Method for recovering organic matters in waste salt

Abstract

The invention provides a method for recovering organic matters in waste salt, and relates to the technical field of resource recovery. Comprising the following steps: S1, taking a certain amount of waste salt containing 2, 3-pentanol, adding deionized water, and uniformly mixing to prepare a saturated waste salt solution; s2, adding 2-pentene into the saturated waste salt solution obtained in the step S1 for extraction, and standing for layering to obtain a mixed solution of pentene and 2, 3-pentanol at the upper layer and a saturated waste salt solution at the lower layer; s3, rectifying the upper-layer solution in the step S2 to obtain 2-pentene, recycling 2, 3-pentanol contained in the waste salt, and performing reduced-pressure stirring distillation on the lower-layer saturated waste salt solution to obtain solid waste salt and a mixture of 2, 3-pentanol and water; the 2-pentanol and the 3-pentanol extracted by the method can be used as raw materials of other products after being rectified, and a feasible scheme is provided for recycling organic matters in the recovered waste salt.

Description

Technical Field

[0001] The present invention relates to the technical field of resource recovery, and in particular to a method for recovering organic matter from waste salt. Background Art

[0002] Industrial waste salt contains a large amount of toxic and harmful substances and has been listed in the hazardous waste list by the environmental protection department. Hazardous waste solid salt refers to waste salt recovered from high-concentration salt-containing organic wastewater in the chemical, pharmaceutical and other industries. Due to the high total organic carbon (TOC) content and complex dissolved total solid composition in the waste salt, many companies are currently forced to treat the solid salt they produce as hazardous waste, resulting in serious waste of resources and the risk of secondary pollution to the ecological environment. Classifying hazardous waste solid salt and comprehensively utilizing it as a resource can not only achieve the recycling and reuse of industrial raw materials such as sodium chloride and sodium sulfate, but will also significantly reduce the landfill load of hazardous waste salt and alleviate the risk of secondary pollution to the environment. Its significance is very important. Summary of the Invention

[0003] In response to the above problems, the present invention provides a method for recovering organic matter from waste salt. The 2-pentanol and 3-pentanol extracted by the method of the present invention can be used as raw materials for other products after distillation, providing a feasible solution for the resource utilization of organic matter in waste salt.

[0004] In order to solve the above problems, the technical solution adopted by the present invention is:

[0005] A method for recovering organic matter from waste salt comprises the following steps: S1, taking a certain amount of waste salt containing 2,3-pentanol, adding deionized water, mixing evenly, and preparing a saturated waste salt solution;

[0006] S2. Add 2-pentene to the saturated waste salt solution obtained in step S1 for extraction, and let stand to separate the layers to obtain an upper layer of a mixed solution of pentene and 2,3-pentanol, and a lower layer of a saturated waste salt solution. S3. Distill the upper layer solution of step S2 to obtain 2-pentene and 2,3-pentanol contained in the waste salt, which can be recycled. The lower layer of the saturated waste salt solution is subjected to reduced pressure stirring distillation to obtain solid waste salt and a mixture of 2,3-pentanol and water. The obtained organic matter can be recycled, and the aqueous phase can be returned to S1 for recycling.

[0007] Utilizing the principle of like dissolves like, alcohols have low solubility in aqueous phase but are easily soluble in substances such as 2-pentene, which can achieve efficient and selective extraction. Using 2-pentene in the plant for extraction does not introduce new impurities and can improve the recovery rate. Waste salt often contains toxic organic matter, and direct landfill or discharge will pollute the soil, groundwater and surrounding ecological environment.

[0008] Recycling organic matter can reduce its environmental risks. Recycling can reduce secondary pollutants such as dioxins and volatile organic compounds (VOCs) that may be produced during incineration or landfill. Recycled organic matter can be purified and reused in production as chemical raw materials (such as solvents and intermediates), reducing dependence on primary resources. The waste salt removed from organic matter can provide nutrients for bacteria in the plant's biochemical treatment pool. This recycling method reduces processing costs for the plant and creates a certain amount of added value.

[0009] Compared with existing technologies, the present invention is simple to operate and can effectively recover organic matter from waste salt, with a recovery rate of up to 60%. Water and 2-pentene are inexpensive and reusable, resulting in low cost. The method is suitable for industrial production. The 2-pentanol and 3-pentanol extracted by the present invention can be used as raw materials for other products after distillation, providing a feasible solution for the resource utilization of organic matter recovered from waste salt.

[0010] Preferably, there is no sodium methoxide in the saturated waste salt solution in step S1.

[0011] Sodium methoxide reacts with water to produce sodium hydroxide and methanol. If the saturated waste salt solution contains sodium methoxide, during the vacuum distillation process, sodium methoxide will react violently with water or moist air, releasing a large amount of heat and producing NaOH and methanol (CH3OH), which will create a safety hazard.

[0012] Preferably, the mass ratio of waste salt to water in step S1 is 1:1.

[0013] This ratio is used to ensure that sodium methoxide is completely removed to prevent residual sodium methoxide in subsequent processes from posing a safety hazard to production.

[0014] Preferably, the mass ratio of 2-pentene to waste salt added in step S2 is 2:1.

[0015] At this ratio, the recovery rate of pentanol is the highest. Adding more 2-pentene will not increase the recovery rate of pentanol, but will increase the energy consumption of recovery and increase the recovery cost.

[0016] Preferably, the moisture content in the upper organic phase in step S2 is less than 0.2%.

[0017] Since amyl alcohol and water form an azeotropic state, if the water content is high, the required purity of the product cannot be achieved.

[0018] Preferably, the COD of the aqueous phase in step S3 is less than 100.

[0019] The COD of the aqueous phase is less than 100, which can reduce the cost of sewage treatment and save costs.

[0020] Preferably, in step S3, water is returned to S1 to be configured as a saturated waste salt solution, and 2-pentene can be returned to S2 as an extractant for recycling.

[0021] The beneficial effects of the present invention are:

[0022] Compared with the existing technology, the present invention is simple to operate and can effectively recover organic matter in waste salt with a recovery rate of up to 60%. It uses inexpensive water and 2-pentene, which are reusable and low-cost. It is suitable for industrial production. The 2-pentanol and 3-pentanol extracted by the method of the present invention can be used as raw materials for other products after distillation, providing a feasible solution for the resource utilization of organic matter in waste salt. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Flow chart of the method of the present invention. DETAILED DESCRIPTION

[0024] The present invention will be further described below with reference to the accompanying drawings and examples.

[0025] Refer to the attached Figure 1 A method for recovering organic matter from waste salt. The present invention provides a method for recovering organic matter from waste salt, comprising the following steps:

[0026] S1. Take a certain amount of waste salt containing 2,3-pentanol, add deionized water, mix well, and prepare a saturated waste salt solution.

[0027] S2. Add 2-pentene to the saturated waste salt solution for extraction, and let it stand to separate into layers to obtain a mixed solution of pentene and 2, 3-pentanol in the upper layer, and a saturated waste salt solution in the lower layer.

[0028] The upper layer solutions of S3 and S2 are subjected to distillation of 2-pentene, and the 2, 3-pentanol contained in the waste salt can be recycled. The saturated waste salt solution in the lower layer is subjected to reduced pressure stirring distillation to obtain solid waste salt and a mixture of 2, 3-pentanol and water. The organic matter can be recycled, and the aqueous phase can be returned to S1 for recycling.

[0029] Utilizing the principle of like dissolves like, alcohols have low solubility in aqueous phase but are easily soluble in substances such as 2-pentene, which can achieve efficient and selective extraction. Using 2-pentene in the plant for extraction does not introduce new impurities and can improve the recovery rate. Waste salt often contains toxic organic matter, and direct landfill or discharge will pollute the soil, groundwater and surrounding ecological environment.

[0030] Recycling organic matter can reduce its environmental risks. Recycling can reduce secondary pollutants such as dioxins and volatile organic compounds (VOCs) that may be produced during incineration or landfill. Recycled organic matter can be purified and reused in production as chemical raw materials (such as solvents and intermediates), reducing dependence on primary resources. The waste salt removed from organic matter can provide nutrients for bacteria in the plant's biochemical treatment pool. This recycling method reduces processing costs for the plant and creates a certain amount of added value.

[0031] Furthermore, in S1, there is no sodium methoxide in the saturated waste salt solution; sodium methoxide reacts with water to generate sodium hydroxide and methanol. If the saturated waste salt solution contains sodium methoxide, during the vacuum distillation process, sodium methoxide will react violently with water or humid air, releasing a large amount of heat and generating NaOH and methanol (CH3OH), which will create a safety hazard.

[0032] Furthermore, in S1, the mass ratio of waste salt to water is 1:1; this ratio is adopted to ensure that sodium methoxide is completely removed to prevent residual sodium methoxide in subsequent processes from posing a safety hazard to production.

[0033] Furthermore, in S2, the mass ratio of the added 2-pentene and waste salt is 2:1; at this ratio, the recovery rate of pentanol is the highest. Adding more 2-pentene will not increase the recovery rate of pentanol, but will increase the energy consumption of recovery and increase the recovery cost.

[0034] Furthermore, in S2, the water content in the upper organic phase is less than 0.2%; since amyl alcohol and water form an azeotropic reaction, if the water content is high, the required purity of the product cannot be achieved.

[0035] Furthermore, in S3, the COD of the aqueous phase is less than 100; the COD of the aqueous phase is less than 100, which can reduce the cost of sewage treatment and save costs.

[0036] Preferably, in S3, the water can be returned to S1 to be configured into a saturated waste salt solution, and the 2-pentene can be returned to S2 as an extractant for recycling; the water can be returned to S1 to be configured into a saturated waste salt solution, and the 2-pentene can be returned to S2 as an extractant for recycling.

[0037] The following is a detailed introduction based on specific implementation methods.

[0038] Implementation Method 1

[0039] The present invention provides a method for recovering waste salt containing organic matter, as shown in the accompanying drawings:

[0040] 1. Take 1 kg of waste salt containing 2,3-pentanol, add 1 L of distilled water and stir evenly until the organic waste salt is completely dissolved to obtain 1 kg / L waste salt solution.

[0041] 2. Add 0.5 kg of 2-pentene to the waste salt solution and let it stand. Separate the upper layer and recycle it. Distill the lower layer under reduced pressure to obtain a mixture of 2,3-pentanol and water. Let it stand and separate the layers. Recycle the upper layer and return to step 1 for the lower layer.

[0042] 3. Return the organic phase obtained in step 2 to the distillation device to purify useful organic matter.

[0043] Implementation Method 2

[0044] This embodiment is substantially the same as embodiment 1, except that, in this embodiment, 1 kg of waste salt containing 2,3-pentanol is weighed and mixed with 1 L of deionized water, and 1 kg of 2-pentene is added.

[0045] Apart from this, this embodiment is identical to Embodiment 1 and will not be described in detail here.

[0046] Implementation 3

[0047] This embodiment is substantially the same as Embodiment 1, except that, in this embodiment, 1 kg of waste salt containing 2,3-pentanol is weighed and mixed with 1 L of deionized water, and 1.5 kg of 2-pentene is added.

[0048] Apart from this, this embodiment is identical to Embodiment 1 and will not be described in detail here.

[0049] Implementation 4

[0050] This embodiment is substantially the same as Embodiment 1, except that, in this embodiment, 1 kg of waste salt containing 2,3-pentanol is weighed and mixed with 1 L of deionized water, and 2.0 kg of 2-pentene is added.

[0051] Apart from this, this embodiment is identical to Embodiment 1 and will not be described in detail here.

[0052] Implementation 5

[0053] Take 1 kg of waste salt containing 2,3-pentanol and add 1 L of distilled water and stir until the organic waste salt is completely dissolved to obtain a 1 kg / L waste salt solution. Let it stand and separate the upper layer for recycling, and the oil-water mixture in the lower layer for hazardous waste disposal.

[0054] Apart from this, this embodiment is identical to Embodiment 1 and will not be described in detail here.

[0055] The organic matter concentrations in the waste salts of Embodiments 1-4 before and after treatment were analyzed, and the results are shown in the following table.

[0056] Implementation Method 1 Implementation Method 2 Implementation 3 Implementation 4 Implementation 5 2.3-Pentanol recovery rate (%) 42.3 43.6 47.5 52.3 33.4 Aqueous phase COD (mg / L) 98 99 96 95 65623 Oil phase moisture (%) 0.20 0.20 0.20 0.15 2.3

[0057] As can be seen from the table, in embodiments 1-4, most of the 2,3-pentanol was recovered after treatment using the recovery method of the present invention, with a recovery rate of up to 55.3%. The COD of the aqueous phase was less than 100 mg / L, and the moisture content of the oil phase was less than 0.2%. If only water was used for washing, the recovery rate of pentanol was only 33.4%, and the moisture content of the oil phase was also relatively high. The COD of the wastewater was as high as over 60,000, which greatly increased the treatment cost.

[0058] Compared with the prior art, the present invention has the following beneficial technical effects:

[0059] Compared with existing technologies, the present invention is simple to operate and can effectively recover organic matter from waste salt, with a recovery rate of up to 60%. Water and 2-pentene are inexpensive and reusable, resulting in low cost. The method is suitable for industrial production. The 2-pentanol and 3-pentanol extracted by the present invention can be used as raw materials for other products after distillation, providing a feasible solution for the resource utilization of organic matter recovered from waste salt.

[0060] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for recovering organic matter from waste salt, characterized in that: The steps include: S1. Take a certain amount of waste salt containing 2,3-pentanol, add deionized water, mix well, and prepare a saturated waste salt solution; S2, adding 2-pentene to the saturated waste salt solution obtained in step S1 for extraction, and allowing to stand for separation to obtain a mixed solution of pentene and 2,3-pentanol in an upper layer, and a saturated waste salt solution in a lower layer; S3. The upper layer solution of step S2 is subjected to distillation to obtain 2-pentene, and the 2, 3-pentanol contained in the waste salt can be recycled. The saturated waste salt solution in the lower layer is subjected to reduced pressure stirring distillation to obtain solid waste salt and a mixture of 2, 3-pentanol and water. The obtained organic matter can be recycled, and the aqueous phase can be returned to S1 for recycling.

2. The method for recovering organic matter from waste salt according to claim 1, wherein: There is no sodium methoxide in the saturated waste salt solution in step S1.

3. The method for recovering organic matter from waste salt according to claim 1, characterized in that: In step S1, the mass ratio of waste salt to water is 1:

1.

4. The method for recovering organic matter from waste salt according to claim 1, wherein: The mass ratio of 2-pentene and waste salt added in step S2 is 2:

1.

5. The method for recovering organic matter from waste salt according to claim 1, characterized in that: The moisture content of the upper organic phase in step S2 is less than 0.2%.

6. The method for recovering organic matter from waste salt according to claim 1, characterized in that: In step S3, the COD of the aqueous phase is less than 100.

7. The method for recovering organic matter from waste salt according to claim 1, characterized in that: In step S3, water is returned to S1 to be prepared into a saturated waste salt solution, and 2-pentene can be returned to S2 as an extractant for recycling.

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