Quick safety judgment and quantitative adjustment method for pH value of ammonium nitrate hot concentrated solution

Abstract

The invention discloses an ammonium nitrate hot concentrated solution pH value safety rapid determination and quantitative adjustment method, and belongs to the field of ammonium nitrate solution safety control, and the method comprises the following steps: preparing ammonium nitrate diluents with different pH values by using nitric acid or ammonia water; establishing a mathematical equation 1 of the pH value of the normal-temperature diluent and the dosage of the pH value regulator; preparing the dry basis with different pH values into a high-concentration sample, heating the high-concentration sample into liquid, and measuring the pH value; establishing a mathematical equation 2 of the pH value of the high-temperature hot concentrated solution and the dosage of the pH value regulator; further establishing a mathematical equation 3 of the pH value of the ammonium nitrate hot concentrated solution and the pH value of the normal-temperature diluent under the high-temperature condition; setting key control parameters of the pH value of the hot concentrated solution at high temperature according to the safety control range of the pH value at normal temperature; and monitoring the pH value of the hot concentrated ammonium nitrate solution in the high-temperature storage tank in a static state in real time, and performing corresponding adjustment treatment. According to the invention, based on the online monitoring result of the pH value of the ammonium nitrate hot concentrated solution, the safety judgment of the pH value is realized, and quantitative adjustment or emergency cut-off is carried out.

Description

Technical Field

[0001] The invention belongs to the field of ammonium nitrate solution safety control, and in particular relates to a method for rapid safety determination and quantitative regulation of pH value of a hot concentrated ammonium nitrate solution. Background Art

[0002] At present, the pH value test method of ammonium nitrate solution at home and abroad is to transfer the hot concentrated ammonium nitrate solution in the storage tank to a room temperature environment and dilute it to 10% concentration with deionized water for testing. The existing technology involves multiple links such as sampling, transfer, dilution and testing, and the detection process is long, which is not conducive to the real-time monitoring of the pH value of the ammonium nitrate solution.

[0003] In the prior art, CN107703254A discloses a method for detecting whether the pH value of ammonium nitrate solution in emulsion explosive is qualified, which is a method for detecting using a pH indicator. This method cannot be automated and continuous, and has low labor efficiency. CN104731122A discloses a method for detecting and adjusting the pH value of ammonium nitrate solution for the production of emulsion explosives, which is an online monitoring method for ammonium nitrate solution. This method cools the ammonium nitrate solution to about 90°C and detects it in a flowing state. At this temperature, the temperature and concentration have a great influence on the pH value of ammonium nitrate. The direct test results of the solution have no guiding significance for storage safety control. At the same time, a large amount of crystals will appear in the ammonium nitrate solution, and the flowing state has a great influence on the pH value of the ammonium nitrate solution. This test method cannot obtain accurate and stable results.

[0004] In summary, the current method for testing the pH value of ammonium nitrate solution at home and abroad is to transfer the hot concentrated ammonium nitrate solution in the storage tank to a room temperature environment and dilute it with deionized water to a concentration of 10% for testing. The existing technology involves multiple links such as sampling, transfer, dilution and testing. The detection process is long, which is not conducive to the automation and continuous monitoring of the pH value of ammonium nitrate solution, and the labor efficiency is low. Some existing patents have optimized the test process of offline analysis, but the test steps are still complicated; another part of the patents invented an online testing method, but this method can only reflect the fluctuation of the pH value of the sample, and cannot determine whether it deviates from the normal range. It cannot realize the monitoring and early warning function, and has limited practical significance. Summary of the invention

[0005] In order to solve the above problems, the present invention proposes a method for rapid safety judgment and quantitative adjustment of the pH value of a hot concentrated ammonium nitrate solution, which realizes rapid safety judgment of the pH value of an ammonium nitrate solution under high temperature conditions and can realize quantitative accurate adjustment and emergency cut-off function when the pH value deviates.

[0006] The technical solution of the present invention is as follows:

[0007] A method for quickly determining and quantitatively adjusting the pH value safety of a hot concentrated ammonium nitrate solution comprises the following steps:

[0008] Step 1, preparing ammonium nitrate dilutions with different pH values ​​using nitric acid or ammonia pH regulator;

[0009] Step 2, the amount of pH regulator added is arranged in mg / kg, a curve is drawn according to the test results, and a mathematical equation 1 between the pH value of the dilution solution and the amount of pH regulator used under normal temperature conditions is established;

[0010] Step 3, according to the amount of regulator in equation 1, prepare ammonium nitrate samples with target concentrations and different pH values, heat them until they are completely melted and test the pH value;

[0011] Step 4, drawing a curve according to the measurement results of step 3, and establishing a mathematical equation 2 for the pH value of the hot concentrated ammonium nitrate solution and the amount of the regulator under high temperature conditions;

[0012] Step 5, according to equation 1 and equation 2, calculate the mathematical equation 3 of the pH value of the hot concentrated ammonium nitrate solution under high temperature conditions and the pH value of the diluted ammonium nitrate solution under normal temperature conditions;

[0013] Step 6: according to the safe control range of pH value at room temperature, set the key control parameter of pH value of hot concentrated ammonium nitrate solution under high temperature conditions;

[0014] Step 7: Use a high-temperature pH meter to detect the pH value of the hot concentrated ammonium nitrate solution in the storage tank in a static state, and adjust the pH value accordingly according to the specific situation.

[0015] Furthermore, the mass concentration of the ammonium nitrate dilution in step 1 is 10%; and the target concentration in step 3 is about 90%.

[0016] Furthermore, the specific process of step 1 is as follows:

[0017] Step 1.1, dissolving 5 g of dry ammonium nitrate solid into 45 g of deionized water to prepare 50 g of ammonium nitrate solution with a mass concentration of 10%;

[0018] Step 1.2, use a pH meter to test the pH value of the solution, accurate to 2 decimal places;

[0019] Step 1.3, using different concentrations of nitric acid or ammonia water to adjust the pH value of the corresponding ammonium nitrate solution;

[0020] Step 1.4, record the concentration and amount of the pH adjuster used to adjust to the target pH value.

[0021] Furthermore, in step 1.3, when nitric acid is selected as the pH regulator, the ammonium nitrate solution is adjusted to a pH value range of 2 to 5 using nitric acid pH regulators of different concentrations, and the amount of nitric acid added is controlled not to exceed 1% of the volume of the original solution; when ammonia water is selected as the pH regulator, the ammonium nitrate solution is adjusted to a pH value range of 5 to 7 using ammonia water pH regulators of different concentrations.

[0022] Furthermore, in step 2, the establishment of mathematical equation 1 includes the following two cases:

[0023] When the pH value of ammonium nitrate solution is between 2 and 5, a quantitative mathematical equation 1-1 between the pH value of ammonium nitrate dilution and the amount of nitric acid added under normal temperature conditions is established. The equation is as follows:

[0024] y1=-0.899lg(a) + 2.0177 (1-1)

[0025] Wherein, a is the amount of nitric acid added, in ml / kg; y1 is the pH value after dilution at room temperature;

[0026] When the pH value of the ammonium nitrate solution is between 5 and 7, a quantitative mathematical equation 1-2 between the pH value and the amount of ammonia added under normal temperature conditions is established. The equation is as follows:

[0027] z1 = 0.9639lg(b) + 7.7870 (1-2)

[0028] Wherein, b is the amount of ammonia water added, in ml / kg; z1 is the pH value after dilution at room temperature.

[0029] Furthermore, the specific process of step 3 is as follows:

[0030] Step 3.1, according to the corresponding relationship between the pH value and the amount of the pH additive added established in step 2, solid ammonium nitrate and the regulator used to adjust the pH value to 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.5, 6.0, 6.5, and 7.0 are mixed at room temperature to form a dry basis;

[0031] Step 3.2, mix the dry base with a small amount of deionized water to prepare a 90% aqueous ammonium nitrate sample, and heat the ammonium nitrate sample in a 130°C oil bath until it is completely melted; the heating process is relatively slow, and proper stirring is performed to accelerate the dissolution. The stirring rate should be controlled to avoid splashing of the solution and reduce water evaporation;

[0032] Step 3.3: After the solution is completely dissolved and there are no particles inside and no solid film on the surface of the solution, use a high-temperature pH meter to measure the pH value of the hot concentrated ammonium nitrate solution; keep the solution still during the test.

[0033] Furthermore, in step 4, the establishment of mathematical equation 2 includes the following two cases:

[0034] In the range of pH value of ammonium nitrate solution from 2 to 5, a quantitative relationship 2-1 between high temperature pH value and regulator is established, and the equation is as follows:

[0035] y2=-0.0125lg(a) + 1.7518 (2-1)

[0036] Wherein, a is the amount of nitric acid added, in ml / kg; y2 is the pH value under high temperature conditions;

[0037] In the range of pH value of ammonium nitrate solution from 5 to 7, a quantitative relationship 2-2 between high temperature pH value and regulator is established, and the equation is as follows:

[0038] z2 = 0.0898lg(b) + 2.098 (2-2)

[0039] Wherein, b is the amount of ammonia added, in ml / kg; z2 is the pH value under high temperature conditions.

[0040] Furthermore, in step 5, a corresponding relationship between the pH values ​​of the same dry-base sample under two temperature conditions is established by mathematical conversion, that is, the corresponding relationship between the pH value of a 10% dilution of a certain aqueous ammonium nitrate sample at room temperature and the pH value of the molten state under high temperature conditions;

[0041] The establishment of mathematical equation 3 includes the following two cases:

[0042] When the pH value of ammonium nitrate solution is between 2 and 5, the conversion relationship between the pH value of diluted ammonium nitrate solution under normal temperature and the pH value of hot concentrated ammonium nitrate solution under high temperature is:

[0043] y2 = 0.1263y1 + 1.4046 (3-1)

[0044] When the pH value of ammonium nitrate solution is between 5 and 7, the conversion relationship between the pH value of diluted ammonium nitrate solution under normal temperature and the pH value of hot concentrated ammonium nitrate solution under high temperature is:

[0045] z2=0.1263z1+1.4046(3-2).

[0046] Furthermore, in step 6,

[0047] When the acidity deviates, under normal temperature conditions, pH = 4.5 is used as the alarm value, and pH = 3.5 is used as the emergency cut-off value. The corresponding pH values ​​under high temperature conditions are calculated and set as the alarm value and cut-off value of the automatic monitoring system.

[0048] When alkalinity deviates, under normal temperature conditions, pH = 5.5 is used as the alarm value and 6.5 is used as the emergency cut-off value. The corresponding pH values ​​under high temperature conditions are calculated and set as the alarm value and cut-off value of the automatic monitoring system.

[0049] Furthermore, in step 7,

[0050] When the pH value is lower than the alarm value of the ammonium nitrate solution, determine the excess degree of nitric acid in the solution according to the mathematical equation 2-1 of the acid-base amount and the pH value established in step 4, and slowly add the corresponding molar amount of liquid ammonia to the ammonium nitrate solution storage tank for neutralization. Pay attention to the storage tank temperature during the filling process to avoid excessive temperature causing thermal decomposition of ammonium nitrate;

[0051] When the pH value is higher than the alarm value of the ammonium nitrate solution, determine the excess degree of liquid ammonia in the solution according to the mathematical equation 2-2 of the acid-base amount and the pH value established in step 4, and slowly add the corresponding molar amount of nitric acid to the ammonium nitrate solution storage tank for neutralization. During the filling process, pay attention to the storage tank temperature to avoid excessive temperature causing thermal decomposition of ammonium nitrate;

[0052] When the pH value is lower than or higher than the emergency cut-off value, spray tap water into the solution to dilute it, gradually cool it down, and discharge it from the storage tank.

[0053] Beneficial technical effects brought by the present invention:

[0054] 1. The relevant control indicators of ammonium nitrate solution are all the test results after dilution at room temperature. The existing test method does not establish a connection between the test results of dilution at room temperature and the test results under high temperature and high concentration conditions. Based on the test standards and test results of ammonium nitrate solution, the present invention establishes the corresponding relationship between the pH value of ammonium nitrate solution and the pH value of hot concentrated solution in the standard method, which can accurately and quickly judge the deviation of the pH value of ammonium nitrate solution under high temperature conditions, and can realize the safety rapid judgment, early warning and acid-base adjustment functions of hot concentrated ammonium nitrate solution.

[0055] 2. Based on experimental tests, the present invention can accurately determine the pH deviation of high-temperature and high-concentration ammonium nitrate solutions and provide a safe control range based on standards and process control conditions. Based on the use of similar equipment, it makes up for the poor practicality of other current methods and has broad market prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 The present invention is a flow chart of a method for rapid safety determination and quantitative adjustment of the pH value of a hot concentrated ammonium nitrate solution. DETAILED DESCRIPTION

[0057] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments:

[0058] The invention is based on the test standard and test results of ammonium nitrate solution, establishes the corresponding relationship between the pH value of the ammonium nitrate solution and the pH value of the hot concentrated solution in the standard method, can accurately and quickly judge the deviation of the pH value of the ammonium nitrate solution under high temperature conditions, and can realize the rapid safety judgment and quantitative regulation of the hot concentrated ammonium nitrate solution.

[0059] like Figure 1 As shown, a method for rapid safety determination and quantitative adjustment of pH value of hot concentrated ammonium nitrate solution comprises the following steps:

[0060] Step 1: Prepare ammonium nitrate solutions (mass concentration 10%) with different pH values ​​using nitric acid or ammonia pH regulator. The specific process is as follows:

[0061] Step 1.1, dissolving 5 g of dry ammonium nitrate solid into 45 g of deionized water to prepare 50 g of ammonium nitrate solution with a mass concentration of 10%;

[0062] Step 1.2, use a pH meter to test the pH value of the solution, accurate to 2 decimal places;

[0063] Step 1.3, using different concentrations of nitric acid or ammonia water to adjust the pH value of the corresponding ammonium nitrate solution; wherein,

[0064] When nitric acid is selected as the pH regulator, the ammonium nitrate solution is adjusted to a pH value range of 2 to 5 using nitric acid pH regulators of different concentrations. To avoid the influence of volume effect on the pH value of the original solution, the amount of nitric acid added should be strictly controlled not to exceed 1% of the volume of the original solution; for example, the ammonium nitrate solution is adjusted to a pH value of 2, 2.5, 3, 3.5, 4, and 4.5 using nitric acid pH regulators of concentrations of 10%, 1%, 0.1%, and 0.01%, respectively.

[0065] When ammonia water is selected as the pH regulator, the ammonium nitrate solution is adjusted to a pH value range of 5 to 7 using ammonia water pH regulator of different concentrations. To avoid the influence of volume effect on the pH value of the original solution, the amount of ammonia water added should be strictly controlled not to exceed 1% of the volume of the original solution; for example, the ammonium nitrate solution is adjusted to a pH value of 5.5, 6.0, 6.5, and 7.0 using ammonia water pH regulator with concentrations of 10%, 1%, and 0.1%, respectively.

[0066] Step 1.4, record the concentration and amount of the pH adjuster (nitric acid or ammonia water) used to adjust to the target pH value.

[0067] Step 2: Arrange the amount of pH regulator added in mg / kg, draw a curve based on the test results, and establish a mathematical equation 1 between the pH value of the dilution solution and the amount of pH regulator at room temperature. The establishment of mathematical equation 1 includes the following two cases:

[0068] When the pH value of ammonium nitrate solution is between 2 and 5, a quantitative mathematical equation 1-1 between the pH value of ammonium nitrate dilution and the amount of nitric acid added under normal temperature conditions is established. The equation is as follows:

[0069] y1=-0.899lg(a) + 2.0177 (1-1)

[0070] Wherein, a is the amount of nitric acid added, in ml / kg; y1 is the pH value after dilution at room temperature;

[0071] When the pH value of the ammonium nitrate solution is between 5 and 7, a quantitative mathematical equation 1-2 between the pH value and the amount of ammonia added under normal temperature conditions is established. The equation is as follows:

[0072] z1 = 0.9639lg(b) + 7.7870 (1-2)

[0073] Wherein, b is the amount of ammonia water added, in ml / kg; z1 is the pH value after dilution at room temperature.

[0074] Step 3: According to the dosage of the regulator in equation 1, prepare ammonium nitrate samples with target concentrations (target concentration is about 90%) and different pH values, heat them until they are completely melted and test the pH value; the specific process is as follows:

[0075] Step 3.1, according to the corresponding relationship between the pH value and the amount of the pH additive added established in step 2, solid ammonium nitrate and the regulator used to adjust the pH value to 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.5, 6.0, 6.5, and 7.0 are mixed at room temperature to form a dry basis;

[0076] Step 3.2, mix the dry base with a small amount of deionized water to prepare a 90% aqueous ammonium nitrate sample, and heat the ammonium nitrate sample in a 130°C oil bath until it is completely melted. The heating process is relatively slow, and appropriate stirring can be used to speed up the dissolution. The stirring rate should be controlled to avoid splashing of the solution and reduce water evaporation;

[0077] Step 3.3, after it is completely dissolved, there are no particles inside and no solid film on the surface of the solution, use a high-temperature pH meter to measure the pH value of the hot concentrated ammonium nitrate solution. The hot concentrated ammonium nitrate solution tested in a high-temperature environment is strongly acidic, and the flow of the solution will reduce the test result of the pH value. Therefore, during the test process, care should be taken to keep the solution still to avoid the impact of the flow state on the test.

[0078] Step 4: Draw a curve based on the measurement results of step 3, and establish mathematical equation 2 for the pH value of the hot concentrated ammonium nitrate solution and the amount of the regulator under high temperature conditions.

[0079] The establishment of mathematical equation 2 includes the following two cases:

[0080] In the range of pH value of ammonium nitrate solution from 2 to 5, a quantitative relationship 2-1 between high temperature pH value and regulator is established, and the equation is as follows:

[0081] y2=-0.0125lg(a) + 1.7518 (2-1)

[0082] Wherein, a is the amount of nitric acid added, in ml / kg; y2 is the pH value under high temperature conditions;

[0083] In the range of pH value of ammonium nitrate solution from 5 to 7, a quantitative relationship 2-2 between high temperature pH value and regulator is established, and the equation is as follows:

[0084] z2 = 0.0898lg(b) + 2.098 (2-2)

[0085] Wherein, b is the amount of ammonia added, in ml / kg; z2 is the pH value under high temperature conditions.

[0086] Step 5: Establish the corresponding relationship between the pH values ​​of the same sample under two temperature conditions through mathematical conversion, that is, the corresponding relationship between the pH value of a certain aqueous ammonium nitrate sample after dilution at room temperature and the pH value in the molten state under high temperature conditions. The specific process is: According to equation 1 and equation 2, the mathematical equation 3 of the pH value of the hot concentrated ammonium nitrate solution under high temperature conditions and the pH value of the diluted ammonium nitrate solution under room temperature conditions is calculated.

[0087] The establishment of mathematical equation 3 includes the following two cases:

[0088] When the pH value of ammonium nitrate solution is between 2 and 5, the conversion relationship between the pH value of diluted ammonium nitrate solution under normal temperature and the pH value of hot concentrated ammonium nitrate solution under high temperature is:

[0089] y2 = 0.1263y1 + 1.4046 (3-1)

[0090] When the pH value of ammonium nitrate solution is between 5 and 7, the conversion relationship between the pH value of diluted ammonium nitrate solution under normal temperature and the pH value of hot concentrated ammonium nitrate solution under high temperature is:

[0091] z2=0.1263z1+1.4046(3-2).

[0092] Step 6: According to the safe control range of pH value at room temperature, set the key control parameters of pH value control of hot concentrated solution under high temperature conditions.

[0093] When the acidity deviates, under normal temperature conditions, pH = 4.5 is used as the alarm value, and pH = 3.5 is used as the emergency cut-off value. The corresponding pH values ​​under high temperature conditions are calculated and set as the alarm value and cut-off value of the automatic monitoring system.

[0094] When alkalinity deviates, under normal temperature conditions, pH = 5.5 is used as the alarm value and 6.5 is used as the emergency cut-off value. The corresponding pH values ​​under high temperature conditions are calculated and set as the alarm value and cut-off value of the automatic monitoring system.

[0095] Step 7: Use a high-temperature pH meter to detect the pH value of the hot concentrated ammonium nitrate solution in the current static state, and adjust the pH value accordingly according to the specific situation. The specific process is as follows:

[0096] When the pH value is lower than the alarm value of the ammonium nitrate solution, determine the excess degree of nitric acid in the solution according to the mathematical equation 2-1 of the acid-base amount and the pH value established in step 4, and slowly add the corresponding molar amount of liquid ammonia to the ammonium nitrate solution storage tank for neutralization. Pay attention to the storage tank temperature during stirring to avoid excessive temperature causing thermal decomposition of ammonium nitrate;

[0097] When the pH value is higher than the alarm value of the ammonium nitrate solution, determine the excess of liquid ammonia in the solution according to the mathematical equation 2-2 of the acid-base amount and the pH value established in step 4, and slowly add the corresponding molar amount of nitric acid to the ammonium nitrate solution storage tank for neutralization. Pay attention to the storage tank temperature during stirring to avoid excessive temperature causing thermal decomposition of ammonium nitrate;

[0098] When the pH value is lower or higher than the emergency cut-off value, spray tap water into the solution to dilute it, gradually cool it down, and discharge it from the storage tank.

[0099] Hot concentrated ammonium nitrate solution for industrial use is solid at room temperature, and pH value determination needs to be measured after dilution at room temperature. The present invention solves the problems of many operation links in pH value measurement of industrial ammonium nitrate solution (concentration exceeds 90%) and difficulty in online monitoring and determination. Through laboratory tests, the corresponding relationship between pH value of hot concentrated solution under high temperature conditions and the value determined by the labeling method under normal temperature conditions, as well as the quantitative relationship between pH value and excess acid and alkali in the solution are established, which not only realizes rapid safety determination and deviation warning of pH value under high temperature conditions, but also realizes automatic adjustment function.

[0100] Example 1

[0101] Step 1. Use dilute nitric acid as a pH regulator to prepare ammonium nitrate solutions with different pH values. Dissolve 5g of dry ammonium nitrate solid in 45g of deionized water to prepare 50g of ammonium nitrate solution with a mass concentration of 10%. Use a pH meter to test the pH value of the solution, accurate to 2 decimal places. Use dilute nitric acid with concentrations of 10%, 1%, 0.1%, and 0.01% to adjust the ammonium nitrate solution to pH values ​​of 2, 2.5, 3, 3.5, 4, and 4.5, respectively. The nitric acid concentrations used, the amount added, and the corresponding pH values ​​are shown in Table 1.1:

[0102] Table 1.1 Nitric Amount Table for Acidification Adjustment of Ammonium Nitrate Solution at Room Temperature

[0103] pH 2 2.5 3 3.5 4 4.5 Nitric acid concentration / % 10 10 1 1 0.1 0.01 Addition amount / ul 460 120 480 150 350 668

[0104] Step 2: Arrange the amount of dilute nitric acid added in mg / kg, and draw a curve of the pH value of ammonium nitrate and the amount of nitric acid added according to the test results. In the range of pH value of ammonium nitrate solution from 2 to 5, establish a quantitative mathematical relationship between pH value and the amount of nitric acid added. The equation is as follows:

[0105] y1=-0.899lg(a)+2.0177(1.1)

[0106] Wherein, a: amount of nitric acid added, unit: ml / kg; y1: pH value after dilution at room temperature.

[0107] Step 3: According to the corresponding relationship between pH value and dilute nitric acid dosage established in step 2, solid ammonium nitrate and the regulator used to adjust the pH value to 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.5, 6.0, 6.5, and 7.0 are mixed at room temperature to form a dry basis. The dry basis is mixed with a small amount of deionized water to form 10% ammonium nitrate samples with different pH values, and the ammonium nitrate samples are heated in a 130° C. oil bath until completely melted.

[0108] Step 4: The heating process is relatively slow. Appropriate stirring can be used to speed up the dissolution. The stirring rate should be controlled to avoid splashing of the solution and reduce water evaporation. After it is completely dissolved, there are no particles inside and no solid film on the surface of the solution, use a high-temperature pH meter to measure the pH value of the hot concentrated ammonium nitrate solution. At the same time, the flow of the solution will reduce the test results of the pH value. Therefore, during the test process, care should be taken to keep the solution still to avoid affecting the test due to the flow state. The nitric acid concentration used, the amount added, and the corresponding pH value are shown in Table 1.2:

[0109] Table 1.2 Amount of nitric acid used to adjust the acidity of high temperature ammonium nitrate solution

[0110] pH 1.66 1.71 1.80 1.84 1.90 1.98 Acid concentration / % 10 10 1 1 0.1 0.01 Addition amount / ul 460 120 480 150 350 668

[0111] y2=-0.0125lg(a)+1.7518(1.2)

[0112] Where: a: amount of nitric acid added, unit: ml / kg; y2: pH value under high temperature conditions.

[0113] Step 5: Based on the test results of step 3, the pH change curve is plotted with the amount of pH adjuster added as the horizontal axis, and a mathematical relationship between the pH value of the hot concentrated ammonium nitrate solution under high temperature conditions and the amount of adjuster used is established. Using the pH adjuster as a bridge, a corresponding relationship between the pH values ​​of the same sample under two temperature conditions is established, that is, the corresponding relationship between the pH value of a certain aqueous ammonium nitrate sample after dilution at room temperature and the pH value in the molten state under high temperature conditions.

[0114] The conversion relationship between the pH value of diluted ammonium nitrate solution at room temperature and the pH value of hot concentrated ammonium nitrate solution at high temperature is:

[0115] y2=0.1263y1+1.4046(1.3)

[0116] According to the safe control range of pH value at normal temperature, set the key value of pH value control of hot concentrated solution under high temperature condition. Under normal temperature condition, pH=4.5 is the alarm lower limit, and the corresponding pH value under high temperature condition is 1.98. pH=3.5 is the emergency cut-off lower limit, and the corresponding pH value under high temperature condition is 1.80. Set pH=1.98 as the alarm value of the automatic monitoring system, and set pH=1.80 as the cut-off value of the automatic monitoring system.

[0117] Step 6. Use a high-temperature pH meter to detect the pH value of the hot concentrated ammonium nitrate solution in a static state in a storage tank. The pH value is 1.89. According to formula (1.3), the corresponding pH value after dilution under normal temperature conditions is 3.9. The solution is acidic and exceeds the safety alarm value. It needs to be adjusted. According to formula (1.2), the excess of nitric acid (concentration 65%) is 0.1620 ml / kg. In a 200 cubic meter storage tank, the ammonium nitrate solution level is 50%, and the mass is about 100 tons, of which the excess of nitric acid (concentration 65%) is 16.20 kg. In order to neutralize the excess nitric acid, 10.53 kg of ammonia water should be added.

[0118] Example 2

[0119] Step 1. Use dilute ammonia water as a pH regulator to prepare ammonium nitrate solutions with different pH values. Dissolve 5g of dry ammonium nitrate solid in 45g of deionized water to prepare 50g of ammonium nitrate solution with a mass concentration of 10%. Use a pH meter to test the pH value of the solution, accurate to 2 decimal places. Use pH regulators with concentrations of 10%, 1%, and 0.1% to adjust the ammonium nitrate solution to pH values ​​of 5.5, 6.0, 6.5, and 7.0, respectively. To avoid the influence of volume effect on the pH value of the original solution, the amount of dilute ammonia water added should be strictly controlled not to exceed 1% of the volume of the original solution. Record the concentration and amount of dilute ammonia water used to adjust to the target pH value. The concentration of ammonia water used, the amount added, and the corresponding pH value are shown in Table 2.1:

[0120] Table 2.1 Ammonia dosage for alkalinity adjustment of ammonium nitrate solution at room temperature

[0121] pH 5.5 6.0 6.5 7.0 Ammonia concentration / % 0.1 0.1 1 10 Addition amount / ul 180 500 200 65

[0122] Step 2: Arrange the amount of diluted ammonia water added in mg / kg, draw a curve of the pH value of ammonium nitrate and the amount of ammonia water added according to the test results, and establish a quantitative mathematical relationship between the pH value and the amount of ammonia water added in the range of 5 to 7 of the pH value of the ammonium nitrate solution.

[0123] z1=0.9639lg(b)+7.7870(2.1)

[0124] Where: b: amount of ammonia water added, unit: ml / kg; z1: pH value after dilution at room temperature.

[0125] Step 3: According to the corresponding relationship between pH value and the amount of pH additive established in step 2, solid ammonium nitrate and the used regulator adjusted to pH values ​​of 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.5, 6.0, 6.5, and 7.0 are mixed at room temperature with dilute ammonia water as a regulator to prepare a dry basis. The dry basis is mixed with a small amount of deionized water to prepare a 90% aqueous ammonium nitrate sample, and the ammonium nitrate sample is heated in a 130° C. oil bath until it is completely melted.

[0126] Step 4. The heating process is relatively slow, and appropriate stirring can be used to speed up the dissolution. The stirring rate should be controlled to avoid splashing of the solution and reduce water evaporation. After it is completely dissolved, there are no particles inside and no solid film on the surface of the solution, use a high-temperature pH meter to measure the pH value of the hot concentrated ammonium nitrate solution. The hot concentrated ammonium nitrate solution tested in a high temperature environment is strongly acidic, and the flow of the solution will reduce the pH test results. Therefore, during the test process, care should be taken to keep the solution still to avoid affecting the test due to the flow state. The ammonia concentration, addition amount, and corresponding pH value used are shown in Table 2.2:

[0127] Table 2.2 Ammonia dosage for alkalinity adjustment of high temperature ammonium nitrate solution

[0128] pH 2.06 2.10 2.15 2.20 Ammonia concentration / % 0.1 0.1 1 10 Addition amount / ul 180 500 200 65

[0129] z2=0.0898lg(b)+2.098(2.2)

[0130] Wherein, b: amount of ammonia water added, unit: ml / kg; z2: pH value under high temperature conditions.

[0131] Step 5: Based on the test results of step 3, the pH change curve is plotted with the amount of pH adjuster added as the horizontal axis, and a mathematical relationship between the pH value of the hot concentrated ammonium nitrate solution under high temperature conditions and the amount of adjuster used is established. Using the pH adjuster as a bridge, a corresponding relationship between the pH values ​​of the same sample under two temperature conditions is established, that is, the corresponding relationship between the pH value of a certain aqueous ammonium nitrate sample after dilution at room temperature and the pH value in the molten state under high temperature conditions.

[0132] The conversion relationship between the pH value of diluted ammonium nitrate solution at room temperature and the pH value of hot concentrated ammonium nitrate solution at high temperature is:

[0133] z2=0.1263z1+1.4046(2.3)

[0134] According to the safe control range of pH value at room temperature, set the key value of pH value control of hot concentrated solution under high temperature conditions. Under room temperature conditions, pH = 5.5 is the alarm lower limit, and the corresponding pH value under high temperature conditions is 2.06. pH = 6.5 is the emergency cut-off lower limit, and the corresponding pH value under high temperature conditions is 2.15. Set pH = 2.06 as the alarm value of the automatic monitoring system, and set pH = 2.15 as the cut-off value of the automatic monitoring system.

[0135] Step 6. Use a high-temperature pH meter to detect the pH value of the hot concentrated ammonium nitrate solution in a static state in a storage tank. The pH value is 2.11. According to formula (2.3), the corresponding pH value after dilution at room temperature is 6.0. The solution is acidic and exceeds the safety alarm value. It needs to be adjusted. According to formula (2.2), the excess of liquid ammonia (concentration 98%) is about 1.00 ml / kg. In a 400 cubic meter storage tank, the ammonium nitrate solution level is 25%, and the mass is about 100 tons, of which the excess of liquid ammonia (concentration 98%) is 100 kg. In order to neutralize the excess ammonia, about 150 kg of 65% nitric acid should be added.

[0136] Example 3

[0137] Step 1. Use dilute nitric acid as a pH regulator to prepare ammonium nitrate solutions with different pH values. Dissolve 5g of dry ammonium nitrate solid in 45g of deionized water to prepare 50g of ammonium nitrate solution with a mass concentration of 10%. Use a pH meter to test the pH value of the solution, accurate to 2 decimal places. Use dilute nitric acid with concentrations of 10%, 1%, 0.1%, and 0.01% to adjust the ammonium nitrate solution to pH values ​​of 2, 2.5, 3, 3.5, 4, and 4.5, respectively. The nitric acid concentrations used, the amount added, and the corresponding pH values ​​are shown in Table 3.1:

[0138] Table 3.1 Nitric Amount Table for Acid Adjustment of Ammonium Nitrate Solution at Room Temperature

[0139] pH 2 2.5 3 3.5 4 4.5 Nitric acid concentration / % 10 10 1 1 0.1 0.01 Addition amount / ul 460 120 480 150 350 668

[0140] Step 2: Arrange the amount of dilute nitric acid added in mg / kg, and draw a curve of the pH value of ammonium nitrate and the amount of nitric acid added according to the test results. In the range of pH value of ammonium nitrate solution from 2 to 5, establish a quantitative mathematical relationship between pH value and the amount of nitric acid added. The equation is as follows:

[0141] y1=-0.899lg(a)+2.0177(3.1)

[0142] Wherein, a: amount of nitric acid added, unit: ml / kg; y1: pH value after dilution at room temperature.

[0143] Step 3: According to the corresponding relationship between pH value and dilute nitric acid dosage established in step 2, solid ammonium nitrate and the regulator used to adjust the pH value to 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.5, 6.0, 6.5, and 7.0 are mixed at room temperature to form a dry basis. The dry basis is mixed with a small amount of deionized water to form 10% ammonium nitrate samples with different pH values, and the ammonium nitrate samples are heated in a 130° C. oil bath until completely melted.

[0144] Step 4: The heating process is relatively slow. Appropriate stirring can be used to speed up the dissolution. The stirring rate should be controlled to avoid splashing of the solution and reduce water evaporation. After it is completely dissolved, there are no particles inside and no solid film on the surface of the solution, use a high-temperature pH meter to measure the pH value of the hot concentrated ammonium nitrate solution. At the same time, the flow of the solution will reduce the test results of the pH value. Therefore, during the test process, care should be taken to keep the solution still to avoid affecting the test due to the flow state. The nitric acid concentration used, the amount added, and the corresponding pH value are shown in Table 3.2:

[0145] Table 3.2 Nitric Amount Table for Acid Adjustment of High-Temperature Ammonium Nitrate Solution

[0146] pH 1.66 1.71 1.80 1.84 1.90 1.98 Acid concentration / % 10 10 1 1 0.1 0.01 Addition amount / ul 460 120 480 150 350 668

[0147] y2=-0.0125lg(a)+1.7518(3.2)

[0148] Where: a: amount of nitric acid added, unit: ml / kg; y2: pH value under high temperature conditions.

[0149] Step 5: Based on the test results of step 3, the pH change curve is plotted with the amount of pH adjuster added as the horizontal axis, and a mathematical relationship between the pH value of the hot concentrated ammonium nitrate solution under high temperature conditions and the amount of adjuster used is established. Using the pH adjuster as a bridge, a corresponding relationship between the pH values ​​of the same sample under two temperature conditions is established, that is, the corresponding relationship between the pH value of a certain aqueous ammonium nitrate sample after dilution at room temperature and the pH value in the molten state under high temperature conditions.

[0150] The conversion relationship between the pH value of diluted ammonium nitrate solution at room temperature and the pH value of hot concentrated ammonium nitrate solution at high temperature is:

[0151] y2=0.1263y1+1.4046(3.3)

[0152] According to the safe control range of pH value at normal temperature, set the key value of pH value control of hot concentrated solution under high temperature condition. Under normal temperature condition, pH=4.5 is the alarm lower limit, and the corresponding pH value under high temperature condition is 1.98. pH=3.5 is the emergency cut-off lower limit, and the corresponding pH value under high temperature condition is 1.80. Set pH=1.98 as the alarm value of the automatic monitoring system, and set pH=1.80 as the cut-off value of the automatic monitoring system.

[0153] Step 6: Use a high-temperature pH meter to detect the pH value of the hot concentrated ammonium nitrate solution in a storage tank at rest, which is 1.77. According to formula (3.3), the corresponding pH value after dilution at room temperature is 2.90. The solution is acidic and exceeds the emergency cut-off lower limit, requiring emergency emptying. Open the tank drain valve to drain the liquid, open the tank spray device, and spray tap water into the solution to dilute it. The solution in the tank is diluted, cooled, and drained at the same time.

[0154] Example 4

[0155] Step 1. Use dilute ammonia water as a pH regulator to prepare ammonium nitrate solutions with different pH values. Dissolve 5g of dry ammonium nitrate solid in 45g of deionized water to prepare 50g of ammonium nitrate solution with a mass concentration of 10%. Use a pH meter to test the pH value of the solution, accurate to 2 decimal places. Use pH regulators with concentrations of 10%, 1%, and 0.1% to adjust the ammonium nitrate solution to pH values ​​of 5.5, 6.0, 6.5, and 7.0, respectively. To avoid the influence of volume effect on the pH value of the original solution, the amount of dilute ammonia water added should be strictly controlled not to exceed 1% of the volume of the original solution. Record the concentration and amount of dilute ammonia water used to adjust to the target pH value. The concentration of ammonia water used, the amount added, and the corresponding pH value are shown in Table 4.1:

[0156] Table 4.1 Ammonia dosage for alkalinity adjustment of ammonium nitrate solution at room temperature

[0157] pH 5.5 6.0 6.5 7.0 Ammonia concentration / % 0.1 0.1 1 10 Addition amount / ul 180 500 200 65

[0158] Step 2: Arrange the amount of diluted ammonia water added in mg / kg, draw a curve of the pH value of ammonium nitrate and the amount of ammonia water added according to the test results, and establish a quantitative mathematical relationship between the pH value and the amount of ammonia water added in the range of 5 to 7 of the pH value of the ammonium nitrate solution.

[0159] z1=0.9639lg(b)+7.7870(4.1)

[0160] Where: b: amount of ammonia water added, unit: ml / kg; z1: pH value after dilution at room temperature.

[0161] Step 3: According to the corresponding relationship between pH value and the amount of pH additive established in step 2, solid ammonium nitrate and the used regulator adjusted to pH values ​​of 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.5, 6.0, 6.5, and 7.0 are mixed at room temperature with dilute ammonia water as a regulator to prepare a dry basis. The dry basis is mixed with a small amount of deionized water to prepare a 90% aqueous ammonium nitrate sample, and the ammonium nitrate sample is heated in a 130° C. oil bath until it is completely melted.

[0162] Step 4. The heating process is relatively slow, and appropriate stirring can be used to speed up the dissolution. The stirring rate should be controlled to avoid splashing of the solution and reduce water evaporation. After it is completely dissolved, there are no particles inside and no solid film on the surface of the solution, use a high-temperature pH meter to measure the pH value of the hot concentrated ammonium nitrate solution. The hot concentrated ammonium nitrate solution tested in a high temperature environment is strongly acidic, and the flow of the solution will reduce the pH test results. Therefore, during the test process, care should be taken to keep the solution still to avoid affecting the test due to the flow state. The ammonia concentration, addition amount, and corresponding pH value used are shown in Table 4.2:

[0163] Table 4.2 Ammonia dosage for alkalinity adjustment of high temperature ammonium nitrate solution

[0164] pH 2.06 2.10 2.15 2.20 Ammonia concentration / % 0.1 0.1 1 10 Addition amount / ul 180 500 200 65

[0165] z2=0.0898lg(b)+2.098(4.2)

[0166] Wherein, b: amount of ammonia water added, unit: ml / kg; z2: pH value under high temperature conditions.

[0167] Step 5: Based on the test results of step 3, the pH change curve is plotted with the amount of pH adjuster added as the horizontal axis, and a mathematical relationship between the pH value of the hot concentrated ammonium nitrate solution under high temperature conditions and the amount of adjuster used is established. Using the pH adjuster as a bridge, a corresponding relationship between the pH values ​​of the same sample under two temperature conditions is established, that is, the corresponding relationship between the pH value of a certain aqueous ammonium nitrate sample after dilution at room temperature and the pH value in the molten state under high temperature conditions.

[0168] z2=0.1263z1+1.4046(4.3)

[0169] According to the safe control range of pH value at room temperature, set the key value of pH value control of hot concentrated solution under high temperature conditions. Under room temperature conditions, pH = 5.5 is the alarm lower limit, and the corresponding pH value under high temperature conditions is 2.06. pH = 6.5 is the emergency cut-off lower limit, and the corresponding pH value under high temperature conditions is 2.15. Set pH = 2.06 as the alarm value of the automatic monitoring system, and set pH = 2.15 as the cut-off value of the automatic monitoring system.

[0170] Step 6: Use a high-temperature pH meter to detect the pH value of the hot concentrated ammonium nitrate solution in a storage tank at rest, which is 2.21. According to formula (4.3), the corresponding pH value after dilution under normal temperature is 7.15. The solution is acidic and exceeds the upper limit of the emergency cut-off. Emergency emptying is required. Open the tank emptying valve to drain the liquid, open the tank spray device, and spray tap water into the solution to dilute it. The solution in the tank is diluted, cooled, and drained at the same time.

[0171] Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by technicians in this technical field within the essential scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A method for rapid safety determination and quantitative adjustment of pH value of hot concentrated ammonium nitrate solution, characterized in that: The steps include: Step 1, preparing ammonium nitrate dilutions with different pH values ​​using nitric acid or ammonia pH regulator; Step 2, the amount of pH regulator added is arranged in mg / kg, a curve is drawn according to the test results, and a mathematical equation 1 between the pH value of the dilution solution and the amount of pH regulator used under normal temperature conditions is established; Step 3, according to the amount of regulator in equation 1, prepare ammonium nitrate samples with target concentrations and different pH values, heat them until they are completely melted and test the pH value; Step 4, drawing a curve according to the measurement results of step 3, and establishing a mathematical equation 2 for the pH value of the hot concentrated ammonium nitrate solution and the amount of the regulator under high temperature conditions; Step 5, according to equation 1 and equation 2, calculate the mathematical equation 3 of the pH value of the hot concentrated ammonium nitrate solution under high temperature conditions and the pH value of the diluted ammonium nitrate solution under normal temperature conditions; Step 6: according to the safe control range of pH value at room temperature, set the key control parameter of pH value of hot concentrated ammonium nitrate solution under high temperature conditions; Step 7: Use a high-temperature pH meter to detect the pH value of the hot concentrated ammonium nitrate solution in the storage tank in a static state, and adjust the pH value accordingly according to the specific situation.

2. The method for rapid safety determination and quantitative adjustment of pH value of hot concentrated ammonium nitrate solution according to claim 1, characterized in that: The mass concentration of the ammonium nitrate dilution in step 1 is 10%; the target concentration in step 3 is 90%.

3. The method for rapid safety determination and quantitative adjustment of pH value of hot concentrated ammonium nitrate solution according to claim 1, characterized in that: The specific process of step 1 is as follows: Step 1.1, dissolving 5 g of dry ammonium nitrate solid into 45 g of deionized water to prepare 50 g of ammonium nitrate solution with a mass concentration of 10%; Step 1.2, use a pH meter to test the pH value of the solution, accurate to 2 decimal places; Step 1.3, using different concentrations of nitric acid or ammonia water to adjust the pH value of the corresponding ammonium nitrate solution; Step 1.4, record the concentration and amount of the pH adjuster used to adjust to the target pH value.

4. The method for rapid safety determination and quantitative adjustment of pH value of hot concentrated ammonium nitrate solution according to claim 3, characterized in that: In the step 1.3, when nitric acid is selected as the pH regulator, the ammonium nitrate solution is adjusted to a pH value range of 2 to 5 using nitric acid pH regulators of different concentrations, and the amount of nitric acid added is controlled not to exceed 1% of the volume of the original solution; when ammonia water is selected as the pH regulator, the ammonium nitrate solution is adjusted to a pH value range of 5 to 7 using ammonia water pH regulators of different concentrations.

5. The method for rapid safety determination and quantitative adjustment of pH value of hot concentrated ammonium nitrate solution according to claim 1, characterized in that: In step 2, the establishment of mathematical equation 1 includes the following two situations: When the pH value of ammonium nitrate solution is between 2 and 5, a quantitative mathematical equation 1-1 between the pH value of ammonium nitrate dilution and the amount of nitric acid added under normal temperature conditions is established. The equation is as follows: y1=-0.899lg(a) + 2.0177 (1-1) Wherein, a is the amount of nitric acid added, in ml / kg; y1 is the pH value after dilution at room temperature; When the pH value of the ammonium nitrate solution is between 5 and 7, a quantitative mathematical equation 1-2 between the pH value and the amount of ammonia added under normal temperature conditions is established. The equation is as follows: z1 = 0.9639lg(b) + 7.7870 (1-2) Wherein, b is the amount of ammonia water added, in ml / kg; z1 is the pH value after dilution at room temperature.

6. The method for rapid safety determination and quantitative adjustment of pH value of hot concentrated ammonium nitrate solution according to claim 1, characterized in that: The specific process of step 3 is as follows: Step 3.1, according to the corresponding relationship between the pH value and the amount of the pH additive added established in step 2, solid ammonium nitrate and the regulator used to adjust the pH value to 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.5, 6.0, 6.5, and 7.0 are mixed at room temperature to form a dry basis; Step 3.2, mix the dry base with a small amount of deionized water to prepare a 90% aqueous ammonium nitrate sample, and heat the ammonium nitrate sample in a 130°C oil bath until it is completely melted; the heating process is relatively slow, and proper stirring is performed to accelerate the dissolution. The stirring rate should be controlled to avoid splashing of the solution and reduce water evaporation; Step 3.3: After the solution is completely dissolved and there are no particles inside and no solid film on the surface of the solution, use a high-temperature pH meter to measure the pH value of the hot concentrated ammonium nitrate solution; keep the solution still during the test.

7. The method for rapid safety determination and quantitative adjustment of pH value of hot concentrated ammonium nitrate solution according to claim 1, characterized in that: In step 4, the establishment of mathematical equation 2 includes the following two situations: In the range of pH value of ammonium nitrate solution from 2 to 5, a quantitative relationship 2-1 between high temperature pH value and regulator is established, and the equation is as follows: y2=-0.0125lg(a) + 1.7518 (2-1) Wherein, a is the amount of nitric acid added, in ml / kg; y2 is the pH value under high temperature conditions; In the range of pH value of ammonium nitrate solution from 5 to 7, a quantitative relationship 2-2 between high temperature pH value and regulator is established, and the equation is as follows: z2 = 0.0898lg(b) + 2.098 (2-2) Wherein, b is the amount of ammonia added, in ml / kg; z2 is the pH value under high temperature conditions.

8. The method for rapid safety determination and quantitative adjustment of pH value of hot concentrated ammonium nitrate solution according to claim 1, characterized in that: In step 5, a corresponding relationship between the pH values ​​of the same dry sample under two temperature conditions is established by mathematical conversion, that is, the corresponding relationship between the pH value of a 10% dilution of a certain aqueous ammonium nitrate sample at room temperature and the pH value of the molten state under high temperature conditions; The establishment of mathematical equation 3 includes the following two cases: When the pH value of ammonium nitrate solution is between 2 and 5, the conversion relationship between the pH value of diluted ammonium nitrate solution under normal temperature and the pH value of hot concentrated ammonium nitrate solution under high temperature is: y2 = 0.1263y1 + 1.4046 (3-1) When the pH value of ammonium nitrate solution is between 5 and 7, the conversion relationship between the pH value of diluted ammonium nitrate solution under normal temperature and the pH value of hot concentrated ammonium nitrate solution under high temperature is: z2=0.1263z1+1.4046(3-2).

9. The method for rapid safety determination and quantitative adjustment of pH value of hot concentrated ammonium nitrate solution according to claim 2, characterized in that: In step 6, When the acidity deviates, under normal temperature conditions, pH = 4.5 is used as the alarm value, and pH = 3.5 is used as the emergency cut-off value. The corresponding pH values ​​under high temperature conditions are calculated and set as the alarm value and cut-off value of the automatic monitoring system. When alkalinity deviates, under normal temperature conditions, pH = 5.5 is used as the alarm value and 6.5 is used as the emergency cut-off value. The corresponding pH values ​​under high temperature conditions are calculated and set as the alarm value and cut-off value of the automatic monitoring system.

10. The method for rapid safety determination and quantitative adjustment of pH value of hot concentrated ammonium nitrate solution according to claim 2, characterized in that: In step 7, When the pH value is lower than the alarm value of the ammonium nitrate solution, determine the excess degree of nitric acid in the solution according to the mathematical equation 2-1 of the acid-base amount and the pH value established in step 4, and slowly add the corresponding molar amount of liquid ammonia to the ammonium nitrate solution storage tank for neutralization. Pay attention to the storage tank temperature during the filling process to avoid excessive temperature causing thermal decomposition of ammonium nitrate; When the pH value is higher than the alarm value of the ammonium nitrate solution, determine the excess degree of liquid ammonia in the solution according to the mathematical equation 2-2 of the acid-base amount and the pH value established in step 4, and slowly add the corresponding molar amount of nitric acid to the ammonium nitrate solution storage tank for neutralization. During the filling process, pay attention to the storage tank temperature to avoid excessive temperature causing thermal decomposition of ammonium nitrate; When the pH value is lower than or higher than the emergency cut-off value, spray tap water into the solution to dilute it, gradually cool it down, and discharge it from the storage tank.

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