration project. The method for producing a tetraalkylammonium salt aqueous solution according to the third aspect of the invention, wherein the dissolution and regeneration process is performed after the first dissolution regeneration process until the acid of the acid aqueous solution that has been introduced is discharged, and after the acid is discharged. The second dissolution regeneration engineering composition comprises the aqueous solution obtained in the first dissolution regeneration project as a target, that is, an aqueous solution of a tetraalkylammonium salt. The method for producing a tetraalkylammonium salt aqueous solution according to claim 6, wherein the first dissolution regeneration project to the second dissolution regeneration project is performed by monitoring the conductivity of the discharge liquid to perform the dissolution regeneration process. Switch.