JPH11157834A - Resource recovering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a continuous operation type resource recovering device for recovering a granular CaF2 capable of being used as a substitute of a fluorite, a pure water and a concd. aqueous ammonia from a spent fluorine- containing liquid chemical. SOLUTION: NH4 F-containing soln. is supplied to the first multi-step column 101' filled with a granular CaCO3 and treated to convert the granular CaCO3 to the granular CaF2 , and the aqueous ammonia is separated and recovered by supplying the treated liquid at the first multi-step column system 101 to an ammonia separating system 103, and the treated liquid from which the ammonia is removed or the treated liquid and the HF-containing liquid or the HF- containing liquid are supplied to the second multi-step column 102 filled with the granular CaCO3 and treated to convert the granular CaCO3 to the granular CF2 , and a water from which the fluorine is removed is recovered, moreover, the granular CaF2 is discharged and recovered in order from the column among the first and second multi-step columns in which the reaction to the CaF2 is finished by a granule transferring system 104 and also the granular CaCO3 is filled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resource recovery apparatus, and more particularly, to a hydrofluoric acid and ammonium fluoride solution used in a semiconductor device manufacturing wet process, which can be replaced with fluorite resources. The present invention relates to a fluorine resource regenerating apparatus for recovering calcium iodide and simultaneously recovering ammonia and water.

[0002]

2. Description of the Related Art In the semiconductor industry, the issue of zero environmental emissions is important. In semiconductor device manufacturing, hydrofluoric acid, sulfuric acid, hydrochloric acid,
In the etching step, a solution containing hydrogen fluoride and ammonium fluoride is indispensable. The amount of these fluoride chemicals used has increased to 100,000 tons per year, and has increased with the development of the semiconductor industry. These used chemicals are concentrated in the wastewater treatment process,
The process is carried out by neutralizing acids and alkalis by slaked lime treatment and generating insoluble fluorine compounds, separating the formed precipitates using a thickener / sedimentation pond, and dehydrating the precipitates using a filter press. The concentrated treatment of various chemicals by this slaked lime treatment method is particularly dominated by the difficulty of removing fluorine compounds, and requires multi-stage and large-capacity treatment equipment. Moreover, the amount of generated sludge is about 100,000 tons per year, which is a heavy burden on the environment.

Further, a large amount of ultrapure water is required for wet cleaning, and the amount of ultrapure water in a plant for processing 30,000 8-inch wafers exceeds about 100,000 tons per month. Reuse is not possible.

[0004] Furthermore, the reserves of fluorite, which is a fluorine resource, are about 220 million tons as economic mining as of 1988, and about 30 million tons under annual consumption of about 6 million tons. It is troublesome to have only an ore life of one year.

[0005]

In view of such circumstances, the present invention relates to hydrofluoric acid (HF) and ammonium fluoride.
Based on the basic principle of generating granular calcium fluoride (CaF ₂ ) by a solid-phase reaction between a (NH ₄ F) -containing solution and granular calcium carbonate (CaCO ₃ ), granular fluorine that can replace used fluorine-containing chemicals with fluorite resources is used. An object of the present invention is to provide a continuous operation type resource regenerating apparatus that recovers calcium iodide and simultaneously recovers pure water and concentrated ammonia water from a treatment liquid.

The problem to be solved by the present invention will be specifically described below. The chemical reactions utilized by the present invention are as follows.

2HF + CaCO ₃ = CaF ₂ + CO ₂ + H ₂ O 2NH ₄ F + CaCO ₃ = CaF ₂ + (NH ₄ ) ₂ CO ₃

1) Problems of treatment method The first problem is a method of effectively utilizing mineral resources and regenerating the resource value of recovered materials. Mined and crushed natural limestone (CaC
O ₃ ), that is, granular calcium carbonate is used in a chemical equivalent amount to the amount of fluorine, and this is converted to granular calcium fluoride (C
A chemical reactor for conversion to aF ₂ ) is required. The recovered sludge generated by adding excess slaked lime like the slaked lime treatment method cannot be reused at all.

The present inventors argue that in order to realize a chemical equivalent reaction between a fluorine compound solution and granular calcium carbonate, a treatment method under countercurrent reaction conditions is necessary. And a treatment method in which the supply direction of calcium carbonate is countercurrent. We also studied the chemical reaction mechanism of ammonium fluoride-containing solution and granular calcium carbonate in detail, clarified that the cause of the poor reactivity was the production of ammonia, and realized a chemical equivalent reaction "heating and degassing reactor. To solve this problem (Japanese Patent Laid-Open No. 5-170).
No. 435, Method for recovering calcium fluoride from fluorine-based etching agent: Omi, Harada, Miki et al., United Sta.
tes Patent 5362461; Method for recovering calcium
fluoride from fluoroetchant, H. Ohmi, H. Harada, N, M
iki et.al.). This technology has revealed for the first time the basic principle and method of recovering particulate calcium fluoride with resource value.

The second problem is the development of a column reaction method. The present inventors have paid attention to the fact that a multistage column system is the most efficient and continuous system in place of the counter-current supply type reaction tank, and presented it as a calcium fluoride recovery method (Japanese Patent Application Laid-Open No. 7-57531). Gazette: Calcium fluoride recovery method, Omi / Miki et al.).

According to this technique, particulate calcium fluoride can be recovered from dilute hydrofluoric acid using a multi-stage column system. A method was also proposed in which a concentrated ammonium fluoride solution-containing solution was treated using a multi-stage column system, and the treated solution was combined with a dilute hydrofluoric acid-based multi-stage column system (IEICE TRANS. ELECTRON., VolE79-).
C, 363, 1996).

2) Problems of Processing Apparatus The key point of the invention presented here is the systematization of the above-mentioned developed technology, aiming at the completion of an apparatus technology that solves the following various system problems.

The first problem is the practical application as an industrial large-scale continuous processing system. Now that the processing scale has been expanded, a system in which continuous operation control and automatic measurement control cannot be reliably guaranteed cannot be realized. For that purpose, it is necessary to set appropriate indices, develop data measurement means and control methods.

The second problem is the problem of automation, simplification and practical application as a physical distribution system. The total system will not be complete unless simple transport of large amounts of raw materials and recovered materials and remote transport to the reuse plant can be carried out smoothly.

The third problem is eligibility for system expansion and system integration. In the era of rapid innovation,
Flexible scalability of equipment capacity is an essential requirement. Also, in an era where more comprehensive and comprehensive environmental measures are needed, the system must be able to be integrated over a wide area.

[0016]

A resource regenerating apparatus according to the present invention is a resource for recovering calcium fluoride, ammonia water and water from a hydrofluoric acid-containing solution and an ammonium fluoride-containing solution used in a semiconductor manufacturing wet station. A regenerator, a first multi-stage column system for treating an ammonium fluoride-containing solution, an ammonia separation system for separating ammonia water from the treatment solution, and a second multi-stage column for treating a hydrofluoric acid-containing solution System and a granular transfer system for filling granular calcium carbonate in each column of the first and second multistage column systems and removing granular calcium fluoride generated by a solid-phase reaction with hydrofluoric acid or ammonium fluoride The first multi-stage column filled with granular calcium carbonate comprises ammonium fluoride. The containing solution is supplied and treated to convert the particulate calcium carbonate into particulate calcium fluoride, and the first multi-stage column system treatment liquid is supplied to the ammonia separation system to separate and recover ammonia water, and to remove ammonia. The system treatment liquid or the treatment liquid and the hydrofluoric acid-containing solution or the hydrofluoric acid-containing solution are supplied to the second multi-stage column system filled with granular calcium carbonate and treated, and the granular calcium carbonate is converted into granular calcium fluoride. Convert and recover water from which fluorine has been removed,
Further, the first and second multi-stage column systems are configured to sequentially take out and recover the particulate calcium fluoride and fill the particulate calcium carbonate with the particulate transfer system from the column where the reaction of the first and second multistage column systems with the calcium fluoride has been completed. It is characterized by having.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION A resource regeneration device according to the present invention will be described.

In the present invention, the solution containing ammonium fluoride is generally referred to as buffered hydrofluoric acid (BHF).
A solution called ammonium fluoride (NH ₄ F),
It is a solution in which hydrofluoric acid (HF) and water are mixed in various ratios. Hereinafter, the HF concentration in this solution is expressed as free HF, and the total HF concentration obtained by adding fluorine present in the composition of NH ₄ F to HF in terms of HF is expressed as T-HF.

First, the first means for realizing the resource regeneration apparatus of the present invention is to utilize a multi-stage column system. When the column is filled with granular calcium carbonate and a dilute hydrofluoric acid solution is passed, granular calcium fluoride is generated, and fluorine in the liquid is completely removed. However, in the case of a solution containing ammonium fluoride, the conversion to granular calcium fluoride is rapid, but a high concentration of ammonia and fluorine remains in the solution. This solution requires the following measures:

The second means is a three-stage treatment of an ammonium fluoride-containing solution. First, treatment is performed in a multi-stage column system, and thereafter, the treatment liquid is subjected to ammonia removal by an ammonia separation system, and the ammonia-removed treatment liquid is passed through the multi-stage column system again. That is, the first stage collects particulate calcium fluoride, the second stage collects ammonia, and the third stage collects water from which fluorine has been removed.

The key point of the present invention lies in the concept that the multi-stage column system for the hydrofluoric acid-containing solution is also used as the third-stage multi-stage column system for the three-stage treatment of the ammonium fluoride-containing solution.

The third means is to index / coefficient column operation parameters. Installation of process monitor, granularity
Control by numerical information such as concentration and content enables continuous operation of the system.

The fourth means is to adopt a water flush method using a water flow as a method for transferring the raw material calcium carbonate and the generated calcium fluoride. As a result, the logistics can be performed quickly and easily until the packaging stage.

The fifth means is to set up an expansion system of equipment capacity and to propose a centralized processing system for a transportable concentrated ammonium fluoride-containing solution. The above measures solve the practical integrity as a continuous processing technique.

FIG. 1 shows an example of the system configuration of the resource regeneration apparatus of the present invention.

The resource regenerating apparatus of the present invention comprises a multi-stage column system 101, 102, an ammonia separation system 103 and a granular material transfer system 104.
Further, the ammonia separation system 103 includes an ammonia evaporator 103-1, an ammonia condenser 103-2, and an ejector 103-3.

Further, the apparatus has a multistage column system 101 for processing a concentrated ammonium fluoride-containing solution and an ammonia separation system 103, and a multistage column system 10 for processing a dilute hydrofluoric acid-containing solution.
The second stream of 2 is composed of and is connected as follows.

Solution flow in series connection For the flow of the processing solution, an apparatus configuration in which the first and second systems are in series is used. That is, the ammonium fluoride-containing solution is supplied to the first series, and the treatment liquid is connected to the second series and merges with the hydrofluoric acid-containing solution. Concentrated ammonia water is recovered from the first series ammonia separation system, and pure water from which fluorine has been removed is recovered from the rear end of the second series.

Transfer of Granules Connected in Parallel For the transfer of granules, an apparatus configuration in which the first system and the second system are in parallel is used. That is, granular calcium carbonate is supplied from the rear end of each multi-stage column system, and granular calcium fluoride is collected from the front end of each stage.

As described above, the resource regenerating apparatus of the present invention is an apparatus capable of efficiently and continuously recovering particulate calcium fluoride, ammonia water and water from an ammonium fluoride-containing solution. However, the present invention can be suitably applied to only a hydrofluoric acid-containing solution, and calcium fluoride and water can be recovered.

Various new technologies using the present resource regeneration device have been developed. Embodiments of the invention will be described in detail below with reference to examples.

[0032]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.
The concentrations shown in the examples are% by weight unless otherwise specified.
It is.

(Embodiment 1) The most important thing for constructing a continuous processing system using multi-stage columns is the setting of the number of column stages. If the number of column stages is not foreseeable, it is impossible to design equipment or operate. The inventors investigated the column reaction under various conditions and studied the breakthrough behavior, and as a result, were able to clarify the means for logically setting the number of column stages using various characteristics of the breakthrough curve as an index. Was.

FIG. 2 shows a model of a multi-stage column breakthrough curve. The breakthrough curve is a change curve of the component concentration in the column effluent with respect to the passage days. The figure shows a state in which the column breakthrough curves for the number of column stages are arranged at a certain interval Y. The characteristics of the breakthrough curve are represented by X, Y, Z and E.

Here, X: days of conversion of granular calcium carbonate to granular calcium fluoride (actually measured values) Y: days of life of granular calcium carbonate packed in the column (calculated value determined by the packed amount) Z: column breakage E-day (actual value) E: exchange period of column The ideal breakthrough curve is that HF does not flow out while calcium carbonate packed in the column is converted to calcium fluoride,
If the HF concentration rises due to breakthrough at the end of the conversion, that is, a vertical breakthrough curve in which X and Z coincide with the time point of the calculated value Y, the actual curve is not so simple.
This is because the reaction speed between the surface of the calcium carbonate particles and the inner core is different. Therefore, the breakthrough curve changes variously depending on various conditions such as the calcium carbonate particle size, the composition and concentration of the treatment solution, the temperature and the flow rate. Such breakthrough characteristics,
The means for grasping by the X, Y, and Z indices will be described.

FIG. 2A shows an example of a breakthrough curve of the concentrated ammonium fluoride treatment, and FIG. 2B shows an example of the breakthrough curve of the diluted hydrofluoric acid treatment. First, in (a), since the reaction speed is high, the breakthrough curve is relatively vertical and close to the calculated value Y. The number of days the tip column reaches X is short, and the breakthrough point Z of the next column is
And a column exchange period E can be taken. In E, the cycle of taking out calcium fluoride in the front end column, filling it with new calcium carbonate, and connecting it as the rear end column is repeated. That is, in this case, the number of column stages may be two.

In FIG. 2B, since the reaction speed is low, the breakthrough point Z appears very quickly, the breakthrough curve is gentle, and X is significantly extended. When the leading column reaches X, the following columns have already passed. It is clear from the figure that the column exchange period E cannot be obtained without the fourth column in order to prevent HF from flowing out of the column.

From the above, it is understood that the number of column stages N is defined by the following equations (1) and (2) using X, Y and Z as indices.

NY + Z = X (1) N = m + 1 (2) m: integer value obtained by rounding up the n value obtained by the equation (1) N: the number of column stages required for the values of X, Y, and Z (1), ( According to 2), the number of stages in the case of FIG.
In 7.5, Y: 5, Z: 4, m = from n = 0.7
1, therefore N = m + 1 = 2. FIG. 2 (b)
The number of stages of X: 15, Y: 5, Z: 2 is n =
From 2.6, m = 3, and therefore N = m + 1 = 4.

X and Z are values that can be measured according to the reaction conditions by a mini-column test. Y as equipment setting condition
Is determined, the number of column stages can be logically set by the above equation.

(Embodiment 2) An important item that cannot be overlooked in the construction of a multi-stage column system is the plan of expansion of the processing capacity. The equipment requires incremental expansion, and may encounter the need for unexpected enhancements. The following three means that can cope with any of them will be presented with examples.

(1) Example of Y Enhancement Means In a multi-stage column arrangement, the column interval is set to about 1.5 times the column diameter. With this space, processing capacity 2
When doubling is required, it is possible to replace the column with a column having a diameter and length of 1.25 times, and to shorten the life of the column to 2Y.

(Part 2) Example of N increasing means An N increasing space according to the equations (1) and (2) is arranged. For example, although N = 4 in FIG. 2B of the first embodiment, if it is expected that the processing capacity will be doubled in the future, N at 1 / 2Y may be obtained by the equations (1) and (2).

Example 1, when the capacity is doubled in FIG. 2B: X:
15, at Y: 2.5 and Z: 2, m from n = 5.2
= 6, and therefore N = m + 1 = 7, so it is sufficient to provide an additional space for three stages of columns of the same size.

(Part 3) Enhancement of Y and N mixing Even if the above two means are mixed and executed, there is no inconvenience in the operation of the column system.

(Embodiment 3) FIG. 3 shows the configuration of a multistage column of this embodiment. In each of the packed columns 301 and 301 ′, a supply port 302 for granular calcium carbonate is provided at the upper or lower part of the column, a particulate calcium fluoride outlet 303 is provided at the lower part of the column, and a particulate calcium fluoride slurry discharge valve 31 is provided.
2. A solution supply port 304, a liquid feed pump 305, a pure water supply port 306, and a solution discharge port 307 and a gas discharge port 308 at the top of the column.

Further, each packed column is provided with a stirrer 309 having a lattice type stirring blade which slightly moves the column packed layer in the horizontal direction and does not short-pass the solution passing through the column in the vertical direction.

Each packed column is provided with a liquid level sensor 310, and is linked with the driving of the liquid sending pump 305 to keep the liquid level in the column constant irrespective of the fluctuation of the solution supply speed.

Each packed column is equipped with a concentration monitor 311 of a non-wetted detection type. This monitor is an electromagnetic field detecting conductivity meter, and the conductivity is measured by an electromagnetic coil installed outside the pipe.

FIG. 4 shows that an electromagnetic field detection type conductivity meter can obtain a conductivity value which is equivalent to that of a normal liquid cell conductivity meter. In the submerged cell type, calcium fluoride fine particles are deposited on the cell surface and continuous measurement cannot be performed, but this non-wetted type monitor has solved this problem.

FIG. 5 shows the relationship between the respective concentrations of HF and NH ₃ and the conductivity. From this relationship, it was clarified that even if ammonia was present at a high concentration in the concentrated ammonium fluoride column treatment solution, the fluorine concentration was measured without being affected by the presence, and a breakthrough curve could be grasped. That is, even if 4 to 5% of NH ₃ is present in the column processing solution, its conductivity corresponds to only 100 ppm or less of the HF number.

Column treatment solution of concentrated ammonium fluoride
The HF concentration of (NH ₃ 4% to 5%, HF 1000 to 4000 ppm) can be measured by this monitor in the presence of ammonia.

(Example 4) The flow rate is important as the operating condition of the packed column. As calculated by the above reaction formula (1), a large amount of about 1.2 m ³ of CO ₂ per kg of HF is used.
Gas is generated.

FIG. 6 shows the relationship between the superficial velocity of the HF solution and the superficial velocity of the CO ₂ gas. The superficial velocity is represented by the volume of solution or gas passing (m ³ / hr) / volume of superficial column (m ³ ). Unless the superficial velocity for summing the supply amount of the HF solution and the generation amount of the reaction gas is controlled to an appropriate value, the packed bed cannot be maintained due to vigorous stirring or particles flowing out. As a result of examining the superficial velocity conditions, as shown in FIG. 6, the superficial velocity of the gas is higher than the superficial velocity of the solution for various treatment liquids, and the higher the HF concentration, the lower the superficial velocity of the gas. It turned out to be more dominant. Therefore, the flow rate should be controlled by the amount of generated CO ₂ gas. The state where the packed bed is kept in a steady state and the packed particles do not flow out of the column significantly depends on the gas generation amount of about 10 (m ³ / hr) /
It revealed that m ³ or less.

Example 5 In the treatment with a dilute hydrofluoric acid solution using a multistage column, the control value of the HF concentration in the column effluent was examined.

FIG. 7 shows the relationship between the HF concentration supplied to the column and the HF concentration in the column effluent. It was revealed that the HF concentration in the effluent had the following relationship depending on the HF concentration supplied to the column. Thus, once the concentration of hydrofluoric acid in the raw water is determined, the concentration of hydrofluoric acid in the column-treated water can be predicted, and the concentration can be reliably controlled. That is, when the HF concentration in the raw water is about 2000 ppm or less near the inflection point of the relationship curve, it can be managed using the following equation.

[0057] ^{C = 15 / (logC 0)} (3) applied to the C ⁰ 2000 ppm or less C ^0: processing raw water concentration of hydrofluoric acid (ppm) C: Column treated water hydrofluoric acid concentration (ppm)

Example 6 A granular calcium carbonate column is converted into granular calcium fluoride by a solid-phase reaction with a dilute hydrofluoric acid solution. At this time, calcium fluoride fine particles are slightly generated. The presence of calcium fluoride microparticles in the column effluent is unacceptable in terms of recovery and use of water and regulation of drainage, so that a means of removal is required.

FIG. 8 shows the measurement results of the concentration of calcium fluoride fine particles in the solution flowing out of the column. That is, it became clear that the fine particles flowed out from the first column of the multi-stage column at a high concentration, but drastically decreased from the subsequent column. This is an effect that the cohesive force of the calcium fluoride fine particles is extremely large. Unlike the conventional method, there is no need to rely on a thickener treatment facility or a filter facility using a flocculant. This is one of the excellent effects of the multistage column system.

Example 7 As described in Example 1, the number of days X in which granular calcium carbonate is converted into granular calcium fluoride is an important index relating to the number of stages in a multi-stage column and further to the equipment volume. Since X depends on the reaction rate,
The larger the concentration of hydrofluoric acid, the larger the concentration. It is important to select the average particle size of the granular calcium carbonate as a condition for increasing the reaction rate.

FIG. 9 shows the relationship between the particle size of calcium carbonate and the reaction conversion. Table 1 shows the results of investigating the average particle diameter D of the calcium carbonate, the relation of dilute hydrofluoric acid HF concentration C ⁰ and convertible days X.

[0062]

[Table 1] 平均 Average particle size of CaCO ₃ D Dilute hydrogen fluoride HF concentration of acid C ⁰ Conversion days X μm ppm Day ─────────────────────────────────── 100 500 16 -21 200 1000 15-20 300 1500 14-19 ───────────────────────────────────

By analyzing Table 1, it was found that the relationship between D, C ⁰ , and X was approximately given by the following equation (4). Thus, by selecting the average particle diameter of the granular calcium carbonate corresponding to the concentration of hydrofluoric acid C ⁰ to be processed, it is possible to appropriately control the conversion days X.

X = 70 (D / C ⁰ ) to 100 (D / C ⁰ ) (4) where D: average particle diameter (μm) of granular calcium carbonate C ⁰ : HF concentration of dilute hydrofluoric acid ( ppm)

Example 8 Granular calcium carbonate (CaC)
One of the features of the basic principle of generating granular calcium fluoride by the solid-state reaction of O ₃ ) is that silica dissolved in the treatment solution is not contained in calcium fluoride. It is known that when calcium fluoride is used as a fluorite replacement resource in the HF generation process, silica causes a calcium fluoride loss of about 11 times its content. The calcium hydroxide treatment has a great merit as compared with the case where all the silica in the treatment solution is contained in the generated calcium fluoride. The present inventors further studied how the silica contained in the particulate calcium carbonate behaves in this solid-phase reaction, and as a result, clarified the facts shown in Table 2 below. That is, the particulate calcium carbonate-containing silica is not contained in the generated calcium fluoride as it is. Despite the solid-state reaction, the particulate calcium carbonate-containing silica was found to dissolve considerably. This is considered to be the effect of the column reaction, that is, the effect that the produced calcium fluoride is washed by the HF solution supplied constantly.

[0066]

[Table 2] カ ル シ ウ ム In calcium carbonate In calcium fluoride Measured value Measured value Predicted value by equation (5)%%% ─────────────────────────────────── NO.1 0.05 0.05 0.06 N0.2 1.3 0.2 0.18 N0.3 2.0 0.3 0.25 ───────────────────────────────────

From the data in Table 2, the following equation (5) is obtained. That is, the silica content of the generated calcium fluoride can be predicted from the content of the granular calcium carbonate silica used as the raw material by the equation (5). This has made it possible to select the quality of raw materials and products.

S _C = 10 (S _F −0.05) (5) S _F is applied to 0.05% or more S _C : SiO ₂ content of calcium carbonate S _F : SiO ₂ content of calcium fluoride rate

(Embodiment 9) FIG. 10 shows the configuration of an ammonia separation system. In this system, the ammonium fluoride-containing solution is passed through the first-stage multi-stage column system 1001 to separate ammonia from the ammonia-containing solution from which most of the fluorine has been removed, and then the dilute hydrofluoric acid solution is treated. This is a continuous fluorine / ammonia / water recovery system in which liquid is sent to a series multistage column system 1011 to completely remove fluorine.

The system comprises an ammonia evaporating tank 1002, a mist separator 1003, an ammonia water condenser 1004, and an ejector 1005. Ammonia evaporating tank is 40 ~ by steam 1006 and ejector 1005
It is heated at 80 ° C. under reduced pressure to 100 to 600 torr. The evaporating ammonia separates the fluoride mist by the mist separator 1003, and the ammonia water condenser 1004
In the condenser 1007, the water is condensed by the cooling water 1008 and collected in the recovered ammonia tank 1009.
In the ejector, the residual ammonia gas is collected by the acidic solution 1010.

The operating conditions of the ammonia separation system are shown below.

Ammonia evaporating tank: Steam heating at 60 ° C. Ammonia water condenser: Cooling water condenser Ejector: 350 to 450 torr Ejector acidic solution: Supply a part of the supply liquid to the first series of multistage column system Collect residual ammonia gas Although sulfuric acid or the like may be used as the acidic solution to be used, it is preferable to use a concentrated ammonium fluoride-containing solution which is the first multistage column system supply solution. Since this solution contains free hydrofluoric acid (HF) and is acidic, ammonia gas can be collected.

Table 3 shows the results of ammonia recovery using the present ammonia recovery apparatus. It shows the amount and composition of the liquid flowing out of the first-stage multistage column system and the amount and composition of the column exhaust gas containing ammonia and carbon dioxide gas generated by the reaction in the column. The effluent is heated in an ammonia evaporator to evaporate ammonia. The evaporating gas is supplied to the ammonia water condenser after the mist containing NH ₄ F is removed by the mist separator. On the other hand, the column exhaust gas is also sucked by the ejector and supplied to the ammonia water condenser. Ammonia water condenses in the cooling condenser of the ammonia water condenser. Since a few percent of ammonia leaks to the ejector side, a part of the column supply number is supplied to the ejector solution, and ammonia is converted to NH ₄ F by a free HF component.
Collect as. Since this ammonia collecting liquid is returned to the feed liquid of the first series multistage column system, it does not cause a loss, and therefore, the ammonia recovery rate is 100%. The recovered ammonia has a composition of (NH ₄ ) ₂ CO ₃ of about 27%, and HF is below the detection limit (0.1 ppm).

[0074]

[Table 3]

(Example 10) An example of comprehensive continuous processing and recovery of a fluorine-containing treatment liquid using an apparatus configuration in which a first series and a second series are connected in series will be described. That is, the ammonium fluoride-containing solution is treated in the first series, and the treatment liquid is combined with the dilute hydrofluoric acid solution in the second series to continuously recover calcium fluoride. Concentrated ammonia water is recovered from the first series ammonia separation system, and pure water from which fluorine has been removed is recovered from the rear end of the second series.

The multi-stage column system is used under the configuration shown in Embodiments 1 and 3 and the control conditions shown in Embodiments 4 to 8.
The ammonia separation system was used in the configuration shown in Example 9. Tables 4 and 5 show the processing results. Table 4 shows the results of fluorine recovery by the first series of multistage column systems, and Table 5 shows the results of fluorine and water recovery by the second series of multistage column systems.

As shown in Table 4, about 98% of fluorine was recovered as calcium fluoride from the ammonium fluoride-containing solution by a multi-column system. Ammonium carbonate and HF 0.28% remain in the column effluent.
Residual fluorine is recovered in a second series.

As already shown in Table 3, the column effluent and the column-evolved gas were treated in an ammonia separation system, and ammonia water ((NH ₄ ) ₂ CO
₍ About 27% for ₃ compositions) is recovered. As described in Example 9, when a part of the column supply liquid was used as the ejector collection liquid and returned to the column, the ammonia recovery rate was about 100%.

As shown in Table 5, the second series of multi-stage column systems were processed by combining the dilute hydrofluoric acid solution with the ammonia removing solution from the first series ammonia separation system to recover calcium fluoride and water. I do. The fluorine recovery rate is almost 100% in total for the first series and the second series.

The recovered water has sufficient purity as a water resource although calcium carbonate is dissolved.

[0081]

[Table 4]

[0082]

[Table 5]

(Embodiment 11) FIG. 11 shows a water-flush type granular material transfer system.

The granular calcium carbonate is transferred from the silo 1101 to a slurry tank 1102, mixed with water 1103 to form a slurry, and supplied to a column 1106 required for a multi-stage column system via a water flash tube 1105 by a slurry pump 1104. You.

The granular calcium fluoride 1107 in the column after the completion of the calcium fluoride conversion passes through a water flush tube from the lower end of the column together with the water supplied from the pump 1108 and passes through a flexible container bag 1109.
Transported to The container bag is water permeable and the transport water flows down to the pit 1110.

[0086] In this way, the particle distribution can be easily carried out without particularly installing a transportation device.

Example 12 Table 6 shows the water content of the granular calcium fluoride filled in the container bag.
The water content is about 18% even immediately after filling. But,
Due to the granularity and the water permeability of the container bag, the moisture content drops to about 15% upon standing. This alone reduces the transport weight by about 1/4 compared to a typical sludge moisture content of about 80%.

By storing the granular calcium fluoride-filled container bag in a dry storage room, the water content can be further reduced. Table 6 shows the effect of lowering the water content when the relative humidity of the drying storage room was maintained at 20 to 60%, preferably at a temperature of 30 to 50 ° C. Due to the dry storage, there is no wetness on the surface of the container bag, and it is possible to carry out mixed transportation, thereby contributing to a reduction in transportation costs.

[0089]

[Table 6] 水分 Water content Container bag surface wetness% ─直 後 Immediately after filling 18 Impossible for mixed loading transportation 15 mixing after standing for filling time Slightly difficult to transport by load Dry storage room After leaving for a while 11-13 Mixed transport is easy ────────────────────────────────条件 Dry storage room conditions: relative humidity 20-60%, temperature 30-
50 ℃

(Thirteenth Embodiment) FIG. 12 illustrates a regional centralized integrated system.

Each semiconductor manufacturing plant 1208, 120
Concentrated ammonium fluoride-containing solution 12 discharged at 8 '
The first series consisting of a multi-stage column system for processing 01 and an ammonia separation system is not installed in each manufacturing plant,
A regional centralized system 1203 is installed, and transport lines 1204 and 1205 are installed between each of the manufacturing plants.

On the other hand, a second series 1202 composed of a multi-stage column system for treating a dilute hydrofluoric acid-containing solution is installed in each factory and is directly processed in each manufacturing plant. Dilute hydrofluoric acid has a large liquid volume, and transporting and treating it is not economically feasible.

A solution 1201 containing concentrated ammonium fluoride
Is connected to the regional centralized system 120 by the transport line 1204.
3 and the treatment liquid is returned to each manufacturing plant via the transportation line 1205 to finish the fluorine / water recovery.

The transport lines 1206 and 1207
Is a calcium carbonate / calcium fluoride transport line.

[0095] Such centralized processing is advantageous for all of the equipment efficiency, the operation efficiency, and the physical distribution transportation efficiency, and is effective.

[0096]

According to the resource regenerating apparatus of the present invention, it is possible to recover granular calcium fluoride which can be used as a fluorite resource from a used hydrofluoric acid and ammonium fluoride solution, and at the same time, conc. Water can also be recovered. That is, according to the present invention, it is possible to provide a continuous operation type resource regenerating apparatus capable of efficiently recovering calcium fluoride, ammonia, and water resources.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing a configuration example of a resource regeneration device of the present invention.

FIG. 2 is a graph showing a breakthrough curve of a multi-stage column.

FIG. 3 is a conceptual diagram illustrating a configuration example of a multi-stage column system.

FIG. 4 is a graph showing the conductivity of an HF solution.

FIG. 5 is a graph showing the relationship between the concentrations of HF and NH ₃ solutions and the conductivity.

FIG. 6 is a graph showing the relationship between the superficial velocity of the HF solution and the superficial velocity of the CO ₂ gas.

FIG. 7 is a graph showing the relationship between the HF initial concentration and the F ion equilibrium concentration.

FIG. 8 is a graph showing the relationship between the concentration of fine calcium fluoride in the column effluent and the number of column stages.

FIG. 9 is a graph showing the relationship between calcium carbonate particle size and reaction conversion.

FIG. 10 is a conceptual diagram showing a configuration example of an ammonia separation system.

FIG. 11 is a conceptual diagram illustrating an example of a water-flush type particle transfer system.

FIG. 12 is a conceptual diagram showing an area centralized processing method of the resource regeneration device of the present invention.

[Explanation of symbols]

101 first multistage column system, 101 ', 102' column, 102 second multistage column system, 103 ammonia separation system, 103-1 ammonia evaporator, 103-2 ammonia condenser, 103-3 ejector, 104 granules Transfer system, 301, 301 'packed column, 302 particulate calcium carbonate supply mechanism, 303 particulate calcium fluoride discharge mechanism, 304 solution supply port, 305 liquid feed pump, 306 pure water supply port, 307 solution discharge port, 308 gas discharge Outlet, 309 stirrer, 310 liquid level sensor, 311 concentration monitor, 1001 first series multi-stage column system, 1002 ammonia evaporation tank, 1003 mist separator, 1004 ammonia water condenser, 1005 ejector, 1006 steam, 1007 con Nsa, 1008 cooling water, 1009 recovered ammonia tank, 1010 acidic solution, 1011 second series multi-stage column system, 1101 CaCO ₃ silos, 1102 slurry tank 1103 water supply port, 1104 slurry pump, 1105 Water flash tube, 1106 CaCO _3, 1107 CaF ₂ , 1108 water supply pump, 1109 CaF ₂ container bag, 1110 pit 1201 concentrated ammonium fluoride containing solution, 1202 second series processing plant, 1203 regional centralized system, 1204, 1205, 1206, 1207 transport line, 1208, 1208 '' Each semiconductor manufacturing plant.

Continuation of the front page (51) Int.Cl. ⁶ Identification symbol FI H01L 21/306 H01L 21/306 Z (72) Inventor Shin Sato 7-1 Morinosatowakamiya, Atsugi-shi, Kanagawa Prefecture Kurita Industry Co., Ltd. (72) Inventor Murai Yukio Hitachi Plant Construction Co., Ltd., 1-13-2 Kita-Otsuka, Toshima-ku, Tokyo (72) Inventor Nobuyuki 1-2-8 Shinsuna, Koto-ku, Tokyo Organo Co., Ltd. (72) Inventor Izumi Kojima 2-4-37 Okada, Atsugi City, Kanagawa Prefecture Inside Nomura Micro Science Co., Ltd. (72) Inventor Masaki Kusuhara 4-2-16 Nihonbashi Muromachi, Chuo-ku, Tokyo Inside Shoko Watanabe Co., Ltd. (72) Inventor Mitsuji Itano Osaka (72) Inventor Toshiro Fukudome 7-227 Kaiyamacho, Sakai-shi, Osaka, Japan Inside (72) Inventor, Tadahiro Omi Yonegabukuro, Aoba-ku, Sendai, Miyagi Prefecture 2 1 of 17 301

Claims (21)

[Claims] 1. A resource regenerating apparatus for recovering calcium fluoride, ammonia water and water from a hydrofluoric acid-containing solution and an ammonium fluoride-containing solution used in a semiconductor manufacturing wet station, comprising: an ammonium fluoride-containing solution; A first multi-stage column system for processing, an ammonia separation system for separating ammonia water from the processing solution, a second multi-stage column system for processing a hydrofluoric acid-containing solution, and the first and second multi-stage columns A granular transfer system in which each column of the system is filled with granular calcium carbonate, and a granular calcium fluoride produced by a solid-phase reaction with hydrofluoric acid or ammonium fluoride is taken out. An ammonium fluoride-containing solution is supplied to the first multi-stage column and treated to form granular calcium carbonate. Is converted to granular calcium fluoride, and the first multi-stage column system treatment liquid is supplied to the ammonia separation system to separate and recover ammonia water, and the ammonia separation system treatment liquid from which ammonia has been removed or the treatment liquid and fluoride Hydrogen-containing solution or hydrofluoric acid-containing solution is supplied to the second multi-stage column system filled with granular calcium carbonate, treated, and converted from particulate calcium carbonate to particulate calcium fluoride to remove water from which fluorine has been removed. Recovered, and further, from the column in which the reaction of the first and second multi-stage column systems to calcium fluoride is completed, the granular calcium fluoride is sequentially taken out and recovered by the granular material transfer system, and the granular calcium carbonate is filled. A resource regenerating apparatus characterized in that it performs the following. 2. The multi-stage column system comprises a plurality of granular calcium carbonate packed columns and a series connection of an ammonium fluoride-containing solution or a hydrofluoric acid-containing solution supply line, and the solution is supplied from the front column to the end column. Wherein the granular calcium carbonate is taken out after being converted into granular calcium fluoride by a tip column, and the tip column is configured to repeat a column cycle filled with particulate calcium carbonate and connected as an end column. 2. The resource regeneration device according to 1. 3. The number of column stages N of the multi-stage column system
Is defined by the following formulas (1) and (2). nY + Z = X (1) N = m + 1 (2) where, X: days of conversion of granular calcium carbonate to granular calcium fluoride (actually measured values) Y: days of life of granular calcium carbonate packed in the column
(Calculated value) Z: Days of breakthrough point of column (actual measurement value) m: Integer value obtained by rounding up n value obtained by equation (1) 4. The resource regeneration apparatus according to claim 3, wherein the expansion of the column processing capacity of the multi-stage column system is performed by increasing the number of life days Y and / or increasing the number of column stages N. . 5. A column of the multi-stage column system, wherein a supply mechanism of granular calcium carbonate is provided at an upper or lower part of the column, a supply mechanism of a solution and pure water and a discharge mechanism of particulate calcium fluoride are provided at a lower part of the column, and a solution and gas of 5. The apparatus according to claim 1, further comprising a discharge mechanism.
A resource regeneration device according to the item. 6. Each column of the multi-stage column system,
6. A stirrer having a lattice-type stirrer that finely moves the column packed bed in the horizontal direction and does not short-pass the solution passing through the column in the vertical direction, is provided. Resource regeneration equipment. 7. Each column of the multi-stage column system comprises:
7. The liquid level sensor according to claim 1, wherein a liquid level sensor is provided, and the liquid level pump is linked to drive the liquid feed pump to maintain the liquid level in the column constant irrespective of the fluctuation of the solution supply speed. Resource regeneration equipment. 8. Each column of the multi-stage column system is provided with a concentration monitor of a non-wetted detection system, and controls a column cycle time and a conversion time to granular calcium fluoride by monitoring a column breakthrough curve. The resource regeneration device according to any one of claims 1 to 7, wherein: 9. The resource regeneration according to claim 8, wherein the concentration monitor is an electromagnetic field detecting conductivity meter, and is controlled by measuring the fluorine concentration without being affected by the coexistence of ammonia. apparatus. 10. In each column of the multi-stage column system, the superficial superposition speed for summing the solution supply amount and the reaction gas generation amount is controlled to a solution supply speed of about 10 (m ³ / hr) / m ³ or less. The resource regeneration device according to any one of claims 1 to 9, wherein: 11. The hydrofluoric acid concentration C ⁰ in the solution supplied to the second multi-stage column system is 2000 ppm.
The resource regenerating apparatus according to any one of claims 1 to 10, wherein the hydrofluoric acid concentration C (ppm) in the treatment liquid is controlled in the following range in the following relation (3). C = 15 / (log C ⁰ ) (3) 12. The method according to claim 1, wherein the fine particles of calcium fluoride generated during the reaction of the particulate calcium carbonate in the tip column of the second multi-stage column system are fixed and aggregated on the particulate calcium carbonate layer in the subsequent column and separated. The resource regeneration device according to any one of claims 1 to 11, wherein 13. The conversion time X of granular calcium carbonate to be packed in each column of the second multi-stage column system is defined as an average particle diameter D (μm) and a dilute hydrofluoric acid concentration C to be treated.
The resource regeneration apparatus according to any one of claims 1 to 12, wherein the resource regeneration apparatus is determined by the following equation (4) corresponding to ⁰ (ppm). X = 70 (D / C ⁰ ) to 100 (D / C ⁰ ) (4) 14. The content of silica S _C of the granular calcium carbonate to be filled in each column of the multistage column system, according to claim, characterized in that selected by the following equation (5) 1
14. The resource regeneration device according to any one of 13). _{S C = 10 (S F -0.05} ) (5) Here, S _C: silica content of granular calcium carbonate S _F: silica content of granulated calcium fluoride 15. The ammonia separation system comprises an ammonia evaporator, a mist separator, an ammonia water condenser, and an ejector, wherein the ammonia evaporator contains ammonia flowing out of the first multi-stage column system. 40-80 ° C from solution, 100-
At 600 torr, the ammonia is removed by evaporation, and the solution from which the ammonia has been removed is supplied to the second multi-stage column system, while the evaporated gas separates fluoride mist in the mist separator and condenses ammonia water in the ammonia condenser. The resource regenerating apparatus according to any one of claims 1 to 14, wherein the concentrated ammonia water is collected to collect the residual ammonia gas in the ejector, and the acidic ammonia solution is collected in the ejector. 16. The resource regenerating apparatus according to claim 15, wherein an ammonium fluoride-containing solution supplied to the first multi-stage column system is used as the acidic solution. 17. The method according to claim 1, wherein, in the granular material transfer system, packing of the granular calcium carbonate from the silo into the column of the multi-stage column system is performed by a water flush method. A resource regeneration device according to claim 1. 18. The method for removing granular calcium fluoride from a column of the multi-stage column system and packing the granular calcium fluoride in a water-flush method in the granular material transfer system, and transferring the granular calcium fluoride slurry to a water-permeable flexible container bag. The resource regenerating apparatus according to any one of claims 1 to 17, wherein the apparatus is a filling method. 19. The resource regenerating apparatus according to claim 18, further comprising a container bag storage room filled with granular calcium fluoride maintained at a relative humidity of 20 to 60%. 20. The resource regeneration apparatus according to claim 19, wherein the temperature of the storage room is maintained at 30 to 50 ° C. 21. A first series of equipment comprising the first multi-stage column system and the ammonia separation system is concentrated in each region, and a second series of equipment comprising a second multi-stage column system for treating a solution containing hydrofluoric acid is provided. 21. The equipment according to claim 1, wherein equipment is dispersed in each factory, and a solution transport line to the centralized first affiliated facility and a return line for processing solution to each factory second affiliated facility are installed to operate as a regional integrated system. The resource regeneration device according to claim 1.