Efficient treatment method of industrial waste salt

Abstract

The application discloses an efficient treatment method of industrial waste salt, comprising the following steps: mixing the industrial waste salt with a certain proportion of functional particles, and performing microwave treatment; wherein the functional particles are composed of first functional particles and second functional particles; the first functional particles are selected from one or more of silicon carbide, diiron trioxide, titanium dioxide and zinc oxide; and the second functional particles are selected from one or more of 2,6-di-tert-butyl-p-cresol, hydroquinone, tert-butyl catechol and copper naphthenate. The functional particles used in the application have multiple functions such as microwave absorption, reaction catalysis, polymerization inhibition and antioxidation, etc. When the functional particles are mixed with the industrial waste salt and subjected to microwave irradiation, the organic and inorganic small molecules can be catalyzed to crack and generate gaseous small molecules, and meanwhile, the organic matters in the industrial waste salt can be prevented from polymerization, so that the increase of the content of organic polymers in the waste salt is avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of purifying industrial waste salt, and more particularly to an efficient treatment method of industrial waste salt. BACKGROUND

[0002] A large amount of high-salt and high-organic wastewater is generated in the industrial production processes of power, coal chemical industry, metallurgy, printing and dyeing, papermaking, etc. The wastewater usually contains more than 3000 mg / L of salt and more than 5000 mg / L of COD, and contains a large amount of toxic and harmful organic matters such as aromatic compounds, heterocyclic compounds, and hydrocarbon compounds. If the wastewater is directly discharged, it will not only cause waste of resources, but also cause environmental pollution. In order to reduce the amount of waste liquid, many enterprises use the method of heating and drying to evaporate the waste salt solution into waste salt, which is commonly known as industrial waste salt. Industrial waste salt includes not only mainstream sodium chloride waste salt, but also potassium sulfate, sodium sulfate, ferrous sulfide waste salt. These industrial waste salts contain a large amount of organic or inorganic impurities and cannot be directly used as industrial raw salt, let alone for edible or medical use. Most manufacturers store them. In particular, the industrial waste salt discharged by chemical enterprises has the characteristics of various types, complex composition, high content of toxic and harmful substances, high treatment cost, and great environmental harm. At present, it has been listed as hazardous waste by the environmental protection department. Therefore, the harmless treatment of industrial waste salt has become a problem to be solved.

[0003] The traditional treatment methods of industrial waste salt include dilution with water, distillation or combustion treatment. The dilution with water cannot change the total amount of high-salt wastewater, but only increases the waste of water. The distillation method evaporates the salt from the wastewater. The evaporated salt cannot be used as industrial salt because it contains a certain amount of organic matter and has a slight odor. The direct thermal combustion method involves spraying waste salt powder into an incinerator, where the organic matter and decomposable components decompose at high temperature. However, sodium chloride industrial waste salt loses a certain proportion (about 10%) of its weight when burned at 500 degrees. When burned at 800℃, it melts and falls to the bottom of the incinerator, causing equipment corrosion and blockage. Other harmless treatments of industrial waste salt have been studied, but many problems remain unsolved. For example, Chinese invention patent CN104344407A proposes a method of using microwave heating to decompose organic matter and decomposable inorganic salt in waste salt. The technical key is to perform microwave treatment in a nitrogen atmosphere at 450-500℃, so that the small molecules of organic and inorganic matter in the waste salt are cracked to generate gas molecules, thereby achieving the harmless treatment of waste salt. However, this technology has the following obvious technical defects: 1) sodium chloride is a weak microwave absorption medium, and it is difficult to achieve efficient heating through microwave treatment; 2) in a nitrogen atmosphere, long-chain organic matter and aromatic, condensed ring, and heterocyclic organic matter often undergo polymerization and coking reactions, rather than oxidative decomposition, which increases the content of organic polymers similar to tar in the waste salt, making it darker in color, and its toxicity does not decrease significantly, but even increases. SUMMARY

[0004] In view of the above defects of the prior art, the purpose of the present application is to find a new method to realize the harmless treatment of industrial waste salt, which can greatly reduce the COD value and nitrate content on the surface of industrial waste salt under low temperature and low energy consumption, and does not affect the content and structure of the main components of industrial waste salt.

[0005] To achieve the above purpose, the present application adopts the following technical solutions:

[0006] In a first aspect, the present application provides an efficient treatment method for industrial waste salt, comprising the following steps:

[0007] mixing the industrial waste salt with a certain proportion of functional particles and performing microwave treatment;

[0008] wherein the functional particles are composed of first functional particles and second functional particles; the first functional particles are selected from one or more of silicon carbide, diiron trioxide, titanium dioxide and zinc oxide; the second functional particles are selected from one or more of 2,6-di-tert-butyl-p-cresol, hydroquinone, tert-butyl catechol and copper naphthenate.

[0009] The functional particles used in the present application have multiple functions such as microwave absorption, reaction catalysis, polymerization inhibition and antioxidant, etc. When mixed with industrial waste salt and subjected to microwave irradiation treatment, they can catalyze the cracking of organic and inorganic small molecules to generate gaseous small molecules, and at the same time prevent the polymerization of organic matter in the industrial waste salt, thereby avoiding the increase of organic polymer content in the waste salt.

[0010] Further, the weight ratio of the functional particles to the industrial waste salt is 10-0.1.

[0011] Further, the weight ratio of the first functional particles to the second functional particles is 10-0.1.

[0012] Further, the temperature of the microwave treatment is 50-900℃. The temperature of the microwave treatment is determined according to the melting point of the industrial waste salt to be treated. For example, when the main components of the industrial waste salt are sodium chloride, sodium sulfate and their hydrates with a melting point around 800℃, the temperature of the microwave treatment can be selected as 200-450℃. When the main components of the industrial waste salt are potassium sulfate and iron sulfide with a melting point around 1000℃, the temperature of the microwave treatment can be selected as 400-800℃.

[0013] Furthermore, when the main component of the industrial waste salt is sodium chloride, the microwave treatment temperature is 200℃-450℃, preferably 200-300℃; when the main component of the industrial waste salt is sodium sulfate, the microwave treatment temperature is 200℃-400℃. It can be understood that, compared with traditional thermal combustion methods, the treatment method of the present invention can further reduce the purification temperature of industrial waste salt.

[0014] Furthermore, the microwave treatment time is 1 min to 300 min.

[0015] Furthermore, the gas atmosphere during the microwave processing is one or a mixture of several of the following: air, nitrogen, carbon dioxide, and argon. It is understood that the method of this invention can be carried out in almost any common atmosphere, including those controlled in a certain proportion of combustible gas, such as a mixture of nitrogen and hydrogen in a certain ratio.

[0016] Furthermore, the frequency of the microwave processing is 915±50MHz or 2450±50MHz.

[0017] Furthermore, prior to microwave treatment, a step of laying a mixture of industrial waste salt and functional particles is included, wherein the thickness of the mixture is between 0.5 cm and 100 cm.

[0018] Furthermore, the particle size of the industrial waste salt is less than 0.5 mm; the particle size of the functional particles is 0.02 mm to 5 mm.

[0019] Furthermore, the microwave treatment process also includes a step of collecting and treating the generated organic waste gas.

[0020] Furthermore, unless otherwise specified, any range described in this invention includes the endpoints, any values ​​between the endpoints, and any subranges formed by the endpoints or any values ​​between the endpoints. Unless otherwise specified, the preparation methods in this invention are conventional methods, and the raw materials used can be obtained from publicly available commercial sources or prepared according to existing technology. Unless otherwise specified, all percentages are mass percentages, and all solutions are aqueous solutions.

[0021] The beneficial effects of this invention are as follows:

[0022] This invention provides an efficient and feasible method for treating industrial waste salt. The method involves mixing specific functional particles with the industrial waste salt to be treated and then subjecting it to microwave irradiation treatment under any atmosphere. This achieves the goal of effectively reducing the COD value and nitrate content on the surface of industrial waste salt under low temperature and low energy consumption conditions, while avoiding the loss of the industrial waste salt's quality. Attached Figure Description

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly introduced. Obviously, the drawings in the following description only constitute some embodiments of the present application, and all other drawings that can be obtained by those skilled in the art without creative effort based on these drawings also belong to the protection scope of the present application.

[0024] Figure 1 A table of component analysis of the industrial waste salt of Example 1 before and after being treated by different methods is shown.

[0025] Figure 2 A sample photo of the industrial waste salt of Example 1 before being treated is shown.

[0026] Figure 3 A sample photo of the industrial waste salt of Example 1 after being treated is shown.

[0027] Figure 4 A sample photo of the industrial waste salt of Example 3 before being treated is shown.

[0028] Figure 5 A sample photo of the industrial waste salt of Example 3 after being treated is shown.

[0029] Figure 6 A sample photo of the industrial waste salt of Comparative Example 1 after being treated is shown. DETAILED DESCRIPTION

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly introduced. Obviously, the drawings in the following description only constitute some embodiments of the present application, and all other drawings that can be obtained by those skilled in the art without creative effort based on these drawings also belong to the protection scope of the present application.

[0031] The purity of all raw materials in the present application is not particularly limited, and the purity of the analytical pure is preferred.

[0032] The source and abbreviation of all raw materials in the present application belong to the conventional source and abbreviation in the art, and are clear and explicit in the field of their relevant use. The skilled in the art can purchase or prepare by conventional method according to the abbreviation and corresponding use.

[0033] Example 1

[0034] 1. Raw material: industrial waste salt of main intermediate of producing macrolide and broad-spectrum antibiotic (main component is sodium chloride) (see Figure 2

[0035] Functional particles: silicon carbide and hydroquinone particles with a mass ratio of 5:1. ​

[0036] 2. Treatment method:

[0037] Microwave group: 150g of industrial waste salt was crushed to a particle size of less than 0.5mm, then mixed with functional particles of a particle size of 2mm (weight ratio of industrial waste salt to functional particles was 1:10), laid in a microwave treatment device with a laying thickness of 8cm, argon as carrier gas, and the microwave generator was turned on, microwave power was 320W, microwave frequency was 2450±50MHz, and the temperature was controlled at 250°C. After microwave treatment for 30min, the mixture was unloaded.

[0038] Pyrolysis group-1: three equal parts of 150g of industrial waste salt were crushed to a particle size of less than 0.5mm, then laid in a pyrolysis device respectively with a laying thickness of 8cm, nitrogen as carrier gas, and heat treatment was carried out at different temperatures. After 120min, the mixture was unloaded.

[0039] Pyrolysis group-2: three equal parts of 150g of industrial waste salt were crushed to a particle size of less than 0.5mm, then laid in a pyrolysis device respectively with a laying thickness of 8cm, air as carrier gas, and heat treatment was carried out at different temperatures. After 120min, the mixture was unloaded.

[0040] 3. Detection and comparison:

[0041] A small amount of industrial waste salt before and after treatment in the above three groups was taken out, washed with water, and then COD was detected by spectrophotometry using a concentrated sulfuric acid / potassium permanganate system, and NO3 - was detected by ultraviolet spectrophotometry. The detection results are shown in Table 1. It can be seen from the table that the COD components and NO3 - in the microwave group before and after treatment were greatly reduced. The COD value of the original sample was 440mg / L, and the COD value of the treated sample was 7mg / L, which was reduced by about 98%. The nitrate content of the original sample was 767.9mg / L, and the nitrate content of the treated sample was 1.806mg / L, which was reduced by nearly 100%. The gas produced was detected by GC, which showed that H2, CO and CO2 were mainly generated. In the pyrolysis group, whether oxygenated or not, the COD components and NO3 - before and after treatment of the waste salt were higher than those in the microwave group.

[0042] 4. Post-treatment: The mixture unloaded from the microwave group was washed with deionized water as shown in Table 2. The sodium chloride therein was dissolved in deionized water and discharged and collected for recrystallization extraction. The silicon carbide particles were recovered by sedimentation separation and reused. Figure 3

[0043] Example 2

[0044] 1. Raw materials: same as in Example 1;

[0045] ​Functional particles: zinc oxide and tert-butyl catechol particles in a mass ratio of 10:1.

[0046] 2. Treatment method: 50 g of industrial waste salt was crushed to a particle size of less than 0.5 mm, then mixed with functional particles of a particle size of 1 mm (weight ratio of industrial waste salt to functional particles was 1:10), and laid in a microwave treatment device with a laying thickness of 5 cm, using nitrogen as the carrier gas, and opening the microwave generator, microwave power was 240 W, microwave frequency was 2450±50 MHz, and the temperature was controlled at 250°C. After microwave treatment for 30 min, the mixture was unloaded.

[0047] 3. Detection and analysis: After the mixture was washed with water, the COD was detected by spectrophotometry using a concentrated sulfuric acid / potassium permanganate tert-butyl catechol system, and NO3 - was determined by ultraviolet spectrophotometry. The detection results showed that the COD component and NO3 - were almost completely decomposed.

[0048] 4. Post-treatment: The unloaded mixture was washed with deionized water, NaCl was dissolved in deionized water and discharged and collected, and recrystallization extraction was performed, and zinc oxide particles were recovered by sedimentation separation for reuse.

[0049] Example 3

[0050] 1. Raw material: industrial waste salt mainly containing sodium sulfate (see Figure 4 );

[0051] Functional particles: ferric sesquioxide and 2,6-di-tert-butyl-p-cresol in a mass ratio of 10:1.

[0052] 2. Treatment method: 10 g of industrial waste salt was crushed to a particle size of less than 0.5 mm, then mixed with functional particles of a particle size of 5 mm in a mass ratio of 1:10, and laid in a microwave treatment device with a laying thickness of 2 cm, using carbon dioxide as the carrier gas, and opening the microwave generator, microwave power was 240 W, microwave frequency was 2450±50 MHz, and the temperature was controlled at less than 300°C. After microwave treatment for 30 min, the mixture was unloaded.

[0053] 3. Detection and analysis: After the mixture was washed with water (see Figure 5 ), a small amount was taken and the COD was detected by spectrophotometry using a concentrated sulfuric acid / potassium permanganate system, and NO3 - was determined by ultraviolet spectrophotometry. The detection results showed that the COD component, crystal water, and byproduct residual carbon in the degradation process were almost completely decomposed.

[0054] 4. Post-treatment: The remaining solid after the mixture was washed with water was separated from the microwave absorption medium by sieving without the need for recovery by recrystallization.

[0055] Comparative Example 1

[0056] 1. Raw materials: same as Example 3

[0057] Functional particles: ferric oxide

[0058] 2. Treatment method: 10 g of industrial waste salt was crushed to a particle size of less than 0.5 mm, then mixed with functional particles of particle size 5 mm at a mass ratio of 1:10, and laid in a microwave treatment device with a laying thickness of 2 cm. Carbon dioxide was used as the carrier gas, and the microwave generator was turned on. The microwave power was 240 W, the microwave frequency was 2450±50 MHz, and the temperature was controlled to be less than 300°C. After microwave treatment for 30 min, the mixture was unloaded.

[0059] 3. Detection and analysis: After the mixture was washed with water (see Figure 6 ), a small amount was taken and the COD was detected by spectrophotometry using a concentrated sulfuric acid / potassium permanganate system. The NO3 - was measured by ultraviolet spectrophotometry. The results showed that the COD components, crystallization water, and by-products residual carbon in the degradation process were almost completely decomposed, but a certain amount of polymer material adhered to the surface of the sodium sulfate salt. At the same time, from Figure 6 it can also be seen that the waste salt surface contains organic polymers similar to tar, resulting in a darker color of the waste salt.

[0060] 4. Post-treatment: The remaining solid after the mixture was washed with water was separated from the microwave absorbing medium by sieving, but the polymers on the surface of the sodium sulfate could not be completely removed.

[0061] Obviously, the above examples of the present application are only examples for the purpose of clearly illustrating the present application, and are not intended to limit the embodiments of the present application. For those skilled in the art, on the basis of the above description, other different forms of changes or variations can also be made, and it is impossible to exhaust all the embodiments here. Any obvious changes or variations derived from the technical solutions of the present application still fall within the protection scope of the present application.

Claims

1. A method for efficient treatment of industrial waste salt, characterized by, The method comprises the following steps: mixing industrial waste salt with a certain proportion of functional particles and carrying out microwave treatment; The functional particles are composed of first functional particles and second functional particles; the first functional particles are selected from one of silicon carbide, ferric oxide and zinc oxide; the second functional particles are selected from one of 2,6-di-tert-butyl-p-cresol, hydroquinone and tert-butyl catechol; The weight ratio of the functional particles to the industrial waste salt is 10-0.1; The weight ratio of the first functional particles to the second functional particles is 10-0.1; When the main component of the industrial waste salt is sodium chloride, the temperature of the microwave treatment is 200-450℃; When the main component of the industrial waste salt is sodium sulfate, the temperature of the microwave treatment is 200-400℃; The time of the microwave treatment is 1-300 minutes; The frequency of the microwave treatment is 915±50MHz or 2450±50MHz; The particle size of the industrial waste salt is less than 0.5mm; the particle size of the functional particles is 0.02-5mm.

2. The efficient processing method of claim 1, wherein, During the microwave treatment, the gas atmosphere is one or a mixture of several of air, nitrogen, carbon dioxide and argon.

3. The efficient processing method of claim 1, wherein, Before the microwave treatment, the method further comprises the step of laying the mixture of the industrial waste salt and the functional particles, and the thickness of the laid mixture is 0.5-100cm.

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