CN112939312A - Titanium dioxide acid wastewater treatment and recovery process - Google Patents
Titanium dioxide acid wastewater treatment and recovery process Download PDFInfo
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- CN112939312A CN112939312A CN202110138763.2A CN202110138763A CN112939312A CN 112939312 A CN112939312 A CN 112939312A CN 202110138763 A CN202110138763 A CN 202110138763A CN 112939312 A CN112939312 A CN 112939312A
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- resin
- titanium dioxide
- acid
- membrane
- sulfuric acid
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- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 title claims abstract description 137
- 239000002253 acid Substances 0.000 title claims abstract description 128
- 239000004408 titanium dioxide Substances 0.000 title claims abstract description 66
- 238000011084 recovery Methods 0.000 title claims abstract description 45
- 238000004065 wastewater treatment Methods 0.000 title claims abstract description 28
- 239000011347 resin Substances 0.000 claims abstract description 208
- 229920005989 resin Polymers 0.000 claims abstract description 208
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims abstract description 136
- 239000012528 membrane Substances 0.000 claims abstract description 97
- 238000001914 filtration Methods 0.000 claims abstract description 55
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 50
- 238000000108 ultra-filtration Methods 0.000 claims abstract description 46
- 150000003839 salts Chemical class 0.000 claims abstract description 36
- 239000002351 wastewater Substances 0.000 claims abstract description 35
- 239000012510 hollow fiber Substances 0.000 claims abstract description 31
- 238000001728 nano-filtration Methods 0.000 claims abstract description 28
- 238000000926 separation method Methods 0.000 claims abstract description 19
- 239000000706 filtrate Substances 0.000 claims abstract description 18
- 238000004064 recycling Methods 0.000 claims abstract description 17
- 238000005342 ion exchange Methods 0.000 claims abstract description 16
- 238000004519 manufacturing process Methods 0.000 claims abstract description 16
- 238000001704 evaporation Methods 0.000 claims abstract description 15
- 230000008020 evaporation Effects 0.000 claims abstract description 12
- 239000012466 permeate Substances 0.000 claims abstract description 12
- 238000005086 pumping Methods 0.000 claims abstract description 6
- 238000000034 method Methods 0.000 claims description 47
- 239000002245 particle Substances 0.000 claims description 27
- 238000011001 backwashing Methods 0.000 claims description 26
- 235000003891 ferrous sulphate Nutrition 0.000 claims description 26
- 239000011790 ferrous sulphate Substances 0.000 claims description 26
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 claims description 26
- 229910000359 iron(II) sulfate Inorganic materials 0.000 claims description 26
- 238000004140 cleaning Methods 0.000 claims description 17
- 238000009295 crossflow filtration Methods 0.000 claims description 11
- 150000002505 iron Chemical class 0.000 claims description 11
- 238000011049 filling Methods 0.000 claims description 9
- 239000012465 retentate Substances 0.000 claims description 9
- 238000001179 sorption measurement Methods 0.000 claims description 9
- 239000003513 alkali Substances 0.000 claims description 7
- 239000004793 Polystyrene Substances 0.000 claims description 6
- 229920002223 polystyrene Polymers 0.000 claims description 6
- 239000002033 PVDF binder Substances 0.000 claims description 5
- 239000003957 anion exchange resin Substances 0.000 claims description 5
- 239000000460 chlorine Substances 0.000 claims description 5
- 229910052801 chlorine Inorganic materials 0.000 claims description 5
- 125000001309 chloro group Chemical group Cl* 0.000 claims description 5
- 150000002500 ions Chemical group 0.000 claims description 5
- 229920002981 polyvinylidene fluoride Polymers 0.000 claims description 5
- 239000011148 porous material Substances 0.000 claims description 5
- 239000012798 spherical particle Substances 0.000 claims description 5
- 239000003960 organic solvent Substances 0.000 claims description 2
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 abstract description 3
- 235000010215 titanium dioxide Nutrition 0.000 description 47
- 230000008569 process Effects 0.000 description 33
- 239000002699 waste material Substances 0.000 description 32
- 239000000243 solution Substances 0.000 description 31
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 16
- 238000002791 soaking Methods 0.000 description 16
- 238000005516 engineering process Methods 0.000 description 14
- 239000012535 impurity Substances 0.000 description 13
- OSGAYBCDTDRGGQ-UHFFFAOYSA-L calcium sulfate Chemical compound [Ca+2].[O-]S([O-])(=O)=O OSGAYBCDTDRGGQ-UHFFFAOYSA-L 0.000 description 10
- CSNNHWWHGAXBCP-UHFFFAOYSA-L Magnesium sulfate Chemical compound [Mg+2].[O-][S+2]([O-])([O-])[O-] CSNNHWWHGAXBCP-UHFFFAOYSA-L 0.000 description 8
- 239000002994 raw material Substances 0.000 description 8
- 239000011780 sodium chloride Substances 0.000 description 8
- 239000000047 product Substances 0.000 description 7
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 6
- 230000008901 benefit Effects 0.000 description 6
- 239000006227 byproduct Substances 0.000 description 6
- 239000000463 material Substances 0.000 description 6
- 230000000694 effects Effects 0.000 description 5
- 229910052742 iron Inorganic materials 0.000 description 5
- 239000012629 purifying agent Substances 0.000 description 5
- 238000007789 sealing Methods 0.000 description 5
- 239000000126 substance Substances 0.000 description 5
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 4
- DIZPMCHEQGEION-UHFFFAOYSA-H aluminium sulfate (anhydrous) Chemical compound [Al+3].[Al+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O DIZPMCHEQGEION-UHFFFAOYSA-H 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 4
- 239000006260 foam Substances 0.000 description 4
- 239000010439 graphite Substances 0.000 description 4
- 229910002804 graphite Inorganic materials 0.000 description 4
- -1 iron ions Chemical class 0.000 description 4
- 229910052943 magnesium sulfate Inorganic materials 0.000 description 4
- 235000019341 magnesium sulphate Nutrition 0.000 description 4
- 229940099596 manganese sulfate Drugs 0.000 description 4
- 235000007079 manganese sulphate Nutrition 0.000 description 4
- 239000011702 manganese sulphate Substances 0.000 description 4
- SQQMAOCOWKFBNP-UHFFFAOYSA-L manganese(II) sulfate Chemical compound [Mn+2].[O-]S([O-])(=O)=O SQQMAOCOWKFBNP-UHFFFAOYSA-L 0.000 description 4
- 229920006395 saturated elastomer Polymers 0.000 description 4
- 238000012545 processing Methods 0.000 description 3
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- 230000002378 acidificating effect Effects 0.000 description 2
- 238000005660 chlorination reaction Methods 0.000 description 2
- 238000003912 environmental pollution Methods 0.000 description 2
- 230000004907 flux Effects 0.000 description 2
- 238000006386 neutralization reaction Methods 0.000 description 2
- 230000008929 regeneration Effects 0.000 description 2
- 238000011069 regeneration method Methods 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 238000005406 washing Methods 0.000 description 2
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 1
- 235000019738 Limestone Nutrition 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- 235000011941 Tilia x europaea Nutrition 0.000 description 1
- 230000004913 activation Effects 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- 125000003118 aryl group Chemical group 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 239000013043 chemical agent Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 239000000084 colloidal system Substances 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 125000004122 cyclic group Chemical group 0.000 description 1
- 230000006378 damage Effects 0.000 description 1
- 238000010612 desalination reaction Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 230000003670 easy-to-clean Effects 0.000 description 1
- 229920001971 elastomer Polymers 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 239000000945 filler Substances 0.000 description 1
- 235000013305 food Nutrition 0.000 description 1
- 125000000524 functional group Chemical group 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 239000008235 industrial water Substances 0.000 description 1
- YDZQQRWRVYGNER-UHFFFAOYSA-N iron;titanium;trihydrate Chemical compound O.O.O.[Ti].[Fe] YDZQQRWRVYGNER-UHFFFAOYSA-N 0.000 description 1
- 239000004571 lime Substances 0.000 description 1
- 239000006028 limestone Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 238000005374 membrane filtration Methods 0.000 description 1
- 229910021645 metal ion Inorganic materials 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
- 239000000049 pigment Substances 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 238000006068 polycondensation reaction Methods 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 238000007639 printing Methods 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000012827 research and development Methods 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 239000013535 sea water Substances 0.000 description 1
- 239000010865 sewage Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 239000011550 stock solution Substances 0.000 description 1
- 150000003467 sulfuric acid derivatives Chemical class 0.000 description 1
- 239000012463 white pigment Substances 0.000 description 1
Classifications
-
- 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
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B17/00—Sulfur; Compounds thereof
- C01B17/69—Sulfur trioxide; Sulfuric acid
- C01B17/90—Separation; Purification
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B17/00—Sulfur; Compounds thereof
- C01B17/69—Sulfur trioxide; Sulfuric acid
- C01B17/90—Separation; Purification
- C01B17/901—Recovery from spent acids containing metallic ions, e.g. hydrolysis acids, pickling acids
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G23/00—Compounds of titanium
- C01G23/04—Oxides; Hydroxides
- C01G23/047—Titanium dioxide
- C01G23/053—Producing by wet processes, e.g. hydrolysing titanium salts
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G49/00—Compounds of iron
- C01G49/14—Sulfates
-
- 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
- C02F1/28—Treatment of water, waste water, or sewage by sorption
-
- 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
- C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
- C02F1/444—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by ultrafiltration or microfiltration
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Environmental & Geological Engineering (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Hydrology & Water Resources (AREA)
- Engineering & Computer Science (AREA)
- Water Supply & Treatment (AREA)
- Separation Using Semi-Permeable Membranes (AREA)
Abstract
The invention belongs to the technical field of wastewater treatment, and particularly relates to a titanium dioxide acid wastewater treatment and recovery process. The titanium dioxide acid wastewater enters an ultrafiltration system and is filtered by a hollow fiber ultrafiltration membrane to obtain membrane filtrate; the obtained membrane filtrate enters an ion exchange system to be adsorbed by resin, wastewater containing ferric salt obtained by separation is recycled by the ferric salt, and the resin adsorbed with free acid is cleaned to obtain relatively pure dilute sulfuric acid; pumping the obtained relatively pure dilute sulfuric acid into a nanofiltration system for filtering, wherein the membrane permeate is pure sulfuric acid, and then carrying out multi-effect evaporation and re-concentration to obtain more than or equal to 50% of clean sulfuric acid for reusing in a titanium dioxide production system. According to the titanium dioxide acid wastewater treatment and recovery process, sulfuric acid, water and ferrous iron in the acid wastewater are efficiently separated, and can be completely recycled in the production process for recycling or resource recycling, so that zero emission of the titanium dioxide acid wastewater is finally realized.
Description
Technical Field
The invention belongs to the technical field of wastewater treatment, and particularly relates to a titanium dioxide acid wastewater treatment and recovery process.
Background
Titanium white powder is considered as a white pigment with the best performance in the world at present, is also an important raw material in the chemical industry, and has a wide application range. The titanium dioxide can be used as pigment and filler in the fields of coating, plastics, printing ink, paper making, rubber, ceramics and the like, and also can be used as additive in the fields of chemical fiber, electronics, food, medicine and the like.
At present, the titanium dioxide is industrially mature, and the production process comprises a sulfuric acid method and a chlorination method. The sulfuric acid method has mature production process technology, can produce two titanium dioxide products of anatase type and rutile type, has the advantages that ilmenite and sulfuric acid which are low in price and easy to obtain can be used as raw materials, the technology is mature, equipment is simple, and anti-corrosion materials are easy to solve; its disadvantages are long technological process, high consumption of sulfuric acid and water, more waste and by-products, and high environmental pollution. The chlorination method can only produce rutile type products, and has the advantages of short flow, easy expansion of production capacity, relatively low energy consumption, less three wastes and capability of obtaining high-quality products; the method has the disadvantages of large investment, complex equipment structure, high requirement on materials and great difficulty in research and development. From now on, the sulfuric acid process production process still occupies an absolute position in China. Therefore, optimizing the production process of the sulfuric acid method titanium dioxide and saving energy and reducing consumption are still key points of research in a future period.
In the process of producing titanium white by a sulfuric acid method, a large amount of acidic wastewater (mainly from a water washing section, a tail gas washing section and the like) is generated, and the acidic wastewater contains free sulfuric acid, ferrous sulfate, metatitanic acid and sulfates of other metal ions. The acid wastewater is generated by 50-100m per 1 ton of titanium dioxide3Acid waste water.
Acid waste water generally chooses limestone or carbide mud to carry out the neutralization, but can correspondingly produce a large amount of calcium sulfate waste residues that contain iron, these waste residues bury deeply a bit, and direct open-air piling is gone on a bit, through the rainwater erodees, and the water that flows out also can cause very big destruction to the environment, so must handle.
Disclosure of Invention
The purpose of the invention is: providing a titanium dioxide acid wastewater treatment and recovery process; the process can realize high-efficiency separation of sulfuric acid, water and ferrous iron in the acid wastewater, can be completely recycled in the production process for recycling or resource recycling, and finally realizes zero emission of the titanium dioxide acid wastewater.
The invention relates to a titanium dioxide acid wastewater treatment and recovery process, which comprises the following steps:
(1) the titanium dioxide acid wastewater enters an ultrafiltration system and is filtered by a hollow fiber ultrafiltration membrane to obtain membrane filtrate;
(2) allowing the membrane filtrate obtained in the step (1) to enter an ion exchange system for resin adsorption, recovering and reusing ferric salt from wastewater containing ferric salt obtained by separation, and cleaning the resin adsorbed with free acid to obtain relatively pure dilute sulfuric acid;
(3) pumping the relatively pure dilute sulfuric acid obtained in the step (2) into a nanofiltration system for filtering, wherein the membrane permeate is pure sulfuric acid, and then carrying out multi-effect evaporation and re-concentration to obtain more than or equal to 50% of clean sulfuric acid for recycling in a titanium dioxide production system.
Wherein:
the concentration of sulfuric acid in the titanium dioxide acid wastewater in the step (1) is 20-24%, the concentration of ferrous sulfate is 5-8g/L, the concentration of titanium dioxide is 2-3g/L, and other impurities such as calcium sulfate, magnesium sulfate, aluminum sulfate, manganese sulfate and the like are also contained.
The hollow fiber ultrafiltration membrane in the step (1) has a filtering pore size of 0.02 micron and is made of modified PVDF so as to have hydrophilicity.
Filtering in the step (1) by adopting a full-automatic continuous operation mode of cross-flow filtration and frequent backwashing; the cross flow filtration time is 30-35 minutes, and the frequent backwashing time is 5-8 minutes; the operating pressure during filtration is less than 2 kg.
Filtering by using the hollow fiber ultrafiltration membrane in the step (1), wherein the retentate of the hollow fiber ultrafiltration membrane is titanium dioxide and suspended matters; the permeate of the hollow fiber ultrafiltration membrane is crude sulfuric acid containing iron salt.
The hollow fiber ultrafiltration membrane in the step (1) adopts a gas-water mixed backwashing mode, and has good backwashing effect and strong performance recovery capability.
And (3) arranging a high-efficiency filtering system at the front end of the ion exchange system in the step (2), wherein the high-efficiency filtering system consists of a coarse filter and a fine filter, and the filtering precision is maintained below 1 micron.
The time of one working period of the resin adsorption in the step (2) is 20-25 minutes.
The resin in the step (2) is strong alkali type anion exchange resin, the resin framework is crosslinked polystyrene, the ion form is chlorine type, the physical form is wet spherical particles, the particle size is 0.1-0.3mm, the exchange capacity is 1.3meq/ml, the backwashing stable density is 690-720g/l, the maximum operation temperature is 60 ℃, and the dissolubility is insoluble in any organic solvent.
Preferably, the resin type in step (2) is Tulsion A-853E, and the manufacturer is American Dusheng resin.
And (3) filling the resin in a short and fixed resin bed in the step (2), and feeding the membrane filtrate into the resin bed in a counter-current water feeding mode.
The height of the resin bed in the step (2) is less than 500mm, the resin tank body is processed in an acid recovery resin tank, after the resin tank is filled with the resin, 10% sodium chloride solution is used for soaking the resin, the soaking time is 2-3 hours, the resin is shrunk in the tank body, and then the resin tank body is filled with new resin again; and a flange sealing structure is adopted, the resin tank body is sealed after the resin is filled again, and then pure water is fed into the resin tank body through a cleaning pump to clean the resin bed.
And (3) preparing the wastewater containing the ferric salt in the step (2) by using a nanofiltration membrane circulating concentration process to obtain a ferrous sulfate product, wherein the ferrous sulfate can be used as a raw material of a byproduct water purifying agent.
And (3) filtering by adopting a special industrial membrane in the nanofiltration system in the step (3), wherein the molecular weight cut-off of the special industrial membrane is 50-500.
And (4) filtering by a nanofiltration system membrane in the step (3), wherein the retentate of the membrane is waste acid solution containing a small amount of ferrous sulfate, and returning the waste acid solution to the ion exchange system for recycling treatment through a resin bed.
The nanofiltration system in the step (3) continuously operates, automatically washes once every two hours, the operation pressure is 40-60 kg, and the working temperature is 40-45 ℃.
The multi-effect evaporation in the step (3) adopts a three-effect graphite evaporator, and 20-24% of sulfuric acid is evaporated and concentrated to be more than or equal to 50%.
The ultrafiltration system is mainly used for removing titanium dioxide and suspended matters in waste acid, and provides guarantee for efficient operation of subsequent nanofiltration system equipment. The ultrafiltration membrane separation technology has the characteristics of small occupied area, good effluent quality, high automation degree and the like; can ensure the quality of produced water for a long time and has good separation capability on suspended particles and macromolecular organic matters.
The ultrafiltration device adopts a full-automatic continuous operation mode of cross flow filtration and frequent backwashing. The system adopts PLC full-automatic control. The ultrafiltration system has the following advantages: A) the filtering membrane has stable chemical performance, acid and alkali resistance and is easy to clean; B) the membrane surface is subjected to hydrophilic modification, so that the water flux is large, and the water quantity attenuation is reduced; C) and a gas-water mixed backwashing mode is adopted, so that the backwashing effect is good and the performance recovery capability is strong.
The hollow fiber ultrafiltration membrane separation technology is widely applied to the separation, concentration and purification of solution and solid matters. It uses the film with selective permeability as separation medium, the film wall is densely distributed with micropores, the stock solution passes through one side of the film under a certain pressure, the solvent and small molecular solute permeate the film wall as filtrate, and the larger molecular solute is retained by the film, so as to achieve the purpose of separating and concentrating the material. The membrane separation process is a dynamic filtration process, macromolecular solute and solid are blocked by the membrane wall and flow out of the membrane component along with the concentrated solution, and the membrane is not easy to be blocked and can be continuously used for a long time. The filtering process can be operated at normal temperature and low pressure, has no phase change, and is efficient and energy-saving.
The ultrafiltration membrane separation device has the characteristics of small occupied area, good effluent quality, high automation level and the like. The ultrafiltration membrane has a compact surface activation layer and a spongy network structure as a supporting layer, so that the ultrafiltration membrane is pressure-resistant, pollution-resistant and long in service life, can ensure the quality of produced water for a long time, has good separation capability on colloid, suspended particles and high molecular substances, and is mainly used for removing suspended matters and titanium dioxide in waste acid in ultrafiltration.
The resin is adopted to recover the free acid in the waste acid in the step (2), so that the purpose of separating the free acid from the ferric salt can be achieved, the concentration of the original waste acid can be slightly improved, the benefit of an enterprise is increased, and the sewage treatment cost is reduced. The process has the following application advantages: the application of fine resin particles increases the specific surface area of unit volume and improves the reaction kinetics; the application of a short resin bed reduces the pressure drop and the equipment size; the design of the fixed resin bed reduces the solution mixing as much as possible and reduces the regeneration time; the chemical efficiency of the feeding and regeneration steps is improved to the maximum extent by a mode of countercurrent water feeding.
The front end of the process adopts a high-efficiency filtering system, the filtering precision is maintained below 1 micron, the high-efficiency operation of a resin system can be ensured, the selection type of the resin is Tulsion A-853E, the particle size range is 0.1-0.3mm, the resin framework is crosslinked polystyrene and is far smaller than the particle size of the resin of domestic equipment, and the application of the resin ball is applicable to the recovery of hydrochloric acid, sulfuric acid, nitric acid, hydrofluoric acid or mixed acid thereof.
The height of a resin bed body is required to be less than 500mm, an acid recovery resin tank body is processed, after the resin is filled, 10% sodium chloride solution is used for soaking the resin, the soaking time is 2-3 hours, the resin is contracted in the tank body, then the resin tank body is filled again with new resin (the principle of the process is applied, the resin ball recovers free acid and can not adsorb iron ions, but because gaps are formed between the resin ball and the ball and between the resin ball and the tank body, waste acid liquor can be remained in the gap space, the content of ferric salt in the waste acid liquor is high, the purity of the washed acid can be influenced, the gap is reduced to the greatest extent to improve the purity of the obtained acid liquor, the gaps between the resin ball and the ball and between the resin ball and the tank body can be reduced to the greatest extent by soaking with salt water and replenishing the resin again), the process adopts a flange sealing structure, the resin tank body is sealed after the resin is filled again, then pure water is fed into the bed body through a cleaning pump to clean the resin bed, salt losing expansion of resin particles after the salt water in the bed body is washed away has certain pressure on the shell wall and the upper and lower top covers of the bed body, and thus the resin is in an ideal filling and compacting state in the tank body. As the particle size of the resin adopted by the process is far smaller than that of the resin adopted by a domestic acid recovery system, and salt foam is filled and compacted, gaps among resin particles are extremely small, and the resin particles do not have unfilled vacant spaces in a bed body, so that a large amount of residual waste acid can be avoided in the waste acid feeding process, the purity of the acid solution obtained in the process of saturated cleaning of the resin with adsorbed acid solution is high, and the residual quantity of iron salt in the acid solution is below 1 g/L.
The membrane technology is a high-efficiency green separation technology. Because the method is a physical separation method and does not add chemical agents, the method is a green technology and cannot cause new environmental pollution. The traditional membrane technology is mainly applied to seawater desalination, urban water treatment and simple industrial water treatment, and the used membrane raw material is mainly a common membrane element and is not suitable for severe industrial application fields of strong acid, strong alkali, strong oxidation and the like.
For industrial application fields such as strong acid, a special membrane technology is required to solve resource recovery and realize environmental protection. The special industrial membrane separation technology is a core technology. The technology mainly comprises the following layers: the film casting technology comprises the following steps: the interface polycondensation of the optimal parameters is carried out by using high-quality materials, alloying and grafting treatment are carried out according to specific application occasions, aromatic groups and functional groups (C-N, C-O, C-M-O) are reasonably proportioned, Newton force and coulomb force are balanced, and hydrogen bonds are utilized to the maximum extent, so that high flux and high retention rate of the membrane are realized.
Compared with the prior art, the invention has the following beneficial effects:
(1) according to the titanium dioxide acid wastewater treatment and recovery process, sulfuric acid, water and ferrous iron in the acid wastewater are efficiently separated, and can be completely recycled in the production process for recycling or resource recycling, so that zero emission of the titanium dioxide acid wastewater is finally realized.
(2) According to the titanium dioxide acid wastewater treatment and recovery process, the acid wastewater is treated into pure water with low salt content, sulfuric acid with concentration of more than 50% and enriched ferrous sulfate through a membrane separation and concentration technology, the pure water and the sulfuric acid are reused in the titanium dioxide production process, the ferrous sulfate can be used as raw materials of a byproduct water purifying agent, and the whole process realizes zero emission and full resource utilization of the materials.
(3) The titanium dioxide acid wastewater treatment and recovery process effectively solves the problem that a large amount of yellow mud paste is generated by the original lime neutralization, realizes the water resource recycling, and has obvious energy-saving and emission-reducing benefits.
(4) The invention relates to a titanium dioxide acid wastewater treatment and recovery process, which adopts an ultrafiltration membrane made of acid-resistant special materials for efficiently separating titanium dioxide and particles in acid wastewater, adopts a resin bed adsorption and nanofiltration membrane cyclic concentration process for separating and recycling ferrous sulfate in the acid wastewater, obtains clean dilute acid by using a special nanofiltration membrane, and then adopts a multi-effect evaporation mode for re-concentration to obtain more than or equal to 50 percent of clean sulfuric acid for the titanium dioxide production link.
Detailed Description
The present invention is further described below with reference to examples.
Example 1
The titanium dioxide acid wastewater treatment and recovery process described in this embodiment 1 comprises the following steps:
(1) the titanium dioxide acid wastewater enters an ultrafiltration system and is filtered by a hollow fiber ultrafiltration membrane to obtain membrane filtrate;
(2) allowing the membrane filtrate obtained in the step (1) to enter an ion exchange system for resin adsorption, recovering and reusing ferric salt from wastewater containing ferric salt obtained by separation, and cleaning the resin adsorbed with free acid to obtain relatively pure dilute sulfuric acid;
(3) pumping the relatively pure dilute sulfuric acid obtained in the step (2) into a nanofiltration system for filtering, wherein the membrane permeate is pure sulfuric acid, and then carrying out multi-effect evaporation and re-concentration to obtain more than or equal to 50% of clean sulfuric acid for recycling in a titanium dioxide production system.
Wherein:
the concentration of sulfuric acid in the titanium dioxide acid wastewater in the step (1) is 20%, the concentration of ferrous sulfate is 7g/L, the concentration of titanium dioxide is 2g/L, and in addition, other impurities such as calcium sulfate, magnesium sulfate, aluminum sulfate, manganese sulfate and the like are also contained.
The hollow fiber ultrafiltration membrane in the step (1) has a filtering pore size of 0.02 micron and is made of modified PVDF so as to have hydrophilicity.
Filtering in the step (1) by adopting a full-automatic continuous operation mode of cross-flow filtration and frequent backwashing; the cross flow filtration time is 30 minutes, and the frequent backwashing time is 5 minutes; the operating pressure during the filtration was 1.5 kg.
Filtering by using the hollow fiber ultrafiltration membrane in the step (1), wherein the retentate of the hollow fiber ultrafiltration membrane is titanium dioxide and suspended matters; the permeate of the hollow fiber ultrafiltration membrane is crude sulfuric acid containing iron salt.
The hollow fiber ultrafiltration membrane in the step (1) adopts a gas-water mixed backwashing mode, and has good backwashing effect and strong performance recovery capability.
And (3) arranging a high-efficiency filtering system at the front end of the ion exchange system in the step (2), wherein the high-efficiency filtering system consists of a coarse filter and a fine filter, and the filtering precision is maintained below 1 micron.
The resin in the step (2) is adsorbed for a working period of 20 minutes.
The resin in the step (2) is strong alkali type anion exchange resin, the resin framework is crosslinked polystyrene, the ion form is chlorine type, the physical form is wet spherical particles, the particle size is 0.2mm, the exchange capacity is 1.3meq/ml, and the backwashing stable density is 700 g/l.
The resin model in the step (2) is Tulsion A-853E, and the manufacturer is American Dusheng resin.
And (3) filling the resin in a short and fixed resin bed in the step (2), and feeding the membrane filtrate into the resin bed in a counter-current water feeding mode.
The height of the resin bed in the step (2) is 450mm, the resin tank body is processed in the acid recovery resin tank body, after the resin tank body is filled with the resin, the resin tank body is soaked in 10% sodium chloride solution for 2.5 hours, the resin is shrunk in the tank body, and then the resin tank body is filled with new resin again; and a flange sealing structure is adopted, the resin tank body is sealed after the resin is filled again, and then pure water is fed into the resin tank body through a cleaning pump to clean the resin bed.
The processing height of the resin bed body is 450mm, the resin tank body is processed after acid recovery, after the resin is filled, 10% sodium chloride solution is used for soaking the resin, the soaking time is 2.5 hours, the resin is shrunk in the tank body, then the resin tank body is filled again with new resin (the principle of the application process is that the resin ball recovers free acid and can not adsorb iron ions, but because gaps are formed between the resin ball and the ball and between the resin ball and the tank body, waste acid liquor can be remained in the gap space, and the content of ferric salt in the waste acid liquor is very high, so that the purity of the washed acid can be influenced, the gap is reduced as much as possible to improve the purity of the obtained acid liquor, the gaps between the resin ball and the ball and between the resin ball and the tank body can be reduced to the greatest extent by soaking with salt water and replenishing the resin again), the process adopts a flange, and the resin tank body is sealed after the resin is filled again, then pure water is fed into the bed body through a cleaning pump to clean the resin bed, salt losing expansion of resin particles after the salt water in the bed body is washed away has certain pressure on the shell wall and the upper and lower top covers of the bed body, and thus the resin is in an ideal filling and compacting state in the tank body. As the particle size of the resin adopted by the process is far smaller than that of the resin adopted by a domestic acid recovery system, and salt foam is filled and compacted, gaps among resin particles are extremely small, and the resin particles do not have unfilled vacant spaces in a bed body, so that a large amount of residual waste acid can be avoided in the waste acid feeding process, the purity of the acid solution obtained in the process of saturated cleaning of the resin with adsorbed acid solution is high, and the residual quantity of iron salt in the acid solution is below 1 g/L.
And (3) preparing the wastewater containing the ferric salt in the step (2) by using a nanofiltration membrane circulating concentration process to obtain a ferrous sulfate product, wherein the ferrous sulfate can be used as a raw material of a byproduct water purifying agent.
And (3) filtering by adopting a special industrial membrane in the nanofiltration system in the step (3), wherein the molecular weight cut-off of the special industrial membrane is 50-500.
And (4) filtering by a nanofiltration system membrane in the step (3), wherein the retentate of the membrane is waste acid solution containing a small amount of ferrous sulfate, and returning the waste acid solution to the ion exchange system for recycling treatment through a resin bed.
The nanofiltration system in the step (3) is continuously operated, and is automatically flushed once every two hours, the operating pressure is 50 kilograms, and the working temperature is 40 ℃.
And (3) evaporating and concentrating 20% of sulfuric acid to 50% by adopting a three-effect graphite evaporator in the multi-effect evaporation.
After the treatment of the working procedures, the concentration of the sulfuric acid evaporated finally is 50%, the yield of the sulfuric acid is 87%, the ferrous sulfate is 90mg/L, other impurities are not detected, and the concentration of the sulfuric acid in the evaporated water is 0.20%, and other impurities are not detected.
Example 2
The titanium dioxide acid wastewater treatment and recovery process described in this embodiment 2 comprises the following steps:
(1) the titanium dioxide acid wastewater enters an ultrafiltration system and is filtered by a hollow fiber ultrafiltration membrane to obtain membrane filtrate;
(2) allowing the membrane filtrate obtained in the step (1) to enter an ion exchange system for resin adsorption, recovering and reusing ferric salt from wastewater containing ferric salt obtained by separation, and cleaning the resin adsorbed with free acid to obtain relatively pure dilute sulfuric acid;
(3) pumping the relatively pure dilute sulfuric acid obtained in the step (2) into a nanofiltration system for filtering, wherein the membrane permeate is pure sulfuric acid, and then carrying out multi-effect evaporation and re-concentration to obtain more than or equal to 50% of clean sulfuric acid for recycling in a titanium dioxide production system.
Wherein:
the titanium dioxide acid wastewater in the step (1) contains 22% of sulfuric acid, 7.5g/L of ferrous sulfate and 2.5g/L of titanium dioxide, and also contains other impurities such as calcium sulfate, magnesium sulfate, aluminum sulfate, manganese sulfate and the like.
The hollow fiber ultrafiltration membrane in the step (1) has a filtering pore size of 0.02 micron and is made of modified PVDF so as to have hydrophilicity.
Filtering in the step (1) by adopting a full-automatic continuous operation mode of cross-flow filtration and frequent backwashing; the cross flow filtration time is 33 minutes, and the frequent backwashing time is 7 minutes; the operating pressure during the filtration was 1.6 kg.
Filtering by using the hollow fiber ultrafiltration membrane in the step (1), wherein the retentate of the hollow fiber ultrafiltration membrane is titanium dioxide and suspended matters; the permeate of the hollow fiber ultrafiltration membrane is crude sulfuric acid containing iron salt.
The hollow fiber ultrafiltration membrane in the step (1) adopts a gas-water mixed backwashing mode, and has good backwashing effect and strong performance recovery capability.
And (3) arranging a high-efficiency filtering system at the front end of the ion exchange system in the step (2), wherein the high-efficiency filtering system consists of a coarse filter and a fine filter, and the filtering precision is maintained below 1 micron.
The resin in the step (2) is adsorbed for a working period of 25 minutes.
The resin in the step (2) is strong alkali type anion exchange resin, the resin framework is crosslinked polystyrene, the ion form is chlorine type, the physical form is wet spherical particles, the particle size is 0.2mm, the exchange capacity is 1.3meq/ml, and the backwashing stable density is 700 g/l.
The resin model in the step (2) is Tulsion A-853E, and the manufacturer is American Dusheng resin.
And (3) filling the resin in a short and fixed resin bed in the step (2), and feeding the membrane filtrate into the resin bed in a counter-current water feeding mode.
The height of the resin bed in the step (2) is 480mm, the resin tank body is processed in the acid recovery resin tank body, after the resin is fully filled, 10% sodium chloride solution is used for soaking the resin, the soaking time is 3.0 hours, the resin is shrunk in the tank body, and then the resin tank body is fully filled with new resin; and a flange sealing structure is adopted, the resin tank body is sealed after the resin is filled again, and then pure water is fed into the resin tank body through a cleaning pump to clean the resin bed.
The processing height of the resin bed body is 480mm, the resin tank body for acid recovery is processed, after the resin is filled, 10% sodium chloride solution is used for soaking the resin, the soaking time is 3.0 hours, the resin is shrunk in the tank body, then the resin tank body is filled again with new resin (the principle of the process is applied, the resin ball recovers free acid and can not adsorb iron ions, but because gaps are formed between the resin ball and the ball and between the resin ball and the tank body, waste acid liquor can be remained in the gap space, and the content of iron salt in the waste acid liquor is very high, so that the purity of the washed acid can be influenced, the gap is reduced as much as possible to improve the purity of the obtained acid liquor, the gaps between the resin ball and the ball and between the resin ball and the tank body can be reduced to the greatest extent by soaking with salt water and replenishing the resin again), the process adopts a flange, and the resin tank body is sealed after the resin is filled again, then pure water is fed into the bed body through a cleaning pump to clean the resin bed, salt losing expansion of resin particles after the salt water in the bed body is washed away has certain pressure on the shell wall and the upper and lower top covers of the bed body, and thus the resin is in an ideal filling and compacting state in the tank body. As the particle size of the resin adopted by the process is far smaller than that of the resin adopted by a domestic acid recovery system, and salt foam is filled and compacted, gaps among resin particles are extremely small, and the resin particles do not have unfilled vacant spaces in a bed body, so that a large amount of residual waste acid can be avoided in the waste acid feeding process, the purity of the acid solution obtained in the process of saturated cleaning of the resin with adsorbed acid solution is high, and the residual quantity of iron salt in the acid solution is below 1 g/L.
And (3) preparing the wastewater containing the ferric salt in the step (2) by using a nanofiltration membrane circulating concentration process to obtain a ferrous sulfate product, wherein the ferrous sulfate can be used as a raw material of a byproduct water purifying agent.
And (3) filtering by adopting a special industrial membrane in the nanofiltration system in the step (3), wherein the molecular weight cut-off of the special industrial membrane is 50-500.
And (4) filtering by a nanofiltration system membrane in the step (3), wherein the retentate of the membrane is waste acid solution containing a small amount of ferrous sulfate, and returning the waste acid solution to the ion exchange system for recycling treatment through a resin bed.
The nanofiltration system in the step (3) is continuously operated, and is automatically flushed once every two hours, the operating pressure is 55 kilograms, and the working temperature is 45 ℃.
And (3) evaporating and concentrating 22% of sulfuric acid to 52% by adopting a three-effect graphite evaporator in the multi-effect evaporation.
After the treatment of the working procedures, the concentration of the finally evaporated sulfuric acid is 52 percent, the yield of the sulfuric acid is 90 percent, the ferrous sulfate is 80mg/L, other impurities are not detected, the concentration of the sulfuric acid in the evaporated water is 0.16 percent, and other impurities are not detected.
Example 3
The titanium dioxide acid wastewater treatment and recovery process described in this embodiment 3 comprises the following steps:
(1) the titanium dioxide acid wastewater enters an ultrafiltration system and is filtered by a hollow fiber ultrafiltration membrane to obtain membrane filtrate;
(2) allowing the membrane filtrate obtained in the step (1) to enter an ion exchange system for resin adsorption, recovering and reusing ferric salt from wastewater containing ferric salt obtained by separation, and cleaning the resin adsorbed with free acid to obtain relatively pure dilute sulfuric acid;
(3) pumping the relatively pure dilute sulfuric acid obtained in the step (2) into a nanofiltration system for filtering, wherein the membrane permeate is pure sulfuric acid, and then carrying out multi-effect evaporation and re-concentration to obtain more than or equal to 50% of clean sulfuric acid for recycling in a titanium dioxide production system.
Wherein:
the titanium dioxide acid wastewater in the step (1) contains 24% of sulfuric acid, 8g/L of ferrous sulfate and 3g/L of titanium dioxide, and also contains other impurities such as calcium sulfate, magnesium sulfate, aluminum sulfate, manganese sulfate and the like.
The hollow fiber ultrafiltration membrane in the step (1) has a filtering pore size of 0.02 micron and is made of modified PVDF so as to have hydrophilicity.
Filtering in the step (1) by adopting a full-automatic continuous operation mode of cross-flow filtration and frequent backwashing; the cross flow filtration time is 35 minutes, and the frequent backwashing time is 8 minutes; the operating pressure during the filtration was 1.8 kg.
Filtering by using the hollow fiber ultrafiltration membrane in the step (1), wherein the retentate of the hollow fiber ultrafiltration membrane is titanium dioxide and suspended matters; the permeate of the hollow fiber ultrafiltration membrane is crude sulfuric acid containing iron salt.
The hollow fiber ultrafiltration membrane in the step (1) adopts a gas-water mixed backwashing mode, and has good backwashing effect and strong performance recovery capability.
And (3) arranging a high-efficiency filtering system at the front end of the ion exchange system in the step (2), wherein the high-efficiency filtering system consists of a coarse filter and a fine filter, and the filtering precision is maintained below 1 micron.
The time of one working period of the resin adsorption in the step (2) is 23 minutes.
The resin in the step (2) is strong alkali type anion exchange resin, the resin framework is crosslinked polystyrene, the ion form is chlorine type, the physical form is wet spherical particles, the particle size is 0.2mm, the exchange capacity is 1.3meq/ml, and the backwashing stable density is 700 g/l.
The resin model in the step (2) is Tulsion A-853E, and the manufacturer is American Dusheng resin.
And (3) filling the resin in a short and fixed resin bed in the step (2), and feeding the membrane filtrate into the resin bed in a counter-current water feeding mode.
The height of the resin bed in the step (2) is 470mm, the resin tank body is processed in the acid recovery resin tank body, after the resin tank body is filled with the resin, the resin tank body is soaked in 10% sodium chloride solution for 2 hours, the resin is shrunk in the tank body, and then the resin tank body is filled with new resin again; and a flange sealing structure is adopted, the resin tank body is sealed after the resin is filled again, and then pure water is fed into the resin tank body through a cleaning pump to clean the resin bed.
The processing height of the resin bed body is 470mm, the resin tank body is processed after acid recovery, after the resin is filled, 10% sodium chloride solution is used for soaking the resin, the soaking time is 2.0 hours, the resin is shrunk in the tank body, then the resin tank body is filled again with new resin (the principle of the process is applied, the resin ball recovers free acid and can not adsorb iron ions, but because gaps are formed between the resin ball and the ball and between the resin ball and the tank body, waste acid liquor can be remained in the gap space, and the content of iron salt in the waste acid liquor is very high, so that the purity of the washed acid can be influenced, the gap is reduced as much as possible to improve the purity of the obtained acid liquor, the gaps between the resin ball and the ball and between the resin ball and the tank body can be reduced to the greatest extent by soaking with salt water and replenishing the resin again), the process adopts a flange, and the resin tank body is sealed after the resin is filled again, then pure water is fed into the bed body through a cleaning pump to clean the resin bed, salt losing expansion of resin particles after the salt water in the bed body is washed away has certain pressure on the shell wall and the upper and lower top covers of the bed body, and thus the resin is in an ideal filling and compacting state in the tank body. As the particle size of the resin adopted by the process is far smaller than that of the resin adopted by a domestic acid recovery system, and salt foam is filled and compacted, gaps among resin particles are extremely small, and the resin particles do not have unfilled vacant spaces in a bed body, so that a large amount of residual waste acid can be avoided in the waste acid feeding process, the purity of the acid solution obtained in the process of saturated cleaning of the resin with adsorbed acid solution is high, and the residual quantity of iron salt in the acid solution is below 1 g/L.
And (3) preparing the wastewater containing the ferric salt in the step (2) by using a nanofiltration membrane circulating concentration process to obtain a ferrous sulfate product, wherein the ferrous sulfate can be used as a raw material of a byproduct water purifying agent.
And (3) filtering by adopting a special industrial membrane in the nanofiltration system in the step (3), wherein the molecular weight cut-off of the special industrial membrane is 50-500.
And (4) filtering by a nanofiltration system membrane in the step (3), wherein the retentate of the membrane is waste acid solution containing a small amount of ferrous sulfate, and returning the waste acid solution to the ion exchange system for recycling treatment through a resin bed.
The nanofiltration system in the step (3) is continuously operated, and is automatically washed once every two hours, the operating pressure is 45 kilograms, and the working temperature is 45 ℃.
And (3) evaporating and concentrating 24% sulfuric acid to 53% by adopting a three-effect graphite evaporator in the multi-effect evaporation.
After the treatment of the above procedures, the concentration of the sulfuric acid evaporated finally is 53%, the yield of the sulfuric acid is 88%, 91 mg of ferrous sulfate per liter, other impurities are not detected, and the concentration of the sulfuric acid in the evaporated water is 0.17%, and other impurities are not detected.
Comparative example 1
The titanium dioxide acid wastewater treatment and recovery process of the comparative example 1 is the same as that in the example 1, and the only difference is that the relatively pure dilute sulfuric acid obtained is directly detected after being adsorbed by the ion exchange system resin without going through the step (3), and the results are as follows: the concentration of the sulfuric acid is 20 percent, the ferrous sulfate is 800mg/L, and other impurities are not detected.
Comparative example 2
The titanium dioxide acid wastewater treatment and recovery process of the comparative example 2 is the same as that in the example 1, and the only difference is that the membrane filtration liquid obtained in the step (1) is directly subjected to nanofiltration treatment without going through the step (2), and then is subjected to multi-effect evaporation concentration to obtain sulfuric acid. After the treatment of the working procedures, the concentration of the finally evaporated sulfuric acid is 50%, the yield of the sulfuric acid is 30%, the ferrous sulfate is 95mg/L, and other impurities are not contained, and the concentration of the sulfuric acid in the evaporated water is about 0.2%, and other impurities are not contained.
Claims (10)
1. A titanium dioxide acid wastewater treatment and recovery process is characterized in that: the method comprises the following steps:
(1) the titanium dioxide acid wastewater enters an ultrafiltration system and is filtered by a hollow fiber ultrafiltration membrane to obtain membrane filtrate;
(2) allowing the membrane filtrate obtained in the step (1) to enter an ion exchange system for resin adsorption, recovering and reusing ferric salt from wastewater containing ferric salt obtained by separation, and cleaning the resin adsorbed with free acid to obtain relatively pure dilute sulfuric acid;
(3) pumping the relatively pure dilute sulfuric acid obtained in the step (2) into a nanofiltration system for filtering, wherein the membrane permeate is pure sulfuric acid, and then carrying out multi-effect evaporation and re-concentration to obtain more than or equal to 50% of clean sulfuric acid for recycling in a titanium dioxide production system.
2. The titanium dioxide acid wastewater treatment and recovery process according to claim 1, characterized in that: the concentration of sulfuric acid in the titanium dioxide acid wastewater in the step (1) is 20-24%, the concentration of ferrous sulfate is 5-8g/L, and the concentration of titanium dioxide is 2-3 g/L.
3. The titanium dioxide acid wastewater treatment and recovery process according to claim 1, characterized in that: the hollow fiber ultrafiltration membrane in the step (1) has a filtering pore size of 0.02 micron and is made of modified PVDF.
4. The titanium dioxide acid wastewater treatment and recovery process according to claim 1, characterized in that: filtering in the step (1) by adopting a full-automatic continuous operation mode of cross-flow filtration and frequent backwashing; the cross flow filtration time is 30-35 minutes, and the frequent backwashing time is 5-8 minutes; the operating pressure during filtration is less than 2 kg.
5. The titanium dioxide acid wastewater treatment and recovery process according to claim 1, characterized in that: filtering by using the hollow fiber ultrafiltration membrane in the step (1), wherein the retentate of the hollow fiber ultrafiltration membrane is titanium dioxide and suspended matters; the permeate of the hollow fiber ultrafiltration membrane is crude sulfuric acid containing iron salt.
6. The titanium dioxide acid wastewater treatment and recovery process according to claim 1, characterized in that: and (3) arranging a high-efficiency filtering system at the front end of the ion exchange system in the step (2), wherein the high-efficiency filtering system consists of a coarse filter and a fine filter, and the filtering precision is maintained below 1 micron.
7. The titanium dioxide acid wastewater treatment and recovery process according to claim 1, characterized in that: the time of one working period of the resin adsorption in the step (2) is 20-25 minutes.
8. The titanium dioxide acid wastewater treatment and recovery process according to claim 1, characterized in that: the resin in the step (2) is strong alkali type anion exchange resin, the resin framework is crosslinked polystyrene, the ion form is chlorine type, the physical form is wet spherical particles, the particle size is 0.1-0.3mm, the exchange capacity is 1.3meq/ml, the backwashing stable density is 690-720g/l, the maximum operation temperature is 60 ℃, and the dissolubility is insoluble in any organic solvent.
9. The titanium dioxide acid wastewater treatment and recovery process according to claim 8, characterized in that: and (3) filling the resin in a short and fixed resin bed in the step (2), and feeding the membrane filtrate into the resin bed in a counter-current water feeding mode.
10. The titanium dioxide acid wastewater treatment and recovery process according to claim 1, characterized in that: filtering by adopting a special industrial membrane in the nanofiltration system in the step (3), wherein the molecular weight cut-off of the special industrial membrane is 50-500;
the nanofiltration system in the step (3) continuously operates, automatically washes once every two hours, the operation pressure is 40-60 kg, and the working temperature is 40-45 ℃.
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| CN113354179A (en) * | 2021-07-13 | 2021-09-07 | 北京水木方科技有限公司 | Recycling treatment method for titanium dioxide waste acid and primary washing waste acid water by sulfuric acid process |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4954262A (en) * | 1988-11-08 | 1990-09-04 | Asahi Glass Company Ltd. | Method and apparatus for recovering sulfuric acid from a titanium sulfate waste liquor |
| CN103015246A (en) * | 2012-12-19 | 2013-04-03 | 成都连接流体分离科技有限公司 | Method for comprehensively using pulping waste water by sulfite method |
| CN103663547A (en) * | 2012-09-24 | 2014-03-26 | 上海凯鑫分离技术有限公司 | Treatment and recovery process of acid wastewater in titanium dioxide production process |
| CN105329953A (en) * | 2015-12-02 | 2016-02-17 | 浙江奇彩环境科技有限公司 | Titanium white waste acid resourceful treatment technology |
| CN107311345A (en) * | 2017-07-28 | 2017-11-03 | 科海思（北京）科技有限公司 | A kind of waste acidity recovery method and apparatus |
| CN107746142A (en) * | 2017-09-13 | 2018-03-02 | 四川绿沃创新环保工程有限公司 | Washery slag acid waste water Zero emission method in a kind of Titanium White Production By Sulfuric Acid Process |
| CN111517553A (en) * | 2020-04-30 | 2020-08-11 | 杭州上拓环境科技股份有限公司 | Titanium dioxide washing wastewater resource utilization treatment process |
-
2021
- 2021-02-01 CN CN202110138763.2A patent/CN112939312A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4954262A (en) * | 1988-11-08 | 1990-09-04 | Asahi Glass Company Ltd. | Method and apparatus for recovering sulfuric acid from a titanium sulfate waste liquor |
| CN103663547A (en) * | 2012-09-24 | 2014-03-26 | 上海凯鑫分离技术有限公司 | Treatment and recovery process of acid wastewater in titanium dioxide production process |
| CN103015246A (en) * | 2012-12-19 | 2013-04-03 | 成都连接流体分离科技有限公司 | Method for comprehensively using pulping waste water by sulfite method |
| CN105329953A (en) * | 2015-12-02 | 2016-02-17 | 浙江奇彩环境科技有限公司 | Titanium white waste acid resourceful treatment technology |
| CN107311345A (en) * | 2017-07-28 | 2017-11-03 | 科海思（北京）科技有限公司 | A kind of waste acidity recovery method and apparatus |
| CN107746142A (en) * | 2017-09-13 | 2018-03-02 | 四川绿沃创新环保工程有限公司 | Washery slag acid waste water Zero emission method in a kind of Titanium White Production By Sulfuric Acid Process |
| CN111517553A (en) * | 2020-04-30 | 2020-08-11 | 杭州上拓环境科技股份有限公司 | Titanium dioxide washing wastewater resource utilization treatment process |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113354179A (en) * | 2021-07-13 | 2021-09-07 | 北京水木方科技有限公司 | Recycling treatment method for titanium dioxide waste acid and primary washing waste acid water by sulfuric acid process |
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