Resourceful treatment method of industrial waste salt sulfate

Abstract

The invention relates to a resourceful treatment method of industrial waste salt sulfate, which is characterized in that the industrial waste salt sulfate reacts with sulfur trioxide at medium temperature to convert the sulfate into pyrosulfate. The process not only can avoid high treatment cost due to treatment of the industrial waste salt sulfate as hazardous waste, but also can avoid potential risks of the industrial waste salt sulfate to the environment, and can also realize resource utilization of the industrial waste salt sulfate and realize circular economy. And in the whole process of recycling the industrial waste salt sulfate, no secondary pollution is generated, and the production requirements of green chemical industry can be met. The industrial waste salt sulfate is turned into wealth, so that the method has very important practical significance and good social benefits, and has important strategic significance for building an environment-friendly and resource-saving society.

Description

Technical Field

[0001] The invention relates to a resource treatment method for industrial waste salt sulfate, belonging to the technical field of post-treatment resource recovery of chemical solid / hazardous waste. Background Art

[0002] With the rapid development of the national economy, people's quality of life has been greatly improved, but the discharge of urban domestic sewage, especially industrial wastewater, has also increased sharply. In particular, some industries, such as printing and dyeing, papermaking, chemicals and pesticides, produce high-salt organic wastewater during the production process. The conventional treatment method for these salty organic wastewaters is evaporation and concentration, and the salt-free condensed water is sent to the sewage station for treatment and then discharged in compliance with the standards. However, there is currently no effective treatment measure for the solid salt obtained by centrifugation. Generally, enterprises simply treat it and outsource it as solid waste, while other enterprises directly dispose of it as hazardous waste, which not only consumes high disposal costs, but also poses greater environmental risks. Therefore, how to convert industrial waste salt sulfate into chemical products is a technical problem that needs to be solved urgently.

[0003] For chemical waste salt sulfate, such as potassium sulfate, the conventional treatment method is to prepare it into a solution for oxidation treatment to remove the organic matter in it, and then use it as fertilizer or other purposes. Although the organic matter in potassium sulfate has been effectively removed, it still contains toxic substances when used for crops, and there is still a certain risk.

[0004] Patent document CN114700354A discloses a method for harmless treatment of industrial waste salt, in which industrial waste salt, conversion aids and auxiliary materials are subjected to high temperature oxidation of organic matter in the industrial waste salt, harmlessly decomposed, melting, crystal deconstruction, dissolution, mineralization precursor formation, solid solution reconstruction, low-temperature eutectic formation and other reactions. The liquid melt generated by the reaction is quenched and cooled to finally obtain a dense solid solution product; the toxic organic matter in the industrial waste salt is completely harmlessly decomposed at high temperature, the precursors for the synthesis of dioxin-type POPs toxic substances that cannot be avoided by conventional high-temperature treatment are eliminated from the source, and the soluble inorganic salt components and heavy metals in the industrial waste salt are sealed in a dense solid solution material network structure, without the risk of environmental dissolution, and can be utilized as a resource. Although this method can completely decompose the toxic organic matter in industrial waste salt harmlessly, the processing steps are complicated and cumbersome, and need to be carried out at high temperature, with high energy consumption and potential safety hazards.

[0005] Therefore, there is an urgent need for a simple, efficient, and non-secondary pollution method for resource treatment of industrial waste salt sulfate. Summary of the invention

[0006] In view of the deficiencies in the prior art, the present invention provides a method for resource processing of industrial waste salt sulfate.

[0007] The present invention utilizes the simplest and most efficient method to process industrial waste salt sulfate as a resource, converts waste salt sulfate into pyrosulfate through specific process parameters, and processes industrial waste salt sulfate efficiently with high yield, thereby avoiding high disposal costs and eliminating possible risks to the environment, and also utilizing the waste salt as a resource to generate great industrial value. The obtained product can be directly used in industry, or used as an ore flux, or used to process chemical waste salt chloride.

[0008] The present invention is achieved through the following technical solutions:

[0009] A method for recycling industrial waste salt sulfate comprises the following steps:

[0010] Industrial waste salt sulfate reacts with sulfur trioxide at 50-200°C to obtain pyrosulfate.

[0011] The equation for the above reaction is shown below:

[0012] R2SO4+SO3→R2S2O7

[0013] Preferably according to the present invention, the industrial waste salt sulfate contains organic matter or does not contain organic matter, and the mass content of organic matter is less than 10% by mass percentage.

[0014] Preferably according to the present invention, the mass content of organic matter is 0-5%.

[0015] Preferably according to the present invention, the mass content of organic matter is 0.5-1%.

[0016] Preferably according to the present invention, the sulfate in the industrial waste salt sulfate is any one of sodium sulfate, potassium sulfate and magnesium sulfate.

[0017] Preferably according to the present invention, the molar ratio of industrial waste salt sulfate to sulfur trioxide is 1:(0.8-2).

[0018] Preferably according to the present invention, the molar ratio of industrial waste salt sulfate to sulfur trioxide is 1:(1-2).

[0019] Preferably according to the present invention, the molar ratio of industrial waste salt sulfate to sulfur trioxide is 1:(1.2-1.5).

[0020] According to the preferred embodiment of the present invention, the reaction temperature is 80-180°C.

[0021] According to the preferred embodiment of the present invention, the reaction temperature is 80-150°C.

[0022] According to the preferred embodiment of the present invention, the reaction time is 10-180 min.

[0023] According to the preferred embodiment of the present invention, the reaction time is 120-180 min.

[0024] According to the preferred embodiment of the present invention, the mass concentration of sulfur trioxide is 80-99%. When the concentration is lower than 80%, the reaction can still proceed, but the reaction efficiency is significantly reduced.

[0025] According to the present invention, preferably, the sulfur trioxide is liquid sulfur trioxide or gaseous sulfur trioxide.

[0026] The technical features and advantages of the present invention are as follows:

[0027] 1. The present invention utilizes the simplest and most efficient method to process industrial waste salt sulfate as a resource. Through specific process parameters, waste salt sulfate is converted into pyrosulfate, and industrial waste salt sulfate is efficiently processed with a high yield. It not only avoids high disposal costs and eliminates possible risks to the environment, but also can be utilized as a resource to generate great industrial value. The obtained product can be directly used in industry, or used as an ore flux, or used to treat chemical waste salt chloride.

[0028] 2. The present invention adopts a one-step treatment to directly convert industrial waste salt sulfate into pyrosulfate. The treatment steps are simple and can be carried out at medium temperature without high temperature. The energy consumption is low and there is no safety hazard. The pyrosulfate yield is high and the purity is high.

[0029] 3. Since sulfur trioxide has strong oxidizing properties, it can effectively remove organic matter that may exist in sulfate. Therefore, the sulfate used in the present invention can be a raw material or a chemical waste salt sulfate containing certain pollutants. DETAILED DESCRIPTION

[0030] In order to further illustrate the present invention, the method for treating industrial waste salt sulfate provided by the present invention is described in detail below with reference to examples.

[0031] The sulfate used in the embodiments provided by the present invention mainly comes from the chemical industry, and is a solid salt obtained by evaporating and concentrating high-salt organic wastewater, with an organic matter content of about 1%.

[0032] The purity detection method of sodium pyrosulfate or potassium pyrosulfate in the embodiment is to detect the content of hydrogen sulfate after dissolving it in water, and then convert it.

[0033] Example 1

[0034] The resource treatment method of industrial waste salt sulfate is as follows:

[0035] Take 66.12g of chemical waste salt sodium sulfate (containing 1.2% organic matter) into the reaction device, heat it to keep the temperature of the whole system stable at 150°C, then slowly add 56g of sulfur trioxide into the reaction device, and slowly add sulfur trioxide into the device in the form of gas, and control the addition rate of sulfur trioxide to ensure that the temperature fluctuation of the system is within ±50°C. If the temperature fluctuation of the system exceeds 50°C, adjust the addition rate of sulfur trioxide. After sulfur trioxide is added, react for another 30min, and obtain 102g of sodium pyrosulfate after cooling. The gas is discharged after being absorbed by two-stage alkali. After testing, the purity of sodium pyrosulfate is 98.30%.

[0036] Experimental Example 1

[0037] Take 58.23g of analytically pure sodium sulfate and add it to the reaction device. Heat it so that the temperature of the whole system is stably maintained at 120°C. Then slowly add 50g of sulfur trioxide to the reaction device. The sulfur trioxide is slowly added to the device in the form of gas. The addition rate of sulfur trioxide is controlled to ensure that the temperature fluctuation of the system is within ±50°C. If the temperature fluctuation of the system exceeds 50°C, adjust the addition rate of sulfur trioxide. After the addition of sulfur trioxide is completed, react for another 30 minutes, and after cooling, 91g of sodium pyrosulfate is obtained. The gas is discharged after being absorbed by two-stage alkali. After testing, the purity of the sodium pyrosulfate is 99.12%.

[0038] By comparing with Example 1, it can be seen that the conversion of chemical waste salt sodium sulfate into sodium pyrosulfate in Example 1 is not much different from the conversion of analytically pure sodium sulfate into sodium pyrosulfate in terms of yield and purity.

[0039] Example 2

[0040] The resource treatment method of industrial waste salt sulfate is as follows:

[0041] Take 58.82g of chemical waste salt potassium sulfate (containing 0.89% organic matter) into the reaction device, heat it to keep the temperature of the whole system stable at 100°C, then slowly add 40g of sulfur trioxide into the reaction device, and slowly add sulfur trioxide into the system in the form of gas, control the addition rate of sulfur trioxide, ensure that the temperature fluctuation of the system is within ±50°C, and adjust the addition rate of sulfur trioxide if the temperature fluctuation of the system exceeds 50°C. After sulfur trioxide is added, react for another 30min, and obtain 85g of potassium pyrosulfate after cooling, and the gas is discharged after being absorbed by two-stage alkali. After testing, the purity of potassium pyrosulfate is 98.19%.

[0042] Comparative Example 1

[0043] The resource recovery method is the same as that described in Example 1, except that:

[0044] The reaction temperature was 300°C, and after cooling, 60.7 g of sodium pyrosulfate was obtained, and the gas was discharged after being absorbed by two-stage alkali. After testing, the purity of the sodium pyrosulfate was 69.32%.

[0045] It can be seen from Comparative Example 1 that the reaction temperature is too high, and the yield and purity of sodium pyrosulfate are greatly reduced.

[0046] Comparative Example 2

[0047] The resource recovery method is the same as that described in Example 1, except that:

[0048] The reaction temperature was 20°C, and after cooling, 34.1 g of sodium pyrosulfate was obtained, and the gas was discharged after being absorbed by two-stage alkali. After testing, the purity of the sodium pyrosulfate was 45.9%.

[0049] It can be seen from Comparative Example 2 that the reaction temperature is too low and the reaction is incomplete, resulting in very low yield and purity of sodium pyrosulfate.

[0050] Comparative Example 3

[0051] The resource recovery method is the same as that described in Example 1, except that:

[0052] The amount of sulfur trioxide added was 16.4 g, and after cooling, 45.51 g of sodium pyrosulfate was obtained, and the gas was discharged after two-stage alkali absorption. After testing, the purity of potassium pyrosulfate was 60.12%.

[0053] It can be seen from Comparative Example 3 that too little sulfur trioxide is used, resulting in incomplete conversion of chemical waste salt sodium sulfate, and the yield and purity of sodium pyrosulfate are relatively low.

[0054] The above embodiments are only used to help understand the method and core idea of ​​the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A method for recycling industrial waste salt sulfate, comprising the following steps: Industrial waste salt sulfate reacts with sulfur trioxide at 50-200°C to obtain pyrosulfate.

2. The resource recovery method according to claim 1, characterized in that: Industrial waste salt sulfate contains organic matter or does not contain organic matter, and the mass content of organic matter is less than 10% by mass.

3. The resource recovery method according to claim 1, characterized in that: The organic matter mass content is 0.5-1%.

4. The resource recovery method according to claim 1, characterized in that: The sulfate in the industrial waste salt sulfate is any one of sodium sulfate, potassium sulfate and magnesium sulfate.

5. The resource recovery method according to claim 1, characterized in that: The molar ratio of industrial waste salt sulfate to sulfur trioxide is 1:(0.8-2).

6. The resource recovery method according to claim 1, characterized in that: The molar ratio of industrial waste salt sulfate to sulfur trioxide is 1:(1-2).

7. The resource recovery method according to claim 1, characterized in that: The reaction temperature is 80-180°C.

8. The resource recovery method according to claim 1, characterized in that: The reaction time is 10-180min.

9. The resource recovery method according to claim 1, characterized in that: The mass concentration of sulfur trioxide is between 80% and 99%. When the concentration is lower than 80%, the reaction can still proceed, but the reaction efficiency is significantly reduced.

10. The resource recovery method according to claim 1, characterized in that: The sulfur trioxide is liquid sulfur trioxide or gaseous sulfur trioxide.