An additive for reducing the crystallization point of saturated ammonium nitrate solution and a method of using the additive

Abstract

The invention discloses an additive for reducing the crystallization point of a saturated ammonium nitrate solution and a use method thereof. The additive comprises glycine, sodium glycine and sodium cocoyl glycine. The use method comprises the following steps: adding the additive into a saturated ammonium nitrate solution, dissolving the additive, and making the additive and the saturated ammonium nitrate solution serve as the water phase of an emulsion explosive or an expanded ammonium nitrate explosive. The additive adopts glycine, sodium glycine and sodium cocoyl glycine, can effectively inhibit the crystallization and crystal growth of ammonium nitrate, and control the crystal shape of ammonium nitrate, and will not produce side effects on a water phase solution, and the crystallization point can be reduced by 10-20 DEG C.

Description

Technical Field

[0001] The invention relates to an additive, in particular to an additive for reducing the crystallization point of a saturated ammonium nitrate solution and a use method thereof. Background Art

[0002] Ammonium nitrate aqueous solution, also known as water phase, is a key component of expanded ammonium nitrate explosives, emulsion explosives, water gel explosives, and slurry explosives. At present, ammonium nitrate aqueous solution (water phase) is usually prepared in two ways. First, according to the formula of explosives, solid ammonium nitrate is crushed and dissolved with sodium nitrate, sodium chloride and other additives at process temperature to form an ammonium nitrate solution of a certain concentration; second, liquid ammonium nitrate is directly used, and the content of each component of the water phase is adjusted according to the formula so that the proportion and concentration of the water phase meet the process requirements for the preparation of explosives.

[0003] The main reason for the crystallization of ammonium nitrate in the water phase is that the temperature coefficient of the ammonium nitrate solution is large. As the temperature decreases, the ammonium nitrate precipitates, resulting in a decrease in the stability and explosive performance of the explosive. Therefore, reducing the crystallization point of the ammonium nitrate solution is an important technical measure for the quality, storage stability and safe production of the explosive. At present, in the preparation process of expanded ammonium nitrate explosives and emulsion explosives, the water phase adopts a remote transportation process, so the crystallization point of the water phase is a key technical parameter, which is of great significance for preventing the blockage of the conveying pipeline connection flange, valve, conveying pump, flow meter, pressure transmitter, etc. due to excessively high crystallization point during normal production. At the same time, for unexpected situations such as water outage, power outage, gas outage, equipment failure, etc. during the production process, the crystallization point of the water phase is of significant significance for preventing pipeline blockage, water phase solution insulation, and safe production. At the same time, reducing the crystallization point of the water phase can reduce energy consumption in the water phase preparation, insulation, remote transportation and pharmaceutical processes. Summary of the invention

[0004] Purpose of the invention: The first purpose of the present invention is to provide an additive with a new formula for reducing the crystallization point of a saturated ammonium nitrate solution; the second purpose of the present invention is to provide a method for using the additive.

[0005] Technical solution: The additive for reducing the crystallization point of saturated ammonium nitrate solution of the present invention comprises glycine, sodium glycinate and sodium cocoyl glycinate.

[0006] Ammonium nitrate is easily soluble in water, which is beneficial to the production of industrial explosives. Glycine [melting point is 233°C (decomposition)] and sodium glycinate (melting point 197-201°C) are easily soluble in water and can form a low eutectic salt with ammonium nitrate, thereby achieving the effect of lowering the crystallization point. Sodium cocoyl glycinate is an amino acid surfactant that can inhibit the formation of ammonium nitrate crystal nuclei and affect the growth and aggregation of crystals, thereby lowering the crystallization point of saturated ammonium nitrate solution.

[0007] Preferably, the additives include 30-55% glycine, 20-35% sodium glycinate, and 25-35% sodium cocoyl glycinate by weight. The combined use of glycine, sodium glycinate, and sodium cocoyl glycinate can inhibit the crystallization and crystal growth of ammonium nitrate, control the crystal shape of ammonium nitrate, and effectively reduce the crystallization point.

[0008] Preferably, the additives contain, by weight, 30-45% glycine, 25-35% sodium glycinate, and 30-35% sodium cocoyl glycinate.

[0009] Preferably, the purity of the glycine is 99.5-99.7%.

[0010] Preferably, the purity of the sodium glycinate is 98-99%.

[0011] Preferably, the purity of the sodium cocoyl glycinate is 93-98%.

[0012] The method for using the additive for reducing the crystallization point of a saturated ammonium nitrate solution of the present invention comprises the following steps: adding the additive into a saturated ammonium nitrate solution, dissolving the additive, and making the additive and the saturated ammonium nitrate solution serve as the water phase of an emulsion explosive or an expanded ammonium nitrate explosive.

[0013] Preferably, the additive is used in an amount of 3-6% of the saturated ammonium nitrate solution.

[0014] Preferably, the additive is used in an amount of 4-5% of the saturated ammonium nitrate solution.

[0015] Preferably, the mass fraction of the saturated ammonium nitrate solution is 91.0-92.5%.

[0016] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: (1) The additive adopts glycine, sodium glycinate and sodium cocoyl glycinate, which can effectively inhibit the crystallization and crystal growth of ammonium nitrate and control the crystal shape of ammonium nitrate without causing any side effects on the aqueous solution, and the crystallization point can be reduced by 10 to 20°C; (2) The emulsion explosive and expanded ammonium nitrate explosive prepared by using the ammonium nitrate aqueous solution containing the additive have excellent detonation performance. DETAILED DESCRIPTION

[0017] The technical solution of the present invention is further described below in conjunction with embodiments.

[0018] Example 1

[0019] The additive for reducing the crystallization point of saturated ammonium nitrate solution of the present invention comprises, by mass fraction, 30% of glycine, 35% of sodium glycinate and 35% of sodium cocoyl glycinate.

[0020] The test steps of crystallization point are as follows:

[0021] (1) Preheat the thermometer, measuring cylinder and beaker in an oven at 90-95°C;

[0022] (2) preparing 300 g of an aqueous solution of ammonium nitrate with a mass concentration of 92.5%, pouring the solution into a dry beaker, adding additives at 3%, 4%, 5% and 6% of the mass of the aqueous solution of ammonium nitrate, heating and stirring the solution in an oil bath at 125-130° C. until the solution is completely dissolved, and then turning off the power supply of the oil bath;

[0023] (3) Pour the aqueous ammonium nitrate solution into a preheated measuring cylinder, insert a preheated thermometer, and cool the aqueous ammonium nitrate solution naturally. During the cooling period, the solution should be gently stirred. When flocculent crystals are observed to precipitate, the temperature at this time is the crystallization point of the water phase. Repeat the test three times and take the average value. The crystallization points of 3%, 4%, 5% and 6% addition amounts are 103°C, 101°C, 98°C and 95°C, respectively.

[0024] Example 2

[0025] The additive for reducing the crystallization point of saturated ammonium nitrate solution of the present invention comprises, by mass fraction: the additive for reducing the crystallization point of saturated ammonium nitrate solution of the present invention comprises, by mass fraction: 40% of glycine, 25% of sodium glycinate, and 35% of sodium cocoyl glycinate.

[0026] The test steps of crystallization point are as follows:

[0027] (1) Preheat the thermometer, measuring cylinder and beaker in an oven at 90-95°C;

[0028] (2) preparing 300 g of an aqueous solution of ammonium nitrate with a mass concentration of 92%, pouring it into a dry beaker, adding 3%, 4%, 5% and 6% of the mass of the aqueous solution of ammonium nitrate as the composite additive, heating and stirring in an oil bath at 125-130° C. until the solution is completely dissolved, and turning off the power of the oil bath;

[0029] (3) Pour the aqueous ammonium nitrate solution into a preheated measuring cylinder, insert a preheated thermometer, and cool the aqueous ammonium nitrate solution naturally. During the cooling period, the solution should be gently stirred. When flocculent crystals are observed to precipitate, the temperature at this time is the crystallization point of the water phase. Repeat the test three times and take the average value. The crystallization points of 3%, 4%, 5% and 6% addition amounts are 101°C, 97°C, 94°C and 92°C, respectively.

[0030] Example 3

[0031] The additive for reducing the crystallization point of saturated ammonium nitrate solution of the present invention comprises, by mass fraction, 35% of glycine, 30% of sodium glycinate and 35% of sodium cocoyl glycinate.

[0032] The test steps of crystallization point are as follows:

[0033] (1) Preheat the thermometer, measuring cylinder and beaker in an oven at 90-95°C;

[0034] (2) preparing 300 g of an aqueous solution of ammonium nitrate with a mass concentration of 91.5%, pouring it into a dry beaker, adding 3%, 4%, 5% and 6% of the mass of the aqueous solution of ammonium nitrate as a composite additive, heating and stirring in an oil bath at 125-130° C. until the solution is completely dissolved, and turning off the power supply of the oil bath;

[0035] (3) Pour the aqueous ammonium nitrate solution into a preheated measuring cylinder, insert a preheated thermometer, and cool the aqueous ammonium nitrate solution naturally. During the cooling period, the solution should be gently stirred. When flocculent crystals are observed to precipitate, the temperature at this time is the crystallization point of the water phase. Repeat the test three times and take the average value. The crystallization points of 3%, 4%, 5% and 6% addition amounts are 98°C, 93°C, 90°C and 84°C, respectively.

[0036] Example 4

[0037] The additive for reducing the crystallization point of saturated ammonium nitrate solution of the present invention comprises, by mass fraction, 55% of glycine, 20% of sodium glycinate, and 25% of sodium cocoyl glycinate.

[0038] The test steps of crystallization point are as follows:

[0039] (1) Preheat the thermometer, measuring cylinder and beaker in an oven at 90-95°C;

[0040] (2) preparing 300 g of an aqueous solution of ammonium nitrate with a mass concentration of 91.0%, pouring it into a dry beaker, adding 3%, 4%, 5% and 6% of the mass of the aqueous solution of ammonium nitrate as the composite additive, heating and stirring in an oil bath at 125-130° C. until the solution is completely dissolved, and turning off the power of the oil bath;

[0041] (3) Pour the ammonium nitrate aqueous solution into a preheated measuring cylinder, insert a preheated thermometer, and cool the ammonium nitrate aqueous solution naturally. During the cooling period, the solution should be gently stirred continuously. When flocculent crystals are observed to precipitate, the temperature at this time is the crystallization point of the water phase. Repeat the test three times and take the average value. The crystallization points of 3%, 4%, 5% and 6% addition amounts are 93°C, 89°C, 83°C and 79°C, respectively.

[0042] Comparative Example 1

[0043] When the concentration of the ammonium nitrate aqueous solution is 91.0-92.5%, without adding glycine, sodium glycinate, or sodium cocoyl glycinate, the crystallization point of the pure ammonium nitrate aqueous solution is as shown in Table 1.

[0044] Table 1 Comparative Example 1 Ammonium nitrate saturated solution crystallization point test data

[0045] Ammonium nitrate concentration% 91.0 91.5 92.0 92.5 Crystallization point℃ 100 102 104 107

[0046] Since no additives are added, the concentration of the saturated ammonium nitrate aqueous solution is relatively high.

[0047] The mass fraction of the ammonium nitrate aqueous solution in Example 1 is 92.5%. When the amount of the additive added is 6%, the crystallization point can be reduced to 95°C. Compared with Comparative Example 1 without adding the additive, the crystallization point is reduced by 12°C.

[0048] The mass fraction of the ammonium nitrate aqueous solution in Example 2 is 92.0%. When the amount of the additive added is 6%, the crystallization point can be reduced to 92°C. Compared with Comparative Example 1 without adding the additive, the crystallization point is reduced by 10°C.

[0049] The mass fraction of the ammonium nitrate aqueous solution in Example 3 is 91.5%. When the amount of the additive added is 6%, the crystallization point can be reduced to 84°C. Compared with Comparative Example 1 without adding the additive, the crystallization point is reduced by 18°C.

[0050] The mass fraction of the ammonium nitrate aqueous solution in Example 4 is 91.0%. When the amount of the additive added is 6%, the crystallization point can be reduced to 79°C. Compared with Comparative Example 1 without adding the additive, the crystallization point is reduced by 21°C.

[0051] Comparative Example 2

[0052] On the basis of Example 4, the additive does not contain glycine, the amount of the additive added is the same as Example 4, and the other conditions remain unchanged. The crystallization point of the ammonium nitrate aqueous solution is shown in Table 2 below.

[0053] Table 2 Comparative Example 2 Ammonium nitrate saturated solution crystallization point test data

[0054]

[0055] It can be seen from Table 2 that, without adding glycine, the crystallization point of the saturated ammonium nitrate solution increases.

[0056] Comparative Example 3

[0057] On the basis of Example 4, the additive does not contain sodium glycinate, the amount of the additive added is the same as Example 4, and the other conditions remain unchanged. The crystallization point of the ammonium nitrate aqueous solution is shown in Table 3 below.

[0058] Table 3 Comparative Example 3 Ammonium nitrate saturated solution crystallization point test data

[0059]

[0060] As shown in Table 3, the crystallization point of the saturated ammonium nitrate solution increases without the addition of sodium glycinate. A variety of salt compounds that are soluble in water and do not react with ammonium nitrate are added to the ammonium nitrate solution to form a multi-element eutectic mixture, which moves the solution in the dissolution direction, prevents the formation of crystals, and reduces the crystallization point. Therefore, when Comparative Examples 2 and 3 do not contain glycine or sodium glycinate, the effect of reducing the crystallization point is reduced.

[0061] Comparative Example 4

[0062] On the basis of Example 4, the composite additive does not contain sodium cocoyl glycinate, the added amount of the additive is the same as Example 4, and the other conditions remain unchanged. The crystallization point of the ammonium nitrate aqueous solution is shown in Table 4.

[0063] Table 4 Comparative Example 1 Ammonium nitrate saturated solution crystallization point test data

[0064]

[0065] As shown in Table 4, under the condition of not adding sodium cocoyl glycinate, the crystallization point of saturated ammonium nitrate solution increases. Surfactant is an effective way and technical means to reduce the crystallization point of ammonium nitrate solution, and the micelle formed by surfactant in solution is adsorbed on the surface of solution to reduce the crystallization point. When sodium cocoyl glycinate surfactant is not added, the crystallization point is increased.

[0066] application

[0067] 1. On the basis of Example 4, an emulsified matrix was prepared, the formula of which was water phase: oil phase = 93:7 (mass percentage), the oil phase was 4% of composite wax and 3% of SPAN-80; considering the cost and the effect of reducing the crystallization point, the amount of the composite additive was 4% of the mass of the water phase. The properties of the emulsion explosive prepared by sensitizing with 3% expanded perlite are as follows:

[0068] Detonation velocity: 4500-4600m / s, intensity 13-15mm, sympathetic detonation distance 5-6cm. Detonation velocity: 3300-3500m / s, intensity 13-14mm, sympathetic detonation distance 4-5cm, the explosion performance still meets the requirements of GB28286-2012, and the addition of additives does not affect the detonation performance of the explosive.

[0069] 2. In the current production process of expanded ammonium nitrate explosive, the concentration of ammonium nitrate aqueous solution is in the range of 91.5-92.0%, and its heating melting and insulation temperature is generally 125-128°C. Taking into account the effect of reducing the crystallization point and the cost, on the basis of Example 3, 3% of the composite additive is added to the aqueous phase. For the preparation of expanded ammonium nitrate explosive, the formula is ammonium nitrate: oil: wood powder = 92:4:4 (mass percentage). In terms of mass percentage, 92% of the ammonium nitrate aqueous solution is mixed with 4% of the liquid composite wax (containing the swelling agent), expanded for 10 minutes under a vacuum condition of -0.092MPa, and then discharged, and mixed with 4% of the dry wood powder to obtain expanded ammonium nitrate explosive, and its explosion performance is as follows:

[0070] Detonation velocity: 3300-3500m / s, intensity 13-14mm, detonation distance 4-5cm, the explosion performance still meets the requirements of GB28286-2012, and the addition of additives does not affect the detonation performance of the explosive.

Claims

1. An additive for reducing the crystallization point of a saturated ammonium nitrate solution, characterized in that: The additives include glycine, sodium glycinate and sodium cocoyl glycinate, and by mass fraction, the glycine content is 30-55%, the sodium glycinate content is 20-35%, and the sodium cocoyl glycinate content is 25-35%. The dosage of the additives is 3-6% of the saturated ammonium nitrate solution.

2. The additive for reducing the crystallization point of saturated ammonium nitrate solution according to claim 1, characterized in that: The additives include, by mass fraction, 30-45% glycine, 25-35% sodium glycinate, and 30-35% sodium cocoyl glycinate.

3. The additive for reducing the crystallization point of saturated ammonium nitrate solution according to claim 1, characterized in that: The purity of the glycine is 99.5-99.7%.

4. The additive for reducing the crystallization point of saturated ammonium nitrate solution according to claim 1, characterized in that The purity of the sodium glycinate is 98-99%.

5. The additive for reducing the crystallization point of saturated ammonium nitrate solution according to claim 1, characterized in that: The purity of the sodium cocoyl glycinate is 93-98%.

6. The additive for reducing the crystallization point of saturated ammonium nitrate solution according to claim 1, characterized in that: The dosage of the additive is 4-5% of the saturated ammonium nitrate solution.

7. A method for using the additive for reducing the crystallization point of saturated ammonium nitrate solution according to claim 1, characterized in that: The following steps are involved: The additive is added into the saturated ammonium nitrate solution and dissolved, so that the additive and the saturated ammonium nitrate solution serve as the water phase of the emulsion explosive or the expanded ammonium nitrate explosive.

8. The method for using the additive for reducing the crystallization point of saturated ammonium nitrate solution according to claim 7, characterized in that: The mass fraction of the saturated ammonium nitrate solution is 91.0-92.5%.

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