CN111039480A - Method and device for reducing salt in mine water - Google Patents

Method and device for reducing salt in mine water Download PDF

Info

Publication number
CN111039480A
CN111039480A CN201910565061.5A CN201910565061A CN111039480A CN 111039480 A CN111039480 A CN 111039480A CN 201910565061 A CN201910565061 A CN 201910565061A CN 111039480 A CN111039480 A CN 111039480A
Authority
CN
China
Prior art keywords
nanofiltration
membrane
mine water
water
treatment
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN201910565061.5A
Other languages
Chinese (zh)
Inventor
赵士明
彭文博
杨文银
章小同
葛乃星
周明
王鹏
孙桂花
杨积衡
范克银
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Jiangsu Jiuwu Hi Tech Co Ltd
Original Assignee
Jiangsu Jiuwu Hi Tech Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Jiangsu Jiuwu Hi Tech Co Ltd filed Critical Jiangsu Jiuwu Hi Tech Co Ltd
Priority to CN201910565061.5A priority Critical patent/CN111039480A/en
Publication of CN111039480A publication Critical patent/CN111039480A/en
Pending legal-status Critical Current

Links

Images

Classifications

    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F9/00Multistage treatment of water, waste water or sewage
    • CCHEMISTRY; METALLURGY
    • C01INORGANIC CHEMISTRY
    • C01DCOMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
    • C01D5/00Sulfates or sulfites of sodium, potassium or alkali metals in general
    • C01D5/16Purification
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00Treatment of water, waste water, or sewage
    • C02F1/02Treatment of water, waste water, or sewage by heating
    • C02F1/04Treatment of water, waste water, or sewage by heating by distillation or evaporation
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00Treatment of water, waste water, or sewage
    • C02F1/22Treatment of water, waste water, or sewage by freezing
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00Treatment of water, waste water, or sewage
    • C02F1/44Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
    • C02F1/442Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by nanofiltration
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00Treatment of water, waste water, or sewage
    • C02F1/44Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
    • C02F1/444Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by ultrafiltration or microfiltration
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00Treatment of water, waste water, or sewage
    • C02F1/52Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
    • C02F1/5236Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using inorganic agents
    • C02F1/5245Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using inorganic agents using basic salts, e.g. of aluminium and iron
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00Treatment of water, waste water, or sewage
    • C02F1/52Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
    • C02F1/54Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using organic material
    • C02F1/56Macromolecular compounds
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00Treatment of water, waste water, or sewage
    • C02F1/66Treatment of water, waste water, or sewage by neutralisation; pH adjustment
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00Treatment of water, waste water, or sewage
    • C02F1/42Treatment of water, waste water, or sewage by ion-exchange
    • C02F2001/425Treatment of water, waste water, or sewage by ion-exchange using cation exchangers
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2103/00Nature of the water, waste water, sewage or sludge to be treated
    • C02F2103/10Nature of the water, waste water, sewage or sludge to be treated from quarries or from mining activities
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02PCLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00Technologies relating to chemical industry
    • Y02P20/10Process efficiency

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Inorganic Chemistry (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Hydrology & Water Resources (AREA)
  • Environmental & Geological Engineering (AREA)
  • Water Supply & Treatment (AREA)
  • Separation Using Semi-Permeable Membranes (AREA)

Abstract

The invention provides a method and a device for reducing salt in mine water. The method comprises a pretreatment system of mine water, a hardness removal system, a membrane method salt reduction system and a crystallization system, wherein 1) impurities such as suspended matters, colloid, coal ash and the like in the mine water are removed through the pretreatment system, so that early-stage preparation is made for a subsequent membrane integration process; 2) the pretreated clear liquid enters ultrafiltration and first-stage nanofiltration to realize the coarse concentration of the mine water, and the water produced by the first-stage nanofiltration can be directly discharged; 3) the first-stage nanofiltration concentrated water enters a hardness removal system, mainly the hardness of the medicament is removed, the concentrated water after the second-stage nanofiltration concentration enters a crystallization system to obtain anhydrous sodium sulfate, and the crystallization mother liquor and nanofiltration produced water are mixed and discharged. By the method and the device, the salt reduction of the mine water and the output of the high-purity anhydrous sodium sulfate are realized at the optimal investment cost and operation cost.

Description

Method and device for reducing salt in mine water
Technical Field
The invention relates to a method and a device for reducing salt in mine water, belonging to the technical field of water treatment.
Background
In the coal mining process, the produced water high-salinity mine water is main waste water of a coal mine, the total inorganic salt content in the mine water is more than 1000mg/L, and the mine water contains Ca2+、Mg2+、K+、Na+、SO4 2-、Cl-、HCO3-Such as a large amount of ions, the water quality is neutral or slightly alkaline, also called bitter. The high-salinity mine water can be discharged and recycled only by desalting treatment.
The traditional treatment method mainly comprises the treatment processes of coagulation, precipitation, filtration, disinfection and the like, and the treated mine water is reused for factory dedusting, ground coal washing and water supplementing, circulating water, greening irrigation and the like; however, the traditional treatment method can only remove suspended matters but not soluble salts in the mine water, so that more salt can be separated out when the mine water is used for factory dedusting, greening irrigation and the like, and finally the mine water can still be gathered underground. In addition, due to the large production amount of the mine water, the treated mine water cannot be consumed, and particularly for coal mine enterprises far away from living areas; and the mine water is directly discharged into peripheral rivers, lakes and even reservoirs, which causes serious pollution to the water environment, so that the treatment and utilization approaches of the mine water become difficult problems to be solved urgently.
At present, the mine water treatment process also comprises reverse osmosis technology, electrodialysis technology and other methods. Chinese patent CN109336323A discloses a method and a system for treating mine water with high mineralization degree. The method comprises a mine water film concentration process and an evaporation crystallization salt separation process, wherein the mine water film concentration process is performed with two-stage concentration, and then the concentration is performed with disc tube type reverse osmosis, so that the salt content of concentrated water reaches 5-8%, and the cost of subsequent evaporation crystallization of concentrated brine is reduced. The process described in this patent has a limited reduction in cost and still produces miscellaneous salts in the subsequent stages.
Disclosure of Invention
The invention aims to provide a high-salinity mine water desalting treatment method which is small in occupied area of an integral process package, low in investment cost and operation cost, high and stable in crystalline product quality and free of miscellaneous salt.
A method for reducing salt in mine water comprises the following steps:
step 1, performing pre-filtration treatment on mine water;
step 2, performing first ultrafiltration treatment on the filtrate obtained in the step 1;
step 3, carrying out first nanofiltration treatment on the filtrate obtained in the step 2;
step 4, carrying out precipitation reaction on the nanofiltration concentrated solution obtained in the step 3 to remove impurity cations;
step 5, performing second ultrafiltration treatment on the wastewater obtained in the step 4, and filtering out precipitates;
step 6, carrying out second nanofiltration treatment on the filtrate obtained in the step 5;
and 7, crystallizing and drying the nanofiltration concentrated solution obtained in the step 6 in sequence to obtain recovered sodium sulfate.
In one embodiment, the pre-filtration treatment in step 1 comprises the treatment steps of coagulation, pre-filtration and activated carbon filtration.
In one embodiment, the coagulant used in the coagulation process is polyaluminum chloride (PAC), Polyacrylamide (PAM), or the like.
In one embodiment, the superconducting magnetic material can be added in the coagulation process for auxiliary coagulation, and the superconducting magnetic material is recovered by a cyclone separation method.
In one embodiment, the superconducting magnetic material is selected from iron sesquioxide particles.
In one embodiment, the removal of impurity cations in step 4 is performed by adding NaOH and Na2CO3A precipitation reaction is carried out.
In one embodiment, the molecular weight cut-off of the nanofiltration membrane in the first nanofiltration process is 150-1000 Da, more preferably 500-1000 Da.
In one embodiment, the molecular weight cut-off of the nanofiltration membrane in the second nanofiltration process is 150-1000 Da, and more preferably 300-500 Da.
In one embodiment, in step 7, the nanofiltration concentrated solution obtained in step 6 is subjected to cation exchange resin to remove impurity cations, and then subjected to a third nanofiltration treatment, and then the concentrated solution subjected to the third nanofiltration is subjected to crystallization and drying treatment in sequence.
In one embodiment, the nanofiltration concentrated solution obtained in the step 6 is subjected to flocculation treatment; in the flocculation process, polyferric chloride is used as a flocculating agent, and a nucleating agent is added at the same time.
In one embodiment, the nucleating agent is hydrophobically modified ferriferrous oxide.
In one embodiment, the molecular weight cut-off of the nanofiltration membrane in the third nanofiltration process is 150-1000 Da, and more preferably 150-300 Da.
An apparatus for desalinating mine water, comprising:
the pre-filter is used for performing pre-filtering treatment on mine water;
the first ultrafiltration membrane is connected to the permeation side of the prefilter and is used for carrying out ultrafiltration treatment on the filtrate of the prefilter;
the first nanofiltration membrane is connected to the permeation side of the first ultrafiltration membrane and is used for performing nanofiltration concentration treatment on the filtrate of the first ultrafiltration membrane;
the precipitation reaction tank is connected to the concentration side of the first nanofiltration membrane and is used for carrying out precipitation reaction on the concentrated solution of the first nanofiltration membrane to remove impurity cations;
NaOH adding tank and Na2CO3An adding tank for respectively adding NaOH and Na into the precipitation reaction tank2CO3
The second ultrafiltration membrane is connected to the precipitation reaction tank and is used for filtering the wastewater subjected to the precipitation reaction to remove the precipitate;
the second nanofiltration membrane is connected to the permeation side of the second ultrafiltration membrane and is used for concentrating the filtrate of the second ultrafiltration membrane;
and the crystallization device is connected to the concentration side of the second nanofiltration membrane and is used for carrying out crystallization treatment on the concentrated solution of the second nanofiltration membrane to obtain the recovered sodium sulfate.
In one embodiment, the pre-filter is one or a combination of a coagulation basin, a sand filter device or an activated carbon filter.
In one embodiment, the material of the first ultrafiltration membrane and the second ultrafiltration membrane is selected from organic materials or inorganic materials; the organic material is PTFE, PVDF, PES, PS or acetate fiber; the inorganic material is alumina, zirconia, titania or silicon carbide.
In one embodiment, the first nanofiltration membrane has a molecular weight cut-off of 150 to 1000Da, more preferably 500 to 1000 Da.
In one embodiment, the molecular weight cut-off of the second nanofiltration membrane is 150-1000 Da, and more preferably 300-500 Da.
In one embodiment, the crystallization device is an evaporative crystallizer or a refrigerated crystallizer.
In one embodiment, the concentrate side of the second nanofiltration membrane is connected to the ion exchange resin column to the third nanofiltration membrane, and the concentrate side of the third nanofiltration membrane is connected to the crystallization apparatus.
In one embodiment, the ion exchange resin column is packed with a cation exchange resin.
In one embodiment, the molecular weight cut-off of the three-stage nanofiltration membrane is 150-1000 Da, and more preferably 150-300 Da.
In one embodiment, the concentration side of the second nanofiltration membrane is connected to a flocculation reactor, a flocculant adding tank and a nucleating agent adding tank are connected to the flocculation reactor, the flocculation reactor is connected to a third ultrafiltration membrane, and the permeation side of the third ultrafiltration membrane is connected to the ion exchange resin column.
In one embodiment, the flocculant addition tank is filled with aluminum sulfate, polyaluminum chloride (PAC), ferrous sulfate, ferric sulfate, or ferric chloride; the nucleating agent adding tank is filled with oleic acid modified ferroferric oxide.
The application of the device in the recovery of sodium sulfate in mine water.
Advantageous effects
The invention takes 'multi-stage nanofiltration' salt reduction as a core, is different from 'multi-stage reverse osmosis' and 'reverse osmosis + nanofiltration', aims to realize the salt reduction of mine water to reach the discharge standard and the output of high-purity anhydrous sodium sulfate to reach the resource utilization of waste salt with optimal investment cost and operation cost, and has obvious technical advantages and originality.
According to the method and the device for reducing the salt of the mine water, disclosed by the invention, the salt reduction of the mine water with high mineralization is realized by mainly utilizing a multi-stage nanofiltration process, compared with multi-stage reverse osmosis, the investment cost is reduced by more than 30%, the operation cost is reduced by more than 25%, the aims of standard discharge of the mine water and resource utilization of waste salt are finally achieved, and solid waste or dangerous waste is not produced.
Drawings
FIG. 1 is a diagram of an apparatus of the present invention;
FIG. 2 is a diagram of another apparatus of the present invention;
FIG. 3 is a diagram of another apparatus of the present invention;
wherein, 1, a prefilter; 2. a first ultrafiltration membrane; 3. a first nanofiltration membrane; 4. a precipitation reaction tank; 5. adding NaOH into a tank; 6. na (Na)2CO3A feeding tank; 7. a second ultrafiltration membrane; 8. a second nanofiltration membrane; 9. a crystallization device; 10. a drying device; 11. ion exchange resin column; 12. a third nanofiltration membrane; 14. a flocculation reactor; 15. a flocculant adding tank; 16. a nucleating agent feeding tank; 17. and a third ultrafiltration membrane.
Detailed Description
The present invention will be described in further detail with reference to the following embodiments. It will be understood by those skilled in the art that the following examples are illustrative of the present invention only and should not be taken as limiting the scope of the invention. The examples do not specify particular techniques or conditions, and are performed according to the techniques or conditions described in the literature in the art or according to the product specifications. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products commercially available.
Approximating language, as used herein throughout the specification and claims, may be applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term or terms, such as "about," is not to be limited to the precise value specified. In at least some instances, the approximating language may correspond to the precision of an instrument for measuring the value. Unless context or language indicates otherwise, range limitations may be combined and/or interchanged, and such ranges are identified and include all the sub-ranges included herein. Other than in the operating examples, or where otherwise indicated, all numbers or expressions referring to quantities of ingredients, reaction conditions, and so forth used in the specification and claims are to be understood as modified in all instances by the word "about".
The recitation of values by ranges is to be understood in a flexible manner to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. For example, a concentration range of "about 0.1% to about 5%" should be interpreted to include not only the explicitly recited concentration of about 0.1% to about 5%, but also include individual concentrations (e.g., 1%, 2%, 3%, and 4%) and sub-ranges (e.g., 0.1% to 0.5%, 1% to 2.2%, 3.3% to 4.4%) within the indicated range.
The term "removal" in the present specification includes not only a case where a target substance is completely removed but also a case where the target substance is partially removed (the amount of the substance is reduced). "purification" in this specification includes the removal of any or specific impurities.
The words "include," "have," or any other variation thereof, as used herein, are intended to cover a non-exclusive inclusion. For example, a process, method, article, or apparatus that comprises a list of elements is not necessarily limited to those elements, but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
The invention provides a method and a device for reducing salt in mine water. The method comprises a pretreatment system of mine water, a hardness removal system, a membrane method salt reduction system and a crystallization system, wherein 1) impurities such as suspended matters, colloid, coal ash and the like in the mine water are removed through the pretreatment system, so that early-stage preparation is made for a subsequent membrane integration process; 2) the pretreated clear liquid enters ultrafiltration and first-stage nanofiltration to realize the coarse concentration of the mine water, and the water produced by the first-stage nanofiltration can be directly discharged; 3) the first-stage nanofiltration concentrated water enters a hardness removal system, mainly the hardness of the medicament is removed, the concentrated water after the second-stage nanofiltration concentration enters a crystallization system to obtain anhydrous sodium sulfate, and the crystallization mother liquor and nanofiltration produced water are mixed and discharged. By the method and the device, the salt reduction of the mine water and the output of the high-purity anhydrous sodium sulfate are realized at the optimal investment cost and operation cost.
In another embodiment, the crystallization mother liquor is discharged in admixture with the first and second nanofiltration product waters, the TDS of the combined discharge water being less than 1600mg/L and the sulphate being less than 650 mg/L.
In another embodiment, the concentrated water after the second-stage nanofiltration concentration is subjected to hardness removal treatment by using an ion exchange resin column, so that divalent ions in the concentrated water can be removed, the purity of sodium sulfate after the concentrated water is crystallized can be improved, and meanwhile, the concentrated water can be subjected to nanofiltration concentration treatment after the divalent ions are removed, so that the load of three-stage nanofiltration membranes can be effectively reduced, and the concentration multiple and flux of the nanofiltration membranes can be improved. When the method is adopted, the mine water is reduced by one-stage nanofiltration, the floor area of the hardness removal sedimentation tank is reduced, and slightly-wide pinena filter membranes are selected by one-stage and two-stage nanofiltration systems for separating salt, so that monovalent salt, calcium ions, magnesium ions and the like can be leaked out as much as possible from produced water, the operating pressure of three-stage nanofiltration is reduced while the produced water is discharged up to the standard, and the recovery rate of the produced water is improved; the salt concentration is improved to 10-20% by three-stage nanofiltration, the consumption of steam is reduced, and the operation cost is reduced; the high-quality anhydrous sodium sulfate is produced by crystallization, the index is superior to the technical requirement of class II first-class products in GB/T6009-2014, and the waste salt is recycled; the membrane produced water can reach the standard and be discharged, the environmental pollution is not caused, and low-value sodium chloride and miscellaneous salt are not generated.
In another embodiment, the molecular weight cut-off of the three-stage nanofiltration membrane is 150-1000 Da, and more preferably 150-300 Da; the three-section nanofiltration membrane improves the salt concentration to 10-20%.
Because the mine water is treated by the method, the mine water contains not only inorganic salt and particle impurities, but also more organic matter COD impurities, the organic matter can not be effectively removed in a pre-flocculation system, a pre-filtration system and an ultrafiltration system, and can be remained in a concentrated solution of a subsequent nanofiltration membrane, and along with the concentration of the nanofiltration membrane, the COD substances can be further concentrated, so that the flux and the concentration multiple of the nanofiltration membrane are influenced, and the purity of the recovered sodium sulfate is also influenced. In another embodiment, after the COD substance in the concentrated water obtained by the two-stage nanofiltration is improved, the concentrated water is flocculated by a deep flocculation method, preferably a polyferric chloride flocculating agent is adopted, and because the ferric ions brought in and remained in the flocculating agent can be removed by a subsequent ion exchange resin column through an ion exchange method, the purity of the recovered concentrated sodium sulfate is not influenced; meanwhile, in order to further improve the flocculation effect of the polyferric chloride, a nucleating agent can be adopted to assist flocculation, so that the flocculation effect of the polyferric chloride can be improved, the nucleating agent adopted can be magnetic ferroferric oxide which has better compatibility with the polyferric chloride and improves the flocculation effect, and in order to further improve the flocculation effect, after the surface of the magnetic ferroferric oxide is subjected to hydrophobic treatment, the magnetic ferroferric oxide can be effectively adsorbed with organic matter impurities in mine water, so that the flocculation effect is improved.
In the above treatment, the water produced by nanofiltration can be directly discharged; the crystallized mother liquor can also be discharged after reaching the standard.
In the above steps, the pretreatment system mainly comprises a sedimentation tank, a coarse filtration device and the like, and can also be defined as a pre-filtration device for removing impurities such as suspended matters, colloids, coal ash and the like in the mine water; the prefiltering device is not particularly limited. Specific examples of the solid-liquid separation treatment include a centrifugal separation system, a squeezing separation system, a filtration system, a floating separation system, and a settling separation system. Examples of the centrifugal separation method include a horizontal continuous centrifuge (screw decanter treatment), a separation plate centrifuge, a centrifugal filter, and a mansion plez type ultracentrifuge, examples of the filtration method include a belt filter, a belt press, a screw press, a precoat filter, and a filter press, examples of the floating separation method include a continuous floating separation device, and examples of the sedimentation separation method include a coagulation sedimentation separator, a rapid sedimentation separator, and the like, but not particularly limited to any of the above. However, the load on the membrane at the time of the microfiltration membrane and/or ultrafiltration membrane treatment can be reduced by any one of the above or a combination thereof.
In the above steps, the adopted ultrafiltration membrane mainly plays a role in precise separation. The term "ultrafiltration membrane" as used herein means a filtration membrane having a pore diameter of 0.001 to 0.01 μm and/or a filtration membrane having a cut-off molecular weight of about 1000 to 300000. Materials for ultrafiltration membranes can be roughly classified into inorganic membranes and organic membranes, and further classified into hydrophobic and hydrophilic. The hydrophobic organic film is not limited thereto, and examples thereof include polysulfone, polyethersulfone, polyether, polyvinylidene fluoride, polyethylene, polypropylene, and the like. The hydrophilic organic film is not limited to this, and examples thereof include polyacrylonitrile, polyamide, polyimide, cellulose acetate, and the like. The filter element shape comprises flat membrane, tubular membrane, spiral membrane, hollow fiber (hollow silk) membrane and all module forms. The filtration method includes a total filtration method and a cross-flow method. The total filtration system is a system in which all of the water supplied to the membrane is filtered. In contrast, the cross-flow method is a method of filtering while suppressing the accumulation of suspended substances or colloids contained in water supplied to a membrane on a membrane surface by causing a water flow to flow parallel to the membrane surface. The cross-flow system includes, but is not limited to, a one-pass system, a back-flush system, and a back-flow system
In the invention, the hardness removal system is mainly added with NaOH and Na2CO3Performing a chemical precipitation reaction to remove impurity cations, first adding CO into crude saline water3 2-And OH-Ions, after reaction, CO3 2-And OH-The ions can make Ca2+、Mg2+Conversion to CaCO respectively3And Mg (OH)2When the crude brine also contains Cs+、Ni+When ionic, CO3 2-And OH-The ions may also convert them to Cs2CO3And Ni (OH)2Then sent into an ultrafiltration membrane for filtration, and CaCO generated by the reactions can be removed3、Mg(OH)2、Cs2CO3And Ni (OH)2Obtaining the purified ultrafiltration clear liquid. Ca as an impurity cation2+、Mg2+、Cs+、Ni+The concentration range of the ion is not particularly limited, and may be in the range of 0.01 to 50g/L, as long as an appropriate precipitant CO is selected according to the concentration of the impurity cation3 2-And OH-The addition of ions converts the impurity cations into precipitate, CO3 2-And OH-The amount of ions added can be calculated by one skilled in the art from the stoichiometric balance. In order to completely convert the impurity cations into precipitates, a precipitating agent selected from NaOH and Na is added2CO3KOH or K2CO3Each of which is added in an amount greater than that required to completely precipitate the impurity cations, for example: adding NaOH and Na2CO3KOH or K2CO3The addition amount of the cationic surfactant is 0.2-0.3 g/L more than the amount required by completely precipitating the impurity cations. The term "complete precipitation" as used herein refers to the amount of desired precipitation calculated from the equilibrium formula of the chemical reaction, and can be calculated by those skilled in the art according to the molar ratio of the chemical reaction, and is not understood to mean that the impurity ions are completely removed in the actual reactionAnd (4) precipitating.
The nanofiltration membrane in the invention is defined as a membrane of a pressure driven membrane which prevents particles smaller than 2nm and dissolved macromolecules. Effective nanofiltration membranes suitable for use in the present invention are preferably such membranes: there is an electric charge on the membrane surface, and thus improved separation efficiency is exhibited by a combination of fine pore separation (particle size separation) and electrostatic separation benefiting from the electric charge on the membrane surface. Therefore, it is necessary to use a nanofiltration membrane capable of removing a high molecular substance by particle size separation while separating an alkali metal ion to be recovered from another ion having a different charge characteristic by means of charge. As a material of the nanofiltration membrane used in the present invention, a polymer material such as cellulose acetate polymer, polyamide, sulfonated polysulfone, polyacrylonitrile, polyester, polyimide, vinyl polymer, or the like can be used. The film is not limited to one composed of only one material, and may be a film containing a plurality of the materials. With respect to the membrane structure, the membrane may be an asymmetric membrane having a dense layer on at least one side of the membrane and having micropores with pore diameters gradually increasing from the dense layer toward the inside of the membrane or the other side; or a composite membrane having a very thin functional layer of another material on the dense layer of the asymmetric membrane.
The ion exchange resin in the invention mainly refers to cation exchange resin, and can adsorb impurity cations in wastewater on the resin in an ion exchange mode to achieve the effect of removing cation impurities. The functional group of the cationic resin is an organic acid, and is classified into two types, i.e., strong acid and weak acid, according to the degree of acidity. The strongly acidic functional group is benzenesulfonic acid, and the weakly acidic functional group includes organophosphates, hydroxy acids and phenols
And the like. Weakly acidic cationic resins containing weakly acidic groups, e.g. carboxyl groups, capable of dissociating H in water+However, since the resin is not highly dissociated, it is generally weakly acidic and thus is a weakly acidic cationic resin. The residual negative charge groups after the resin dissociation can be absorbed and combined with other cations in the solution, thereby generating cation exchange effect.
The flocculant used in the present invention is not particularly limited as long as it can flocculate organic impurities in the wastewater, and aluminum sulfate, polyaluminum chloride (PAC), ferrous sulfate, ferric chloride, organic polymeric flocculant, and the like can be used. In addition, a nucleating agent can be added on the basis of the flocculating agent to assist in realizing the effect of improving flocculation. The nucleating agent is not particularly limited, and for example, bentonite, powdered activated carbon, activated silicic acid, and the like can be used. Preferably, the ferroferric oxide nucleating agent subjected to surface hydrophobic modification treatment is adopted, and the preparation process can be that the ferroferric oxide nucleating agent contains 5wt% of Fe3O4Adding oleic acid into the absolute ethyl alcohol solution, wherein the addition amount of the oleic acid is Fe3O4And 3 times of the total amount of the acid, uniformly stirring, reacting at 80 ℃ for about 1 hour, filtering out the precipitate, washing with ethanol, and drying to obtain the oleic acid modified ferroferric oxide nucleating agent.
In the following examples, the mine water used had a water quality of COD 11ppm, TDS 3450ppm, total hardness 1920ppm, sulfate 1300 ppm.
Based on the above method, the device provided by the invention is shown in FIGS. 1-3:
in one embodiment, the apparatus as shown in fig. 1, comprises:
the pre-filter 1 is used for performing pre-filtering treatment on mine water;
the first ultrafiltration membrane 2 is connected to the permeation side of the prefilter 1 and is used for carrying out ultrafiltration treatment on the filtrate of the prefilter 1;
the first nanofiltration membrane 3 is connected to the permeation side of the first ultrafiltration membrane 2 and is used for performing nanofiltration concentration treatment on the filtrate of the first ultrafiltration membrane 2;
the precipitation reaction tank 4 is connected to the concentration side of the first nanofiltration membrane 3 and is used for carrying out precipitation reaction on the concentrated solution of the first nanofiltration membrane 3 to remove impurity cations;
NaOH adding tank 5 and Na2CO3An adding tank for respectively adding NaOH and Na into the precipitation reaction tank 42CO3
The second ultrafiltration membrane 7 is connected to the precipitation reaction tank 4 and is used for filtering the wastewater subjected to the precipitation reaction to remove the precipitate;
the second nanofiltration membrane 8 is connected to the permeation side of the second ultrafiltration membrane 7 and is used for concentrating the filtrate of the second ultrafiltration membrane 7;
and the crystallization device 9 is connected to the concentration side of the second nanofiltration membrane 8 and is used for carrying out crystallization treatment on the concentrated solution of the second nanofiltration membrane 8 to obtain the recovered sodium sulfate.
In one embodiment, the pre-filter 1 is one or a combination of a coagulation basin, a sand filter device or an activated carbon filter.
In one embodiment, the material of the first ultrafiltration membrane 2 and the second ultrafiltration membrane 7 is selected from organic materials or inorganic materials; the organic material is PTFE, PVDF, PES, PS or acetate fiber; the inorganic material is alumina, zirconia, titania or silicon carbide.
In one embodiment, the first nanofiltration membrane 3 has a molecular weight cut-off of 150 to 1000Da, more preferably 500 to 1000 Da.
In one embodiment, the molecular weight cut-off of the second nanofiltration membrane 8 is 150 to 1000Da, more preferably 300 to 500 Da.
In one embodiment, the crystallization device 9 is an evaporative crystallizer or a refrigerated crystallizer.
As shown in the apparatus of fig. 2, in one embodiment, the concentration side of the second nanofiltration membrane 8 is connected to the ion exchange resin column 11 and the third nanofiltration membrane 12, and the concentration side of the third nanofiltration membrane 12 is connected to the crystallization apparatus 9.
In one embodiment, the ion exchange resin column 11 is packed with cation exchange resin.
In one embodiment, the molecular weight cut-off of the three-stage nanofiltration membrane is 150-1000 Da, and more preferably 150-300 Da.
In the apparatus shown in fig. 3, in one embodiment, the concentration side of the second nanofiltration membrane 8 is connected to a flocculation reactor 14, a flocculant adding tank 15 and a nucleating agent adding tank 16 are connected to the flocculation reactor 14, the flocculation reactor 14 is connected to a third ultrafiltration membrane 17, and the permeation side of the third ultrafiltration membrane 17 is connected to the ion exchange resin column 11.
In one embodiment, flocculant addition tank 15 is filled with aluminum sulfate, polyaluminum chloride (PAC), ferrous sulfate, ferric sulfate, or ferric chloride; the nucleating agent adding tank 16 is filled with oleic acid modified ferroferric oxide.
Example 1
The mine water firstly enters a coagulation system after the flow and the water quality of the mine water are buffered by an adjusting tank, 15ppm PAC and 10ppm PAM are added into a feeder, supernatant liquid respectively passes through sand filtration and active carbon to obtain clarified liquid of a pretreatment system, COD is 7mg/L, TDS is 3100mg/L, sulfate radical is 1320mg/L, and SS is 26 mg/L, and the clarified liquid enters an ultrafiltration and first-stage nanofiltration system. The ultrafiltration is performed by 50nm ceramic ultrafiltration membrane under 0.3MPa and 3m/s cross flow velocity, and the stable flux of the ceramic membrane is maintained at 171L/m2H, the molecular weight cut-off of the first stage nanofiltration is 800Da, the operating pressure is 1.0Mpa, and the concentration is carried out.
Directly discharging the water produced by the first-stage nanofiltration; the first stage nanofiltration concentrated water enters a hardness removal system, mainly comprising a medicament for removing hardness, sodium carbonate and sodium hydroxide are added to remove calcium and magnesium ions and the like, and the pH value is adjusted to 12.5. The softened mine water has the total hardness of 120 ppm, then is filtered by a 50nm ceramic ultrafiltration membrane, is operated under the pressure of 0.3MPa and the cross flow velocity of 3m/s to remove generated precipitates, the ultrafiltered filtrate is concentrated by two-stage nanofiltration, the molecular weight cut-off of the two-stage nanofiltration is 400Da, the operating pressure is 1.5MPa, concentration is carried out, the concentration multiple reaches 7.2 times when the flux of the two-stage nanofiltration membrane is reduced by 70 percent, and the produced water is directly discharged; enabling concentrated water obtained by the second-stage nanofiltration to enter a crystallization system, and performing freeze crystallization to obtain sodium sulfate crystals, wherein the crystallization temperature is-5 ℃, and the sodium sulfate crystals are dried to obtain anhydrous sodium sulfate, the whiteness of the product is 89%, the sodium sulfate content is 97.3%, and the water content is 0.1%; and (3) mixing and discharging the crystallization mother liquor and the first-stage nanofiltration produced water and the second-stage nanofiltration produced water, wherein the TDS is 1130mg/L, and the sulfate radical is 72 mg/L.
Example 2
The mine water firstly enters a coagulation system after the flow and the water quality of the mine water are buffered by an adjusting tank, and a feeder feeds 20ppm Fe2O315ppm PAC and 10ppm PAM, and recovering Fe from the concentrated solution through a cyclone separator2O3And repeatedly used in a coagulation system; the supernatant is againRespectively performing sand filtration and activated carbon to obtain clear liquor of a pretreatment system, wherein COD is 7mg/L, TDS is 3200mg/L, sulfate radical is 1300mg/L, and SS is 22 mg/L, and the clear liquor enters an ultrafiltration and one-section nanofiltration system. The ultrafiltration is performed by 50nm ceramic ultrafiltration membrane under 0.3MPa and 3m/s cross flow velocity, and the stable flux of the ceramic membrane is maintained at 213L/m2H, the molecular weight cut-off of the first stage nanofiltration is 800Da, the operating pressure is 1.0Mpa, and the concentration is carried out.
Directly discharging the water produced by the first-stage nanofiltration; the first stage nanofiltration concentrated water enters a hardness removal system, mainly comprising a medicament for removing hardness, sodium carbonate and sodium hydroxide are added to remove calcium and magnesium ions and the like, and the pH value is adjusted to 12.5. The softened mine water with the total hardness of 110 ppm is filtered by a 50nm ceramic ultrafiltration membrane, the operation is carried out under the pressure of 0.3MPa and the cross flow velocity of 3m/s to remove generated precipitates, the ultrafiltered filtrate is concentrated by two-stage nanofiltration, the molecular weight cut-off of the two-stage nanofiltration is 400Da, the operation pressure is 1.5MPa, the concentration is carried out, when the flux of the two-stage nanofiltration membrane is reduced by 70%, the concentration multiple reaches 8 times, and the produced water is directly discharged; enabling concentrated water obtained by the second-stage nanofiltration to enter a crystallization system, and performing freeze crystallization to obtain sodium sulfate crystals, wherein the crystallization temperature is-5 ℃, and the sodium sulfate crystals are dried to obtain anhydrous sodium sulfate, the whiteness of the product is 90%, the sodium sulfate content is 97.8%, and the water content is 0.1%; and (3) discharging the crystallization mother liquor and the water produced by the first-stage nanofiltration and the second-stage nanofiltration in a mixed manner, wherein the TDS is 1100mg/L, and the sulfate radical is 70 mg/L.
As can be seen from a comparison of example 1 and example 2, in the flocculation of mine water, magnetic Fe is used2O3When the flocculant is used as an auxiliary coagulant, the coagulation effect can be effectively improved, the stable flux in the subsequent ceramic membrane filtration process is improved, the flocculation effect can be effectively improved, the COD of the treated wastewater is reduced, and the purity of the recovered sodium sulfate is improved.
Example 3
The mine water firstly enters a coagulation system after the flow and the water quality of the mine water are buffered by an adjusting tank, and 15ppm Fe is added by an adding device2O320ppm PAC and 10ppm PAM, and recovering Fe from the concentrated solution through a cyclone separator2O3And repeatedly used in a coagulation system; the supernatant is respectively filtered by sand and activated carbon to obtain the productClear liquid of the treatment system has COD of 8mg/L, TDS of 3100mg/L, sulfate of 1300mg/L and SS of 20mg/L, and enters an ultrafiltration and first-stage nanofiltration system. The ultrafiltration is performed by 50nm ceramic ultrafiltration membrane under 0.4MPa and 4m/s cross flow velocity, and the stable flux of the ceramic membrane is maintained at 242L/m2H, the molecular weight cut-off of the first stage nanofiltration is 800Da, the operating pressure is 1.0Mpa, and the concentration is carried out.
Directly discharging the water produced by the first-stage nanofiltration; the first stage nanofiltration concentrated water enters a hardness removal system, mainly comprising a medicament for removing hardness, sodium carbonate and sodium hydroxide are added to remove calcium and magnesium ions and the like, and the pH value is adjusted to 12.0. The total hardness of softened mine water is 100 ppm, then the softened mine water is filtered by a 50nm ceramic ultrafiltration membrane, the operation is carried out under the pressure of 0.4MPa and the cross flow velocity of 4m/s, the generated precipitate is removed, the ultrafiltered filtrate is concentrated by two-stage nanofiltration, the molecular weight cut-off of the two-stage nanofiltration is 400Da, the operation pressure is 1.5MPa, the concentration is carried out, when the flux of the two-stage nanofiltration membrane is reduced by 70%, the concentration multiple reaches 8.4 times, and the produced water is directly discharged; enabling concentrated water obtained by the second-stage nanofiltration to enter a crystallization system, and performing freeze crystallization to obtain sodium sulfate crystals, wherein the crystallization temperature is-5 ℃, and the sodium sulfate crystals are dried to obtain anhydrous sodium sulfate, the whiteness of the product is 90%, the sodium sulfate content is 97.6%, and the moisture is 0.1%; and (3) discharging the crystallization mother liquor and the water produced by the first-stage nanofiltration and the second-stage nanofiltration in a mixed manner, wherein the TDS is 1050mg/L, and the sulfate radical is 65 mg/L.
Example 4
The mine water firstly enters a coagulation system after the flow and the water quality of the mine water are buffered by an adjusting tank, and 15ppm Fe is added by an adding device2O320ppm PAC and 10ppm PAM, and recovering Fe from the concentrated solution through a cyclone separator2O3And repeatedly used in a coagulation system; and respectively filtering the supernatant with sand and active carbon to obtain a clarified liquid of a pretreatment system, wherein COD is 8mg/L, TDS is 3100mg/L, sulfate is 1300mg/L, and SS is 20mg/L, and the clarified liquid enters an ultrafiltration and first-stage nanofiltration system. The ultrafiltration is performed by 50nm ceramic ultrafiltration membrane under 0.4MPa and 4m/s cross flow velocity, and the stable flux of the ceramic membrane is maintained at 242L/m2H, the molecular weight cut-off of the first stage nanofiltration is 800Da, the operating pressure is 1.0Mpa, and the concentration is carried out.
Directly discharging the water produced by the first-stage nanofiltration; the first stage nanofiltration concentrated water enters a hardness removal system, mainly comprising a medicament for removing hardness, sodium carbonate and sodium hydroxide are added to remove calcium and magnesium ions and the like, and the pH value is adjusted to 12.0. The total hardness of softened mine water is 100 ppm, then the softened mine water is filtered by a 50nm ceramic ultrafiltration membrane, the operation is carried out under the pressure of 0.4MPa and the cross flow velocity of 4m/s, the generated precipitate is removed, the ultrafiltered filtrate is concentrated by two-stage nanofiltration, the molecular weight cut-off of the two-stage nanofiltration is 400Da, the operation pressure is 1.5MPa, the concentration is carried out, when the flux of the two-stage nanofiltration membrane is reduced by 70%, the concentration multiple reaches 8.6 times, and the produced water is directly discharged; concentrated water COD of the second-stage nanofiltration is 14mg/L, the concentrated water is softened by a cation exchanger to remove residual calcium and magnesium ions, weak-acid cation exchange resin is filled in the ion exchanger to reduce the total hardness to 35ppm, the softened mine water enters the third-stage nanofiltration to further improve the salt concentration to 120g/L, the three-stage nanofiltration adopts the molecular weight cutoff of 300Da, the operation is carried out under the condition of 2.0MPa, the concentration multiple is 2.3 times, the flux of the three-stage nanofiltration membrane is reduced by 60%, when the crystallization is carried out by the three-stage nanofiltration, the three-stage nanofiltration produced water is mixed with the first-stage nanofiltration produced water and the second-stage nanofiltration produced water to be discharged, the three-stage nanofiltration concentrated water enters a crystallization system to be subjected to freezing crystallization to obtain sodium sulfate crystals, the crystallization temperature is-5 ℃, the sodium sulfate crystals are dried to obtain anhydrous sodium sulfate; the crystallization mother liquor and the three-stage nanofiltration produced water are mixed with the first-stage nanofiltration produced water and the second-stage nanofiltration produced water and discharged, wherein the TDS is 960mg/L, and the sulfate radical is 55 mg/L.
It can be seen from examples 3 and 4 that after the concentrated water obtained by the two-stage nanofiltration is treated by the ion exchange resin, the hardness of the concentrated water can be effectively reduced, the concentration multiple of nanofiltration can be further increased, the subsequent crystallization process is facilitated, and the purity of the obtained recovered sodium sulfate can be increased.
Example 5
The mine water firstly enters a coagulation system after the flow and the water quality of the mine water are buffered by an adjusting tank, and 15ppm Fe is added by an adding device2O320ppm PAC and 10ppm PAM, and recovering Fe from the concentrated solution through a cyclone separator2O3And repeatedly used in a coagulation system; the supernatant fluid is respectively filtered by sand and activated carbon to obtain clarified liquid of a pretreatment system,COD is 7mg/L, TDS is 3100mg/L, sulfate is 1300mg/L, SS is 20mg/L, and enter ultrafiltration and one-stage nanofiltration system. The ultrafiltration is performed by 50nm ceramic ultrafiltration membrane under 0.4MPa and 4m/s cross flow velocity, and the stable flux of the ceramic membrane is maintained at 242L/m2H, the molecular weight cut-off of the first stage nanofiltration is 800Da, the operating pressure is 1.0Mpa, and the concentration is carried out.
Directly discharging the water produced by the first-stage nanofiltration; the first stage nanofiltration concentrated water enters a hardness removal system, mainly comprising a medicament for removing hardness, sodium carbonate and sodium hydroxide are added to remove calcium and magnesium ions and the like, and the pH value is adjusted to 12.0. The total hardness of softened mine water is 100 ppm, then the softened mine water is filtered by a 50nm ceramic ultrafiltration membrane, the operation is carried out under the pressure of 0.4MPa and the cross flow velocity of 4m/s, the generated precipitate is removed, the ultrafiltered filtrate is concentrated by two-stage nanofiltration, the molecular weight cut-off of the two-stage nanofiltration is 400Da, the operation pressure is 1.5MPa, the concentration is carried out, when the flux of the two-stage nanofiltration membrane is reduced by 70%, the concentration multiple reaches 8.6 times, and the produced water is directly discharged; the concentrated water COD of the two-stage nanofiltration is 14mg/L, 10ppm of polyferric chloride flocculant and 5ppm of ferroferric oxide nucleating agent are added for flocculation reaction, the COD of the produced water after the reaction is reduced to 5mg/L, a flocculation product is filtered by a 50nm ceramic ultrafiltration membrane, the ultrafiltration adopts 0.2Mpa pressure, 3m/s membrane surface flow rate and stable flux 293L/m2H, softening raw water produced by an ultrafiltration membrane by using a cation exchanger to remove residual calcium and magnesium ions, wherein the ion exchanger is filled with weakly acidic cation exchange resin to reduce the total hardness to 24ppm, feeding the softened mine water into three-stage nanofiltration to further improve the salt concentration to 130g/L, performing three-stage nanofiltration by using a molecular weight cut-off of 300Da under the condition of 2.0MPa, wherein the concentration multiple is 2.8 times, the flux of the three-stage nanofiltration is reduced by 60%, when the three-stage nanofiltration is performed for crystallization, mixing the three-stage nanofiltration water produced with the first-stage nanofiltration water and the second-stage nanofiltration water produced, feeding the three-stage nanofiltration water into a crystallization system, performing freeze crystallization to obtain sodium sulfate crystals, wherein the crystallization temperature is-5 ℃, drying the sodium sulfate crystals to obtain anhydrous sodium sulfate, and the product has the whiteness of 93%, the sodium sulfate content of 98.; the crystallization mother liquor and the three-section nanofiltration water production are mixed and discharged with the first-section nanofiltration water production and the second-section nanofiltration water production, the TDS is 940mg/L, and the sulfate radical is 50 mg/L.
It can be seen from the examples 4 and 5 that after the concentrated water obtained by the two-stage nanofiltration is flocculated by the polyferric chloride, the COD in the nanofiltration concentrated solution can be effectively reduced, the concentration in the subsequent nanofiltration process can be realized, the concentration multiple is increased, and the load in the crystallization process is reduced.
Example 6
The mine water firstly enters a coagulation system after the flow and the water quality of the mine water are buffered by an adjusting tank, and 15ppm Fe is added by an adding device2O320ppm PAC and 10ppm PAM, and recovering Fe from the concentrated solution through a cyclone separator2O3And repeatedly used in a coagulation system; and respectively filtering the supernatant with sand and active carbon to obtain a clarified liquid of a pretreatment system, wherein COD is 8mg/L, TDS is 3100mg/L, sulfate is 1300mg/L, and SS is 20mg/L, and the clarified liquid enters an ultrafiltration and first-stage nanofiltration system. The ultrafiltration is performed by 50nm ceramic ultrafiltration membrane under 0.4MPa and 4m/s cross flow velocity, and the stable flux of the ceramic membrane is maintained at 242L/m2H, the molecular weight cut-off of the first stage nanofiltration is 800Da, the operating pressure is 1.0Mpa, and the concentration is carried out.
Directly discharging the water produced by the first-stage nanofiltration; the first stage nanofiltration concentrated water enters a hardness removal system, mainly comprising a medicament for removing hardness, sodium carbonate and sodium hydroxide are added to remove calcium and magnesium ions and the like, and the pH value is adjusted to 12.0. The total hardness of softened mine water is 100 ppm, then the softened mine water is filtered by a 50nm ceramic ultrafiltration membrane, the operation is carried out under the pressure of 0.4MPa and the cross flow velocity of 4m/s, the generated precipitate is removed, the ultrafiltered filtrate is concentrated by two-stage nanofiltration, the molecular weight cut-off of the two-stage nanofiltration is 400Da, the operation pressure is 1.5MPa, the concentration is carried out, when the flux of the two-stage nanofiltration membrane is reduced by 70%, the concentration multiple reaches 8.6 times, and the produced water is directly discharged; the concentrated water COD of the two-stage nanofiltration is 14mg/L, 10ppm of polyferric chloride flocculant and 5ppm of oleic acid modified ferroferric oxide nucleating agent are added for flocculation reaction, the COD of the produced water after the reaction is reduced to 1 mg/L, a flocculation product is filtered by a 50nm ceramic ultrafiltration membrane, the ultrafiltration adopts 0.2Mpa pressure, 3m/s membrane surface flow rate and stable flux of 315L/m2H, softening the raw water of the ultrafiltration membrane by a cation exchanger to remove residual calcium and magnesium ions, and filling a weak acid cation exchange resin in the ion exchanger to reduce the total hardnessWhen the concentration of the softened mine water reaches 21ppm, the softened mine water enters a three-section nanofiltration system to further improve the salt concentration to 130g/L, the three-section nanofiltration system adopts the molecular weight cutoff of 300Da, the operation is carried out under the condition of 2.0MPa, the concentration multiple is 3.0 times, the flux of the three-section nanofiltration system is reduced by 60%, when the three-section nanofiltration system is used for crystallization, the three-section nanofiltration water produced is mixed with the first-section nanofiltration water and the second-section nanofiltration water produced and discharged, the three-section nanofiltration concentrated water enters a crystallization system to be subjected to freezing crystallization to obtain sodium sulfate crystals, the crystallization temperature is-5 ℃, the sodium sulfate crystals are dried to obtain anhydrous sodium sulfate, the whiteness of the; the crystallization mother liquor and the three-section nanofiltration water production are mixed with the first-section nanofiltration water production and the second-section nanofiltration water production and then discharged, wherein the TDS is 920mg/L, and the sulfate radical is 45 mg/L.
It can be seen from the examples 5 and 6 that the oleic acid modified ferroferric oxide nucleating agent can be effectively adsorbed with organic pollutants in the nanofiltration concentrated solution, so that the flocculation effect is improved, the COD in the nanofiltration concentrated solution is reduced, the concentration multiple of the subsequent concentration nanofiltration concentration process is improved, the COD substances are prevented from being retained in the concentrated solution, and the purity of the recovered sodium sulfate is also improved.

Claims (10)

1. A method for reducing salt in mine water is characterized by comprising the following steps:
step 1, performing pre-filtration treatment on mine water;
step 2, performing first ultrafiltration treatment on the filtrate obtained in the step 1;
step 3, carrying out first nanofiltration treatment on the filtrate obtained in the step 2;
step 4, carrying out precipitation reaction on the nanofiltration concentrated solution obtained in the step 3 to remove impurity cations;
step 5, performing second ultrafiltration treatment on the wastewater obtained in the step 4, and filtering out precipitates;
step 6, carrying out second nanofiltration treatment on the filtrate obtained in the step 5;
and 7, crystallizing and drying the nanofiltration concentrated solution obtained in the step 6 in sequence to obtain recovered sodium sulfate.
2. The method for reducing the salt content of the mine water as claimed in claim 1, wherein the pre-filtering treatment in the step 1 comprises the treatment steps of coagulation, pre-filtering and activated carbon filtering; the coagulant used in the coagulation process includes polyaluminium chloride (PAC), Polyacrylamide (PAM) and the like; in the coagulation process, a superconducting magnetic material can be added for auxiliary coagulation, and the superconducting magnetic material is recovered by a cyclone separation method; the superconducting magnetic material is selected from iron sesquioxide particles.
3. The method of claim 1, wherein the step 4 of removing impurity cations is adding NaOH and Na2CO3Carrying out a precipitation reaction; the molecular weight cut-off of the nanofiltration membrane in the first nanofiltration process is 150-1000 Da, and more preferably 500-1000 Da; the molecular weight cut-off of the nanofiltration membrane in the second nanofiltration process is 150-1000 Da, and more preferably 300-500 Da.
4. The method for reducing the salt content of the mine water as claimed in claim 1, wherein in the 7 th step, the nanofiltration concentrated solution obtained in the 6 th step is subjected to cation exchange resin impurity removal cation treatment and third nanofiltration treatment in sequence, and then the third nanofiltration concentrated solution is subjected to crystallization and drying treatment in sequence.
5. The method for reducing the salt of the mine water as claimed in claim 1, wherein the nanofiltration concentrated solution obtained in the step 6 is subjected to flocculation treatment; in the flocculation process, polyferric chloride is used as a flocculating agent, and a nucleating agent is added at the same time; the nucleating agent is hydrophobically modified ferroferric oxide; and in the third nanofiltration process, the molecular weight cut-off of the nanofiltration membrane is 150-1000 Da, and more preferably 150-300 Da.
6. A device for reducing salt in mine water, comprising:
the pre-filter (1) is used for performing pre-filtering treatment on mine water;
the first ultrafiltration membrane (2) is connected to the permeation side of the prefilter (1) and is used for carrying out ultrafiltration treatment on the filtrate of the prefilter (1);
the first nanofiltration membrane (3) is connected to the permeation side of the first ultrafiltration membrane (2) and is used for performing nanofiltration concentration treatment on the filtrate of the first ultrafiltration membrane (2);
the precipitation reaction tank (4) is connected to the concentration side of the first nanofiltration membrane (3) and is used for carrying out precipitation reaction on the concentrated solution of the first nanofiltration membrane (3) to remove impurity cations;
NaOH adding tank (5) and Na2CO3An adding tank (6) for respectively adding NaOH and Na into the precipitation reaction tank (4)2CO3
The second ultrafiltration membrane (7) is connected to the precipitation reaction tank (4) and is used for filtering the wastewater subjected to the precipitation reaction to remove the precipitate;
the second nanofiltration membrane (8) is connected to the permeation side of the second ultrafiltration membrane (7) and is used for concentrating the filtrate of the second ultrafiltration membrane (7);
and the crystallization device (9) is connected to the concentration side of the second nanofiltration membrane (8) and is used for carrying out crystallization treatment on the concentrated solution of the second nanofiltration membrane (8) to obtain the recovered sodium sulfate.
7. The mine water desalination device of claim 6, characterized in that the pre-filter (1) is one or a combination of a coagulation basin, a sand filter device or an activated carbon filter; the first ultrafiltration membrane (2) and the second ultrafiltration membrane (7) are made of organic materials or inorganic materials; the organic material is PTFE, PVDF, PES, PS or acetate fiber; the inorganic material is alumina, zirconia, titanium oxide or silicon carbide; the cut-off molecular weight of the first nanofiltration membrane (3) is 150-1000 Da, and more preferably 500-1000 Da; the molecular weight cut-off of the second nanofiltration membrane (8) is 150-1000 Da, and more preferably 300-500 Da.
8. The mine water desalination device of claim 6, characterized in that the crystallization device (9) is an evaporative crystallizer or a refrigerated crystallizer; the concentration side of the second nanofiltration membrane (8) is connected to the ion exchange resin column (11) and to the third nanofiltration membrane (12), and the concentration side of the third nanofiltration membrane (12) is connected to the crystallization device (9); cation exchange resin is filled in the ion exchange resin column (11); the molecular weight of the three-section nanofiltration membrane cutoff (12) is 150-1000 Da, and more preferably 150-300 Da.
9. The mine water desalting device according to claim 6, wherein the concentration side of the second nanofiltration membrane (8) is connected to a flocculation reactor (14), the flocculation reactor (14) is connected with a flocculant adding tank (15) and a nucleating agent adding tank (16), the flocculation reactor (14) is connected to a third ultrafiltration membrane (17), and the permeation side of the third ultrafiltration membrane (17) is connected to the ion exchange resin column (11); aluminum sulfate, polyaluminum chloride, ferrous sulfate, ferric sulfate or ferric chloride are filled in the flocculating agent adding tank (15); the nucleating agent adding tank (16) is filled with oleic acid modified ferroferric oxide.
10. Use of the mine water desalination device of claim 6 for recovering sodium sulfate from mine water.
CN201910565061.5A 2019-06-27 2019-06-27 Method and device for reducing salt in mine water Pending CN111039480A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201910565061.5A CN111039480A (en) 2019-06-27 2019-06-27 Method and device for reducing salt in mine water

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201910565061.5A CN111039480A (en) 2019-06-27 2019-06-27 Method and device for reducing salt in mine water

Publications (1)

Publication Number Publication Date
CN111039480A true CN111039480A (en) 2020-04-21

Family

ID=70231724

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201910565061.5A Pending CN111039480A (en) 2019-06-27 2019-06-27 Method and device for reducing salt in mine water

Country Status (1)

Country Link
CN (1) CN111039480A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111792764A (en) * 2020-09-08 2020-10-20 山东格润内泽姆环保科技有限公司 Underground coal mine full-membrane modular mine wastewater treatment method and device

Citations (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101215060A (en) * 2007-12-27 2008-07-09 江苏工业学院 Device for treating oil field waste water
CN103050211A (en) * 2012-12-31 2013-04-17 江苏理工学院 Organic magnetic composite material and preparing method thereof
CN103232132A (en) * 2013-03-25 2013-08-07 四川环能德美科技股份有限公司 Magnetic separation method and apparatus for mine water underground treatment
CN105399302A (en) * 2015-12-21 2016-03-16 广东金颢轩环境工程设备科技有限公司 Deep sludge magnetization dehydration treatment method
CN105540988A (en) * 2016-01-15 2016-05-04 航天圣诺(北京)环保科技有限公司 Effluent treatment technology and system based on combination of super magnetic separation and microwave energy technology
CN106396164A (en) * 2016-02-15 2017-02-15 青岛沃赛海水淡化科技有限公司 Industrial acidic wastewater treatment process
CN106976938A (en) * 2017-04-24 2017-07-25 大连理工大学 A kind of method of wadding magnetism separation technical finesse production of propylene oxide waste water
CN107399885A (en) * 2017-08-24 2017-11-28 天津市水利科学研究院 A kind of cleaning system and its method with the coagulation cyclone filter backwashed
CN107619144A (en) * 2017-10-20 2018-01-23 侯新春 A kind of high slat-containing wastewater divides salt process for reclaiming and system
CN107867744A (en) * 2017-10-31 2018-04-03 安徽舜禹水务股份有限公司 One kind loading flocculation sewage water treatment method
CN108298759A (en) * 2018-04-09 2018-07-20 北矿机电科技有限责任公司 A kind of urban sewage treatment system and method based on the separation of magnetic enhanced coagulation
CN108439724A (en) * 2018-05-21 2018-08-24 苏州乔纳森新材料科技有限公司 A kind of heavy metal-polluted method for treating water based on magnetic ferroferric oxide nanometer particle
CN207933209U (en) * 2017-12-28 2018-10-02 江苏久吾高科技股份有限公司 A kind of middle water zero discharge processing unit
CN108996785A (en) * 2018-07-02 2018-12-14 广州汉泰环境技术有限公司 A kind of high slat-containing wastewater thoroughly divides salt crystallization processes and its system
CN109231632A (en) * 2018-11-05 2019-01-18 华电水务工程有限公司 The processing method and system of a kind of highly mineralized mine water reuse and resource utilization
CN211497269U (en) * 2019-06-27 2020-09-15 江苏久吾高科技股份有限公司 Device for reducing salt in mine water

Patent Citations (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101215060A (en) * 2007-12-27 2008-07-09 江苏工业学院 Device for treating oil field waste water
CN103050211A (en) * 2012-12-31 2013-04-17 江苏理工学院 Organic magnetic composite material and preparing method thereof
CN103232132A (en) * 2013-03-25 2013-08-07 四川环能德美科技股份有限公司 Magnetic separation method and apparatus for mine water underground treatment
CN105399302A (en) * 2015-12-21 2016-03-16 广东金颢轩环境工程设备科技有限公司 Deep sludge magnetization dehydration treatment method
CN105540988A (en) * 2016-01-15 2016-05-04 航天圣诺(北京)环保科技有限公司 Effluent treatment technology and system based on combination of super magnetic separation and microwave energy technology
CN106396164A (en) * 2016-02-15 2017-02-15 青岛沃赛海水淡化科技有限公司 Industrial acidic wastewater treatment process
CN106976938A (en) * 2017-04-24 2017-07-25 大连理工大学 A kind of method of wadding magnetism separation technical finesse production of propylene oxide waste water
CN107399885A (en) * 2017-08-24 2017-11-28 天津市水利科学研究院 A kind of cleaning system and its method with the coagulation cyclone filter backwashed
CN107619144A (en) * 2017-10-20 2018-01-23 侯新春 A kind of high slat-containing wastewater divides salt process for reclaiming and system
CN107867744A (en) * 2017-10-31 2018-04-03 安徽舜禹水务股份有限公司 One kind loading flocculation sewage water treatment method
CN207933209U (en) * 2017-12-28 2018-10-02 江苏久吾高科技股份有限公司 A kind of middle water zero discharge processing unit
CN108298759A (en) * 2018-04-09 2018-07-20 北矿机电科技有限责任公司 A kind of urban sewage treatment system and method based on the separation of magnetic enhanced coagulation
CN108439724A (en) * 2018-05-21 2018-08-24 苏州乔纳森新材料科技有限公司 A kind of heavy metal-polluted method for treating water based on magnetic ferroferric oxide nanometer particle
CN108996785A (en) * 2018-07-02 2018-12-14 广州汉泰环境技术有限公司 A kind of high slat-containing wastewater thoroughly divides salt crystallization processes and its system
CN109231632A (en) * 2018-11-05 2019-01-18 华电水务工程有限公司 The processing method and system of a kind of highly mineralized mine water reuse and resource utilization
CN211497269U (en) * 2019-06-27 2020-09-15 江苏久吾高科技股份有限公司 Device for reducing salt in mine water

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
张葆宗 主编: "《反渗透处理应用技术》", 31 March 2004, 中国电力出版社, pages: 41 - 43 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111792764A (en) * 2020-09-08 2020-10-20 山东格润内泽姆环保科技有限公司 Underground coal mine full-membrane modular mine wastewater treatment method and device
CN111792764B (en) * 2020-09-08 2021-02-19 格润内泽姆新水务有限公司 Underground coal mine full-membrane modular mine wastewater treatment method and device

Similar Documents

Publication Publication Date Title
US6113797A (en) High water recovery membrane purification process
CA2913308C (en) Wastewater treatment processes employing high rate chemical softening systems
CN108623104A (en) A kind of high-salinity wastewater zero-emission processing method and processing device based on NF membrane allotment
US6027649A (en) Process for purifying water using fine floc and microfiltration in a single tank reactor
CN109970232B (en) Treatment method and device for waste brine
KR102248622B1 (en) Elimination of sodium sulfate from biologically treated wastewater
AU2008202302A1 (en) High Water Recovery Membrane Purification Process
CN106430785A (en) Method and device for reusing reclaimed water with zero discharge
CN110577229B (en) Method and device for recycling waste salt
CN208667421U (en) A kind of high-salinity wastewater zero-emission processing unit based on nanofiltration membrane allotment
CN108623055B (en) Zero-discharge softening process and device for pulping and papermaking wastewater
CN102656122B (en) Enhanced high water recovery membrane process
CN110759570A (en) Treatment method and treatment system for dye intermediate wastewater
CN211497269U (en) Device for reducing salt in mine water
CN111039480A (en) Method and device for reducing salt in mine water
CN210915600U (en) Recycling device of RO strong brine
CN111635050A (en) Method and device for treating high-salinity mine water
CN206529365U (en) A kind of Treated sewage reusing device of zero-emission
AU2009210363A1 (en) Enhanced High Water Recovery Membrane Process
WO2009102442A1 (en) Desalination of water containing high silica content
CN115367902B (en) Pretreatment method for high-salt wastewater and application thereof
WO2022210467A1 (en) High-performance pretreatment system for desulfurized wastewater for reverse osmosis membrane
CN116444106B (en) High-hardness high-sulfate type coal mine water treatment method and device
JP7350886B2 (en) water treatment equipment
JPH04290591A (en) Water treating device

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination