TWI635054B - Method and apparatus for producing fertilizer by treating phosphoric acid mixed acid waste liquid - Google Patents

Abstract

A method and apparatus for producing a fertilizer by treating a phosphoric acid mixed acid waste liquid. When the mixed acid waste liquid (fatigue liquid) containing a high concentration of phosphoric acid, nitric acid, and acetic acid generated by an etching step of aluminum or the like is treated, the concentration of phosphoric acid and nitric acid in the mixed acid waste liquid is measured, and then added based on the measurement. The calculated amount of monoammonium phosphate (Diammonium phosphate; (NH ₄ ) ₂ HPO ₄ ) was allowed to react with phosphoric acid and nitric acid. Thereby, phosphoric acid and nitric acid were recovered, and a powder of ammonium dihydrogen phosphate (NH ₄ H ₂ PO ₄ ) which can be used as a fertilizer was obtained. The processing apparatus used for this includes a solid-liquid mixing reactor having a heating mechanism and a mixing and stirring mechanism, a measurement input device that measures and inputs the waste liquid, a powder input device, and a control mechanism.

Description

Method and apparatus for producing fertilizer by treating phosphoric acid mixed acid waste liquid Field of invention

The present invention mainly relates to a method of treating a waste liquid containing a high concentration of phosphoric acid, nitric acid and acetic acid so that it can be utilized as a fertilizer. In particular, it relates to a method of processing and recycling an etching liquid for producing a wiring pattern containing aluminum or an alloy thereof after repeating use in manufacturing a flat panel display or the like.

Background of the invention

A liquid crystal display device or an organic EL display device which is generally used as a flat panel display includes an array substrate on which a wiring pattern is formed. The wiring pattern on the array substrate often includes a single layer film formed of aluminum or an alloy thereof, or a laminated film thereof with molybdenum or the like. Aluminum or its alloy has characteristics such as low electric resistance and high reflectance, and thus is widely used for various wirings on the array substrate, patterns of pixel electrodes, and the like. An etchant containing 50% by weight or more of phosphoric acid, nitric acid, and acetic acid is usually used for the production of such an aluminum-based pattern.

When such an etchant having a high viscosity is repeatedly used, a kind of "fatigue" such as the dissolution of aluminum and molybdenum is intensified, so that it is necessary to replace it with a new etching liquid. Therefore, the waste liquid discharged from the etching processing apparatus is classified into two types: a waste acid containing a high concentration of phosphoric acid which is discarded as a fatigue liquid, a thin cleaning waste which adheres to a glass substrate and is washed away in a water washing step. liquid. The etching solution contains a high concentration of phosphoric acid, so the viscosity is high and adheres to the glass. The amount of the substrate to be washed and discarded in the water washing step is large, and about 60% to 70% of the total amount of liquid used is discarded as the washing drainage. However, the remaining 30 to 40% is separated as a fatigue liquid containing a high concentration of phosphoric acid.

In recent years, with the increase in the size of factories that produce flat panel displays, the amount of fatigue liquid and cleaning wastewater derived from the above etching liquid has increased, and there is a problem that the processing cost is large. The washing wastewater containing phosphoric acid is mainly treated by a sedimentation separation method, but a large amount of sludge is generated, so there is a problem that the treatment cost of the sludge is large.

Therefore, in recent years, a technique for recovering phosphoric acid in the wastewater has been proposed (for example, Patent Documents 1 to 2 below). In Patent Document 1, a mixed liquid of a trialkyl phosphate and an aromatic organic solvent is used as an extracting agent to extract acetic acid and nitric acid, and the phosphoric acid remains in the extraction residual liquid. In Patent Document 2, by performing reverse osmosis membrane treatment while maintaining a low pH, only phosphoric acid is concentrated, and acetic acid and nitric acid are removed together with permeated water.

Prior art literature

Patent Document 1: Japanese Special Open 2004-160292

Patent Document 2: International Publication WO2009/119684 (Japan Re-Formation) 2009/119684; Japanese license 5413192)

Regarding the method of Patent Document 1, a large amount of a chemical agent and an organic solvent are required, and there is a problem in terms of cost and environment. Further, regarding the method of Patent Document 2, it is necessary to compare large-scale equipment, and it is considered that the equipment investment will become large. Further, with regard to these methods, phosphoric acid is recovered as an aqueous solution containing impurities, and thus cannot be directly Used in phosphate fertilizers, etc. Further, in these methods, acetic acid cannot be efficiently separated from nitric acid, and it is considered that it is difficult to reuse nitric acid.

In the factory of a large-scale liquid crystal display device in Japan, a chemical industry supply company, a water supply wastewater treatment company, and a glass substrate supply company have formed a large industrial center, and it has been established to transfer the fatigue fluid and the like to the chemical supply company. A method of recycling and other processes. However, there are many separate large liquid crystal display device factories that do not belong to this method. Therefore, representatively, there are many cases in which a high-concentration fatigue liquid generated in an amount of 70 tons/month to 150 tons/month is entrusted to an external waste liquid processing company. This commissioned processing expense is also expensive in the current situation, and with the strengthening of environmental protection regulations and the like, there is a tendency for the commissioned processing expenses to further increase.

The present invention has been made in view of the above problems, and it is desired to provide a waste liquid containing a high concentration of phosphoric acid, nitric acid, and acetic acid which can be produced by an etching step of aluminum or the like at a low cost, and it is not necessary to invest large amounts for this purpose. A method and a treatment device for a phosphate-based mixed acid waste liquid of a device. Further, it is desirable to provide a treatment method and a treatment apparatus which can directly use a product obtained by recovering phosphoric acid as a fertilizer.

The treatment method of the present invention is characterized in that, in a preferred embodiment, a waste liquid containing a concentration of 50% by weight or more of phosphoric acid, 0.1 to 15% by weight of nitric acid, and 0.5 to 20% by weight of acetic acid (A) When the treatment is carried out, at least the concentration of phosphoric acid and nitric acid is measured, and then ammonium dihydrogen phosphate (Diammonium phosphate; (NH ₄ ) ₂ HPO ₄ ) calculated according to the measurement is added to make it and phosphoric acid. The reaction with nitric acid is carried out, and phosphoric acid and nitric acid are recovered by the reaction, and a powder (C) of ammonium dihydrogen phosphate (NH ₄ H ₂ PO ₄ ) which can be used as a fertilizer is obtained.

The treatment apparatus (10) of the present invention is characterized in that it treats a waste liquid (A) containing phosphoric acid having a concentration of 50% by weight or more, 0.1 to 15% by weight of nitric acid, and 0.5 to 20% by weight of acetic acid. The apparatus (10) includes: a storage tank (20) for storing the waste liquid, a concentration measuring device (27) for measuring a concentration of phosphoric acid and nitric acid in the stored waste liquid (A), and a heating mechanism (12) And a solid-liquid mixing reactor (1) of the mixing and agitating mechanism (11), a measuring waste liquid (A), and a measuring input device (19) which is introduced into the solid-liquid mixing reactor (1), and an ammonium monohydrogen phosphate is introduced. The powder input device (17, 18) of the powder (B), and the control mechanism (3) composed of a microcomputer and/or a personal computer, and the control mechanism (3) performs the following operations: controlling the concentration measuring device (27) To automatically determine the concentration of phosphoric acid and nitric acid, and calculate the ammonium monohydrogen phosphate just reacted with phosphoric acid and nitric acid based on the concentration thus measured and the prescribed amount of the waste liquid (A) charged into the solid-liquid mixing reactor (1). The theoretical amount of (diammonium phosphate) is controlled by the powder input device (17, 18) so that the theoretical amount of monoammonium phosphate (phosphoric acid) The ammonium (B) powder (B) is charged into the solid-liquid mixing reactor (1), and the heating mechanism (12) and the mixing and agitating mechanism (11) are controlled so that the powder (B) of the monoammonium phosphate to be charged is heated. After the temperature is 55 to 85 ° C, the measurement input device (19) is controlled, and the waste liquid (A) of the predetermined input amount is dispersed on the powder (B) of monoammonium phosphate in the solid-liquid mixing reactor (1). Then, the heating mechanism (12) and the mixing and agitating mechanism (11) are controlled, and heating and mixing at 55 to 85 ° C are continued until the reaction is completed.

Low operating costs and equipment costs for processing, can recycle phosphorus The product obtained from acid and nitric acid is used almost directly as a fertilizer.

1‧‧‧ solid-liquid mixed reactor

3‧‧‧Control device

10‧‧‧Processing device

11‧‧‧Agitating blades (mixing and stirring mechanism)

12‧‧‧heating jacket (heating mechanism)

13‧‧‧Nozzles

14‧‧‧Export

15‧‧‧Exhaust piping

16‧‧‧Attracting exhaust mechanism

17‧‧‧Measuring hopper (powder input device)

17A‧‧‧Quantitative supply screw (quantitative supply machine)

18‧‧‧Quantum storage hopper (powder input device)

18A‧‧‧Vibration feeder

19‧‧‧Measurement pump (measurement input device)

20‧‧‧Fatigue fluid storage tank

21~24, 26‧‧‧Fatigue fluid piping

25‧‧‧Circulating pump

27‧‧‧Concentration measuring device

28‧‧‧Fertilizer storage tank

29‧‧‧ (exhaust) concentration meter

A‧‧‧Fatigue liquid (mixed acid waste)

B‧‧‧Phosphoric acid monoammonium phosphate (diammonium phosphate) powder

C‧‧‧Phosphorus dihydrogen phosphate powder (phosphoric acid fertilizer)

Fig. 1 is a block diagram showing a schematic configuration of a processing apparatus according to an embodiment.

Form for implementing the invention

The fatigue liquid (mixed acid waste liquid) discharged from the wet etching step of aluminum as described above for manufacturing a flat panel display or the like usually contains aluminum and molybdenum formed by etching in addition to high concentration of phosphoric acid and nitric acid/acetic acid. Stable composition without other ingredients. The composition of the constituents of the fatigue fluid (mixed acid waste liquid) often has almost constant characteristics, and thus the use of the main components other than acetic acid and moisture in the mixed acid waste liquid can be used as a phosphate fertilizer. That is, since the composition of the fatigue liquid is almost constant, the same phosphate fertilizer can be obtained under the same conditions.

According to the present invention, phosphoric acid and nitric acid in a fatigue liquid containing a high concentration of phosphoric acid, which is discarded from an aluminum etching processing apparatus at regular intervals, are subjected to a solid-liquid displacement reaction with ammonium monohydrogen phosphate powder. A powder containing a high concentration of ammonium dihydrogen phosphate and a small amount of ammonium nitrate was obtained by the solid-liquid displacement reaction. The powder can be directly used as a phosphate-based fertilizer, so that it is not required to process commissioned expenses or other processing costs, and can be commercialized and sold.

The acid dissociation constant pKa of nitric acid/phosphoric acid/acetic acid in the high-concentration fatigue liquid is NO ₃ ^- = -1.8, H ₂ PO ₄ ^- = 2.15, and CH ₃ COO ^- = 4.76, and the strength of the acid becomes small in this order. Therefore, nitric acid and phosphoric acid strongly bind to the ammonium ion, and a precipitate is formed as in the following Reaction Formula-1 and Reaction Formula-2. On the other hand, the equilibrium of the displacement reaction with acetic acid is largely shifted to the left, and almost all of the acetic acid is present as it is in the form of acetate ions.

Displacement reaction of ammonium monohydrogen phosphate with nitric acid (NH ₄ ) ₂ HPO ₄ +HNO ₃ → NH ₄ H ₂ PO ₄ +NH ₄ NO ₃ ↓--reaction formula-1

Displacement reaction of hydrazine monohydrogen phosphate with phosphoric acid (NH ₄ ) ₂ HPO ₄ +H ₃ PO ₄ → 2NH ₄ H ₂ PO ₄ ↓--reaction formula-2

Displacement reaction of ammonium monohydrogen phosphate with acetic acid (NH ₄ ) ₂ HPO ₄ +CH ₃ COOH ← → NH ₄ H ₂ PO ₄ +CH ₃ COONH ₄ --reaction formula-3

In a preferred embodiment, the theoretical equivalent amount of high concentration fatigue fluid is added to a known amount of heated monoammonium phosphate powder. The theoretical equivalent here is the theoretical equivalent of ammonium dihydrogen phosphate formed by the consumption of nitric acid and phosphoric acid according to the above Reaction Scheme-1 and Reaction Scheme-2. After the addition of the high-concentration fatigue liquid, heating and mixing are also continued to complete the displacement reaction. At the same time, acetic acid and water contained therein are removed by evaporation, thereby obtaining a mixed powder containing 90% or more of ammonium dihydrogen phosphate and a low concentration of ammonium nitrate. The acetic acid evaporated together with the water may be recovered by an adsorbent or the like, but may be exhausted to the atmosphere. According to the method and apparatus of the present invention, drainage or the like is not generated from the treatment equipment of the fatigue liquid at all, and environmental protection is emphasized. Further, it is possible to recover high-concentration phosphoric acid and nitric acid in the fatigue liquid as valuable articles such as fertilizer.

A preferred embodiment of the processing apparatus according to the present invention includes: a fatigue liquid storage tank, a mechanism for automatically measuring a concentration of phosphoric acid and nitric acid in the fatigue liquid, a solid-liquid mixing reactor including a heating mechanism and an exhaust mechanism, A device for measuring a monoammonium phosphate powder and introducing it into a powder measuring machine of a solid-liquid mixing reactor, an ammonium dihydrogen phosphate powder produced by storage, and a control mechanism using a microcomputer and/or a personal computer.

In the preferred embodiment, the fatigue liquid discarded from the aluminum etching processing equipment or the like is first stored in the fatigue liquid storage tank at regular intervals. Then, at least every time the new fatigue fluid is received, or each time the processing operation is started, at least the concentration of phosphoric acid and nitric acid in the fatigue fluid in the fatigue fluid storage tank is measured by the automatic measuring mechanism according to the control of the control mechanism, or Their total concentration. This measurement uses a concentration measuring device including, for example, a sensor having a glass electrode for measuring a phosphate ion concentration, a sensor for measuring a nitrate ion concentration by an ion electrode method, and the like. Then, the amount of the monoammonium phosphate powder which should be supplied to the solid-liquid mixing reactor is determined by the control means based on the measured value and the capacity of the solid-liquid mixing reactor. Further, on the basis of this, a theoretical amount of ammonium monohydrogen phosphate powder was measured by a powder measuring machine and supplied to a solid-liquid mixing reactor. For example, the ratio of the input amount to the theoretical amount may be 95 to 105%, preferably 97 to 103%, more preferably 98 to 102%, further preferably 99 to 101%, and more preferably 99.5. ~100.5%, particularly suitable for 99.7~100.3%. Then, after heating the ammonium monohydrogen phosphate powder to a predetermined temperature, the fatigue liquid is guided from the fatigue liquid storage tank to the upper portion of the solid-liquid mixing reactor, and is added dropwise or by stirring to the stirring ammonium monohydrogen phosphate. powder. Then, heating is continued in such a manner that the inside of the solid-liquid mixing reactor is maintained at a predetermined temperature, and acetic acid gas and water vapor generated from the heating reactor are discharged from the solid-liquid mixing reactor. The specified temperature here can be suitably set to, for example, 55 to 85 ° C, which is particularly suitable. It should be set to 60~80 °C.

In a preferred embodiment, a hygrometer or a water concentration meter may be provided in the exhaust pipe from the solid-liquid mixing reactor, and a water concentration meter and an acetic acid concentration meter may be provided. When the measured humidity or the water concentration is equal to or lower than a predetermined value, or when the measured values obtained by the water concentration meter and the acetic acid concentration meter are each equal to or lower than a predetermined value, it is possible to determine that the replacement reaction is completed. For example, when the humidity measured by the hygrometer sensor is reduced to a predetermined value in a range of preferably 40 to 60%, particularly preferably in a range of 45 to 55%, or by a moisture concentration meter When the value measured by the sensor and the acetic acid concentration meter sensor reaches a predetermined value within a range of preferably 0.2 to 2%, particularly preferably within a range of 0.3 to 1%, the completion of the replacement reaction can be judged. When it is judged that the displacement reaction is completed by the control from the control device, the heating and the agitation mixing are stopped, and the powder in the solid-liquid mixing reactor is discharged to be guided to the storage position. The storage position is suitably packaged in a container for powder shipment or transported to a bagging facility. For the measurement of the humidity or the water vapor concentration, for example, a dew point measurement type or a conductivity type sensor can be used. For the measurement of the acetic acid vapor concentration, for example, a gas sensor using a polymer material and a crystal oscillator can be used.

In a preferred embodiment, the fatigue liquid to be treated generally comprises 40 to 90% by weight of phosphoric acid, preferably 50 to 90% by weight, more preferably 50 to 80% by weight, further preferably 60 to 80% by weight, and preferably 0.1. ~15% by weight of nitric acid, more preferably 0.5 to 10% by weight, further preferably 1 to 5% by weight, particularly preferably 1 to 3% by weight, preferably 0.5 to 20% by weight of acetic acid, more preferably 2 to 20% by weight Further suitable for containing 5~15% by weight, especially suitable package Contains 7 to 13% by weight. The ions of the metal such as aluminum or molybdenum contained in the fatigue liquid can be removed by, for example, passing through a cylinder containing a cation exchange resin before the above treatment. Further, the fatigue liquid to be treated may be previously removed by filtration before the cation exchange or before introduction into the fatigue liquid storage tank.

Example

Next, the description will be specifically made according to an embodiment of the present invention. Fig. 1 is a block diagram showing an outline of a processing apparatus 10 for processing a phosphate-based mixed acid waste liquid to produce a fertilizer. The processing apparatus 10 includes a solid-liquid mixing reactor 1, a quantitative storage hopper 18, a measuring pump 19, a fatigue liquid storage tank 20, fatigue fluid pipings 21 to 26, a concentration measuring device 27, and a control device 3. The predetermined amount of the monoammonium phosphate powder B is supplied from the metering hopper 18 to the solid-liquid mixing reactor 1.

The solid-liquid mixing reactor 1 is provided with a stirring blade 11 and a heating jacket 12, and a nozzle 13 for dispersing a fatigue liquid is provided in an upper portion of the inside. Further, a discharge port 14 for discharging the product is provided at the lower portion, and an exhaust pipe 15 is connected to the upper portion. Further, in the middle of the exhaust pipe 15, a concentration meter 29 for measuring the concentration of moisture or acetic acid vapor in the exhaust gas is provided, and the concentration meter 29 is electrically connected to the control device 3. The exhaust pipe 15 is connected to a suction and exhaust mechanism 16 including a blower (air blower). The suction venting mechanism 16 can use an exhaust line provided in a usual factory equipment. In the specific example shown in the drawing, the solid-liquid mixing reactor 1 has a V-shaped cross section, and the screw-shaped inclined left and right agitating blades 11 perform the rotation around the axis of the agitating blade 11 and the central axis surrounding the solid-liquid mixing reactor 1. The revolution.

In addition, in the specific example shown, the quantitative storage hopper 18 is equipped with The door and the vibrating feeder 18A are discharged, and the ammonium monohydrogen phosphate powder previously added to the metering hopper 18 in a predetermined amount is supplied to the solid-liquid mixing reactor 1 once in a short time. Further, in the specific example shown, a measuring hopper 17 for supplying a predetermined amount of ammonium monohydrogen phosphate powder to the quantitative storage hopper 18 is provided. The measuring hopper 17 includes, for example, a metering machine 17A including screw blades as shown in the drawing, and can be precisely controlled by, for example, measuring the weight of the powder in the hopper. After the quantitative storage hopper 18 is supplied to the solid-liquid mixing reactor 1, a predetermined amount of ammonium monohydrogen phosphate powder is previously supplied into the quantitative storage hopper 18 by a quantitative supply device such as the measuring hopper 17 until the next injection.

On the other hand, the measuring pump 19 can use a diaphragm or a plunger type precision pump. The actions of the respective engines of the agitating blades 11, the heater device of the heating jacket 12, the measuring hopper 17, the metering hopper 18, the measuring pump 19, and the like can be collectively controlled by the control device 3, and the operator can also appropriately control .

The self-fatigue liquid storage tank 20 supplies the fatigue fluid through the fatigue liquid discharge pipe 23, the fatigue liquid supply pipe 22 connected to the downstream end thereof, and the measuring pump 19. The return pipe 21 is also connected to the downstream end of the fatigue liquid discharge pipe 23, and the fatigue liquid is circulated by the circulation pump 25 provided in the middle of the return pipe 21 or the fatigue liquid discharge pipe 23, and the respective acids in the fatigue liquid storage tank 20 are used. Stirring was carried out in such a way that the concentration was uniform. In the middle of the fatigue liquid discharge pipe 23, the measurement pipe 24 having a small diameter is branched and returned to the fatigue liquid storage tank 20. A concentration measuring device 27 is provided in the middle of the measuring pipe 24, and at least the concentration of phosphoric acid and nitric acid or the total concentration thereof is measured. It should be noted that the concentration measuring device 27 and the circulation pump 25 are electrically connected to the control device 3 and are control. The concentration measuring device 27 may be provided integrally with the above-described control device 3, and a part of the functions of the above-described control device 3 may be provided. Further, it is also possible to measure not only the concentration of phosphoric acid and nitric acid by the concentration measuring device 27 but also the water concentration and the acetic acid concentration.

Next, a description will be given of a preferred embodiment of the operation of the processing apparatus 1.

The fatigue liquid containing a high concentration of phosphoric acid is supplied to the fatigue liquid storage tank 20 by the piping 26 from the etching processing equipment. As described above, when a certain amount or more is stored in the fatigue liquid storage tank 20, the sensor is detected by the sensor or is known by the operator, and the circulation pump 25 is started. This fatigue liquid is circulated and supplied to the concentration measuring device 27 through the fatigue liquid discharge pipe 23 and the measurement pipe 24. After a predetermined cycle time has elapsed, the concentration measuring device 27 starts measuring the concentration of nitric acid, acetic acid, phosphoric acid, and water in the fatigue liquid by the control of the control device 3. Then, when the measurement is completed, the circulation of the fatigue liquid is stopped, and based on the measurement result, the theoretical amount (M) of the fatigue liquid required for converting a certain amount (W) of ammonium monohydrogen phosphate to ammonium dihydrogen phosphate is obtained. the amount. The predetermined amount (W) herein can be set in advance as an appropriate amount to be supplied to the solid-liquid mixing reactor 1, for example, as an optimum amount for stirring the powder.

On the other hand, in the quantitative storage hopper 18, the above-mentioned amount (W/Kg) of monoammonium phosphate powder can be measured in advance and stored. Then, the entire amount thereof was supplied to the solid-liquid mixing reactor 1, and stirring and heating were started. When it is detected by a temperature sensor or the like that the temperature of the powder in the solid-liquid mixing reactor 1 reaches about 70 ° C, the above-mentioned theoretical amount (M/1) of the fatigue liquid is fed to the solid-liquid mixing reaction via the measuring pump 19. Inside the device 1. Then, through the nozzle 13, is adding The fatigue liquid was dispersed and dispersed on the thermally stirred monoammonium phosphate powder to carry out a reaction. It should be noted that when the measuring pump 19 is operated, the circulation pump 25 can be operated in advance.

The acetic acid gas and the water vapor generated in the solid-liquid mixing reactor 1 can be discharged to the atmosphere through the exhaust pipe 15 and the suction and exhaust mechanism 16. In addition, in order to smoothly remove acetic acid and water, the inside of the solid-liquid mixing reactor 1 may be slightly set to a negative pressure by the suction/exhaust mechanism 16. For example, it can be set to a reduced pressure state of only 0.1 to 0.3 atmospheres lower than the atmospheric pressure. Further, nitrogen or air may be introduced from the bottom of the solid-liquid mixing reactor 1 as needed to promote the removal of acetic acid and water. Incidentally, the heating jacket 12 may be used for heating during the reaction, and the internal temperature of the solid-liquid mixing reactor 1 is particularly preferably maintained at 60 to 80 ° C, for example, about 70 ° C. Further, the suction exhaust gas or the like for removing acetic acid and water may be started after the reaction proceeds to some extent.

When the humidity of the exhaust gas is 50% or less by the concentration meter 29 provided in the middle of the exhaust pipe 15, or when it is detected that the water concentration and the acetic acid concentration in the exhaust gas are both 0.5% or less, the control device can be used. 3 judge the completion of the reaction, stop attracting exhaust gas and heating. That is, the humidity of 50% in the exhaust gas or the water content and the acetic acid concentration of 0.5% or less can be used as an index for completing the replacement reaction of monoammonium phosphate to ammonium dihydrogen phosphate.

In the following, the results of the recovery test for the phosphoric acid and nitric acid as the phosphate fertilizer will be described. In the following Tables 1 to 3, it is shown that a commercially available reagent is used, and a simulated phosphoric acid mixed acid waste liquid having a known concentration is prepared according to a composition different from each other, and the test is performed by the treatment apparatus 1 of the above embodiment. fruit. In addition, in Table 4 below, the fatigue liquid (phosphoric acid mixed acid waste liquid) of the etching liquid was taken from the factory of the liquid crystal display device, and the results of the test were similarly performed. As shown in Tables 1 to 3, the recovery rates of nitric acid and phosphoric acid in the waste liquid were both 99% or more. Only moisture and volatile acetic acid are discharged from the processing device 1. That is, moisture and volatile acetic acid are only released from the exhaust line to the existing exhaust system typically provided on plant equipment. Therefore, a method and a manufacturing apparatus for a fertilizer which is an environmentally friendly waste chemical containing a mixed acid of a phosphoric acid-based acid which does not generate industrial waste at all is obtained.

In each table, "theoretical amount of (NH ₄ ) ₂ HPO ₄ " is the theoretical amount of ammonium monohydrogen phosphate required to treat 100.0 g of the waste liquid, and according to the composition described in the second paragraph of each table, The reaction formula-1 and the reaction formula-2 are calculated. Here, the leftmost data column describes the amount calculated from the reaction formula-1 for nitric acid (HNO ₃ ) (the second data column from the left) and the amount calculated for the phosphoric acid (H ₃ PO ₄ ) (from left to right) The sum of the 3 data fields). On the other hand, "the theoretical yield of NH ₄ H ₂ PO ₄ " is the theoretical amount of ammonium dihydrogen phosphate which is calculated and expressed in the same manner. In addition, the "measured recovery rate" is a percentage obtained by dividing the yield of NH ₄ H ₂ PO ₄ ("measured NH ₄ H ₂ PO ₄ yield") by "the theoretical yield of NH ₄ H ₂ PO ₄ ". In Table 1, the measured recovery rate is described only at the lower end of the column of phosphoric acid (H ₃ PO ₄ ), which is a value obtained by correcting the "measured recovery rate" based on the amount of moisture ("0.06 g") in the product. It is considered that the values of "measured recovery rate" in Tables 2 to 4 are larger than those in Table 1 because the hygroscopicity of ammonium nitrate (NH ₄ NO ₃ ) is large. In other words, when the amount of water is corrected, it is considered that almost no theoretical amount is obtained, and it is considered that there is almost no case where the recovered nitric acid is evaporated and lost.

As described above, according to the embodiment of the present invention, the excellent effects summarized as follows are obtained. In a manufacturing apparatus of a flat panel display or other electronic device, an etching process of an aluminum film or the like on a glass substrate uses 50% or more of phosphoric acid as a main component and further contains an etching liquid having a high viscosity of nitric acid and acetic acid. It is divided into the following two types: a waste acid containing a high concentration of phosphoric acid and a thin cleaning waste liquid which is adhered to a glass substrate and washed in a water washing step are periodically renewed from the etching processing apparatus as a fatigue liquid. The amount of waste acid containing high-concentration phosphoric acid has increased with the increase in size of plants in recent years. The expenditures handled by the Ministry of Industrial Waste Processors increased. Further, this waste liquid is particularly difficult to be recovered and reused by a relatively simple device because of the reason of containing acetic acid or the like. The above-described treatment method and treatment apparatus utilize the characteristics that the components constituting the waste acid are often constant components, and the use of the main components other than acetic acid and moisture in the spent acid can be used as a phosphate fertilizer. By using this recycling technology, it is possible to eliminate the burden of the processing of the industrial waste disposal agent, and it is possible to obtain a large profit by selling the recovered phosphate fertilizer to the outside, and it is possible to reduce the processing and recovery equipment from the waste liquid without limitation. The amount of waste.

In the description of the above-described embodiment, the fatigue liquid (mixed acid waste liquid) discharged from the etching processing equipment for manufacturing a flat panel display has been described, but the fatigue liquid discharged from the etching processing equipment for manufacturing other semiconductor equipment and electronic equipment is also The exact same. In the description of the above embodiment, the case where the powder of monoammonium hydrogen phosphate is put into the solid-liquid mixing reactor 1 and heated sufficiently to disperse the fatigue liquid has been described. However, depending on the case, the powder of monoammonium phosphate preliminarily heated in the hopper and the fatigue liquid may be introduced almost simultaneously. Further, in the above description of the embodiment, the case where the amount of the monoammonium phosphate monophosphate powder is fixed and the theoretical amount of the fatigue liquid (mixed acid waste liquid) is added has been described. However, the fatigue liquid (mixed acid waste liquid) may be fixed in reverse. The amount of input was put into a calculated amount of ammonium monohydrogen phosphate powder.

In the above description of the embodiment, the case where the solid-liquid mixing reactor 1 is vertical, that is, the central axis is oriented in the vertical direction has been described. However, the horizontal type, that is, the shaft of the agitator or the like may be arranged in the horizontal direction. For example, a plurality of blades may be rotated about a horizontal axis to perform agitation.

In the above description of the embodiment, the measurement device for inputting the fatigue liquid in the solid-liquid mixing reactor 1 has been described as the measurement pump 19. However, for example, a solenoid valve, a cock, and a weight measuring device may be included. After being stored in a container at a predetermined weight, it is sent to the solid-liquid mixing reactor 1. Further, although the case where the powder of monoammonium phosphate is introduced into the solid-liquid mixing reactor 1 from the quantitative storage hopper 18 has been described, it may be directly introduced into the solid-liquid mixing reactor 1 from the measuring hopper 17.

Claims (10)

A treatment method for treating a waste liquid containing phosphoric acid having a concentration of 50% by weight or more, 0.1 to 15% by weight of nitric acid, and 0.5 to 20% by weight of acetic acid, and measuring the concentration of phosphoric acid and After the concentration of nitric acid or the total concentration thereof, an amount of ammonium monohydrogen phosphate (diammonium phosphate) calculated based on the thus measured concentration and the amount of the waste liquid input is added to react with phosphoric acid and nitric acid. The reaction is used to recover phosphoric acid and nitric acid, and a powder of ammonium dihydrogen phosphate which can be used as a fertilizer is obtained. The treatment method according to claim 1, wherein a substance in a powder form is used as ammonium monohydrogen phosphate, wherein a powder of monoammonium phosphate is used in a solid-liquid mixed reactor having a heating mechanism and a stirring mixing mechanism. After the mixture was heated in a solid-liquid mixing reactor and heated, the waste liquid was dispensed into a powder of ammonium monohydrogen phosphate, and then heating and stirring were continued to obtain a powder of ammonium dihydrogen phosphate. According to the treatment method of claim 1 or 2, after the powder of monoammonium hydrogen phosphate is charged and heated to 55 to 85 ° C, heating and stirring mixing in the temperature range are continued. The treatment method according to claim 1 or 2, wherein the acetic acid and the water are discharged by an exhaust pipe for performing exhaust gas from the reaction site. According to the processing method of claim 4, the moisture vapor concentration or the humidity in the exhaust gas discharged through the exhaust pipe is measured, and the value of the obtained water vapor concentration is in the range of 0.2 to 2%, or the value of the humidity. When the temperature reaches 40~60%, judge the reaction is completed, or determine the acetic acid vapor concentration and water vapor concentration. When the values of the obtained acetic acid vapor concentration and the water vapor concentration were in the range of 0.2 to 2%, respectively, it was judged that the reaction was completed, and heating and stirring mixing were stopped. According to the processing method of claim 2, when the powder of monoammonium hydrogen phosphate is charged, the calculated amount of the powder of monoammonium phosphate is measured in advance and stored in a quantitative storage tank, and the solid storage tank is solidified. The liquid mixing reactor was charged in the entire amount at a time, and when the waste liquid was charged, the powder of monoammonium hydrogen phosphate was stirred and mixed, and the waste liquid was supplied and dispersed as the stirring and mixing progressed. A processing apparatus for treating a waste liquid containing phosphoric acid having a concentration of 50% by weight or more, 0.1 to 15% by weight of nitric acid, and 0.5 to 20% by weight of acetic acid, wherein the treatment apparatus is provided a storage tank for storing the waste liquid, a concentration measuring device for measuring a concentration of phosphoric acid and nitric acid in the stored waste liquid, a solid-liquid mixed reactor having a heating mechanism and a mixing and agitating mechanism, measuring waste liquid, and a measurement input device that is introduced into a solid-liquid mixing reactor, a powder input device that inputs a powder of monoammonium hydrogen phosphate, and a control mechanism; and the control unit performs an operation of controlling the concentration measuring device to automatically measure the concentrations of phosphoric acid and nitric acid, Calculating the theoretical amount of ammonium monohydrogen phosphate (diammonium phosphate) which reacts with phosphoric acid and nitric acid according to the concentration thus measured and the prescribed input amount of the waste liquid into the solid-liquid mixing reactor, and controlling the powder input device So that the theoretical amount of ammonium monohydrogen phosphate (diammonium phosphate) powder is put into the solid-liquid mixing reactor, Controlling the heating mechanism and the mixing and agitation mechanism such that the powder of the monoammonium hydrogen phosphate charged is heated to 55 to 85 ° C, and then controlling the measuring input device to disperse the prescribed amount of the waste liquid in the solid-liquid mixing reaction On the powder of ammonium monohydrogen phosphate in the apparatus, the heating mechanism and the mixing and stirring mechanism are then controlled, and heating and mixing and stirring at 55 to 85 ° C are continued until the reaction is completed. The processing apparatus according to claim 7 is characterized in that the middle of the exhaust pipe from which the exhaust gas from the inside of the solid-liquid mixing reactor is sent is provided for measuring the moisture vapor concentration or humidity in the exhaust gas, or the acetic acid vapor concentration and the water vapor concentration. Exhaust gas concentration meter; the control mechanism determines that the reaction is completed when the value of the obtained water vapor concentration reaches 0.2 to 2%, or the value of the obtained humidity is in the range of 40 to 60%, or When the values of the acetic acid vapor concentration and the water vapor concentration were respectively in the range of 0.2 to 2%, it was judged that the reaction was completed, and the heating and stirring were stopped. The processing apparatus according to claim 7 or 8, comprising a nozzle for spraying the waste liquid into the solid-liquid mixing reactor. The processing apparatus according to claim 7 or 8, wherein the powder input device comprises: a quantitative storage tank, and a measurement supply device for measuring and supplying the powder of monoammonium phosphate to the quantitative storage tank; the control mechanism controls the measurement In the supply device, the theoretical amount of the ammonium monohydrogen phosphate powder is previously put into the quantitative storage tank, and then the discharge mechanism of the quantitative storage tank is controlled, and the entire amount of the powder located inside the quantitative storage tank is once put into the solid solution. Mix in the reactor.