CN113510140B - Waste salt recycling treatment system and method - Google Patents

Waste salt recycling treatment system and method Download PDF

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Publication number
CN113510140B
CN113510140B CN202110942270.4A CN202110942270A CN113510140B CN 113510140 B CN113510140 B CN 113510140B CN 202110942270 A CN202110942270 A CN 202110942270A CN 113510140 B CN113510140 B CN 113510140B
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salt
pyrolysis
effect evaporator
tank
water
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CN113510140A (en
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田磊
孙凌凌
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Shaanxi Chemical Research Institute Co ltd
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Shaanxi Chemical Research Institute Co ltd
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    • 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
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
    • C01D3/00—Halides of sodium, potassium or alkali metals in general
    • C01D3/04—Chlorides
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
    • C01D3/00—Halides of sodium, potassium or alkali metals in general
    • C01D3/14—Purification
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
    • C01D5/00—Sulfates or sulfites of sodium, potassium or alkali metals in general
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
    • C01D5/00—Sulfates or sulfites of sodium, potassium or alkali metals in general
    • C01D5/16—Purification
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
    • C01D5/00—Sulfates or sulfites of sodium, potassium or alkali metals in general
    • C01D5/18—Dehydration
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F9/00—Multistage treatment of water, waste water or sewage
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10B—DESTRUCTIVE DISTILLATION OF CARBONACEOUS MATERIALS FOR PRODUCTION OF GAS, COKE, TAR, OR SIMILAR MATERIALS
    • C10B53/00—Destructive distillation, specially adapted for particular solid raw materials or solid raw materials in special form
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/001—Processes for the treatment of water whereby the filtration technique is of importance
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/02—Treatment of water, waste water, or sewage by heating
    • C02F1/04—Treatment of water, waste water, or sewage by heating by distillation or evaporation
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/42—Treatment of water, waste water, or sewage by ion-exchange
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
    • C02F1/442—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by nanofiltration
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
    • C02F1/5281—Installations for water purification using chemical agents
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/66—Treatment of water, waste water, or sewage by neutralisation; pH adjustment
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2301/00—General aspects of water treatment
    • C02F2301/08—Multistage treatments, e.g. repetition of the same process step under different conditions

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Inorganic Chemistry (AREA)
  • Environmental & Geological Engineering (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Hydrology & Water Resources (AREA)
  • Water Supply & Treatment (AREA)
  • Separation Using Semi-Permeable Membranes (AREA)
  • Heat Treatment Of Water, Waste Water Or Sewage (AREA)

Abstract

The invention discloses a waste salt recycling treatment system which comprises a carbonization pyrolysis unit, a brine refining unit and a salt separation crystallization unit which are connected in sequence; the brine refining unit comprises a salt dissolving tank, a high-efficiency sedimentation tank, a filtering device, a COD removing device and an ion exchanger which are connected in sequence; the efficient sedimentation tank is provided with a medicament adding port and a stirring device, the efficient sedimentation tank and the filtering device are connected with a sludge dewatering device, and the sludge dewatering device is also connected with a sludge recovery tank; the sludge dewatering device is also provided with a liquid outlet which is connected with the efficient sedimentation tank through a water return pipe. Meanwhile, the invention also discloses a method for recycling waste salt by adopting the system. According to the waste salt recycling treatment system provided by the invention, the waste salt is refined, and the removal rate of organic matters can reach more than 60% through carbonization and pyrolysis, and meanwhile, the product-grade sodium chloride and sodium sulfate are recovered.

Description

Waste salt recycling treatment system and method
Technical Field
The invention belongs to the technical field of waste salt treatment, and particularly relates to a waste salt recycling treatment system and method.
Background
In the industrial production process, especially in coal chemical industry, chemical fertilizers, pesticides, biochemical industry and the like, industrial salt residues such as non-specific industry rectification residues (HW 11), pesticide industry (HW 04), medicine industry (HW 02), organic halide-containing waste (HW 45) and the like often generate a large amount of solid waste salts, and the main components are sodium chloride and sodium sulfate. These waste salts often contain some amount of organic or other impurities such as heavy metals, and national related legal documents also classify these waste salts as hazardous waste. At present, the waste salt is generally stored in a centralized manner in a warehouse of an enterprise, but how to completely realize harmless recycling becomes an industrial problem to be solved urgently.
The existing waste salt treatment technology mainly comprises landfill, incineration and resource comprehensive utilization. The landfill is to send the waste salt into a rigid landfill site for sanitary landfill disposal according to the technical specification of landfill after solidification of concrete and the like. The incineration is to heat the waste salt to 900 ℃, and the inorganic salt is melted and flows into the furnace bottom and is recovered after cooling. Because the fluctuation of the melting point interval of the waste salt is large, adverse phenomena such as slag bonding, caking and the like are very easy to occur in the incineration treatment process, and the process stability is influenced.
The dangerous waste salt has large yield and environmental hazard, has great reuse value, treats the waste salt, realizes the recycling of the waste salt, not only can solve the difficult problem of environmental pollution, but also can bring considerable benefits.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides a waste salt recycling treatment system and a waste salt recycling treatment method, which can effectively remove organic matters in waste salt and recycle sodium chloride and sodium sulfate.
The waste salt recycling treatment system comprises a carbonization pyrolysis unit, a brine refining unit and a salt separating crystallization unit which are sequentially connected, wherein the brine refining unit comprises a salt dissolving tank, a high-efficiency sedimentation tank, a filtering device, a COD removal device and an ion exchanger which are sequentially connected; the efficient sedimentation tank is provided with a medicament adding port and a stirring device, the efficient sedimentation tank and the filtering device are connected with a sludge dewatering device, and the sludge dewatering device is also connected with a sludge recovery tank; the sludge dewatering device is also provided with a liquid outlet which is connected with the efficient sedimentation tank through a water return pipe.
Preferably, the salt separating crystallization unit comprises a nanofiltration device, an evaporation crystallization device and a mother liquor tank which are connected in sequence;
the evaporation crystallization device is also connected with a salt dissolving tank; the mother liquor tank is connected with the carbonization pyrolysis unit; an inlet of the nanofiltration device is connected with an ion exchanger;
The evaporation crystallization device is a four-effect evaporation crystallizer; the four-effect evaporation crystallizer comprises a first-effect evaporator, a second-effect evaporator, a third-effect evaporator and a fourth-effect evaporator which are sequentially connected; the bottoms of the second effect evaporator and the fourth effect evaporator are respectively provided with a refined salt slurry outlet;
the water outlet and the concentrated water outlet of the nanofiltration device are respectively connected with the feed inlets of the third-effect evaporator and the first-effect evaporator.
Preferably, the carbonization pyrolysis unit comprises a primary pyrolysis device and a secondary pyrolysis device which are sequentially connected, and the primary pyrolysis device and the secondary pyrolysis device are both connected with the tail gas purification unit; the secondary pyrolysis device is connected with the salt dissolving tank; the primary pyrolysis device is connected with the mother liquor tank.
Preferably, the primary pyrolysis device and the secondary pyrolysis device are both fixed beds or fluidized beds.
Preferably, the fixed bed is a rotary kiln or a rake furnace.
Preferably, the heating modes of the primary pyrolysis device and the secondary pyrolysis device are electric heating, natural gas heating or microwave heating.
Preferably, the carbonization pyrolysis unit further comprises a first crushing device and a second crushing device, wherein the first crushing device is connected with an inlet of the primary pyrolysis device, and the primary pyrolysis device and the secondary pyrolysis device are connected through the second crushing device.
Preferably, the filter device is formed by connecting a multi-medium filter device and an ultrafiltration device, or is one of a tubular ultrafiltration device and an immersed ultrafiltration device.
Preferably, the sludge dewatering device is a filter press.
Preferably, the ion exchanger is a chelating resin ion exchanger.
The method for recycling the waste salt adopts the waste salt recycling treatment system for treatment, and comprises the following steps:
(1) Carbonization and pyrolysis:
The waste salt enters a first crushing device, is crushed until the particle size is smaller than 20mm, then enters a first-stage pyrolysis device, the oxygen content is controlled to be 0-1%, is heated to 200-500 ℃, stays for 20-30 min, enters a second crushing device, is crushed again, enters a second-stage pyrolysis device, is subjected to deep pyrolysis, and is heated to 500-800 ℃ and stays for 40-60 min after the oxygen content is controlled to be 3-5% by supplementing air;
pyrolysis gas generated by the primary pyrolysis device and the secondary pyrolysis device enters a tail gas purification unit, and is discharged after reaching the standard;
(2) And (3) brine refining:
Adding the carbon-containing salt slag obtained by the secondary pyrolysis device into a salt dissolving tank, supplementing water with the hardness of less than 10mg/L, stirring and dissolving to obtain brine with the concentration of 15-25 wt%, adding a medicament into the brine, removing the hardness, silicon, alkalinity, heavy metals and solid impurities in the brine by precipitation solid-liquid separation, adjusting the pH value of the effluent of the high-efficiency precipitation tank to 6.5-8.5 by sulfuric acid, and then, entering a filtering device, wherein the turbidity of produced water of the filtering device is controlled to be less than 0.2NTU, and the produced water passes through a COD removal device and an ion exchanger to ensure that the COD of the concentrated brine entering a salt separation crystallization unit is less than 100mg/L and the hardness of the concentrated brine is less than 0.1mg/L;
The backwash water of the filtering device, filter residues and precipitated sludge generated by the high-efficiency precipitation tank enter a sludge dehydration device for solid-liquid separation, filtrate generated by the sludge dehydration device is discharged from a liquid discharge port and returned to the high-efficiency precipitation tank through a water return pipe, and the generated sludge enters a sludge recovery tank for standby;
(3) Salt separation crystallization unit:
pumping the concentrated brine produced by the brine refining unit to a nanofiltration device to obtain nanofiltration produced water and nanofiltration concentrated water;
the nanofiltration concentrated water is pumped into a first effect evaporator in a four-effect evaporation crystallizer, sequentially passes through the first effect evaporator and a second effect evaporator, water is evaporated, then is condensed and recovered, and a refined salt slurry outlet of the second effect evaporator is used for discharging slurry containing sodium sulfate, and the slurry is centrifuged and dried to finally produce sodium sulfate;
The nanofiltration product water is pumped into a third-effect evaporator in a four-effect evaporation crystallizer, sequentially passes through the third-effect evaporator and the fourth-effect evaporator, is condensed and recovered after the water is evaporated, and discharges slurry containing sodium chloride at a refined salt slurry outlet of the fourth-effect evaporator, and the slurry is centrifuged and dried to finally produce sodium chloride;
In the evaporation crystallization process, condensed water recovered by the evaporation crystallization device enters a salt dissolving tank, and generated mother liquor is discharged to a mother liquor tank and then returned to the primary pyrolysis device for treatment.
Preferably, in the step (1), the primary pyrolysis device is heated to 350-400 ℃, and the secondary pyrolysis device is heated to 550-600 ℃.
Preferably, in the step (2), the agent is at least one of PAC, na 2CO3, naOH.
The invention has the advantages that:
According to the waste salt recycling treatment system provided by the invention, the waste salt is refined, and the removal rate of organic matters can reach more than 60% through carbonization and pyrolysis, and meanwhile, the product-grade sodium chloride and sodium sulfate are recovered.
Drawings
FIG. 1 is a schematic diagram of the structural connections of a waste salt reclamation system;
FIG. 2 is a schematic diagram of the connection of a nanofiltration device to an evaporative crystallization device;
Wherein, 1-first effect evaporator, 2-second effect evaporator, 3-third effect evaporator, 4-fourth effect evaporator, 5-nanofiltration device.
Detailed Description
The invention is further described below with reference to the drawings.
Example 1
The waste salt recycling treatment system comprises a carbonization pyrolysis unit, a brine refining unit and a salt separating crystallization unit which are sequentially connected, wherein the brine refining unit comprises a salt dissolving tank, a high-efficiency sedimentation tank, a filtering device, a COD removal device and an ion exchanger which are sequentially connected; the efficient sedimentation tank is provided with a medicament adding port and a stirring device, the efficient sedimentation tank and the filtering device are connected with a sludge dewatering device, and the sludge dewatering device is also connected with a sludge recovery tank; the sludge dewatering device is also provided with a liquid outlet which is connected with the efficient sedimentation tank through a water return pipe.
Example 2
On the basis of the embodiment 1, the salt separation crystallization unit comprises a nanofiltration device, an evaporation crystallization device and a mother liquor tank which are connected in sequence;
the evaporation crystallization device is also connected with a salt dissolving tank; the mother liquor tank is connected with the carbonization pyrolysis unit; an inlet of the nanofiltration device is connected with an ion exchanger;
the evaporation crystallization device is a four-effect evaporation crystallizer; the four-effect evaporation crystallizer comprises a first-effect evaporator 1, a second-effect evaporator 2, a third-effect evaporator 3 and a fourth-effect evaporator 4 which are sequentially connected; the bottoms of the second effect evaporator 2 and the fourth effect evaporator 4 are respectively provided with a refined salt slurry outlet;
The water outlet and the concentrated water outlet of the nanofiltration device 5 are respectively connected with the feed inlets of the third-effect evaporator 3 and the first-effect evaporator 1.
Example 3
On the basis of the embodiment 2, the carbonization pyrolysis unit comprises a primary pyrolysis device and a secondary pyrolysis device which are sequentially connected, wherein the primary pyrolysis device and the secondary pyrolysis device are connected with the tail gas purification unit; the secondary pyrolysis device is connected with the salt dissolving tank; the primary pyrolysis device is connected with the mother liquor tank.
Preferably, the primary pyrolysis device and the secondary pyrolysis device are both fixed beds or fluidized beds.
Preferably, the fixed bed is a rotary kiln or a rake furnace.
Preferably, the heating modes of the primary pyrolysis device and the secondary pyrolysis device are electric heating, natural gas heating or microwave heating.
Example 4
On the basis of embodiment 3, the carbonization pyrolysis unit further comprises a first crushing device and a second crushing device, wherein the first crushing device is connected with an inlet of the primary pyrolysis device, and the primary pyrolysis device and the secondary pyrolysis device are connected through the second crushing device.
Example 5
Based on the embodiment 4, the filtering device is formed by connecting a multi-medium filtering device and an ultrafiltration device, or is one of a tubular ultrafiltration device and an immersed ultrafiltration device.
Preferably, the sludge dewatering device is a filter press.
Preferably, the ion exchanger is a chelating resin ion exchanger.
Preferably, an activated carbon adsorption layer is arranged in the COD removing device.
Example 6
The method for recycling the waste salt adopts the waste salt recycling treatment system for treatment, and comprises the following steps:
(1) Carbonization and pyrolysis:
The waste salt enters a first crushing device, is crushed until the particle size is smaller than 20mm, then enters a first-stage pyrolysis device, the oxygen content is controlled to be 0-1%, is heated to 200-500 ℃, stays for 20-30 min, enters a second crushing device, is crushed again, enters a second-stage pyrolysis device, is subjected to deep pyrolysis, and is heated to 500-800 ℃ and stays for 40-60 min after the oxygen content is controlled to be 3-5% by supplementing air;
pyrolysis gas generated by the primary pyrolysis device and the secondary pyrolysis device enters a tail gas purification unit, and is discharged after reaching the standard;
Evaporating and gasifying water in the waste salt through primary pyrolysis, and pre-pyrolyzing the waste salt at the same time; air is added during secondary pyrolysis, so that the rapid pyrolysis of organic matters can be promoted;
Through the carbonization pyrolysis, organic matters in the waste salt are pyrolyzed into combustible gas (CO, H 2、VOCs、NOx、SOx) and a small amount of coke, wherein the content of NO x in the combustible gas is 0-0.7wt% and the content of SO x in the combustible gas is 0-0.2wt%; the main component of the pyrolyzed waste salt is inorganic salt and a small amount of carbonized slag;
The tail gas purification unit is treated by the prior art until reaching the emission standard, for example, the tail gas purification unit comprises a secondary combustion chamber, a waste heat boiler, a quenching tower, a dry deacidification system, a bag-type dust remover, an induced draft fan, a water scrubber, an alkaline scrubber, a flue gas whitening device and a chimney which are connected in sequence; the pyrolysis gas is subjected to oxygen-enriched combustion through a secondary combustion chamber, heated to 1100 ℃ and stays for more than 2 seconds, high-temperature flue gas at the outlet of the secondary combustion chamber enters a waste heat boiler, after denitrification and flue gas quenching of the waste heat boiler, dry deacidification is performed through adding active carbon and quicklime, then dust removal is performed through a bag-type dust remover, wet deacidification is performed through an induced draft fan after entering a water scrubber and an alkaline scrubber, and standard discharge is performed through a chimney after flue gas whitening;
(2) And (3) brine refining:
Adding the carbon-containing salt slag obtained by the secondary pyrolysis device into a salt dissolving tank, supplementing water with the hardness of less than 10mg/L, stirring and dissolving to obtain brine with the concentration of 15-25 wt%, adding a medicament into a high-efficiency sedimentation tank, wherein the medicament is at least one of PAC, na 2CO3 and NaOH, removing the hardness, silicon, alkalinity, heavy metals and solid impurities in the brine by solid-liquid separation through sedimentation, adjusting the pH value of the effluent of the high-efficiency sedimentation tank to 6.5-8.5 by sulfuric acid, then adding the effluent into a filtering device, controlling the turbidity of produced water of the filtering device to be less than 0.2NTU, and ensuring that the COD (chemical oxygen demand) of the produced water entering a salt separation crystallization unit is less than 100mg/L and the hardness of the produced water is less than 0.1mg/L through a COD removing device and an ion exchanger;
The backwash water of the filtering device, filter residues and precipitated sludge generated by the high-efficiency precipitation tank enter a sludge dehydration device for solid-liquid separation, filtrate generated by the sludge dehydration device is discharged from a liquid discharge port and returned to the high-efficiency precipitation tank through a water return pipe, and the generated sludge enters a sludge recovery tank for standby;
(3) Salt separation crystallization unit:
pumping the concentrated brine produced by the brine refining unit to a nanofiltration device 5, primarily separating sodium chloride and sodium sulfate in the water, and obtaining nanofiltration produced water rich in sodium chloride and nanofiltration concentrated water rich in sodium sulfate;
The nanofiltration concentrated water is pumped into a first effect evaporator 1 in a four-effect evaporation crystallizer, sequentially passes through the first effect evaporator 1 and a second effect evaporator 2, is condensed and recovered after water is evaporated, and discharges slurry containing sodium sulfate at a refined salt slurry outlet of the second effect evaporator 2, and the slurry is centrifuged and dried to finally produce sodium sulfate;
The nanofiltration product water is pumped into a third effect evaporator 3 in a four effect evaporation crystallizer, sequentially passes through the third effect evaporator 3 and the fourth effect evaporator 4, is condensed and recovered after the water is evaporated, and discharges slurry containing sodium chloride at a refined salt slurry outlet of the fourth effect evaporator 4, and the slurry is centrifuged and dried to finally produce sodium chloride;
In the evaporation crystallization process, condensed water recovered by an evaporation crystallization device enters a salt dissolving tank; some components (COD and the like) can be continuously concentrated and enriched, and in order not to influence the stable operation of the evaporative crystallization device, a part of aging mother liquor needs to be periodically pumped out, and the generated mother liquor is discharged to a mother liquor tank and then returned to the primary pyrolysis device for treatment.
Anhydrous sodium sulfate product obtained after treatment of waste salt at least reaches industrial anhydrous sodium sulfate (GB/T6009-2014)The standard of the standard product is required, and the sodium chloride at least meets the standard of industrial dry salt (second grade) in industrial salt (GB/T5462-2015).
Preferably, in the step (1), the primary pyrolysis device is heated to 350-400 ℃, and the secondary pyrolysis device is heated to 550-600 ℃.
Example 7
The waste salt raw material is derived from a chemical plant, and the components and the contents contained in the raw material are shown in table 1.
TABLE 1 raw material composition
；
The method provided by the invention is used for treating the waste salt raw material, and specifically comprises the following steps:
(1) Carbonization and pyrolysis:
The waste salt enters a first crushing device, is crushed until the particle size is smaller than 20mm, then enters a first-stage pyrolysis device, the oxygen content is controlled to be 0-1%, is heated to 350-400 ℃, stays for 20-30 min, enters a second crushing device, is crushed again, enters a second-stage pyrolysis device, is subjected to deep pyrolysis, and is heated to 550-600 ℃ for 40-60 min after the oxygen content is controlled to be 3-5% by supplementing air; the primary pyrolysis device and the secondary pyrolysis device both adopt electrically heated rotary kilns;
The pyrolysis gas generated by the primary pyrolysis device and the secondary pyrolysis device enters a tail gas purification unit, and is discharged after reaching the standard by adopting the prior art;
(2) And (3) brine refining:
Adding the carbon-containing salt slag obtained by the secondary pyrolysis device into a salt dissolving tank, supplementing water with the hardness of less than 10mg/L, stirring and dissolving to obtain brine with the concentration of 15-25wt%, adding a medicament into a high-efficiency sedimentation tank, wherein the medicament is PAC, na 2CO3 and NaOH, removing the hardness, silicon, alkalinity, heavy metals and solid impurities in the brine by solid-liquid separation, adjusting the pH value of the effluent of the high-efficiency sedimentation tank to 6.5-8.5 by sulfuric acid, and then, adding the effluent into a filtering device, wherein the turbidity of produced water of the filtering device is controlled to be less than 0.2NTU, and the COD of the produced water is ensured to be less than 100mg/L and the hardness of the concentrated brine entering a salt separation crystallization unit by a COD removing device and an ion exchanger;
The backwash water of the filtering device, filter residues and precipitated sludge generated by the high-efficiency precipitation tank enter a sludge dehydration device for solid-liquid separation, filtrate generated by the sludge dehydration device is discharged from a liquid discharge port and returned to the high-efficiency precipitation tank through a water return pipe, and the generated sludge enters a sludge recovery tank for standby;
Wherein, the filtering device adopts an immersed ultrafiltration device, the sludge dewatering device adopts a filter press, the ion exchanger adopts a chelating resin ion exchanger, and the COD removing device is provided with an active carbon adsorption layer;
(3) Salt separation crystallization unit:
Pumping the concentrated brine produced by the brine refining unit to a nanofiltration device, and 5, primarily separating sodium chloride and sodium sulfate in the water to obtain nanofiltration product water rich in sodium chloride and nanofiltration concentrated water rich in sodium sulfate;
The nanofiltration concentrated water is pumped into a first effect evaporator 1 in a four-effect evaporation crystallizer, sequentially passes through the first effect evaporator 1 and a second effect evaporator 2, is condensed and recovered after water is evaporated, and discharges slurry containing sodium sulfate at a refined salt slurry outlet of the second effect evaporator 2, and the slurry is centrifuged and dried to finally produce sodium sulfate;
The nanofiltration product water is pumped into a third effect evaporator 3 in a four effect evaporation crystallizer, sequentially passes through the third effect evaporator 3 and the fourth effect evaporator 4, is condensed and recovered after the water is evaporated, and discharges slurry containing sodium chloride at a refined salt slurry outlet of the fourth effect evaporator 4, and the slurry is centrifuged and dried to finally produce sodium chloride;
In the evaporation crystallization process, condensed water recovered by an evaporation crystallization device enters a salt dissolving tank; some components (COD and the like) are continuously concentrated and enriched, about 0.2t/h of aging mother liquor is periodically extracted, and the generated mother liquor is discharged to a mother liquor tank and then returned to a first-stage pyrolysis device for further treatment;
By adopting the method, 2.5 ten thousand tons of waste salt are treated annually, the annual operation time is 7200 hours, and the annual production of sodium chloride refined salt after delivery is 0.96 ten thousand tons/year, and the anhydrous sodium sulfate is 0.94 ten thousand tons/year.
The obtained refined sodium chloride salt and anhydrous sodium sulfate were respectively detected, and the results are shown in Table 2, wherein indexes of anhydrous sodium sulfate and sodium chloride are respectively referred to industrial anhydrous sodium sulfate (GB/T6009-2014)The quality standard and industrial salt (GB/T5462-2015) are carried out by industrial dry salt (second grade).
TABLE 2 detection index and results of refined salt
As can be seen from Table 2, the treatment method provided by the invention is used for treating waste salt, and the obtained anhydrous sodium sulfate product reaches industrial anhydrous sodium sulfate (GB/T6009-2014)The index requirement of the qualified product is that the sodium chloride meets the index requirement of the industrial dry salt (second grade) in industrial salt (GB/T5462-2015).

Claims (6)

1. A method for recycling waste salt is characterized in that: the method comprises the steps of adopting a waste salt recycling treatment system to carry out treatment, wherein the waste salt recycling treatment system comprises a carbonization pyrolysis unit, a brine refining unit and a salt separation crystallization unit which are sequentially connected, and the brine refining unit comprises a salt dissolving tank, a high-efficiency sedimentation tank, a filtering device, a COD removal device and an ion exchanger which are sequentially connected; the efficient sedimentation tank is provided with a medicament adding port and a stirring device, the efficient sedimentation tank and the filtering device are connected with a sludge dewatering device, and the sludge dewatering device is also connected with a sludge recovery tank; the sludge dewatering device is also provided with a liquid outlet which is connected with the high-efficiency sedimentation tank through a water return pipe;
The salt separation crystallization unit comprises a nanofiltration device, an evaporation crystallization device and a mother liquor tank which are connected in sequence;
the evaporation crystallization device is also connected with a salt dissolving tank; the mother liquor tank is connected with the carbonization pyrolysis unit; an inlet of the nanofiltration device is connected with an ion exchanger;
The evaporation crystallization device is a four-effect evaporation crystallizer; the four-effect evaporation crystallizer comprises a first-effect evaporator (1), a second-effect evaporator (2), a third-effect evaporator (3) and a fourth-effect evaporator (4) which are sequentially connected; the bottoms of the second effect evaporator (2) and the fourth effect evaporator (4) are respectively provided with a refined salt slurry outlet;
The water outlet and the concentrated water outlet of the nanofiltration device (5) are respectively connected with the feed inlets of the third-effect evaporator (3) and the first-effect evaporator (1);
The carbonization pyrolysis unit comprises a primary pyrolysis device and a secondary pyrolysis device which are sequentially connected, and the primary pyrolysis device and the secondary pyrolysis device are both connected with the tail gas purification unit; the secondary pyrolysis device is connected with the salt dissolving tank; the primary pyrolysis device is connected with the mother liquor tank;
The carbonization pyrolysis unit further comprises a first crushing device and a second crushing device, the first crushing device is connected with an inlet of the primary pyrolysis device, and the primary pyrolysis device is connected with the secondary pyrolysis device through the second crushing device;
the method for recycling the waste salt comprises the following specific steps:
(1) Carbonization and pyrolysis:
The waste salt enters a first crushing device, is crushed until the particle size is smaller than 20mm, then enters a first-stage pyrolysis device, the oxygen content is controlled to be 0-1%, is heated to 200-500 ℃, stays for 20-30 min, enters a second crushing device, is crushed again, enters a second-stage pyrolysis device, is subjected to deep pyrolysis, and is heated to 500-800 ℃ and stays for 40-60 min after the oxygen content is controlled to be 3-5% by supplementing air;
pyrolysis gas generated by the primary pyrolysis device and the secondary pyrolysis device enters a tail gas purification unit, and is discharged after reaching the standard;
(2) And (3) brine refining:
Adding the carbon-containing salt slag obtained by the secondary pyrolysis device into a salt dissolving tank, supplementing water with the hardness of less than 10mg/L, stirring and dissolving to obtain brine with the concentration of 15-25 wt%, adding a medicament into the brine, removing the hardness, silicon, alkalinity, heavy metals and solid impurities in the brine by precipitation solid-liquid separation, adjusting the pH value of the effluent of the high-efficiency precipitation tank to 6.5-8.5 by sulfuric acid, and then, entering a filtering device, wherein the turbidity of produced water of the filtering device is controlled to be less than 0.2NTU, and the produced water passes through a COD removal device and an ion exchanger to ensure that the COD of the concentrated brine entering a salt separation crystallization unit is less than 100mg/L and the hardness of the concentrated brine is less than 0.1mg/L;
The backwash water of the filtering device, filter residues and precipitated sludge generated by the high-efficiency precipitation tank enter a sludge dehydration device for solid-liquid separation, filtrate generated by the sludge dehydration device is discharged from a liquid discharge port and returned to the high-efficiency precipitation tank through a water return pipe, and the generated sludge enters a sludge recovery tank for standby;
(3) Salt separation crystallization unit:
pumping the concentrated brine produced by the brine refining unit to a nanofiltration device (5) to obtain nanofiltration product water and nanofiltration concentrated water;
The nanofiltration concentrated water is pumped into a first-effect evaporator (1) in a four-effect evaporation crystallizer, sequentially passes through the first-effect evaporator (1) and a second-effect evaporator (2), is condensed and recovered after water evaporation, and discharges slurry containing sodium sulfate at a refined salt slurry outlet of the second-effect evaporator (2), and the slurry is centrifuged and dried to finally produce sodium sulfate;
The nanofiltration product water is pumped into a third-effect evaporator (3) in the four-effect evaporation crystallizer, sequentially passes through the third-effect evaporator (3) and the fourth-effect evaporator (4), is condensed and recovered after the water is evaporated, and discharges slurry containing sodium chloride at a refined salt slurry outlet of the fourth-effect evaporator (4), and the slurry is centrifuged and dried to finally produce sodium chloride;
In the evaporation crystallization process, condensed water recovered by the evaporation crystallization device enters a salt dissolving tank, and generated mother liquor is discharged to a mother liquor tank and then returned to the primary pyrolysis device for treatment.
2. The method for recycling waste salt according to claim 1, characterized by comprising the steps of: the primary pyrolysis device and the secondary pyrolysis device are fixed beds or fluidized beds; the fixed bed is a rotary kiln or a rake type furnace; the heating modes of the primary pyrolysis device and the secondary pyrolysis device are electric heating, natural gas heating or microwave heating.
3. The method for recycling waste salt according to claim 1, characterized by comprising the steps of: the filtering device is formed by connecting a multi-medium filtering device and an ultrafiltration device, or is one of a tubular ultrafiltration device and an immersed ultrafiltration device.
4. The method for recycling waste salt according to claim 1, characterized by comprising the steps of: the sludge dewatering device is a filter press; the ion exchanger is a chelating resin ion exchanger.
5. The method for recycling waste salt according to claim 1, characterized by comprising the steps of: in the step (1), the primary pyrolysis device is heated to 350-400 ℃, and the secondary pyrolysis device is heated to 550-600 ℃.
6. The method for recycling waste salt according to claim 1, characterized by comprising the steps of: in the step (2), the medicament is at least one of PAC, na 2CO3 and NaOH.
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Citations (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3257165A (en) * 1959-05-15 1966-06-21 Ciba Ltd Continuous method for the purification of brine
CN105461134A (en) * 2015-12-01 2016-04-06 陕西省石油化工研究设计院 Technology and device applied to recycling of high-salinity wastewater in coal chemical industry
CN106745076A (en) * 2016-11-21 2017-05-31 大唐国际化工技术研究院有限公司 A kind of method that Industrial Wastewater Treatment is produced carnallite resource
CN207130086U (en) * 2017-06-07 2018-03-23 神华集团有限责任公司 A kind of salt-containing waste water treating device
CN108275817A (en) * 2018-01-22 2018-07-13 浙江开创环保科技股份有限公司 A kind of processing method of the high salinity waste water reclaiming of high rigidity
CN109970079A (en) * 2019-04-02 2019-07-05 江苏杰林环保科技有限公司 A kind of chemical industry abraum salt refining methd
CN110201975A (en) * 2019-05-30 2019-09-06 北京航天环境工程有限公司 A kind of abraum salt recycling treatment disposal system and application
CN110357334A (en) * 2018-12-05 2019-10-22 内蒙古荣信化工有限公司 Coal water slurry gasification waste water divides salt crystallization zero-discharge treatment system and method
CN110372013A (en) * 2019-07-30 2019-10-25 天津理工大学 A method of refining industrial salt is prepared using industrial waste salt
CN110606612A (en) * 2019-11-04 2019-12-24 江苏中电创新环境科技有限公司 Coal coking high-salinity wastewater recycling treatment process
CN110624938A (en) * 2019-09-28 2019-12-31 江苏朗誉环保设备有限公司 Treatment system for hazardous waste salt production by-products
CN110877943A (en) * 2019-01-31 2020-03-13 内蒙古久科康瑞环保科技有限公司 Method and system for recycling mixed salt
CN211739098U (en) * 2020-03-21 2020-10-23 深圳市海文环保技术有限公司 Chemical waste salt recycling treatment system
CN111842408A (en) * 2020-06-23 2020-10-30 北京航天环境工程有限公司 Cooperative treatment and recycling system, application and method for waste salt, waste acid, waste alkali and waste activated carbon
CN215391554U (en) * 2021-08-17 2022-01-04 陕西省石油化工研究设计院 Waste salt resourceful treatment system

Patent Citations (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3257165A (en) * 1959-05-15 1966-06-21 Ciba Ltd Continuous method for the purification of brine
CN105461134A (en) * 2015-12-01 2016-04-06 陕西省石油化工研究设计院 Technology and device applied to recycling of high-salinity wastewater in coal chemical industry
CN106745076A (en) * 2016-11-21 2017-05-31 大唐国际化工技术研究院有限公司 A kind of method that Industrial Wastewater Treatment is produced carnallite resource
CN207130086U (en) * 2017-06-07 2018-03-23 神华集团有限责任公司 A kind of salt-containing waste water treating device
CN108275817A (en) * 2018-01-22 2018-07-13 浙江开创环保科技股份有限公司 A kind of processing method of the high salinity waste water reclaiming of high rigidity
CN110357334A (en) * 2018-12-05 2019-10-22 内蒙古荣信化工有限公司 Coal water slurry gasification waste water divides salt crystallization zero-discharge treatment system and method
CN110877943A (en) * 2019-01-31 2020-03-13 内蒙古久科康瑞环保科技有限公司 Method and system for recycling mixed salt
CN109970079A (en) * 2019-04-02 2019-07-05 江苏杰林环保科技有限公司 A kind of chemical industry abraum salt refining methd
CN110201975A (en) * 2019-05-30 2019-09-06 北京航天环境工程有限公司 A kind of abraum salt recycling treatment disposal system and application
CN110372013A (en) * 2019-07-30 2019-10-25 天津理工大学 A method of refining industrial salt is prepared using industrial waste salt
CN110624938A (en) * 2019-09-28 2019-12-31 江苏朗誉环保设备有限公司 Treatment system for hazardous waste salt production by-products
CN110606612A (en) * 2019-11-04 2019-12-24 江苏中电创新环境科技有限公司 Coal coking high-salinity wastewater recycling treatment process
CN211739098U (en) * 2020-03-21 2020-10-23 深圳市海文环保技术有限公司 Chemical waste salt recycling treatment system
CN111842408A (en) * 2020-06-23 2020-10-30 北京航天环境工程有限公司 Cooperative treatment and recycling system, application and method for waste salt, waste acid, waste alkali and waste activated carbon
CN215391554U (en) * 2021-08-17 2022-01-04 陕西省石油化工研究设计院 Waste salt resourceful treatment system

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