Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
  • B01D61/02—Reverse osmosis; Hyperfiltration ; Nanofiltration
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
  • B01D61/02—Reverse osmosis; Hyperfiltration ; Nanofiltration
  • B01D61/025—Reverse osmosis; Hyperfiltration
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
  • B01D61/02—Reverse osmosis; Hyperfiltration ; Nanofiltration
  • B01D61/04—Feed pretreatment
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/02—Treatment of water, waste water, or sewage by heating
  • C02F1/04—Treatment of water, waste water, or sewage by heating by distillation or evaporation
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/42—Treatment of water, waste water, or sewage by ion-exchange
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
  • C02F1/441—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by reverse osmosis
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2311/00—Details relating to membrane separation process operations and control
  • B01D2311/04—Specific process operations in the feed stream; Feed pretreatment
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2311/00—Details relating to membrane separation process operations and control
  • B01D2311/18—Details relating to membrane separation process operations and control pH control
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
  • C02F2103/34—Nature of the water, waste water, sewage or sludge to be treated from industrial activities not provided for in groups C02F2103/12 - C02F2103/32
  • C02F2103/346—Nature of the water, waste water, sewage or sludge to be treated from industrial activities not provided for in groups C02F2103/12 - C02F2103/32 from semiconductor processing, e.g. waste water from polishing of wafers
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
  • C02F2103/34—Nature of the water, waste water, sewage or sludge to be treated from industrial activities not provided for in groups C02F2103/12 - C02F2103/32
  • C02F2103/40—Nature of the water, waste water, sewage or sludge to be treated from industrial activities not provided for in groups C02F2103/12 - C02F2103/32 from the manufacture or use of photosensitive materials

Definitions

• the present invention relates to a method and apparatus for recovering phosphoric acid from phosphoric acid-containing water using a reverse osmosis device, and in particular, from a washing wastewater containing phosphoric acid after etching a liquid crystal substrate, a wafer or other electronic equipment.
• the present invention relates to a method and apparatus for recovering phosphoric acid suitable for recovery of valuable materials such as acid and pure water which is treated water.
• An etching solution containing phosphoric acid is used for etching liquid crystal substrates, wafers and other electronic devices.
• the high-concentration waste etchant generated in the etching process is recovered and recycled, but the electronic equipment after etching is washed with pure water, and a large amount of low-concentration washing wastewater is generated.
• Such washing wastewater contains components such as phosphoric acid, nitric acid, acetic acid, and other acid components, and metal ions and other impurities eluted by etching. Is pure water.
• etching cleaning wastewater is treated by mixing with other wastewater.
• a common treatment technique for wastewater containing phosphoric acid or hydrofluoric acid is coagulation sedimentation.
• problems such as increased treatment costs due to the use of a large amount of chemicals and the generation of a large amount of sludge, and an increase in environmental burden.
• an increase in water-soluble ions due to a large amount of chemicals added in the coagulation sedimentation treatment increases the power cost due to the increase in operating pressure in the reverse osmosis membrane process, the quality of the treated water, and the generation of scale.
• the ion exchange method leads to an increase in the amount of regenerant used.
• Patent Document 1 Japanese Patent Publication No. 2006-75820
• ions such as phosphoric acid and nitric acid are removed with an ion exchange resin, and pure water and phosphate are recovered.
• the ability to pass through H-cation resin to make sodium dihydrogen phosphate The regeneration of the thione resin consumes acids such as hydrochloric acid, and the sodium hydroxide used in the regeneration of the anion resin also wastes.
• Patent Document 1 Japanese Patent Publication 2006—75820
• An object of the present invention is to transport high-purity phosphoric acid useful as a recovered material from a phosphoric acid-containing water at low cost and efficiently, which can be transported in a high concentration liquid state with a simple configuration and operation. It is to propose a method and an apparatus for recovering recoverable phosphoric acid.
• the present invention is a method and apparatus for recovering phosphoric acid from the following phosphate ion-containing water.
• Reverse osmosis treatment is performed by supplying phosphoric acid-containing water to the reverse osmosis device under the condition of PH3 or less, acid other than phosphoric acid is permeated to the permeate chamber side together with water, and phosphoric acid is introduced to the concentrate chamber side.
• a method for recovering phosphoric acid comprising concentrating and recovering a phosphoric acid concentrate.
• Phosphoric acid-containing water is supplied to the reverse osmosis unit under conditions of PH3 or less and phosphoric acid concentration;! ⁇ 15 wt%, and membrane separation treatment is performed to allow acids other than phosphoric acid to permeate to the permeate chamber side together with water. Then, the phosphoric acid is concentrated to the concentrated liquid chamber side, and the phosphoric acid concentrated liquid is recovered, and a method for recovering phosphoric acid is provided.
• the above-mentioned (1) or (2) has a process of taking out the concentrate from the concentrate chamber and circulating it to the concentrate chamber, and adding reverse phosphoric acid treatment water to the circulating concentrate. ) How to describe.
• a reverse osmosis device that performs membrane separation treatment of phosphoric acid-containing water under a pH of 3 or less, allows acids other than phosphoric acid to permeate to the permeate chamber side together with water, and concentrates phosphoric acid to the concentrate chamber side;
• a raw water supply unit for supplying phosphoric acid-containing water to the concentrate chamber side of the reverse osmosis membrane device under a condition of PH3 or less;
• a phosphoric acid recovery apparatus comprising: a concentrated phosphoric acid solution extraction unit that extracts a concentrated phosphoric acid solution from the concentrated liquid chamber side of the reverse osmosis device.
• Membrane separation treatment is performed under conditions where the phosphoric acid-containing water is PH3 or less and the phosphoric acid concentration is! ⁇ 15% by weight to allow acids other than phosphoric acid to permeate to the permeate chamber side together with water, and phosphoric acid is concentrated in the concentrate chamber.
• a reverse osmosis device that concentrates to the side,
• a phosphoric acid-containing water supply section for supplying phosphoric acid-containing water to a concentration chamber side of the reverse osmosis device under conditions of PH3 or less and phosphoric acid concentration;
• a concentrated phosphoric acid solution extraction section for extracting the concentrated phosphoric acid solution from the concentrated liquid chamber side of the reverse osmosis device, and a circulation path for circulating the concentrated phosphoric acid solution extracted from the concentrated phosphoric acid solution extraction unit to the concentrated liquid chamber side;
• recovery apparatus characterized by having.
• the phosphoric acid-containing water to be treated can be used without limitation as long as it contains phosphoric acid.
• Phosphate ions 50-; 10000 mg / L, especially 50-200 Contains Omg / L, pH is 3 or less, especially 2.8 or less, in any case 1 or more, especially 1.
• acid components such as nitrate ions and acetate ions, other anions, cations such as metal ions, and other impurities may be contained.
• Phosphoric acid-containing water that is particularly preferable as a treatment target is low-concentration cleaning wastewater that is generated when pure water cleaning is performed after etching with a phosphoric acid-containing etching solution for liquid crystal substrates, wafers, and other electronic devices.
• cleaning wastewater after etching include phosphate ions 50 to 2000 mg / L, nitrate ions 10 to 500 mg / L, acetate ions 5 to 300 mg / L, and ⁇ 1 ⁇ 8 to 2 ⁇ 8.
• the phosphoric acid-containing water in order to recover phosphoric acid from phosphoric acid-containing water, is supplied to the reverse osmosis membrane device under conditions of ⁇ ⁇ 3 or less and phosphoric acid concentration; It is preferable to perform a membrane separation treatment. In the present invention, it is preferable to remove impurities including cations and / or anions as a pretreatment before supplying the phosphoric acid-containing water to the reverse osmosis membrane device.
• precipitate separation removal of solids by filtration, etc., removal of cations such as metal ions by cation exchange resin, and removal of anions such as perchloric acid, molybdic acid and organic acid complexes by anion exchange resin, etc. be able to.
• a pretreatment apparatus used in such a pretreatment process a general apparatus adopted for the above purpose is used. Is used.
• cation exchange resin a strong acid or weak acid cation exchange resin can be used. However, when these strong thiones are exchanged and removed using the H-form strong acid force thione exchange resin, the acid component of the treatment liquid increases. It is preferable because it becomes easy to adjust the pH to 3 or less.
• the cation exchange resin may be a chelate resin.
• a strongly basic or weakly basic cation exchange resin can be used as the anion exchange resin.
• the cation exchange resin is used in an acid form such as phosphoric acid form, and passes through phosphoric acid, nitric acid, acetic acid, etc. to remove other impurity anions.
• the reverse osmosis device in the membrane separation step is also called an RO device, which is partitioned into a permeate chamber and a concentrate chamber by a reverse osmosis (RO) membrane,
• the phosphoric acid concentration is 1 to; 15% by weight is supplied to the concentrated liquid chamber side to perform reverse osmosis membrane treatment, and acid other than phosphoric acid is permeated to the permeate liquid chamber side together with water. And is configured to concentrate phosphoric acid to the concentrate chamber side.
• a phosphoric acid-containing water supply part for supplying phosphoric acid-containing water and a concentrated phosphoric acid liquid extracting part for taking out the concentrated phosphoric acid liquid.
• a permeate extractor for taking out the permeate is formed on the permeate chamber side of the reverse osmosis membrane device.
• a circulation path is formed between the concentrated phosphoric acid solution take-out part and the phosphoric acid-containing water supply part to circulate the concentrated phosphoric acid solution taken out from the concentrated phosphoric acid solution take-out part to the concentrated liquid chamber side.
• Reverse osmosis membranes allow water to permeate by osmotic pressure, or conversely pressurize to a pressure higher than osmotic pressure to supply the liquid to be treated and allow water to permeate by reverse osmosis, while allowing salt, organic matter, and other solutes to pass through. It is a semi-permeable membrane that prevents it from passing through! /.
• the material of the reverse osmosis membrane is not particularly limited as long as it has the above-mentioned characteristics, and examples thereof include a polyamide permeable membrane, a polyimide permeable membrane, a cellulose permeable membrane, and may be an asymmetric reverse permeable membrane.
• a composite reverse osmosis membrane in which an active skin layer having substantially selective separability is formed on a microporous support is preferred.
• the reverse osmosis device may be any device as long as it has such a reverse osmosis membrane. The thing provided with is preferable.
• the membrane module is not particularly limited.
• a tubular membrane module for example, a tubular membrane module, a planar membrane module, a spiral membrane module, and a hollow fiber membrane module can be cited.
• a known apparatus can be used, and a highly permeable apparatus operated at a low pressure is preferable.
• the phosphoric acid-containing water in the membrane separation step, is used under conditions of pH 3 or less, preferably 1 to 15% by weight, more preferably 2 to 10% by weight.
• the membrane separation (reverse osmosis) treatment is performed by supplying to the reverse osmosis membrane device under the condition of%. If the phosphoric acid-containing water is obtained at a pH of 3 or less, the power that can be supplied to the reverse osmosis membrane device without adjusting the pH as it is. Adjusting the pH by adding a pH adjuster such as hydrochloric acid or nitric acid if necessary. You can!
• the phosphoric acid concentration is concentrated to 1% by weight or more by performing membrane separation treatment while circulating the concentrate through the circulation path.
• a batch-type treatment may be performed in which the circulating fluid is replaced when it is concentrated to 1% by weight or more.
• the concentrated solution is circulated while circulating the concentrated solution concentrated to a phosphoric acid concentration; It is preferable to add low-concentration phosphoric acid-containing water to the solution and take out the concentrated solution partly as a phosphoric acid concentrated solution because an apparent one-time treatment can be performed.
• reverse osmosis treatment is performed by adding diluted water to the circulating concentrate, thereby reducing the removal rate of acids other than phosphoric acid. Can be increased.
• dilution water recovered water from which impurities have been removed from the permeated water can be used.
• acids other than phosphoric acid such as nitric acid and acetic acid permeate through the reverse osmosis membrane together with water. Move to the liquid chamber side and take out from the permeate chamber side.
• Phosphoric acid is prevented from permeating through the reverse osmosis membrane and remains on the concentrate chamber side to be concentrated, so that it can be recovered from the concentrate chamber side as a phosphoric acid concentrate.
• the concentrate on the concentrate chamber side may be passed through temporarily or may be circulated to increase the concentration rate.
• the reverse osmosis membrane blocking rate is higher than that of the nonionic substance even if the molecular weight is the same. It is said that it is overwhelmingly easy to stop.
• the rejection rate of acids other than phosphoric acid such as nitric acid and acetic acid under pH 3 or lower
• the rejection rate when a normal phosphoric acid-containing etching solution is treated with a film is 1% or less.
• the blocking rate is the rate at which the reverse osmosis membrane blocks solute permeation, and is expressed by the following equation (1).
• Rejection rate (%) (1— C / (C-C) 1/2 ) X 100 ⁇ ⁇ ⁇ (! (In formula (1), C is the solute concentration at the inlet of the feed liquid, C is the solute concentration at the outlet of the concentrate, and C is the permeability of
• ((C-C) 1/2 ) represents a geometric mean
• (C / (C-C) 1/2 ) represents a concentrated solution
• the ratio of the solute concentration of the permeate to the (synergistic) average concentration of the solute For this reason, the lower the blocking rate, the more the solute permeates to the permeate side. Although it is easy to recognize that the rejection rate will not be negative in the normal concept, the rejection rate may be negative due to the composition of the equation (1), and in this case, the permeated liquid concentration is higher than the solute concentration of the concentrate. It shows that solutes with high solute concentration permeate with high permeability.
• the rejection rate of acids other than phosphoric acid is negative.
• the phosphoric acid concentration is 1% by weight or more, particularly 2% by weight or more, other than phosphoric acid remaining in the concentrate. This means that the acid concentration is low, and a highly concentrated phosphoric acid concentrate is obtained. If the concentration of phosphoric acid in the concentrate is too high, membrane treatment cannot be performed due to osmotic pressure, so the upper limit of the concentration of phosphoric acid in the concentrate is 15% by weight, preferably 10% by weight.
• the permeated water of the reverse osmosis membrane device taken out from the permeate chamber side contains permeated acids such as phosphoric acid, nitric acid, and acetic acid, these permeates from the permeated water of the reverse osmosis membrane device. Pure water can be recovered by removing acid and other impurities with an impurity removing device. In this case, an ion exchange device using an ion exchange resin can be employed as the impurity removal device.
• the anion exchange resin used here is preferably an OH type strongly basic cation or weakly basic cation exchange resin, and the cation exchange resin is preferably an H type strongly acidic cation exchange resin.
• An electroregenerative ion exchange device is a device in which an ion exchange resin layer is partitioned by a cation exchange resin membrane and a cation exchange resin membrane, and a cathode and an anode are arranged at both ends. Ion exchange is performed by passing the liquid through the anode and regenerating while energizing.
• the ion exchange resin used in the electric regeneration type ion exchange device is intended only for removal of acid and other anions, it is possible to fill only the anion exchange resin. In this case, a mixed bed of cation exchange resin and anion exchange resin can be filled.
• the acid concentrate discharged by regeneration is a concentrate such as phosphoric acid, nitric acid, and acetic acid.
• the phosphoric acid concentrated liquid taken out from the concentrated liquid chamber side has most of acids other than phosphoric acid such as nitric acid and acetic acid removed.
• Purification by post-treatment can be performed to increase purity and concentration.
• purification by post-treatment it is possible to purify by removing acids other than phosphoric acid from the phosphoric acid concentrate by anion exchange.
• an anion exchange device is provided as a purification device, the concentrated solution is passed through the anion exchange resin layer, strong acid ions such as nitric acid are removed from the concentrated solution, and a high concentration containing almost no strong acid ions such as nitric acid is removed. Phosphoric acid can be recovered.
• the purification device can be provided in the concentrated solution circulation line of the reverse osmosis device, but is preferably provided in a line for extracting the concentrated solution from the circulation line.
• Anion exchange resin Is preferably an OH-type or PO-type strongly basic anion exchange resin.
• acetic acid remains in the phosphoric acid concentrate, the acetic acid cannot be completely removed even by the anion exchange resin. Therefore, the volatile components such as acetic acid are removed to increase the purity and concentration of the recovered phosphoric acid solution.
• concentrate the phosphoric acid concentrate with an evaporative concentrator remove volatile components together with water, concentrate, and collect high-concentration phosphoric acid containing almost no volatile components such as acetic acid. That power S.
• a known apparatus such as a rotary evaporator can be used as the evaporative concentration apparatus.
• the phosphoric acid recovered by the above is useful as a recovered material and can be transported in a high-concentration liquid state, and can be recovered as concentrated and highly pure phosphoric acid.
• reverse osmosis treatment is performed under the condition of pH 3 or less.
• phosphoric acid-containing water as raw water is usually obtained in an acidic state of PH 3 or less, it is easily adjusted by injecting a pH adjuster such as hydrochloric acid. be able to.
• the method and apparatus for recovery can be obtained by performing reverse osmosis treatment with a simple configuration and operation under conditions of pH 3 or lower, and in some cases, phosphoric acid concentration; It can be recovered as a concentrate.
• the amount of regenerant used and the amount of waste generated can be reduced, the processing cost can be lowered, and high-purity concentrated phosphoric acid and pure water can be recovered.
• reverse osmosis treatment is performed by supplying phosphoric acid-containing water to a reverse osmosis device under a pH of 3 or less, and an acid other than phosphoric acid together with water enters the permeate chamber side.
• an acid other than phosphoric acid together with water enters the permeate chamber side.
• the phosphoric acid-containing water is supplied to the reverse osmosis device under the conditions of pH 3 or lower and the phosphoric acid concentration;! Can be transported in a high-concentration liquid form with a simple configuration and operation by allowing water to permeate to the permeate chamber side with water, concentrating phosphoric acid to the concentrate chamber side, and collecting the phosphoric acid concentrate. , To recover high-purity phosphoric acid useful as a recovered material from phosphoric acid-containing water at a lower cost and more efficiently Can do.
• FIG. 1 is a flow diagram of a phosphoric acid recovery method and apparatus in one embodiment.
• FIG. 2 is a flow diagram of a phosphoric acid recovery method and apparatus according to another embodiment.
• FIG. 3 is a graph showing the results of Example 3.
• FIG. 1 is a flow diagram of a phosphoric acid recovery apparatus in one embodiment.
• 1 is a raw water tank that stores raw water la.
• 2 is a cation exchange tower having a cation exchange resin layer 2a.
• 3 is a concentrate tank and stores the concentrate 3a.
• a reverse osmosis device 4 is divided into a permeate chamber 4b and a concentrate chamber 4c by a reverse osmosis membrane 4a.
• An anion exchange tower 5 has an anion exchange resin layer 5a.
• 7 is a recovered water tank, which stores recovered water 7a.
• 5b is a second anion exchange tower having an anion exchange resin layer 5c.
• 8 is an evaporative concentrator that evaporates and separates volatile components with water and concentrates the phosphoric acid solution.
• 9 is a recovered phosphoric acid tank, which stores the recovered phosphoric acid solution 9a.
• P is a pressure pump, which is a raw water tank 1, a cation exchange tower 2, and a concentrated liquid tank.
• the anion exchange tower 5 and the recovery water tank 7 constitute a permeate extraction section, and among these, the anion exchange tower 5 constitutes an impurity removing device.
• the second canyon exchange column 5b, the evaporating and concentrating device 8 and the recovered phosphoric acid tank 9 constitute a concentrated phosphoric acid liquid take-out section, and among these, the second anion exchanging column 5b and the evaporating and concentrating device 8 constitute a refining device.
• raw water la (phosphate ion-containing water) that has been subjected to precipitation separation, filtration, and the like as a pretreatment step is introduced into raw water tank 1 from line L1.
• the raw water la in the raw water tank 1 is introduced into the cation exchange tower 2 from the line L2 and passed through, and the cation exchange resin layer 2a exchanges cations to exchange cations such as aluminum, indium and other metal ions contained in the raw water. Adsorb and remove.
• the cation exchange resin layer 2a it is preferable to use an H-type strongly acidic cation exchange resin.
• the weak thione water that is the treated water of the cation exchange tower 2 is introduced into the concentrate tank 3 from the line L5 and stored.
• Phosphoric acid-containing water as raw water is usually obtained in an acidic state of pH 3 or lower, and even when the pH is high, acid is generated by cation exchange as a pretreatment and becomes a state of pH 3 or lower.
• it may be supplied to the reverse osmosis apparatus 4 as it is.
• phosphoric acid-containing water can be obtained in a state close to pH 3, so it should be easily adjusted by injecting a pH adjuster such as hydrochloric acid into line L5 or concentrate tank 3. Power S can be.
• the weak thione water (concentrate 3a) in the concentrate tank 3 is pressurized by the pressure pump P and introduced from the line L6 into the concentrate chamber 4c of the reverse osmosis device 4, and reverse osmosis treatment is performed by the reverse osmosis membrane 4a. Then, acid other than phosphoric acid such as nitric acid and acetic acid is allowed to permeate to the permeate chamber 4b side together with water to concentrate phosphoric acid to the concentrate chamber 4c side.
• acid other than phosphoric acid such as nitric acid and acetic acid is allowed to permeate to the permeate chamber 4b side together with water to concentrate phosphoric acid to the concentrate chamber 4c side.
• the permeate that has permeated through the permeate chamber 4b of the reverse osmosis device 4 is introduced into the ayuon exchange tower 5 from the line L7, and is passed through the anion exchange resin layer 5a to exchange the anion.
• the anions other than phosphate ions such as nitric acid and acetic acid contained in the permeate are removed by exchange adsorption and purified, and the treated water is taken out from the line L8 to the recovered water tank 7 and stored as recovered water 7a.
• the anion exchange tower 5 employs the force of using the ayuon exchange resin layer 5a filled with the OH type strongly basic aion exchange resin and adopts a multi-layer or mixed bed type with the H form cation exchange resin to remove impurities other than the anion. It may be removed.
• a regenerant containing an alkali such as 2 to 10% by weight of an aqueous alkali solution such as sodium hydroxide or potassium hydroxide is passed through the line L9. Regenerate and drain the eluted salt from line L10.
• a regenerant containing acid When using a cation exchange resin, pass a regenerant containing acid. To play.
• the concentrate concentrated in the concentrate chamber 4c of the reverse osmosis device 4 is introduced from the line LI 1 to the second anion exchange tower 5b, passed through the water, and is subjected to anion exchange in the anion exchange resin layer 5c for concentration.
• the remaining anions other than phosphate ions, such as nitric acid and acetic acid, are removed by exchange adsorption and purified.
• the anion exchange resin layer 5c is strongly basic anion exchange of OH type or PO type.
• anion exchange resin layer 5c is saturated with anions other than phosphate ions, it is regenerated by passing a regenerant containing alkali from line L12, and the eluted salt is discharged from line L13.
• the phosphoric acid solution from which the anions other than phosphate ions have been removed in the second anion exchange column 5b still contains a volatile component such as acetic acid, it is introduced into the evaporation concentrator 8 from the line L14, distilled, and water At the same time, the volatile components are evaporated and separated and discharged from line L15.
• the concentrated phosphoric acid solution obtained by removing the volatile components by the evaporation concentrating device 8 is introduced into the recovered phosphoric acid tank 9 from the line L16 and stored as the recovered phosphoric acid solution 9a.
• a known evaporating and concentrating device such as a rotary evaporator can be used.
• the concentrated liquid in the concentrated liquid chamber 4c of the reverse osmosis device 4 is circulated from the line L17 or L18 to the concentrated liquid tank 3 to increase the concentration rate, and is stored with the concentrated liquid 3a by the force S.
• the phosphoric acid solution 9a recovered by the above method is useful as a recovered material and can be transported practically because it is recovered in a high-concentration liquid state, and is recovered as concentrated phosphoric acid with high purity. it can.
• reverse osmosis treatment is performed under the condition of pH 3 or less.
• phosphoric acid-containing water as raw water is usually obtained in an acidic state of pH 3 or less, and even if the pH is high, even as a pretreatment, it can be replaced by Since the pH is 3 or less, it is not necessary to adjust the pH if it is supplied as it is to treat it under the condition of pH 3 or less.
• Chemicals such as acids and alkalis are limited to cations regenerants in cation exchange tower 2 and anion regenerants in anion exchange tower 5 and second anion exchange tower 5b. Necessary for recovering phosphoric acid. Not.
• the recovery method and device can be recovered as a phosphate concentrate by reverse osmosis treatment under conditions of pH 3 or less with a simple configuration and operation. . As a result, the amount of regenerant used and the amount of waste generated can be reduced, the processing cost can be reduced, and high-purity concentrated phosphoric acid and pure water can be recovered.
• the phosphoric acid-containing water is supplied to the reverse osmosis device 4 under the condition of pH 3 or lower, and reverse osmosis treatment is performed by the reverse osmosis membrane 4a.
• the phosphoric acid By allowing the phosphoric acid to pass through the concentrated liquid chamber 4c and recovering pure water and phosphoric acid concentrated liquid, it can be transported as a high-concentration liquid with a simple configuration and operation. High-purity phosphoric acid and pure water useful as recovered materials can be efficiently recovered from phosphoric acid-containing water at low cost.
• FIG. 2 is a flowchart of a phosphoric acid recovery method and apparatus according to another embodiment.
• 1 is a raw water tank that stores raw water la.
• 2 is a cation exchange tower having a cation exchange resin layer 2a.
• 3 is a concentrate tank, which stores concentrate 3a.
• Reference numeral 4 denotes a reverse osmosis device, which is divided into a permeate chamber 4b and a concentrate chamber 4c by a reverse osmosis membrane 4a.
• An anion exchange tower 5 has an anion exchange resin layer 5a.
• a desalination chamber 6a and a concentration chamber 6b are partitioned by an anion exchange membrane 6c, and a cathode chamber 6e is partitioned by a cation exchange membrane 6d outside the desalination chamber 6a.
• the anode chamber 6g is partitioned by the force thione exchange membrane 6f on the outside, the mixed-salt-type ion exchange layers 6h and 6i are provided in the desalting chamber 6a and the concentration chamber 6b, the cathode ( ⁇ ) in the cathode chamber 6e, and the anode chamber 6g in the anode chamber 6g.
• An anode (+) is provided.
• Reference numeral 7 is a recovery water tank for storing recovered water 7a.
• 8 is an evaporation concentrator that evaporates and separates volatile components together with water and concentrates the phosphoric acid solution.
• 9 is a recovered phosphoric acid tank, which stores the recovered phosphoric acid solution 9a.
• 10 is a biological denitrification device.
• P is a pressure pump, and constitutes the raw water supply unit together with the raw water tank 1, the cation exchange tower 2, the anion exchange tower 5 and the concentrated liquid tank 4, and of these, the cation exchange tower 2 and the anion exchange Tower 5 constitutes the pretreatment device.
• the electric regenerative ion exchange device 6 and the collection water tank 7 constitute a permeate extraction unit, and the electric regenerative ion exchange device 6 constitutes an impurity removal device.
• the evaporating and concentrating device 8 and the recovered phosphoric acid tank 9 constitute a concentrated phosphoric acid solution extraction section, and the evaporating and concentrating device 8 constitutes a purification device.
• the raw water la (phosphate ion-containing water), from which impurities have been removed by precipitation separation, filtration or the like as a pretreatment step, is introduced into the raw water tank 1 from the line L21.
• original Raw water la in tank 1 is introduced from line L22 to cation exchange tower 2 and passed through, and cation exchange is performed in cation exchange resin layer 2a to exchange and adsorb cations such as aluminum, indium, and other metal ions contained in the raw water. And remove.
• the cation exchange resin layer 2a it is preferable to use an H-type strongly acidic cation exchange resin.
• the cation exchange resin layer 2a is saturated, it is regenerated by passing a regenerant containing an acid such as hydrochloric acid from the line L23, and the eluted cation is recovered from the line L24.
• the weak thione water which is the treated water of the cation exchange tower 2, is introduced into the anion exchange tower 5 from the line L25 and passed therethrough, and the anion exchange resin layer 5a is used to exchange the anion so that perchloric acid contained in the raw water Aion such as molybdic acid or organic acid complex is removed by exchange adsorption.
• the anion exchange resin layer 5a it is preferable to use a phosphoric acid type strongly basic cation exchange resin.
• a regeneration agent containing alkali such as sodium hydroxide is passed through the line L26 to regenerate, and the eluted anion is recovered from the line L27.
• acid such as phosphoric acid is passed through line L26 to make the anion exchange resin into phosphoric acid form.
• the treated water of the anion exchange tower 5 is introduced into the concentrate tank 3 from the line L28.
• Phosphoric acid-containing water as raw water is usually obtained in an acidic state of PH 3 or less, and can be supplied to the reverse osmosis apparatus 4 as it is for reverse osmosis treatment under conditions of pH 3 or less.
• phosphoric acid-containing water is obtained in a state close to pH 3, so it can be easily adjusted by injecting a pH adjuster such as hydrochloric acid into line L28 or concentrate tank 3. it can.
• the phosphoric acid-containing water in the concentrate tank 3 is pressurized by the pressure pump P and introduced into the concentrate chamber 4c of the reverse osmosis device 4 from the line L31, and membrane separation (reverse osmosis treatment) is performed by the reverse osmosis membrane 4a. Then, acid other than phosphoric acid such as nitric acid and acetic acid is allowed to permeate to the permeate chamber 4b side together with water, and phosphoric acid is concentrated to the concentrate chamber 4c side.
• membrane separation reverse osmosis treatment
• the permeate that has permeated through the permeate chamber 4b of the reverse osmosis device 4 is introduced from the line L35 into the desalination chamber 6a of the electric regenerative ion exchanger 6 and a voltage is applied between the anode (+) and the cathode (one).
• the anions such as phosphoric acid, nitric acid, and acetic acid contained in the permeate and the remaining cations are removed by exchange adsorption for purification, and the treated water is taken out from the line L36 to the recovered water tank 7 and stored as recovered water 7a.
• the anions such as acids adsorbed on the mixed bed ion exchange layer 6h pass through the anion exchange membrane 6c to the concentration chamber 6b and are adsorbed on the mixed bed ion exchange layer 6i.
• the anion adsorbed by regeneration is eluted while flowing a part of the permeate from L37 to the concentrating chamber 6b, and sent to the biological denitrifier 10 from the line L38 for biological denitrification. Since the cations adsorbed on the mixed bed type ion exchange layer 6 h permeate the cathode chamber 6e, the electrode solution flows from the anode chamber 6g through the line L39 to the cathode chamber 6e and is discharged from the line L40.
• a part of the concentrated liquid concentrated in the concentrated liquid chamber 4c of the reverse osmosis apparatus 4 and taken out from the line L34 is introduced into the evaporative concentration apparatus 8 and distilled to evaporate volatile components such as acetic acid together with water. Separated and discharged from line L41.
• the concentrated phosphoric acid solution obtained by removing the volatile components by the evaporation concentrating device 8 is introduced into the recovered phosphoric acid tank 9 from the line L42 and stored as the recovered phosphoric acid solution 9a.
• the evaporation concentrator 8 a known evaporation concentrator such as a rotary evaporator is used.
• the recovered water 7a from the recovered water tank 7 is supplied as dilution water to the concentrated liquid tank 3 through the line L43 by the pump P2, and the circulating concentrated liquid 3a is diluted to perform reverse osmosis treatment.
• the concentration of an acid other than phosphoric acid can be further reduced, and a high-purity phosphoric acid concentrate can be recovered.
• the amount of the recovered water 7a supplied to the concentrate tank 3 is an amount that maintains the condition of the concentrated concentrate carboxylic acid concentration! As a result, the permeation efficiency of acids other than phosphoric acid due to high concentration of the circulating concentrated liquid can be prevented, and the phosphoric acid purity of the concentrated liquid can be increased.
• the recovered phosphoric acid solution 9a recovered by the above method is useful as a recovered material, and can be transported practically because it is recovered in a high-concentration liquid state. It can be recovered as an acid. In this case, reverse osmosis treatment is performed under the condition of pH 3 or less.
• the phosphoric acid-containing water as raw water is usually obtained in an acidic state of pH 3 or less, it is not necessary to adjust pH especially if it is supplied as it is.
• the chemicals such as acid and alkali are limited to the regenerant for cations in the cation exchange tower 2 and the regenerant for anions in the anion exchange tower 3, and are not necessary for recovering phosphoric acid or purifying permeate.
• the recovery method and equipment can be recovered as a phosphate concentrate by reverse osmosis treatment under the conditions of pH 3 or less and phosphate concentration; Is possible.
• the amount of chemicals used and the amount of waste generated can be reduced, the processing cost can be reduced, and high-purity concentrated phosphoric acid and pure water can be recovered.
• the phosphoric acid-containing water is supplied to the reverse osmosis apparatus 4 under the conditions of pH 3 or lower and phosphoric acid concentration; Osmosis treatment Simple structure and operation by allowing acid other than phosphoric acid to pass through to the permeate chamber 4b side with water, concentrating phosphoric acid to the concentrate chamber 4c side, and collecting pure water and phosphoric acid concentrate Therefore, high-purity phosphoric acid and pure water, which can be transported in a high-concentration liquid state and are useful as a recovered product, can be efficiently recovered from the phosphoric acid-containing water at low cost.
• the embodiment of the present invention is not limited to FIGS. 1 and 2.
• the second anion exchange column is connected to the line L34. It is also possible to install it at the front stage of the evaporation concentrator 8.
• the reverse osmosis device 4 and the electric regenerative ion exchange device 6 for purifying the permeate are a simple demineralization chamber 6a and a concentration chamber 6b separated by an anion exchange membrane 6c.
• An electric regenerative ion exchange apparatus is used, and an anion exchange membrane and a cation exchange membrane are alternately arranged between a cathode chamber and an anode chamber to form a desalting chamber and a concentration chamber. It is also possible to use a normal electrodeionization device in which a desalting chamber is filled with an ion exchanger.
• Nitto Denko Corporation's reverse osmosis membrane ES-20 manufactured by Nitto Denko Co., Ltd. was passed through 0 ⁇ 7MPa of raw water with conductivity of 122mS / m containing diacid 550mg / L, nitric acid 50mg / L and acetic acid 50mg / L.
• the solution was subjected to reverse osmosis treatment to obtain a 6-fold concentrated concentrate (brine) (Example 1).
• a sodium hydroxide aqueous solution was poured into the raw water to adjust to PH6, and the same test was performed (Comparative Example 1).
• Example 1 The results of the rejection rates of phosphoric acid, nitric acid, and acetic acid are shown in Table 1.
• phosphoric acid was removed and nitric acid and acetic acid permeated and separated, whereas in Comparative Example 1, all were removed. It can be seen that they are not separated.
• the waste water was treated with the equipment shown in Fig. 1 to recover phosphoric acid and pure water.
• Cation exchange tower 2 was filled with 10 L of H-type strongly acidic cation exchange resin (DiaionSKlB, manufactured by Mitsubishi Chemical Corporation) and regenerated with hydrochloric acid.
• the anion exchange tower 5 was filled with 10 L each of OH type strongly basic anion exchange resin (Diaion SA11A, manufactured by Mitsubishi Chemical Corporation) and regenerated with sodium hydroxide.
• Second Anion Exchange Tower 5b is a PO-type strongly basic cation exchange resin (Made by Mitsubishi Chemical Corporation, Diaion SA).
• 11A is filled with 10L, regenerated to OH form with sodium hydroxide, and then converted to PO form with phosphoric acid concentrate.
• the reverse osmosis device 4 was reverse osmosis treated by passing 0.7 MPa through a device having a spiral membrane module of reverse osmosis membrane ES-20 manufactured by Nitto Denko Corporation and concentrated 6 times.
• a rotary evaporator was used to concentrate the phosphoric acid concentration to 75%. Table 2 shows the concentration of each component in each process.
• the concentration of phosphoric acid in the concentrate decreases linearly as the nitric acid rejection is negative when the concentration is 1% by weight or more, and the phosphoric acid concentration is 2% by weight or less, and the phosphoric acid concentration is 4%. It can be seen that the permeation of nitric acid is promoted at% or less. Similar results were obtained with acetic acid.
• the present invention relates to a method and apparatus for recovering phosphoric acid and pure water from phosphoric acid-containing water, in particular a liquid. It can be used in a method and apparatus for recovering phosphoric acid and other valuable materials from the cleaning waste water after etching crystal substrates, wafers, and other electronic devices, and phosphoric acid suitable for recovering pure water as treated water.

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