CN109550771B - Method and device for removing organic pollutants in industrial waste salt - Google Patents
Method and device for removing organic pollutants in industrial waste salt Download PDFInfo
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- CN109550771B CN109550771B CN201811512864.6A CN201811512864A CN109550771B CN 109550771 B CN109550771 B CN 109550771B CN 201811512864 A CN201811512864 A CN 201811512864A CN 109550771 B CN109550771 B CN 109550771B
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- 238000001704 evaporation Methods 0.000 claims abstract description 38
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- 238000001471 micro-filtration Methods 0.000 claims description 56
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- 239000012528 membrane Substances 0.000 claims description 46
- 239000010936 titanium Substances 0.000 claims description 43
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 40
- 229910052719 titanium Inorganic materials 0.000 claims description 40
- 238000010438 heat treatment Methods 0.000 claims description 25
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 claims description 24
- YADSGOSSYOOKMP-UHFFFAOYSA-N dioxolead Chemical compound O=[Pb]=O YADSGOSSYOOKMP-UHFFFAOYSA-N 0.000 claims description 23
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims description 22
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- 239000011780 sodium chloride Substances 0.000 claims description 18
- GVFOJDIFWSDNOY-UHFFFAOYSA-N antimony tin Chemical compound [Sn].[Sb] GVFOJDIFWSDNOY-UHFFFAOYSA-N 0.000 claims description 16
- 230000008020 evaporation Effects 0.000 claims description 16
- LJCFOYOSGPHIOO-UHFFFAOYSA-N antimony pentoxide Chemical compound O=[Sb](=O)O[Sb](=O)=O LJCFOYOSGPHIOO-UHFFFAOYSA-N 0.000 claims description 14
- 239000002893 slag Substances 0.000 claims description 14
- 238000003860 storage Methods 0.000 claims description 14
- 238000006243 chemical reaction Methods 0.000 claims description 13
- 238000005374 membrane filtration Methods 0.000 claims description 12
- XOLBLPGZBRYERU-UHFFFAOYSA-N tin dioxide Chemical compound O=[Sn]=O XOLBLPGZBRYERU-UHFFFAOYSA-N 0.000 claims description 12
- 239000011229 interlayer Substances 0.000 claims description 11
- 229910052697 platinum Inorganic materials 0.000 claims description 11
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- 238000005273 aeration Methods 0.000 claims description 10
- 229910052751 metal Inorganic materials 0.000 claims description 10
- 239000002184 metal Substances 0.000 claims description 10
- 239000000706 filtrate Substances 0.000 claims description 8
- CJTCBBYSPFAVFL-UHFFFAOYSA-N iridium ruthenium Chemical compound [Ru].[Ir] CJTCBBYSPFAVFL-UHFFFAOYSA-N 0.000 claims description 8
- 239000002245 particle Substances 0.000 claims description 8
- 230000003197 catalytic effect Effects 0.000 claims description 7
- HTXDPTMKBJXEOW-UHFFFAOYSA-N dioxoiridium Chemical compound O=[Ir]=O HTXDPTMKBJXEOW-UHFFFAOYSA-N 0.000 claims description 7
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- WOCIAKWEIIZHES-UHFFFAOYSA-N ruthenium(iv) oxide Chemical compound O=[Ru]=O WOCIAKWEIIZHES-UHFFFAOYSA-N 0.000 claims description 6
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- 238000001514 detection method Methods 0.000 description 5
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- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- CBENFWSGALASAD-UHFFFAOYSA-N Ozone Chemical compound [O-][O+]=O CBENFWSGALASAD-UHFFFAOYSA-N 0.000 description 1
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- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 1
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- 238000012986 modification Methods 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 239000012452 mother liquor Substances 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
- 239000007800 oxidant agent Substances 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 231100000719 pollutant Toxicity 0.000 description 1
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- SUKJFIGYRHOWBL-UHFFFAOYSA-N sodium hypochlorite Chemical compound [Na+].Cl[O-] SUKJFIGYRHOWBL-UHFFFAOYSA-N 0.000 description 1
- HPALAKNZSZLMCH-UHFFFAOYSA-M sodium;chloride;hydrate Chemical compound O.[Na+].[Cl-] HPALAKNZSZLMCH-UHFFFAOYSA-M 0.000 description 1
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
- B09B—DISPOSAL OF SOLID WASTE NOT OTHERWISE PROVIDED FOR
- B09B3/00—Destroying solid waste or transforming solid waste into something useful or harmless
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
- B09B—DISPOSAL OF SOLID WASTE NOT OTHERWISE PROVIDED FOR
- B09B5/00—Operations not covered by a single other subclass or by a single other group in this subclass
Landscapes
- Engineering & Computer Science (AREA)
- Environmental & Geological Engineering (AREA)
- Water Treatment By Electricity Or Magnetism (AREA)
- Treatment Of Water By Oxidation Or Reduction (AREA)
- Physical Water Treatments (AREA)
Abstract
The invention relates to a method and a device for removing organic pollutants in industrial waste salt, which specifically comprise the following steps: dissolving waste salt in water, preparing salt-containing sewage through pretreatment, and regulating the pH value of the salt-containing sewage to be neutral; performing primary filtration; then decomposing organic pollutants by an electrocatalytic oxidation method, treating for 1-3 hours, and adding alkali to adjust the pH value to be alkaline; then micro-nano air floatation treatment is carried out, and secondary filtration is carried out; and (3) sequentially evaporating, crystallizing and washing the treated salt-containing sewage until the crystallized salt reaches a preset standard. The invention adopts the treatment method combining electrocatalytic treatment and micro-nano air floatation, and has the advantages of high efficiency, wide application range, simple process flow and strong controllability.
Description
Technical Field
The invention belongs to the technical field of industrial waste salt treatment, and particularly relates to a method and a device for removing organic pollutants in industrial waste salt.
Background
In the industrial production process, waste salt containing various toxic and harmful substances is usually produced, the byproduct salt slag per year in the whole country reaches more than 500 ten thousand tons, and a plurality of factories generate a phenomenon of expanding warehouse, so that the treatment difficulty is extremely high. At present, no corresponding standard exists for treating chemical waste salt, a large amount of toxic and harmful substances are contained in the waste salt, most enterprises treat the waste salt as dangerous solid waste, and therefore, the enterprises can bear huge dangerous solid waste treatment cost. Along with the increasing demand of people for green environment, along with the gradual rise of environmental protection requirements, solid waste salt must be reasonably treated so as to realize the harmlessness of the solid waste salt to the environment and realize the effective comprehensive recycling of waste resources.
For the treatment of such waste salts, the measures generally taken at present are: and (1) landfill treatment. However, the method needs to occupy a large amount of sites, so that land resources are seriously wasted, and percolate generated by waste residues can cause serious threat to underground water and surrounding ecological systems. (2) chemical oxidation treatment. After washing with saturated byproduct salt, a certain amount of chemical oxidant such as sodium hypochlorite, hydrogen peroxide, ozone and the like is added to oxidize the organic pollutants, so that clean salt is obtained. However, the method has higher cost, great difficulty in condition control, no guarantee of treatment efficiency and easy secondary pollution initiation. (3) washing treatment. Washing the waste salt with water or organic solvent, washing the impurity in the waste salt as much as possible, evaporating the washing mother liquor to produce high concentration waste water, biochemical treatment and advanced oxidation to reduce the chemical oxygen demand of the waste water, and reusing to prepare the washing liquid. The treated waste salt can be used in chlor-alkali industry after centrifugal drying. However, the method has a small application range, is only suitable for waste salt with low impurity content and simple impurity components, and has low organic pollutant removal efficiency. (4) high-temperature oxidation treatment. The waste salt is treated at high temperature, so that organic impurities in the waste salt are oxidized into CO 2, CO and water vapor at high temperature, and the aim of removing the organic impurities is fulfilled. However, in the treatment process, equipment such as a fluidized bed furnace, a rotary kiln and the like is easy to cause problems such as ring formation, agglomeration and the like at high temperature, so that industrialization is difficult to realize. (5) The precipitation crystallization method is to dissolve waste salt with water, then add alkali liquor to react, part of metal ions can form hydroxide precipitate, the main component of the solution is sodium chloride, then carry out slag-water separation, and the salt can be recovered by airing. However, the method has poor organic pollutant removal effect, low purity of recovered salt and small application range.
How to design and develop a new waste salt treatment technology so as to achieve the effects of high efficiency of removing organic pollutants in waste salt, full recycling of salt, simple and convenient operation condition method, small occupied area and the like, and finally achieve the effect of reducing treatment cost as much as possible, which becomes a problem to be solved in the current stage of a plurality of chemical enterprises and environmental protection departments.
Disclosure of Invention
The invention aims to solve the problems, and provides a method and a device for removing organic pollutants in industrial waste salt, which solve the technical problems of high energy consumption, low efficiency, easiness in causing secondary pollution, large occupied area and the like in the prior art.
According to one aspect of the present invention, there is provided a method for removing organic contaminants from industrial waste salts, comprising the steps of:
Dissolving waste salt in water, preparing salt-containing sewage with specific mass fraction through magnetic stirring and heating ultrasonic pretreatment, and removing scum on the surface of the salt-containing sewage; adjusting the pH value of the pretreated saline sewage to 7.0-10.0, and carrying out primary filtration on the saline sewage subjected to micro-nano air floatation by using a micro-filtration membrane with a fixed particle size; treating the filtered salt-containing sewage by using an electrocatalytic oxidation method, adopting pulse direct current power supply, outputting square waves, setting the duty ratio to be 3:1-8:1, setting the pulse frequency to be 0.01-1 Hz, and setting the treatment time to be 1-3 h; regulating the pH value of the salt-containing sewage after electrocatalytic oxidation treatment to 11.0-13.0, and then carrying out micro-nano air floatation treatment, and timely removing surface scum during treatment; carrying out secondary filtration on the salt-containing sewage after micro-nano air floatation treatment; evaporating and crystallizing the salt-containing sewage obtained after the secondary filtration, stopping evaporating and crystallizing each time the volume of the salt-containing sewage is reduced to a fixed proportion of the original volume, recovering the precipitated crystalline salt reaching a preset standard, washing the crystalline salt which does not reach the standard, performing a tertiary filtration step, merging the residual salt-containing sewage which is not crystallized with the washing filtrate, performing electrocatalytic oxidation treatment again, and continuing evaporating and crystallizing until the precipitated crystalline salt completely reaches the preset standard.
Wherein, in the pretreatment step, the rotating speed of magnetic stirring is 10-500 rpm, the heating temperature is 40-60 ℃, the power of ultrasonic treatment is 50-150W, the treatment time is 10-30 min, and the mass fraction of the prepared saline sewage is more than or equal to 25.0%.
In the electrocatalytic oxidation treatment step, a titanium metal plate or a stainless steel plate is used as a cathode, and one of a titanium-based tin-antimony electrode, a titanium-based tin-antimony interlayer lead dioxide electrode, a titanium-based ruthenium-iridium electrode or a platinum electrode is used as an anode, wherein the titanium-based tin-antimony electrode is an inactive electrode coated with an antimony pentoxide doped tin dioxide coating on the titanium plate; the lead dioxide electrode of the titanium-based tin-antimony interlayer is an inactive electrode which takes a titanium plate as a base material, takes an antimony pentoxide doped tin dioxide coating as an interlayer and takes lead dioxide as a surface active layer; the titanium-based ruthenium iridium electrode is prepared by dipping and brushing a titanium substrate etched by polishing acid with sol containing ruthenium dioxide and iridium dioxide; the platinum electrode is a metal platinum plating electrode.
Wherein, in the micro-nano air floatation treatment step, the particle size of air bubbles generated by aeration is between 50nm and 10 mu m, the gas flow rate is 3 to 10m 3/h, and the residence time of the air bubbles in the saline sewage is 2 to 10min.
Wherein the aperture of the micro-filtration membrane for the primary filtration is 0.45 mu m, the aperture of the micro-filtration membrane for the secondary filtration is 0.22 mu m, the aperture of the micro-filtration membrane for the tertiary filtration is 0.11 mu m, the treatment time of each stage is 10-30 min, and the transmembrane pressure of each stage is 0.05-0.20 MPa.
Wherein, in the step of evaporating, crystallizing and washing, the evaporating temperature is 60-100 ℃, and the salt-containing sewage is evaporated to 20-40% of the original volume; during water washing treatment, the mass ratio of the substandard crystalline salt to the pure water or the deionized water is 2:1-5:1.
According to another aspect of the invention, a removing device used in the removing method is provided, which comprises a pretreatment subsystem, a microfiltration membrane primary filtering subsystem, an electrocatalytic oxidation treatment subsystem, a micro-nano air floater system, a microfiltration membrane secondary filtering subsystem and an evaporative crystallization subsystem which are sequentially communicated, a water washing subsystem communicated with a non-standard crystallization salt outlet of the evaporative crystallization subsystem and a microfiltration membrane tertiary filtering subsystem communicated with an outlet of the water washing subsystem, wherein the outlet of the microfiltration membrane tertiary filtering subsystem is communicated with a concentrated solution outlet of the evaporative crystallization subsystem and then with an inlet of the electrocatalytic oxidation treatment subsystem to form a circulation; the removal device also includes a power subsystem that provides power to the various subsystems.
The removal device further comprises a crystallized salt storage box and a slag storage box, wherein the slag storage box is communicated with a slag outlet at the bottom of the electrocatalytic oxidation treatment subsystem through a control valve, and the crystallized salt storage box is communicated with a crystallized salt outlet at the bottom of the water washing subsystem through a control valve.
The pretreatment subsystem comprises a feeding tank, a magnetic stirrer, an ultrasonic probe and a heating plate attached to the wall of the feeding tank, the microfiltration membrane filtration subsystem comprises a filter and a filtering tank, the filter is sequentially communicated with the microfiltration membrane, the electrocatalytic oxidation treatment subsystem comprises a catalytic tank, an anode plate, a cathode plate and a slag collecting box positioned below the anode plate and the cathode plate in the catalytic tank, the micro-nano air floater system comprises a reaction tank, a micro-nano aeration head arranged at the bottom of the reaction tank and a scraper suspended above the reaction tank, and the evaporation crystallization subsystem comprises an evaporation crystallization tank, another heating plate and the stirrer; the water washing subsystem comprises a water washing tank and another stirrer.
The magnetic stirrer, the ultrasonic probe, the heating plate, the filter, the anode plate, the cathode plate, the micro-nano aeration head, the scraper, the other heating plate, the stirrer and the other stirrer are all connected with the electric subsystem.
In the invention, a titanium metal plate or a stainless steel plate is used as a cathode, one of a titanium-based tin-antimony electrode, a titanium-based tin-antimony interlayer lead dioxide electrode, a titanium-based ruthenium-iridium electrode or a platinum electrode is used as an anode, and the electrode can perform oxygen evolution and hydrogen evolution in electrocatalytic oxidation, so that on one hand, aeration reoxygenation effect can be realized, and on the other hand, water disturbance can be increased; the electrocatalytic oxidation adopts pulse direct current power supply and square wave output, under the conditions that the duty ratio is 5:1 and the pulse frequency is 0.1Hz, the electrode can separate out more tiny bubbles, the air floatation effect is further enhanced, meanwhile, the strong oxidation effect of various active oxygen free radicals generated by the electrode is combined, the transmission structure of emulsified oil in the saline sewage is easier to break, and the electrochemical treatment effect is enhanced.
Further, the flow rate of gas during micro-nano air floatation is set to be 3-10 m 3/h, the residence time of bubbles in the saline sewage is set to be 2-10 min, the particle size of micro-nano bubbles is set to be distributed between 50nm and 10 mu m, the specific surface area of the generated micro-nano bubbles is large, the capturing capability is strong, the effect of micro-nano air floatation can be fully exerted, the service life of equipment can be greatly prolonged, and the energy consumption is saved. After the solution is subjected to electrocatalytic oxidation treatment, most of refractory organic matters with higher molecular weight are oxidized and decomposed into organic matters with smaller molecular weight, and then the solution is subjected to micro-nano air floatation treatment, so that the solution can be decomposed and mineralized to a great extent, and colloid particles in the solution can be floated. Under the operating conditions provided by the invention, the combination of the electrocatalytic oxidation treatment technology and the micro-nano air floatation treatment technology can generate a superposition effect, so that the treatment effect is doubled.
The magnetic stirring heating ultrasonic pretreatment is used for accelerating the dissolution speed of the waste salt, and the solubility of the waste salt can be further greatly improved due to the reduction of the activation energy and the cavitation effect of the ultrasonic, so that the treatment capacity of the salt solution is reduced, and the treatment efficiency is improved.
The invention has the following beneficial effects:
1. The method for treating the waste salt by combining the electrocatalytic treatment and the air floatation filtration treatment has good treatment effect and various pollutant treatment types; the electrocatalytic oxidation device has strong treatment capacity and wide application range, and the electrode plate is durable, and compared with the single electrocatalytic oxidation technology or micro-nano air floatation filtration treatment, the purification efficiency is as high as more than 90%, and the purification efficiency of the single electrocatalytic oxidation technology or micro-nano air floatation filtration treatment is only 20-30%.
2. The method has the advantages of low-cost and easily-obtained raw materials, and the treated crystalline salt can be recycled, is convenient for large-scale application in actual production, and has higher practical value.
3. The method has low equipment requirement, simple equipment, simple maintenance and low operation cost.
Drawings
Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. Also, like reference numerals are used to designate like parts throughout the figures. In the drawings:
FIG. 1 shows a schematic process flow diagram of a removal method according to an embodiment of the invention;
Fig. 2 shows a schematic view of a removal device according to an embodiment of the invention.
Detailed Description
Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.
The invention provides a method for effectively removing organic pollutants in industrial waste salt and a specific device suitable for the method. The basic idea of the invention is that the pretreatment step, the microfiltration membrane filtration step, the electrocatalytic oxidation treatment step, the micro-nano air floatation step and the evaporative crystallization water washing step are sequentially used for treating the waste salt, and the effects of the steps are effectively overlapped by using a specific electrode and setting proper parameters in the steps, so that the treatment process of the organic matters is simple and effective.
As shown in fig. 1, a method for removing organic pollutants in industrial waste salt comprises the following steps:
1, pretreatment: dissolving waste salt in water, fully mixing and stirring by a magnetic stirrer at a stirring rotating speed of 10-500 rpm, heating and carrying out ultrasonic treatment at a heating temperature of 40-60 ℃ for 10-30 min, setting ultrasonic power to be 50-150W, and preparing the salt water with mass fraction not less than 25.0%; removing scum on the upper layer of the solution by using a scraper; the pH value of the solution is regulated to 7.0-10.0 by hydrochloric acid and sodium hydroxide.
2, Microfiltration membrane filtration: and (3) carrying out primary microfiltration membrane filtration treatment on the solution, placing the pretreated solution in a 0.45 mu m microfiltration membrane filtration device, and carrying out microfiltration membrane filtration treatment on the solution to remove particulate matters in the solution.
3, Electrocatalytic oxidation treatment: and (3) carrying out electrocatalytic oxidation treatment on the solution after the primary filtration to remove a large amount of organic pollutants in the solution. Placing the solution filtered by the microfiltration membrane into an electrocatalytic oxidation reaction tank, inserting an anode plate and a cathode plate, connecting a direct current stabilized power supply externally, supplying pulse direct current, outputting square waves, setting the duty ratio to be 5:1, setting the pulse frequency to be 0.1Hz, electrifying to perform electrocatalytic oxidation treatment for 1-3 h, and adjusting the pH value of the solution to 11.0-13.0 by using sodium hydroxide after the electrocatalytic oxidation treatment.
And 4, micro-nano air floatation: and carrying out micro-nano air floatation treatment on the waste salt solution. Placing the solution after electrocatalytic oxidation in a reaction tank, arranging a micro-nano air floatation device at the bottom of the reaction tank, connecting a direct current stabilized power supply, carrying out micro-nano air floatation treatment on the solution in the reaction tank for 10-30 min, lifting dissolved oxygen in a water body, and rapidly realizing reoxygenation. In the air floatation process, scum generated on the surface of the solution is removed for 1-3 times per minute, and the micro-nano air floatation treatment is followed by secondary filtration treatment by a micro-filtration membrane with the diameter of 0.22 mu m.
And 5, evaporating and crystallizing: evaporating and crystallizing the solution, and washing the crystallized salt with water. And (3) placing the supernatant fluid after the secondary filtration treatment of the microfiltration membrane in an evaporation crystallizer, evaporating and crystallizing at the evaporating temperature of 60-100 ℃, crystallizing until the volume of the solution is reduced to 20-40% of the original volume, and placing the rest solution which is not crystallized in an electrocatalytic oxidation reaction tank for electrocatalytic oxidation retreatment, wherein the treatment steps and the method are the same as above. The crystallization salt is tested according to the physicochemical index of the industrial salt, and if the test meets the two-level standard of refined industrial salt-industrial dry salt-in industrial salt (GB/T5462-2015), the crystallization salt is recycled. If the test does not reach the standard, washing the crystallized salt with pure water or deionized water, wherein the mass ratio of the crystallized salt to the pure water or deionized water is 2:1-5:1 during the washing treatment. Performing tertiary filtration treatment on the crystal salt subjected to water washing treatment by using a microfiltration membrane with the diameter of 0.11 mu m, and placing the water washing filtrate in an electrocatalytic oxidation reaction tank for electrocatalytic oxidation retreatment, wherein the treatment steps and the treatment methods are the same; and testing the filtered crystalline salt again until the test of the re-treated crystalline salt reaches the standard, and recycling the crystalline salt.
The generation method of the micro-nano bubbles specifically comprises the following steps: injecting compressed air or oxygen into the pump, and forming stable bubbles in a nozzle mixing chamber of the pump to perform two-phase flow; at the nozzle outlet, in the form of a liquid thread or liquid line containing a large number of tiny bubbles. The liquid is ejected in the form of liquid threads or liquid lines containing a large number of tiny bubbles due to the extrusion shearing action of bubbles on the liquid; in the extremely short distance from the nozzle, the bubbles are promoted to expand and break rapidly due to the severe change of the pressure inside and outside the bubbles, and meanwhile, the liquid film around the bubbles is broken to form fine particle groups, so that micro-nano bubbles are further formed. The particle size of air bubbles generated by aeration is between 50nm and 10 mu m, the gas flow rate is between 3 and 10m 3/h, and the residence time of the air bubbles in the saline sewage is between 2 and 10min.
The treatment time of the three levels of filtration is set to be 10-30 min, and the transmembrane pressure is set to be 0.05-0.20 MPa. Using a titanium metal plate or a stainless steel plate as a cathode, and using one of a titanium-based tin-antimony electrode, a titanium-based tin-antimony interlayer lead dioxide electrode, a titanium-based ruthenium-iridium electrode or a platinum electrode as an anode, wherein the titanium-based tin-antimony electrode is an inactive electrode coated with an antimony pentoxide doped tin dioxide coating on the titanium plate; the lead dioxide electrode of the titanium-based tin-antimony interlayer is an inactive electrode which takes a titanium plate as a base material, takes an antimony pentoxide doped tin dioxide coating as an interlayer and takes lead dioxide as a surface active layer; the titanium-based ruthenium iridium electrode is prepared by dipping and brushing a titanium substrate etched by polishing acid with sol containing ruthenium dioxide and iridium dioxide; the platinum electrode is a metal platinum plating electrode.
In order to match the removing method, the invention also provides a removing device suitable for the removing method. As shown in fig. 2, the removing device comprises a pretreatment subsystem 1, a microfiltration membrane primary filtering subsystem 2, an electrocatalytic oxidation treatment subsystem 3, a micro-nano air floater system 4, a microfiltration membrane secondary filtering subsystem 6, an evaporation crystallization subsystem 5, a water washing subsystem 7 communicated with a non-standard crystallization salt outlet of the evaporation crystallization subsystem 5 and a microfiltration membrane tertiary filtering subsystem 8 communicated with an outlet of the water washing subsystem 7, wherein an outlet of the microfiltration membrane tertiary filtering subsystem 8 is communicated with a concentrated solution outlet of the evaporation crystallization subsystem 5 and then with an inlet of the electrocatalytic oxidation treatment subsystem 3 in sequence, so that circulation is formed; the removal device also includes a power subsystem that provides power to the various subsystems.
The pretreatment subsystem 1 comprises a feeding pool 11, a magnetic stirrer 12, an ultrasonic probe 13 and a heating plate 14 attached to the wall of the feeding pool, the microfiltration membrane filtration subsystem comprises a filter 100 and a filter pool 200 which are sequentially communicated, the electrocatalytic oxidation treatment subsystem 3 comprises a catalytic pool, an anode plate and a cathode plate which are positioned in the catalytic pool, and a slag collecting box positioned below the anode plate and the cathode plate in the catalytic pool, the micro-nano air floater system 4 comprises a reaction tank, a micro-nano aeration head 41 arranged at the bottom of the reaction tank, a scraper 42 suspended above the reaction tank, and the evaporation crystallization subsystem 5 comprises an evaporation crystallization pool 51, another heating plate 52 and a stirrer; the water wash subsystem 7 includes a water wash tank 71 and another agitator.
The magnetic stirrer 12, the ultrasonic probe 13, the heating plate 14, the filter 100, the anode plate, the cathode plate, the micro-nano aeration head 41, the scraper 42, the other heating plate 52, the stirrer and the other stirrer are all connected with the electric subsystem.
The removing device further comprises a crystallized salt storage tank 10 and a slag storage tank 11, wherein the slag storage tank 11 is communicated with a slag outlet at the bottom of the electrocatalytic oxidation treatment subsystem 3 through a control valve, and the crystallized salt storage tank 10 is communicated with a crystallized salt outlet at the bottom of the water washing subsystem 7 through a control valve. The number of the anode plates and the cathode plates is three, the anode plates and the cathode plates are all arranged along the height of the electrocatalytic oxidation treatment subsystem 4, and the distance between each group of anode plates and the cathode plates is 10-30 mm. When the crystallization salt entering the water washing subsystem passes the test, a control valve corresponding to the crystallization salt outlet is opened, and the crystallization salt storage box is utilized to realize the recovery of the crystallization salt reaching the standard. The slag storage bin 11 is opened at random for collecting organic contaminants left over during the electrocatalytic oxidation process.
And when the system is required to be internally connected, the control valve and the pressure pump are started, and the conversion of the treatment object in the system is realized by utilizing the pressure difference.
The method for removing organic contaminants from the industrial waste salt of the present invention will be further described by way of specific examples.
Example 1 method for removing Industrial waste salt X1
The industrial waste salt to be treated is 1 ton. Dissolving the waste salt in water, and stirring at 300rpm; the heating temperature is kept at 50 ℃; the ultrasonic time is 15min, the ultrasonic power is 100W, the salt water with the mass fraction of 25.0% is prepared, and the pH value of the solution is adjusted to 8.0 by hydrochloric acid and sodium hydroxide. Then the solution is subjected to microfiltration membrane filtration treatment, and the solution is filtered by a microfiltration membrane with a thickness of 0.45 μm for 10min under a transmembrane pressure of 0.10 MPa.
Then carrying out electrocatalytic oxidation treatment on the solution, wherein in the electrocatalytic oxidation treatment process, an anode plate is selected from Ti/SnO 2-Sb2O5 (titanium-based tin antimony) electrodes, a cathode plate is selected from a polished titanium metal plate, pulse direct current power supply is adopted, square wave output is adopted, the duty ratio is 5:1, the pulse frequency is 0.1Hz, the electrolysis time is 0.5h, the current density is 15mA/cm 2, the electrode plate distance is 30mm, and the pH value of the solution after the electrocatalytic oxidation treatment is adjusted to 11.0. And then carrying out micro-nano air floatation treatment on the solution. Micro-nano air floatation is carried out for 10min, the air flow rate is 5m 3/h, and scum on the upper layer of the solution is removed by using a scraper. Then the solution is subjected to secondary filtration treatment by a microfiltration membrane, and the solution is subjected to secondary filtration by a microfiltration membrane of 0.22 mu m for 10min under the transmembrane pressure of 0.15 MPa.
Then evaporating and crystallizing the solution, and washing the crystallized salt with water. Heating the supernatant in an evaporation crystallizer for evaporation crystallization, wherein the evaporation temperature is 80 ℃, the crystallization treatment degree is selected to reduce the solution volume to 15%, testing the crystallized salt, performing primary water washing treatment and secondary water washing treatment on the unqualified crystallized salt by pure water, wherein the mass ratio of the crystallized salt to the pure water is 3:1 during the water washing treatment, performing microfiltration membrane tertiary filtration treatment on the water-washed crystallized salt, and performing tertiary filtration for 10min by using a microfiltration membrane with the thickness of 0.22 mu m under the transmembrane pressure of 0.15 MPa. And (3) performing electrocatalytic oxidation secondary treatment and tertiary treatment on the residual solution which is not crystallized and the water washing filtrate.
Analysis and test:
Numbering the processing flows, and monitoring the content of the organic pollutants in the flows corresponding to each numbering. The important water quality index changes of the polluted salt solution are shown in table 1, and the important index changes of the waste salt are shown in table 2.
Table 1: treatment data of dirty salt solution under corresponding flow
| ② Pretreatment of | ③ Electrocatalytic treatment | ④ Air floatation filtering | ⑥ Secondary electrocatalytic treatment | ⑧ Three electrocatalytic treatments | |
| TOC(mg/L) | 1190 | 900 | 722 | 213 | 8 |
| Total nitrogen (mg/L) | 710 | 210 | 190 | 70 | 5 |
| Ammonia nitrogen (mg/L) | 590 | 95 | 80 | 10 | 2 |
Table 2: data before and after treatment of industrial waste salt
| ① As is | ⑤ Batch crystallization | ⑦ Two-batch crystallization | ⑨ Three batches of crystals | |
| TOC(mg/kg) | 3600 | 60.12 | 11.50 | 1.02 |
| NaCl(％) | 90.52 | 98.21 | 98.89 | 99.31 |
| Total nitrogen (mg/kg) | 2200 | 15.2 | 2.1 | 0.6 |
| Ammonia nitrogen (mg/kg) | 1800 | 3.6 | 0.7 | 0.3 |
Example 2 method for removing Industrial waste salt X2
Example 2 is a modification of example 1, except that the membrane is filtered with a 0.22 μm microfiltration membrane for 15min at a transmembrane pressure of 0.15MPa, a Ti/SnO 2-Sb2O5/PbO2 (titanium-based tin-antimony interlayer lead dioxide) electrode is selected as the anode plate during the electrocatalytic oxidation treatment, the electrolysis time is 3h, the current density is 20mA/cm 2, the plate spacing is 20mm, the pH value of the solution after the electrocatalytic oxidation treatment is adjusted to 10.5, the micro-nano air flotation is 30min, the gas flow rate is 10m 3/h, the membrane is subjected to secondary filtration with a 0.11 μm microfiltration membrane for 15min at a transmembrane pressure of 0.20MPa, the non-standard crystalline salt is subjected to primary water washing treatment with pure water, the non-crystalline residual solution and the water washing filtrate are subjected to secondary electrocatalytic oxidation treatment with a 0.11 μm microfiltration membrane for 15min at a transmembrane pressure of 0.20MPa, and the mass ratio of the crystalline salt to pure water is 2:1 during the water washing treatment.
Analysis and test:
Through detection, the TOC value in the waste salt pretreatment solution is reduced from 1190mg/L to 6mg/L after secondary electrocatalytic oxidation treatment; the total nitrogen content is reduced from 710mg/L to 4mg/L; the ammonia nitrogen content is reduced from 590mg/L to 2mg/L.
The TOC value in the waste salt is reduced from 3600mg/kg to 1.01mg/kg after one water washing treatment; the sodium chloride content is improved from 90.52% to 99.41%; the total nitrogen content is reduced from 2200mg/kg to 0.5mg/kg; the ammonia nitrogen content is reduced from 1800mg/kg to 0.2mg/kg.
Example 3 method for removing Industrial waste salt X3
Dissolving waste salt in water, stirring at a rotation speed of 10rpm, maintaining the heating temperature at 40 ℃, carrying out ultrasonic treatment for 30min, and carrying out ultrasonic treatment at 50W to prepare 25.0% by mass of salt water, removing scum on the upper layer of the solution by using a scraper, and regulating the pH value of the solution to 7.0 by using hydrochloric acid and sodium hydroxide; the solution was subjected to microfiltration membrane filtration treatment, and was subjected to filtration with a 0.45 μm microfiltration membrane under a transmembrane pressure of 0.05MPa for 10 minutes. Carrying out electrocatalytic oxidation treatment on the solution, wherein in the electrocatalytic oxidation treatment process, an anode plate is a Ti/RuO 2-IrO2 (titanium-based ruthenium iridium) electrode, a cathode plate is a titanium metal plate subjected to polishing treatment, pulse direct current power supply is adopted, square wave output is adopted, the duty ratio is 8:1, the pulse frequency is 1Hz, the electrolysis time is 3h, the current density is 30mA/cm 2, the distance between electrode plates is 20mm, and the pH value of the solution after the electrocatalytic oxidation treatment is adjusted to 13.0; micro-nano air floatation is carried out on the treated saline water for 20min, the air flow rate is 10m 3/h, the residence time of bubbles in the saline sewage is 2min, and the particle size of the bubbles is about 50 nm; the solution was subjected to a microfiltration membrane secondary filtration treatment, and was subjected to a microfiltration membrane secondary filtration under a transmembrane pressure of 0.05MPa for 10 minutes.
Evaporating and crystallizing the solution, and washing the crystallized salt with water. Heating and evaporating the supernatant liquid after electrocatalytic crystallization in an evaporating crystallizer, wherein the evaporating temperature is 100 ℃, and the crystallization treatment degree is selected to reduce the volume of the solution to 20%. And testing the crystalline salt, performing primary water washing treatment and secondary water washing treatment on the crystalline salt which does not reach the standard by using pure water, performing microfiltration membrane tertiary filtration treatment on the crystalline salt after the water washing treatment, and performing tertiary filtration for 10min by using a microfiltration membrane with the thickness of 0.11 mu m under the transmembrane pressure of 0.05 MPa. And (3) carrying out electrocatalytic oxidation secondary treatment and tertiary treatment on the residual solution which is not crystallized and the water washing filtrate, wherein the mass ratio of the crystalline salt to the pure water is 5:1 during the water washing treatment.
Analysis and test:
Through detection, the TOC value in the waste salt pretreatment solution is reduced from 1190mg/L to 5mg/L after three times of electrocatalytic oxidation treatment; the total nitrogen content is reduced from 710mg/L to 7mg/L; the ammonia nitrogen content is reduced from 590mg/L to 3mg/L.
The TOC value in the waste salt is reduced from 3600mg/kg to 1.12mg/kg after the secondary water washing treatment; the NaCl content is improved from 90.52% to 99.42%; the total nitrogen content is reduced from 2200mg/kg to 0.6mg/kg; the ammonia nitrogen content is reduced from 1800mg/kg to 0.3mg/kg.
Example 4 method for removing Industrial waste salt X4
Dissolving waste salt in water, stirring at 500rpm, maintaining the heating temperature at 60 ℃, ultrasonic time at 10min and ultrasonic power at 150W to prepare 60.0% mass fraction brine, removing scum on the upper layer of the solution by using a scraper, and regulating the pH value of the solution to 10.0 by using hydrochloric acid and sodium hydroxide; carrying out microfiltration membrane filtration treatment on the solution, and filtering the solution for 30min by using a microfiltration membrane with the thickness of 0.45 mu m under the transmembrane pressure of 0.20 MPa; carrying out electrocatalytic oxidation treatment on the solution, wherein a platinum electrode is selected as an anode plate in the electrocatalytic oxidation treatment process, a titanium metal plate subjected to polishing treatment is selected as a cathode plate, pulse direct current power supply and square wave output are adopted, the duty ratio is 3:1, the pulse frequency is 0.1Hz, the electrolysis time is 1h, the current density is 10mA/cm 2, the distance between the electrode plates is 10mm, and the pH value of the solution after the electrocatalytic oxidation treatment is adjusted to 11.0; micro-nano air floatation is carried out on the residual salt water for 30min, the air flow rate is 3m 3/h, the residence time of bubbles in the salt-containing sewage is 10min, and the particle size of the bubbles is about 10 mu m; the solution was subjected to microfiltration membrane secondary filtration treatment, and was subjected to secondary filtration with a 0.22 μm microfiltration membrane under a transmembrane pressure of 0.20MPa for 10min.
Evaporating and crystallizing the solution, and washing the crystallized salt with water. Heating and evaporating the supernatant liquid after electrocatalytic crystallization in an evaporating crystallizer, wherein the evaporating temperature is 60 ℃, and the crystallization treatment degree is selected to reduce the volume of the solution to 15%. And testing the crystalline salt, performing primary water washing treatment and secondary water washing treatment on the crystalline salt which does not reach the standard by using pure water, performing microfiltration membrane tertiary filtration treatment on the crystalline salt after the water washing treatment, and performing tertiary filtration for 10min by using a microfiltration membrane with the thickness of 0.11 mu m under the transmembrane pressure of 0.20 MPa. And (3) carrying out electrocatalytic oxidation secondary treatment and tertiary treatment on the residual solution which is not crystallized and the water washing filtrate, wherein the mass ratio of the crystalline salt to the pure water is 2:1 during the water washing treatment.
Analysis and test:
Through detection, the TOC value in the waste salt pretreatment solution is reduced from 1190mg/L to 7mg/L after three times of electrocatalytic oxidation treatment; the total nitrogen content is reduced from 710mg/L to 7mg/L; the ammonia nitrogen content is reduced from 590mg/L to 2mg/L.
The TOC value in the waste salt is reduced from 3600mg/kg to 1.03mg/kg after the secondary water washing treatment; the NaCl content is improved from 90.52% to 99.40%; the total nitrogen content is reduced from 2200mg/kg to 0.7mg/kg; the ammonia nitrogen content is reduced from 1800mg/kg to 0.3mg/kg.
Comparative example
1 Ton of industrial waste salt was taken from the same batch as in example 1 for treatment. Directly preparing waste salt into salt-containing sewage with the mass fraction of 25.0% without pretreatment and electrocatalytic oxidation treatment steps, and then carrying out micro-nano air floatation and evaporative crystallization treatment. Other processing conditions were consistent with example 1.
And (3) analysis and detection:
Through detection, the TOC value in the waste salt pretreatment solution is reduced from 1190mg/L to 1095mg/L after one-time treatment of micro-nano air floatation; 825mg/L after secondary treatment of micro-nano air flotation, 621mg/L after tertiary treatment of micro-nano air flotation; the total nitrogen content is reduced from 710mg/L to 557mg/L of one-time treatment of micro-nano air floatation; 389mg/L after the micro-nano air floatation secondary treatment and 196mg/L after the micro-nano air floatation tertiary treatment; the ammonia nitrogen content is reduced from 590mg/L to 460mg/L for one micro-nano air floatation, 343mg/L for secondary micro-nano air floatation treatment and 211mg/L for three times of micro-nano air floatation treatment.
The TOC value in the waste salt is reduced from 3600mg/kg to 2102mg/kg after one-batch crystallization, 1041mg/kg after two-batch crystallization and 469mg/k after three-batch crystallization; the sodium chloride content is increased from 90.52% to 92.12% after one batch of crystallization treatment, to 92.97% after two batches of crystallization treatment, and to 93.25% after three batches of crystallization treatment; the total nitrogen content is reduced from 2200mg/kg to 1522mg/kg after one batch of crystallization treatment, 967mg/kg after two batches of crystallization treatment and 501mg/kg after three batches of crystallization treatment; the ammonia nitrogen content is reduced from 1800mg/kg to 1321mg/kg after one batch of crystallization treatment, 814mg/kg after two batches of crystallization treatment, 376mg/kg after three batches of crystallization treatment.
As can be seen from comparison of the treatment results of comparative example and example 1, the treatment effects of the separate micro-nano air floatation and electrocatalytic oxidation reactions on TOC, total nitrogen and ammonia nitrogen in wastewater and waste salt are relatively weak, and the recovery efficiency of the target waste salt is low, but when the two steps are overlapped with each other and the pretreatment step (i.e. the treatment method of example 1) is added, the treatment effect and the treatment efficiency can be doubled, which means that the two steps generate the overlapping effect in the treatment process of organic matters.
In conclusion, the method for removing the organic pollutants in the industrial waste salt combines the pretreatment technology, the microfiltration membrane filtration, the electrocatalytic oxidation, the micro-nano air floatation and the evaporative crystallization technology, greatly improves the removal efficiency of the organic pollutants in the waste salt, effectively removes the impurities in the industrial waste salt, fully recycles the salt, and greatly reduces the treatment cost.
The present invention is not limited to the above-mentioned embodiments, and any changes or substitutions that can be easily understood by those skilled in the art within the technical scope of the present invention are intended to be included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (5)
1. The method for removing the organic pollutants in the industrial waste salt is characterized by comprising the following steps of:
Dissolving waste salt in water, preparing salt-containing sewage by magnetic stirring and heating ultrasonic pretreatment, and removing scum on the surface of the salt-containing sewage;
adjusting the pH value of the pretreated saline sewage to 7.0-10.0 by using hydrochloric acid and sodium hydroxide, and performing primary filtration on the saline sewage by using a microfiltration membrane;
Treating the filtered salt-containing sewage by using an electrocatalytic method, supplying power by pulse direct current, outputting square waves, wherein the duty ratio is 3:1-8:1, the pulse frequency is 0.01-1 Hz, and the current density is 2-30 mA/cm 2;
Adjusting the pH value of the salt-containing sewage subjected to electrocatalytic treatment to 11.0-13.0 by sodium hydroxide, and then performing micro-nano air floatation treatment, wherein surface scum is removed in time during treatment; in the micro-nano air floatation treatment step, air bubbles generated by aeration have the particle size of 50 nm-10 mu m, the gas flow rate of 3-10 m 3/h, and the residence time of the air bubbles in the saline sewage is 2-10 min;
carrying out secondary filtration on the salt-containing sewage after micro-nano air floatation treatment;
Sequentially carrying out evaporative crystallization water washing treatment on the salt-containing sewage obtained after the secondary filtration, carrying out tertiary filtration on the crystal salt after the water washing treatment, merging the residual salt-containing sewage with the water washing filtrate, carrying out electrocatalytic oxidation treatment again, and continuing to carry out evaporative crystallization until the precipitated crystal salt completely reaches a preset standard; the aperture of the micro-filtration membrane for primary filtration is 0.45 mu m, the aperture of the micro-filtration membrane for secondary filtration is 0.22 mu m, the aperture of the micro-filtration membrane for tertiary filtration is 0.11 mu m, the treatment time of each stage is 10-30 min, and the transmembrane pressure of each stage is 0.05-0.20 MPa.
2. The method for removing organic pollutants from industrial waste salt according to claim 1, wherein the rotation speed of the magnetic stirring is 10-500 rpm, the heating temperature is 40-60 ℃, the power of ultrasonic treatment is 50-150W, the treatment time is 10-30 min, and the mass fraction of the prepared salt-containing sewage is more than or equal to 25.0%.
3. The method for removing organic pollutants from industrial waste salt according to claim 1, wherein in the step of electrocatalytic treatment, a titanium metal plate or stainless steel plate is used as a cathode, and one of a titanium-based tin-antimony electrode, a titanium-based tin-antimony interlayer lead dioxide electrode, a titanium-based ruthenium-iridium electrode or a platinum electrode is used as an anode, wherein the titanium-based tin-antimony electrode is an inactive electrode coated with an antimony pentoxide doped tin dioxide coating on a titanium plate; the lead dioxide electrode of the titanium-based tin-antimony interlayer is an inactive electrode which takes a titanium plate as a base material, takes an antimony pentoxide doped tin dioxide coating as an interlayer and takes lead dioxide as a surface active layer; the titanium-based ruthenium iridium electrode is prepared by dipping and brushing a titanium substrate etched by polishing acid with sol containing ruthenium dioxide and iridium dioxide; the platinum electrode is a metal platinum plating electrode.
4. The method for removing organic pollutants from industrial waste salt according to claim 1, wherein in the step of evaporating, crystallizing and washing, the evaporating temperature is 60-100 ℃, and the salt-containing sewage is evaporated to 20-40% of the original volume; and during water washing treatment, the mass ratio of the substandard crystalline salt to the pure water or the deionized water is 2:1-5:1.
5. The device for removing organic pollutants in industrial waste salt according to any one of claims 1-4, which is characterized by comprising a pretreatment subsystem (1), a microfiltration membrane primary filtration subsystem (2), an electrocatalytic oxidation treatment subsystem (3), a micro-nano air floater system (4), a microfiltration membrane secondary filtration subsystem (6) and an evaporation crystallization subsystem (5) which are sequentially communicated, a water washing subsystem (7) communicated with a non-standard crystallization salt outlet of the evaporation crystallization subsystem (5) and a microfiltration membrane tertiary filtration subsystem (8) communicated with an outlet of the water washing subsystem (7), wherein a filtrate outlet of the microfiltration membrane tertiary filtration subsystem (8) is communicated with a concentrated solution outlet of the evaporation crystallization subsystem (5) and then with an inlet of the electrocatalytic oxidation treatment subsystem (3) to form a circulation; the removing device also comprises an electric subsystem for providing electric energy for each subsystem;
The removing device further comprises a crystallized salt storage tank (10) and a slag storage tank, wherein the slag storage tank is communicated with a slag outlet at the bottom of the electrocatalytic oxidation treatment subsystem (3) through a control valve, and the crystallized salt storage tank (10) is communicated with a crystallized salt outlet at the bottom of the water washing subsystem (7) through a control valve;
The pretreatment subsystem (1) comprises a feeding tank (11), a magnetic stirrer (12), an ultrasonic probe (13) and a heating plate (14) attached to the wall of the feeding tank, the microfiltration membrane filtration subsystem comprises a filter (100) and a filter tank (200) with microfiltration membranes, which are sequentially communicated, the electrocatalytic oxidation treatment subsystem (3) comprises a catalytic tank, an anode plate, a cathode plate and a slag collecting box positioned below the anode plate and the cathode plate in the catalytic tank, the micro-nano air floater system (4) comprises a reaction tank, a micro-nano aeration head (41) arranged at the bottom of the reaction tank and a scraper (42) suspended above the reaction tank, and the evaporation crystallization subsystem (5) comprises an evaporation crystallization tank (51), another heating plate and a stirrer; the water washing subsystem (7) comprises a water washing tank (71) and another stirrer;
The magnetic stirrer (12), the ultrasonic probe (13), the heating plate (14), the filter (100), the anode plate, the cathode plate, the micro-nano aeration head (41), the scraper (42), the other heating plate, the stirrer and the other stirrer are all connected with the electric power subsystem.
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| CN110054203B (en) * | 2019-04-12 | 2021-07-27 | 河海大学 | A kind of resource utilization method of industrial waste salt |
| CN109956483A (en) * | 2019-04-12 | 2019-07-02 | 河海大学 | A kind of harmless and resourceful method of waste salt in chemical industry |
| CN110328218B (en) * | 2019-07-30 | 2020-10-23 | 湖南中森环境科技有限公司 | Resource utilization method of salt slag polluted by organic matters |
| CN110548750B (en) * | 2019-09-05 | 2024-04-23 | 上海晶宇环境工程股份有限公司 | Waste salt recycling treatment process and special equipment thereof |
| CN112830614A (en) * | 2021-04-07 | 2021-05-25 | 上海电气集团股份有限公司 | Method and device for treating industrial waste salt |
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