WO2019045130A1 - Method for preparing high-purity ammonium dihydrogen phosphate using ammonium phosphate waste liquid - Google Patents

Abstract

The present invention relates to a method for preparing ammonium dihydrogen phosphate using an ammonium phosphate waste liquid. According to the present invention, a powder state of ammonium dihydrogen phosphate having purity of 98 %(w/w) or more can be prepared from the ammonium phosphate waste liquid. Furthermore, environmental contamination can be reduced by recycling the ammonium phosphate waste liquid, and ammonium dihydrogen phosphate can be obtained at high yield and low cost by a simple preparation process.

Description

Process for producing high purity ammonium dihydrogen phosphate using ammonium phosphate waste solution

The present invention relates to a method for producing high purity ammonium dihydrogen phosphate using an ammonium phosphate waste liquid.

Liquid waste is inevitably generated and discharged according to industrial activities such as manufacturing, processing and cleaning processes of various products. In the case of acidic or basic liquid waste (waste liquid) . The acidic or basic waste liquid generated in the electronic industry is generated in washing process of various parts, semiconductor and LCD etching process, and contains a large amount of various harmful substances. Therefore, when such acidic or basic waste liquid is discharged as it is, , Odor generation, and the like, as well as economical loss due to waste of recoverable resources. Therefore, development of treatment and recycling technology for solving the problem is important.

The present invention relates to a method for recycling ammonium wastewater, which is one of such liquid wastes, and in particular, to a method for producing ammonium dihydrogenphosphate from ammonium wastewater. Monoammonium phosphate (MAP) is an ammonium tribasic acid, also known as ammonium monophosphate or ammonium primary phosphate. Ammonium dihydrogen phosphate is a colorless crystalline form and is used as an extinguishing agent, a dye dispersant, an enamel glaze, a flame retardant, a matting carbonizer, a fire retardant, a yeast culture agent and the like for medical purposes, such as cavity prevention agent, penicillin, streptomycin, . In addition, as a food additive, the second dibasic ammonium phosphate is used as yeast growth, fermentation enhancement, fermented food and synthetic swelling agent raw material.

In the present invention, ammonium phosphate waste liquid to be a raw material is obtained by neutralizing ammonia gas generated in a semiconductor production process with a phosphoric acid solution. Since the phosphoric acid solution is used for simply collecting ammonia gas, a low-cost phosphoric acid solution can be used. For example, a mixed phosphoric acid waste solution (composed of phosphoric acid, nitric acid and acetic acid) generated in a semiconductor production process can be used. The production of ammonium dihydrogen phosphate which can be used for various purposes by using the ammonium phosphate waste liquid as a raw material can solve the environmental pollution problem caused by the waste liquid and has an advantage that resources can be recycled.

As a method for producing ammonium dihydrogen phosphate in the past, a method of producing an ammonium monophosphate compound having a purity of 98% or more from an etching process waste liquid (Korean Patent Registration No. 10-0436173), a method of producing a phosphate ammonium hydrogen phosphate powder by treating a phosphate- (Japanese Laid-Open Patent Application No. 2016-16375) and the like are disclosed in the prior art.

However, the method of producing the ammonium dihydrogen phosphate compound as an etching process waste solution is not economical in terms of cost as compared with the method using the ammonium phosphate waste liquid of the present manufacturing method because a large amount of expensive pure ammonia is used. In addition, when the phosphorus acid mixed wastewater is treated to obtain a powder of ammonium dihydrogen phosphate, ammonium ion is added to the phosphoric acid-1-adduct ion to form a salt to precipitate ammonium dihydrogen phosphate. On the contrary, The method using the saturated ammonium phosphate waste solution and the pH range for precipitation do not exist, and the reproducibility of the composition ratio of phosphoric acid and ammonium in the ammonium dihydrogen phosphate is unclear.

On the other hand, a method for producing high purity ammonium dihydrogenphosphate in which the pH is adjusted by adding a phosphoric acid solution to recycle the ammonium phosphate waste liquid and then concentrating under reduced pressure and cooling to induce precipitation has not been disclosed yet.

It is an object of the present invention to provide a method for producing high purity ammonium dihydrogen phosphate using an ammonium phosphate waste liquid.

The present invention

(1 step) adding a phosphoric acid solution to the ammonium phosphate waste solution to adjust the pH to 4.5 to 5.5;

(Step 2) Concentrating the waste solution obtained in Step 1 under reduced pressure until about 40 to 60% of the total weight of the waste solution is obtained, thereby obtaining a concentrated solution;

(Step 3) The concentrate of the two steps is transferred to a cooling vessel at 10 to 30 占 폚 and stirred to precipitate ammonium dihydrogen phosphate;

(Step 4) To remove acetic acid contained in ammonium dihydrogen phosphate precipitated in step 3, methanol is added to convert acetic acid to methyl acetate; And

(5) drying the ammonium dihydrogenphosphate in a drier, and removing methyl acetate from the ammonium fluoride waste liquid. The present invention relates to a method for producing high purity ammonium dihydrogenphosphate using a low concentration ammonium phosphate waste liquid.

The ammonium phosphate waste solution used in the above step is produced by neutralizing the ammonia gas generated in the semiconductor production process with a mixed phosphoric acid waste solution (composed of phosphoric acid, nitric acid, acetic acid, etc.) derived from the semiconductor process. At this time, the amount of ammonium phosphate waste solution is 20 ~ 30% of phosphorus (P) component, 6 ~ 8% of nitrogen (N) component and 0.2 ~ 2%, the pH was 6.0 to 6.8, and the specific gravity was 1.2 to 1.3.

A phosphoric acid solution is added to the ammonium phosphate waste solution to adjust the pH to 4.5 to 5.5. If the pH is less than 4.5, the amount of phosphoric acid should be added, which is not economical. If the pH is more than 5.5, the reaction is not sufficiently carried out or by-products are produced, and the yield and purity of the final ammonium phosphate dihydrogen phosphate are low I do not.

Although the concentration of the phosphoric acid solution added in the first step is preferably high, it is possible to produce ammonium hydrogen phosphate at a very low cost by using a low-cost recycled phosphoric acid having a low concentration of 60 to 85% of the phosphoric acid solution.

The waste solution obtained in the above two steps is decompressed to a minus 0.08 to 0.1 MPa (0.210 to 0.013 atm, 160 to 10 mmHg) until the residual amount is about 40 to 60% of the total weight, Lt; / RTI >

In the above three steps, the concentrate is stirred at 10 to 30 DEG C to precipitate ammonium dihydrogenphosphate. However, even if the reaction is carried out at a reaction temperature of less than 10 ° C or more than 30 ° C or at a reaction temperature of 10 to 30 ° C, the reaction time is terminated in a state in which ammonium dihydrogen phosphate is not sufficiently precipitated If the yield is low, it is not economical.

In step 4 above, methanol is used to remove the acetic acid contained in the solid ammonium hydrogen dihydrogen phosphate. The removal of acetic acid is preferably carried out after ammonium dihydrogenphosphate precipitates in a solid state. When methanol is added to remove acetic acid in a solution state before ammonium dihydrogenphosphate precipitates in a solid state, toxicity It is not preferable because it causes gas.

In step 5 above, ammonium dihydrogen phosphate is dried in a drier at a temperature of 90 DEG C or less, preferably 60 to 90 DEG C to remove methyl acetate and moisture on the ammonium dihydrogen phosphate to obtain ammonium dihydrogen phosphate powder do. At this time, when the drying is carried out at a temperature higher than 90 ° C., ammonium hydrogen phosphate decomposes to generate ammonia gas, which causes problems in the discharge of waste water.

The present invention relates to a method for producing ammonium dihydrogen phosphate using an ammonium phosphate waste liquid, and can produce powdery ammonium p-hydroxyphenylacetate from an ammonium phosphate waste liquid. In addition, recycling the ammonium phosphate waste solution not only reduces environmental pollution, but also has the advantage of obtaining ammonium dihydrogen phosphate with high yield and low cost by a simple manufacturing process.

1 is a flowchart showing a method for producing ammonium p-hydroxyphosphate of high purity using an ammonium phosphate waste solution according to an embodiment of the present invention.

Fig. 2 shows the composition of the elements of the sample through the energy dispersive X-ray spectroscopy.

FIG. 3 (A) shows the detection of cations according to elution time of a standard sample through ion chromatography.

FIG. 3 (B) shows the detection of anions according to elution time of a standard sample through ion chromatography.

4 (A) shows the detection of phosphate ion (PO ₄ ^3- ) according to elution time of the sample of Experimental Example 3 through ion chromatography.

FIG. 4 (B) shows the detection of ammonium ion (NH ₄ ⁺ ) according to elution time of the sample of Experimental Example 3 through ion chromatography.

Hereinafter, preferred embodiments of the present invention will be described in detail. However, the present invention is not limited to the embodiments described herein but may be embodied in other forms. Rather, the intention is to provide an exhaustive, complete, and complete disclosure of the principles of the invention to those skilled in the art.

<Experimental Example 1> Determination of composition of ammonium waste solution of ammonium phosphate>

In the present invention, the ammonia gas generated in the semiconductor manufacturing process is neutralized with phosphoric acid and collected, and the resulting ammonium phosphate waste solution is collected for use as a raw material. The waste liquid was identified by the composition of the ingredients in Table 1. On the other hand, the ammonium phosphate waste solution contains phosphorus (P) in an amount of 20 to 30%, nitrogen (N) in an amount of 6 to 8%, and acetic acid 0.2 ~ 2% of the total.

< Experimental Example  2. Ammonium dihydrogenphosphate  Manufacturing>

(1) Example 1 and Comparative Example 1

800 g of ammonium phosphate waste solution whose composition was confirmed as shown in Table 1 was placed in a round flask of a vacuum rotary centrifuge of 1 L capacity and 85% phosphoric acid solution was mixed while rotating at a speed of 30 to 45 rpm to adjust the pH to the values shown in Table 2 1-1 to 1-3 and Comparative Examples 1-1 to 1-4. In addition, 85% phosphoric acid solution was not added to Comparative Example 1-4.

Thereafter, the pressure is reduced to minus 0.08 to 0.1 MPa (0.210 to 0.013 atmosphere (atm), 160 to 10 mmHg) and then concentrated at 50 to 75 ° C for 5 to 7 hours to about 50 to 55% . Thereafter, the concentrate is sufficiently cooled in a cooling vessel at 10 to 30 DEG C to precipitate ammonium dihydrogen phosphate.

The precipitated ammonium dihydrogen phosphate crystals were dehydrated in a centrifuge and then the precipitated ammonium dihydrogenphosphate precipitated to remove acetic acid contained in the crystals was converted into methyl acetate by adding methanol to the methyl acetate and heated in a vacuum drier at a temperature of 60 to 90 Lt; 0 &gt; C for 2 to 3 hours.

(2) the compositional contents of phosphate and ammonium ion according to the pH conditions of Example 1 and Comparative Example 1

The compositional contents of the ammonium dihydrogenphosphate prepared in the pH range of 3.5 to 6.5 were measured by ion chromatography and the results are shown in Table 3. The results are shown in Table 3, Theoretical compositional contents of the components are as shown in the last row of Table 3.

The method of Examples 1-1 to 1-3 of the present invention is a case of producing ammonium dihydrogen phosphate by adjusting the pH of the ammonium phosphate solution to 4.5 to 5.5 by adding a 85% 1 to 1-4 are cases where ammonium dihydrogen phosphate is produced at different pH conditions. The results shown in Table 3 confirm that the phosphoric acid ion (PO ₄ ^3- ) compositional ratio of the ammonium dihydrogen phosphate prepared at about pH 5.0 in Example 1-2 is the most similar to the phosphoric acid composition value of the theoretical ammonium dihydrogen phosphate I could.

<Experimental Example 3> Analysis of components of ammonium dihydrogenphosphate manufactured in a factory>

8 m ^{3 of} factory 6.6 Tons of phosphorus ammonium phosphate having the same composition as shown in Table 1 was added to a 8-lauge condenser and stirred, and 0.4 T of 85% purified phosphoric acid was added to adjust the pH to 5.0 as in Example 1-2. It is possible to obtain 50 to 55% of the total weight for 5 to 7 hours under the condition of 75 DEG C, minus 0.08 to 0.1 MPa (0.210 to 0.013 atmosphere (atm), 160 to 10 mmHg) Concentrate until time. Thereafter, the concentrate is sufficiently cooled in a cooling vessel at 10 to 30 DEG C to precipitate ammonium dihydrogen phosphate.

The precipitated ammonium dihydrogen phosphate crystals were dehydrated in a centrifuge and then the precipitated ammonium dihydrogenphosphate precipitated to remove acetic acid contained in the crystals was converted into methyl acetate by adding methanol to the methyl acetate and heated in a vacuum drier at a temperature of 60 to 90 Lt; 0 &gt; C for 2 to 3 hours to obtain ammonium dihydrogen phosphate crystals from which moisture and methyl acetate had been removed. The composition and composition of ammonium dihydrogen phosphate obtained from the production plant were confirmed using the following analyzing apparatuses and methods.

<Experimental Example 4> Analysis of components of ammonium dihydrogenphosphate>

(1) Identification of molecular structure of ammonium dihydrogenphosphate by X-ray diffractometer (XRD)

In order to confirm the crystallinity of ammonium dihydrogenphosphate, the sample of Experimental Example 3 was uniformly prepared in powder form and mounted on a Rigaku Ultima IV X-ray diffractometer to obtain XRD data. When the position and intensity of the diffraction peak of the sample of Experimental Example 3 are compared with the XRD reference pattern of the reference compound of ICDD (International Center for Diffraction Data), the crystal structure of the sample can be predicted by the following mixture of Table 4 .

(2) Elemental analysis: EA )

Experimental Example 3 on Carbon, Nitrogen, Hydrogen and Sulfur The elemental analysis of the sample was carried out to determine the proportion of the elements of the sample 3 and to confirm the reproducibility of the experimental results The sample of Experimental Example 3 was repeated three times in the same manner. Elemental analysis was performed using Thermo Scientific Flash 2000.

Table 5 shows the elemental analysis results for carbon, nitrogen, hydrogen, and sulfur of the sample of Experimental Example 3. The results of the analysis show that carbon and sulfur are almost absent and nitrogen and hydrogen are 13.3 wt% and 5.43 wt %. &Lt; / RTI &gt; Converting the content percent of the nitrogen and hydrogen as mole are each 0.009 mol and 0.053 mol, N: H = 0.009 : 0.053 = 1: 6 to dihydrogenphosphate of ammonium (NH ₄ H ₂ PO ₄₎ non-1 of nitrogen and hydrogen in the : 6.

(3) Elemental analysis of ammonium dihydrogenphosphate using energy dispersive X-ray fluorescence spectrometer ( EDS)

Experimental Example 3 with Energy Dispersive X-ray Spectroscopy (EDS) Experimental Example 3 The surface of a sample was uniformly prepared and then the surface of the sample was measured using a scanning electron beam in a vacuum state. The results are shown in Fig. 2 shows that the sample of Experimental Example 3 is consistent with the composition of the ammonium dihydrogen phosphate (NH ₄ H ₂ PO ₄ ) composed of elements of nitrogen (N), oxygen (O) and phosphorus (P) (Na) and potassium (K) were contained as impurities. However, hydrogen (H) can not be measured by EDS, so that no peak of hydrogen appears.

4, an inductively coupled plasma emission analyzer (Inductively coupled plasma optical emission spectrometer: ICP-OES), the quantitative analysis of phosphorus (P) using a

Quantitative analysis and reliability evaluation were performed using standard solutions of phosphorus (P). The concentration of the standard solution was prepared at the concentrations of 0.1, 1 and 10 mg / kg, and the solution of the sample 3 was subjected to ultrasonic treatment for 3 minutes so that the ammonium dihydrogen phosphate completely dissolved. Standard and sample solutions were performed with a Thermo Fisher Scientific iCAP 7400 Duo Inductively Coupled Plasma Spectrometer, and the analytical conditions for ICP-OES are shown in Table 6.

(P) standard solution was prepared, and the relationship between the concentration and the peak intensity was set to a confidence curve of 99.99% according to the least squares method. Experimental Example 3 The content ratio of phosphorus (P) was measured 26.7%. This result was consistent with the theoretical content ratio of phosphorus (P) in ammonium dihydrogen phosphate to 26.9% within the error range of the equipment.

(5) Composition analysis of ammonium dihydrogenphosphate by ion chromatography (IC)

In order to quantitatively identify anions and cations, F ^- , Cl ^- , Br ^- , NO ₃ ^- , PO ₄ ^3- and SO ₄ ^2- are used as anions and Na ⁺ , NH ₃ ⁺ , K ⁺ , Mg ^{2 +} And Ca ^{2 +} were selected to prepare 5 ppm standard solutions, and the standard solutions were measured for retention times in the anion column and the cation column of ion chromatography. Experimental Example 3 A sample was dissolved by using ultrasonic waves and filtered using a syringe filter to prepare a sample solution. Using Metrohm ICFLEX 930 ion chromatography, standard solutions and sample solutions were compared to identify individual ions.

4 (A) and 4 (B) show the detection of cations and anions according to the elution time of the standard sample by ion chromatography, respectively, and FIGS. 4 (A) and 4 The detection of phosphate ion and ammonium ion over time is shown in Table 7 as the composition weight (wt%).

Experimental Example 3 Obtained from Ion Chromatography The compositions of phosphorus ion and ammonium ion in the ammonium dihydrogen phosphate (82.5% and 16.6%) were 82.6% and 15.7%, respectively, compared with the theoretical composition amounts of ammonium dihydrogen phosphate And the difference between them is almost the same within the error range.

(6) Moisture analysis (Karl Fischer titration)

EXPERIMENTAL EXAMPLE 3 The sample was sealed in a cylindrical container, and moisture content at the operating temperature was measured three times in Meotrhm 860 KF Thermoprep Moisture Analyzer and 852 Titrando. The results are shown in Table 8.

As can be seen from Table 8, the water content of the Experimental Sample 3 is less than 0.5 wt%.

(7) Analysis result

The sample of Experimental Example 3 produced by the manufacturing method of the present invention was analyzed by the X-ray diffraction (XRD), elemental analysis (EA) and energy dispersive X-ray spectroscopy (EDS) This hydrogen ammonium was confirmed to be correct. The ammonium dihydrogen phosphate contained 26.7% of phosphorus through inductively coupled plasma emission spectrometry (ICP-OES), and the constituent ions of PO ₄ ^3- and NH ₄ ⁺ through ion chromatography (IC) were 82.5 wt% and 16.6 wt%, respectively. It was also confirmed that the ammonium dihydrogen phosphate was a high purity crystal having a purity of 98 wt% or more and a moisture content of less than 0.5 wt%.

Claims (4)

(1 step) adding a phosphoric acid solution to the ammonium phosphate waste solution to adjust the pH to 4.5 to 5.5; (Step 2) Concentrating the waste solution obtained in Step 1 under reduced pressure until about 40 to 60% of the total weight of the waste solution is obtained, thereby obtaining a concentrated solution; (Step 3) The concentrate of the two steps is transferred to a cooling vessel at 10 to 30 占 폚 and stirred to precipitate ammonium dihydrogen phosphate; (Step 4) To remove acetic acid contained in ammonium dihydrogen phosphate precipitated in step 3, methanol is added to convert acetic acid to methyl acetate; And (5 steps) removing methyl acetate while drying ammonium dihydrogen phosphate in a drier; Wherein the ammonium bicarbonate solution is a mixture of ammonium bicarbonate and ammonium bicarbonate. The method according to claim 1, Wherein the ammonium phosphate waste solution comprises 20 to 30% of phosphorus (P), 6 to 8% of nitrogen (N), and 0.2 to 2% of acetic acid. The method according to claim 1, Wherein the waste solution is concentrated at a reduced pressure of 0.08 to 0.1 MPa (0.210 to 0.013 atmosphere (atm), 160 to 10 mmHg) at 50 to 75 ° C in the above two steps. The method according to claim 1, Wherein the drying in step 5 is performed at 60 to 90 占 폚.

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