CN111715664A - Treatment method for recycling carbonized industrial waste salt - Google Patents

Treatment method for recycling carbonized industrial waste salt Download PDF

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Publication number
CN111715664A
CN111715664A CN202010590294.3A CN202010590294A CN111715664A CN 111715664 A CN111715664 A CN 111715664A CN 202010590294 A CN202010590294 A CN 202010590294A CN 111715664 A CN111715664 A CN 111715664A
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salt
polluted
carbonization
industrial
introducing
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CN202010590294.3A
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Inventor
丁治椿
仲文
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Suzhou Joyfa Environmental Technology Corp ltd
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Suzhou Joyfa Environmental Technology Corp ltd
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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B09DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
    • B09BDISPOSAL OF SOLID WASTE NOT OTHERWISE PROVIDED FOR
    • B09B3/00Destroying solid waste or transforming solid waste into something useful or harmless
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B09DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
    • B09BDISPOSAL OF SOLID WASTE NOT OTHERWISE PROVIDED FOR
    • B09B3/00Destroying solid waste or transforming solid waste into something useful or harmless
    • B09B3/40Destroying solid waste or transforming solid waste into something useful or harmless involving thermal treatment, e.g. evaporation
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B09DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
    • B09BDISPOSAL OF SOLID WASTE NOT OTHERWISE PROVIDED FOR
    • B09B5/00Operations not covered by a single other subclass or by a single other group in this subclass
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B09DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
    • B09BDISPOSAL OF SOLID WASTE NOT OTHERWISE PROVIDED FOR
    • B09B2101/00Type of solid waste
    • B09B2101/02Gases or liquids enclosed in discarded articles, e.g. aerosol cans or cooling systems of refrigerators

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  • Engineering & Computer Science (AREA)
  • Environmental & Geological Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Heat Treatment Of Water, Waste Water Or Sewage (AREA)
  • Processing Of Solid Wastes (AREA)

Abstract

The invention discloses a resource treatment method after carbonization of industrial polluted salt, which comprises the following steps: (1) sending industrial sewage salt containing certain moisture into drying equipment for pre-drying, so that the moisture content in the industrial sewage salt is reduced to below 1%; (2) introducing the pre-dried industrial polluted salt into a carbonization furnace, and carbonizing at 600-800 ℃ to remove organic matters in the polluted salt; (3) cooling the carbonized polluted salt, introducing the cooled polluted salt into a salt dissolving system for dissolving, and then sequentially carrying out primary filtration and ultrafiltration to remove carbon black generated in the carbonization process; (4) introducing the filtered solution into a softener, adding a softening agent into the softener, and standing for 30-60 min to settle precipitates; (5) and introducing the softened polluted salt solution into an evaporative crystallization system for salt separation treatment. The resource treatment method after the carbonization of the industrial polluted salt can effectively prevent the industrial polluted salt from melting, caking and bonding, thoroughly decompose and carbonize organic matters, and improve the purity of inorganic salt.

Description

Treatment method for recycling carbonized industrial waste salt
Technical Field
The invention relates to the technical field of waste recycling treatment, in particular to a recycling treatment method for carbonized industrial waste salt.
Background
In the production process of a plurality of organic or inorganic chemical products, a large amount of high-salt wastewater is generated due to process requirements, wherein the content of sodium chloride and sodium sulfate is higher than 2%, the content of sodium chloride and sodium sulfate is more than 10%, and the content of sodium chloride and sodium sulfate is even more than 20%, and the high-salt wastewater is high-salt wastewater which is mostly subjected to evaporative crystallization or MVR evaporative crystallization in the currently mature treatment process; this produces a large amount of by-product miscellaneous salts (mixed salts of NaCl and sodium sulfate). The sodium chloride/sodium sulfate content of the salt is more than 95 percent, and simultaneously, the salt contains a large amount of organic or inorganic impurities, can not be directly used as industrial raw material salt, can not be used for food or medical use, and is stockpiled by most manufacturers. The long-term stacking of the mixed salt of sodium chloride and sodium sulfate not only occupies a large amount of fields, but also has great threat to the environment, salt and impurities are easy to lose, the surrounding soil is salinized, the surrounding vegetation is endangered, and meanwhile, the mixed salt causes pollution to surrounding rivers, water sources, rice fields and the like.
At present, the treatment method adopted for the byproduct polluted salt generated by the industrial high-salinity wastewater mainly comprises the following steps: burying, washing, high-temperature burning, carbonizing and the like. The landfill method has simple treatment mode, but occupies a large amount of land resources, and the poor treatment easily causes pollution to soil and underground water resources, thereby bringing great threat to the living environment of people. The washing method mainly adopts water washing and chemical solvents to treat the polluted salt, the method has accurate control on the dosage of the chemical solvents, and secondary hazardous wastes are easy to generate. The high-temperature incineration means that harmful organic materials in the polluted salt are decomposed or removed through high-temperature oxidation incineration, the purpose of harmless treatment is achieved, inorganic salt melting is not needed to be controlled, the harmful materials are prevented from being produced, the operation technology difficulty is high, and the polluted salt melting, caking, bonding or equipment blocking is easily caused.
Disclosure of Invention
The invention aims to solve the technical problem of providing a resource treatment method for carbonized industrial waste salt, so as to solve various defects of the conventional treatment method.
In order to solve the technical problem, the invention provides a resource treatment method of carbonized industrial waste salt, which comprises the following steps:
(1) sending industrial sewage salt containing certain moisture into drying equipment for pre-drying, so that the moisture content in the industrial sewage salt is reduced to below 1%;
(2) introducing the pre-dried industrial polluted salt into a carbonization furnace, and carbonizing at 600-800 ℃ to remove organic matters in the polluted salt;
(3) introducing carbonized polluted salt into a salt dissolving system for dissolving, and then sequentially carrying out primary filtration and ultrafiltration to remove carbon black generated in the carbonization process;
(4) introducing the filtered solution into a softener, adding a softening agent into the softener, and standing for 30-60 min to settle precipitates;
(5) and introducing the softened polluted salt into an evaporative crystallization system for salt separation treatment.
Further, in the step (1), the drying equipment is a fluidized bed, and the drying temperature is 70-80 ℃. Drying is carried out in a fluidized bed mode, so that the water content of industrial polluted salt can be quickly reduced to be lower than 1%, the energy consumption is remarkably reduced, and the polluted salt can be prevented from being solidified in the drying process. Of course, other drying means may be used.
Further, in the step (2), the carbonization time is 6-8 h.
Further, in the step (2), the gas generated by carbonization is sent to a tail gas treatment system for harmless treatment. The innocent treatment comprises the following steps: and introducing gas generated by carbonization into a combustion device for combustion, and recovering waste heat from the generated tail gas.
Further, in the step (3), the primary filtering equipment is a filter press, and the pressure is 6-8 kg; the size of the mesh of the filter screen for ultrafiltration is 0.01-0.1 μm. The solid carbon particles in the contaminated salt solution are thoroughly separated by primary filtration and ultrafiltration.
And (3) further, in the step (3), introducing the filtered substances of the primary filtration and the ultrafiltration into a filter cake dissolving tank for dissolving, and performing pressure filtration on the dissolved solution through a pressure filter to obtain the carbon black for later use.
Further, in the step (4), the softening agent is sodium carbonate and sodium hydroxide, and Ca in the solution is enabled to be contained by adding the softening agent2+、Mg2+And precipitating metal impurity ions.
Further, in the step (5), the evaporative crystallization adopts a salt and nitrate co-production process.
The invention has the beneficial effects that:
1. the invention adopts a low-temperature carbonization technology, and technological parameters such as carbonization temperature, time and the like can be adjusted and controlled along with the physicochemical characteristics of materials, so that toxic and harmful organic substances which are complex in components, high in content and difficult to degrade in the polluted salt can be effectively removed, the decomposition and carbonization are more sufficient and thorough, and the technical problems that inorganic salt is easy to melt, agglomerate, bond with equipment, cannot continuously run and the like in the carbonization process are solved.
2. According to the resource treatment method, the carbonized polluted salt is subjected to salt melting, filtering, softening and evaporative crystallization treatment again, so that the purity of the inorganic salt is obviously improved, the inorganic salt can be reused, secondary wastes which are difficult to treat are not generated in the production process, the waste of resources is reduced, the damage of waste water to the environment is reduced, and the resource treatment method has good economic and social benefits.
Drawings
FIG. 1 is a flow chart of a method for recycling inorganic salts in industrial wastewater according to the present invention;
FIG. 2 is a process flow diagram of the one-time planning of the polluted salt reclamation of example 1.
Detailed Description
The present invention is further described below in conjunction with the following figures and specific examples so that those skilled in the art may better understand the present invention and practice it, but the examples are not intended to limit the present invention.
As described in the background art, the treatment methods adopted for the byproduct polluted salt generated by the industrial high-salinity wastewater at present mainly include: burying, washing, high-temperature burning, carbonizing and the like. However, these methods have inherent disadvantages, which limit the resource utilization of inorganic salts in industrial wastewater.
Referring to fig. 1, in order to solve the technical problem, the invention provides a method for treating industrial waste salt after carbonization for recycling, which comprises the following steps:
(1) sending industrial sewage salt containing certain moisture into drying equipment for pre-drying, so that the moisture content in the industrial sewage salt is reduced to below 1%;
(2) introducing the pre-dried industrial polluted salt into a carbonization furnace, and carbonizing at 600-800 ℃ to remove organic matters in the polluted salt;
(3) introducing carbonized polluted salt into a salt dissolving system for hydrolysis, and then sequentially carrying out primary filtration and ultrafiltration to remove carbon black generated in the carbonization process;
(4) introducing the filtered solution into a softener, adding a softening agent into the softener, and standing for 30-60 min to settle precipitates;
(5) introducing the softened polluted salt into an evaporative crystallization system for salt separation treatment;
(6) and dehydrating and drying the separated salt to obtain refined salt.
In the invention, the industrial polluted salt generally contains 40-50% of water, and the water content of the industrial polluted salt is rapidly reduced to below 1% by a pre-drying means, so that the industrial polluted salt forms particles with good fluidity so as to be convenient for carbonization. The pre-drying can adopt a drying mode commonly used in the field, preferably fluidized bed drying, and the drying temperature is preferably 70-80 ℃. The fluidized bed drying is adopted, so that the drying speed is high, the energy consumption is reduced, and the solidification of the polluted salt in the drying process can be prevented.
And (4) carbonizing the pre-dried polluted salt in a carbonization furnace, wherein the carbonization time is preferably 6-8 h. Organic matters in the polluted salt are converted into solid carbon particles through carbonization, and a carbon salt mixture is formed. The invention adopts a low-temperature carbonization process, the carbonization temperature of the low-temperature carbonization process is lower than that of the conventional carbonization process, and the technical problems that inorganic salt is melted, agglomerated and bonded with equipment, the equipment cannot continuously run and the like in the carbonization process are solved.
And (3) sending the gas generated after carbonization into a tail gas treatment system for harmless treatment, wherein the harmless treatment comprises the following steps: and introducing gas generated by carbonization into a combustion device for combustion, and recovering waste heat from the generated tail gas.
In the invention, the primary filtering equipment is a filter press, and the pressure is 6-8 kg; the size of the mesh of the filter screen for ultrafiltration is 0.01-0.1 μm. Through primary filtration and ultrafiltration, solid carbon particles in the polluted salt solution are thoroughly separated, which is beneficial to improving the purity of subsequent inorganic salt.
In order to realize the recycling of carbon particles in the polluted salt, the filtered substances of primary filtration and ultrafiltration are introduced into a filter cake dissolving tank for dissolving, and the dissolved solution is subjected to filter pressing by a filter press to obtain carbon black, and the carbon black is recovered for later use after being dried.
In the invention, the softening agent is sodium carbonate and sodium hydroxide, and Ca in the solution is enabled to be contained by adding the softening agent2+、Mg2+And the purity is further improved by metal impurity ion sedimentation.
In the invention, the evaporative crystallization system can adopt a single-effect evaporation mode, a multi-effect evaporation mode or an MVR evaporation mode.
Example 1
The first-stage planning of the waste salt recycling of 2 production lines in a certain place has the total salt amount of 3 ten thousand tons/h, takes sodium chloride and sodium sulfate as main materials, and has the following raw material classification: 2.25 ten thousand tons of NaCl per year, 0.75 ten thousand tons of Na2SO4. The sodium chloride production line considers a capacity of 0.4 ten thousand tons/year in the fourth phase.
Referring to fig. 2, dry salt generated in a carbonization workshop enters a salt dissolving system and is dissolved into undersaturated brine; removing impurities which affect the salt quality, such as carbon black, calcium, magnesium, heavy metals and the like in the brine through a filtering system and a softening system; pumping the pretreated brine to a sodium chloride low-temperature evaporation system for evaporation and crystallization, carrying out solid-liquid separation on supersaturated solution through a centrifuge to obtain crystallized salt, continuously concentrating sodium sulfate in centrifugal mother liquor, discharging the mother liquor to the sodium sulfate high-temperature evaporation system when the sodium sulfate is close to saturation, separating out sodium sulfate due to reduction of solubility, changing sodium chloride into unsaturated components due to increase of solubility, further separating out sodium sulfate by continuously evaporating water, gradually enabling the concentration of sodium chloride to be close to the saturation point under the temperature condition, and discharging the sodium sulfate centrifugal mother liquor to the sodium chloride low-temperature evaporation system. The sodium chloride and the sodium sulfate are separated by recycling.
The above-mentioned embodiments are merely preferred embodiments for fully illustrating the present invention, and the scope of the present invention is not limited thereto. The equivalent substitution or change made by the technical personnel in the technical field on the basis of the invention is all within the protection scope of the invention. The protection scope of the invention is subject to the claims.

Claims (7)

1. A treatment method for recycling industrial polluted salt after carbonization is characterized by comprising the following steps:
(1) sending industrial sewage salt containing certain moisture into drying equipment for pre-drying, so that the moisture content in the industrial sewage salt is reduced to below 1%;
(2) introducing the pre-dried industrial polluted salt into a carbonization furnace, and carbonizing at 600-800 ℃ to remove organic matters in the polluted salt;
(3) cooling the carbonized polluted salt, introducing the cooled polluted salt into a salt dissolving system for dissolving, and then sequentially carrying out primary filtration and ultrafiltration to remove carbon black generated in the carbonization process;
(4) introducing the filtered solution into a softener, adding a softening agent into the softener, and standing for 30-60 min to settle precipitates;
(5) and introducing the softened polluted salt solution into an evaporative crystallization system for salt separation treatment.
2. The method for treating carbonized industrial waste salt as claimed in claim 1, wherein in the step (1), the drying equipment is a fluidized bed, and the drying temperature is 70-80 ℃.
3. The method for treating carbonized industrial waste salt as claimed in claim 1, wherein in the step (2), the carbonization time is 6-8 h.
4. The method according to claim 1, wherein in the step (2), the gas generated by the carbonization is sent to a tail gas treatment system for harmless treatment.
5. The method for recycling the carbonized industrial waste salt as claimed in claim 1, wherein in the step (3), the primary filtering equipment is a filter press, and the pressure is 6-8 kg; the size of the mesh of the filter screen for ultrafiltration is 0.01-0.1 μm.
6. The method for recycling industrial waste salt after carbonization as claimed in claim 1, wherein in the step (3), the filtered substances obtained by primary filtration and ultrafiltration are introduced into a filter cake dissolving tank for dissolution, and the dissolved solution is subjected to pressure filtration by a filter press to obtain the carbon black for recycling.
7. The method for treating industrial waste salt as reclaimed after carbonization as claimed in claim 1, wherein in the step (4), the softening agent is sodium carbonate and sodium hydroxide.
CN202010590294.3A 2020-06-24 2020-06-24 Treatment method for recycling carbonized industrial waste salt Pending CN111715664A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115246649A (en) * 2021-08-09 2022-10-28 江苏美东环境科技有限公司 Method for preparing fertilizer-grade potassium chloride from potassium chloride organic hazardous waste salt
CN115246650A (en) * 2021-08-09 2022-10-28 江苏美东环境科技有限公司 Method for preparing industrial potassium sulfate from hazardous organic waste salt containing potassium chloride and sodium sulfate

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107803395A (en) * 2017-12-11 2018-03-16 广州叶林环保科技有限公司 A kind of organic abraum salt low-temperature carbonization handling process
CN108278613A (en) * 2018-04-04 2018-07-13 江苏科行环保股份有限公司 The apparatus and method that industrial dangerous waste salt disposition and resource utilization utilize
CN109081488A (en) * 2018-08-03 2018-12-25 北京朗新明环保科技有限公司 A kind of method and system of industry strong brine resource utilization
CN110627290A (en) * 2019-11-07 2019-12-31 中化工程集团环保有限公司 High salt waste water resourceful treatment system
CN110756172A (en) * 2019-07-10 2020-02-07 内蒙古中泰汇金环保科技有限公司 Inorganic salt hazardous waste recycling treatment process

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107803395A (en) * 2017-12-11 2018-03-16 广州叶林环保科技有限公司 A kind of organic abraum salt low-temperature carbonization handling process
CN108278613A (en) * 2018-04-04 2018-07-13 江苏科行环保股份有限公司 The apparatus and method that industrial dangerous waste salt disposition and resource utilization utilize
CN109081488A (en) * 2018-08-03 2018-12-25 北京朗新明环保科技有限公司 A kind of method and system of industry strong brine resource utilization
CN110756172A (en) * 2019-07-10 2020-02-07 内蒙古中泰汇金环保科技有限公司 Inorganic salt hazardous waste recycling treatment process
CN110627290A (en) * 2019-11-07 2019-12-31 中化工程集团环保有限公司 High salt waste water resourceful treatment system

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115246649A (en) * 2021-08-09 2022-10-28 江苏美东环境科技有限公司 Method for preparing fertilizer-grade potassium chloride from potassium chloride organic hazardous waste salt
CN115246650A (en) * 2021-08-09 2022-10-28 江苏美东环境科技有限公司 Method for preparing industrial potassium sulfate from hazardous organic waste salt containing potassium chloride and sodium sulfate

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Application publication date: 20200929