Acid-base neutralization filtering method for waste acid treatment in explosive and powder process

Abstract

The invention discloses an acid-base neutralization and filtration method for waste acid treatment in an explosive and powder process, which comprises the following steps: 1) adding water and a first alkaline reagent into explosive waste acid after acidification reaction, stirring while cooling, carrying out ultrasonic treatment, washing, filtering and recovering solid particles to obtain a first treatment solution with the acidity reduced to the pH value of 0.5-1; and 2) heating the first treatment liquid, adding a second alkaline reagent, cooling while stirring, carrying out ultrasonic treatment, washing, and filtering by using a ceramic filter plate to recover solid particles so as to obtain a neutralized treatment material.By adopting the method, the problems of large impurity amount and high possibility of blockage in filtration during initial treatment of the waste acid can be solved.

Description

Technical Field

[0001] The invention belongs to the technical field of explosives and pyrotechnics, and in particular relates to an acid-base neutralization and filtering method for treating waste acid in explosives and pyrotechnics. Background Art

[0002] Explosives factories discharge a large amount of acidic wastewater during the acid production process. The wastewater contains a variety of highly toxic substances. Therefore, the waste acid must be treated to meet the emission standards before it can be discharged. However, since the waste acid after the reaction contains a variety of organic compounds, there are problems such as easy clogging in the early filtration and difficulty in precipitation of small molecular particles in the later stage during the washing and precipitation process. As a result, it is difficult to fully remove impurities in the initial waste acid treatment process, and multiple post-treatments are required before it can be discharged. Therefore, in the initial waste acid treatment process, method optimization is required to ensure that the impurities in the waste acid are significantly reduced during the initial treatment. Summary of the invention

[0003] In order to solve the problems of large amount of impurities and easy clogging of the filter in the initial treatment of the above-mentioned waste acid, the present invention provides an acid-base neutralization filtration method for treating the waste acid in the explosive process.

[0004] The acid-base neutralization and filtration method for treating waste acid from explosives and propellants of the present invention comprises the following steps: 1) adding water and a first alkaline reagent to the spent explosive acid after the acidification reaction, stirring and ultrasonically treating the spent explosive acid while cooling the spent explosive acid, washing the spent explosive acid, filtering and recovering the solid particles, and obtaining a first treated liquid with the acidity reduced to a pH of 0.5-1; 2) After heating the first treatment liquid, add the second alkaline reagent, cool it down while stirring, ultrasonically treat it, wash it, and use a ceramic filter plate to filter and recover the solid particles to obtain a neutralized treatment liquid.

[0005] In step 1), the volume ratio of waste acid to water is 1:5-20, and the molar ratio of the acid radical of the waste acid to the hydroxide radical of the first alkaline reagent is 10:2-7; the waste acid is one or more of nitric acid, nitric acid and sulfuric acid, sulfuric acid, acetic acid and hydrochloric acid; the first alkaline reagent is one or more of potassium hydroxide, sodium hydroxide, calcium hydroxide and quicklime, and quicklime will turn into calcium hydroxide when it meets water.

[0006] In step 1), the explosive is any one of hexanitrohexaazaisowurtzitane (CL-20 or HNIW), triaminotrichlorobenzene (TCTNB), octogen (HMX), hexogen (RDX), and trinitrotoluene (TNT).

[0007] In step 1), the starting temperature of the cooling is 60°C-70°C, the cooling is to 0°C-20°C, and the temperature gradient of the cooling is 0.3-10°C / min.

[0008] In step 2), the molar ratio of the acid radical of the first treatment solution to the hydroxide radical of the second alkaline agent is 10:5-10, and the second alkaline agent is one or more of potassium hydroxide, sodium hydroxide, calcium hydroxide, and quicklime. The first alkaline agent and the second alkaline agent may be the same or different.

[0009] In step 2), the temperature is raised to 70°C-85°C, and the temperature is lowered to 20°C, and the temperature gradient of the temperature reduction is 0.3-10°C / min.

[0010] In step 2), the pore size of the ceramic filter plate is 0.5-80 microns.

[0011] In step 1) and step 2), the ultrasonic vibration frequency is 50-200 kHz, the vibration frequency gradient is 0-30 kHz / min, and the waste acid washing time is 5-30 min.

[0012] Beneficial effects: The present invention adds an alkaline reagent to the waste acid after the reaction for neutralization, performs stirring and ultrasonic treatment, adds a ceramic filter plate layer during the filtration process, utilizes micropores that produce a capillary effect, makes the capillary force in the micropores greater than the force applied by the vacuum, and performs waste liquid filtration; the filtration method of the present invention can improve the problem of easy clogging of the initial waste acid filtration, effectively precipitates and recovers fine particles in the waste acid, reduces the impurity content of the waste liquid, and improves the waste acid treatment efficiency. DETAILED DESCRIPTION

[0013] The present invention will now be further described in detail by way of examples, but the present invention is not limited to the examples. Example

[0014] Take 1L of TNT nitric-sulfuric mixed acid waste acid with a total nitrate and sulfate concentration of 5 mol / L determined by chromatography and 5L of deionized water and add them into a beaker in sequence, add 2.5 mol of potassium hydroxide, cool from 60°C to 0°C while stirring, the temperature gradient is 5°C / min, use an ultrasonic instrument to perform ultrasonic treatment, increase the ultrasound from 50 kHz to 60 kHz, the gradient is 2 kHz / min, the washing time is 10 minutes, and use ordinary filter paper to filter and recover solid particles to obtain a first treatment liquid with the acidity reduced to a pH of 0.5-1.

[0015] The nitrate and sulfate concentrations in the first treatment liquid were determined by chromatography to be 2.5 mol / L in total. 1L was taken out and heated to 70°C. 2.5 mol of potassium hydroxide was added. The temperature was lowered from 70°C to 20°C while stirring. The temperature gradient was 10°C / min. Ultrasonic treatment was performed using an ultrasonic instrument. The ultrasound was increased from 50 kHz to 60 kHz with a gradient of 2 kHz / min. The washing time was 10 minutes. The waste acid was neutralized and filtered using a ceramic filter plate with a pore size of 40 microns produced by Ivans (Jiaozuo) New Materials Co., Ltd. to recover solid particles. The COD content of the neutralized wastewater was 800 mg / mL. Example

[0016] 1L of CL-20 nitric acid waste acid with a nitrate concentration of 5 mol / L determined by chromatography and 5L of deionized water are added to a beaker in sequence, and 2.5 mol of potassium hydroxide is added. The mixture is cooled from 70°C to 20°C while being stirred, with a temperature gradient of 5°C / min. Ultrasonic treatment is performed using an ultrasonic instrument, and the ultrasound is maintained at 80 kHz. The washing time is 10 minutes. Ordinary filter paper is used for filtering and recovering solid particles, so as to obtain a first treatment liquid with the acidity reduced to a pH of 0.5-1.

[0017] The nitrate concentration in the first treatment liquid was determined to be 5 mol / L by chromatography, 1 L of the solution was taken out and heated to 70°C, 2.5 mol of potassium hydroxide was added, and the temperature was lowered from 70°C to 20°C while stirring, the temperature gradient was 10°C / min, the ultrasound was maintained at 80 kHz, the washing time was 10 minutes, the waste acid was neutralized, and a ceramic filter plate with a pore size of 40 microns produced by Ivans (Jiaozuo) New Materials Co., Ltd. was used to filter and recover solid particles, and the neutralized wastewater COD content was 1000 mg / mL.

[0018] Comparative Example 1 Take 1L of TNT nitric-sulfuric mixed acid waste acid with a total nitrate and sulfate concentration of 5 mol / L determined by chromatography and 5L of deionized water and add them into a beaker in sequence, add 2.5 mol of potassium hydroxide each time in two times, stir at 25°C, wash for 10 minutes, wash twice, and the COD content of the obtained wastewater is 2000 mg / mL.

[0019] Comparative Example 2 Take 1L of CL-20 nitric acid waste acid with a nitrate concentration of 5 mol / L determined by chromatography and 5L of deionized water and add them into a beaker in sequence, add 2.5 mol of potassium hydroxide twice, stir at 25°C, wash for 10 minutes, wash twice, and the COD content of the obtained wastewater is 2800 mg / mL.

[0020] The above-mentioned technologies not specifically mentioned are all referred to the prior art.

[0021] Based on the above-mentioned ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above-mentioned description. The technical scope of the present invention is not limited to the contents of the specification.

Claims

1. A method for acid-base neutralization and filtration for treating waste acid from explosives and propellants, characterized in that: The following steps are involved: 1) adding water and a first alkaline reagent to the spent explosive acid after the acidification reaction, stirring and ultrasonically treating the spent explosive acid while cooling the spent explosive acid, washing the spent explosive acid, filtering and recovering the solid particles, and obtaining a first treated liquid with the acidity reduced to a pH of 0.5-1; 2) After heating the first treatment liquid, add the second alkaline reagent, cool it down while stirring, ultrasonically treat it, wash it, and use a ceramic filter plate to filter and recover the solid particles to obtain a neutralized treatment liquid.

2. The acid-base neutralization filtration method for treating waste acid from explosives and propellants according to claim 1, characterized in that: In step 1), the volume ratio of waste acid to water is 1:5-20, and the molar ratio of the acid radical of the waste acid to the hydroxide radical of the first alkaline reagent is 10:2-7; the waste acid is one or more of nitric acid, nitric acid and sulfuric acid, sulfuric acid, acetic acid and hydrochloric acid; and the first alkaline reagent is one or more of potassium hydroxide, sodium hydroxide, calcium hydroxide and quicklime.

3. The acid-base neutralization filtration method for treating waste acid from explosives and propellants according to claim 1, characterized in that: In step 1), the explosive is any one of hexanitrohexaazaisowurtzitane, triaminotrichlorobenzene, octogen, hexogen, and trinitrotoluene.

4. The acid-base neutralization filtration method for treating waste acid from explosives and propellants according to claim 1, characterized in that: In step 1), the starting temperature of the cooling is 60°C-70°C, the cooling is to 0°C-20°C, and the temperature gradient of the cooling is 0.3-10°C / min.

5. The acid-base neutralization and filtration method for treating waste acid from explosives and propellants according to claim 1, characterized in that: In step 2), the molar ratio of the acid radical of the first treatment solution to the hydroxide radical of the second alkaline agent is 10:5-10, and the second alkaline agent is one or more of potassium hydroxide, sodium hydroxide, calcium hydroxide, and quicklime.

6. The acid-base neutralization filtration method for treating waste acid from explosives and propellants according to claim 1, characterized in that: In step 2), the temperature is raised to 70°C-85°C, and the temperature is lowered to 20°C, and the temperature gradient of the temperature reduction is 0.3-10°C / min.

7. The acid-base neutralization filtration method for treating waste acid from explosives and propellants according to claim 1, characterized in that: In step 2), the pore size of the ceramic filter plate is 0.5-80 microns.

8. The acid-base neutralization filtration method for treating waste acid from explosives and propellants according to claim 1, characterized in that: In step 1) and step 2), the ultrasonic vibration frequency is 50-200 kHz, the vibration frequency gradient is 0-30 kHz / min, and the waste acid washing time is 5-30 min.