WO2021065732A1 - 高濃度鉄系凝集剤とその製造方法 - Google Patents

高濃度鉄系凝集剤とその製造方法 Download PDF

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Publication number
WO2021065732A1
WO2021065732A1 PCT/JP2020/036337 JP2020036337W WO2021065732A1 WO 2021065732 A1 WO2021065732 A1 WO 2021065732A1 JP 2020036337 W JP2020036337 W JP 2020036337W WO 2021065732 A1 WO2021065732 A1 WO 2021065732A1
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Prior art keywords
concentration
iron
reaction
sulfate
solution
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PCT/JP2020/036337
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English (en)
French (fr)
Japanese (ja)
Inventor
洋介 桂
正寛 伴
達郎 戸嶋
正貴 中島
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Nittetsu Mining Co Ltd
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Nittetsu Mining Co Ltd
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Priority to CN202080068376.XA priority Critical patent/CN114466824B/zh
Priority to MYPI2022001348A priority patent/MY209506A/en
Priority to KR1020227014081A priority patent/KR20220069092A/ko
Publication of WO2021065732A1 publication Critical patent/WO2021065732A1/ja
Anticipated expiration legal-status Critical
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    • 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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D21/00—Separation of suspended solid particles from liquids by sedimentation
    • B01D21/01—Separation of suspended solid particles from liquids by sedimentation using flocculating agents
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
    • C02F1/5236—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using inorganic agents

Definitions

  • the present invention relates to a high-concentration iron-based flocculant used for wastewater treatment and a method for producing the same.
  • Patent Document 1 includes adding sodium nitrite and an oxidizing agent as catalysts to a ferrous sulfate (FeSO 4 ) solution, which is an iron-based raw material, at room temperature and pressure for about 10 hours.
  • FeSO 4 ferrous sulfate
  • a method of obtaining a solution of ferric polysulfate ([Fe 2 (OH) n (SO 4 ) 3-n / 2 ] m, where 0 ⁇ n ⁇ 2, m is a natural number) by advancing the oxidation reaction over a period of time. Is described. However, since this method requires a long time for the reaction, it has been required to shorten the reaction time by some method.
  • magnetite Fe 3 O 4
  • the molar ratio of sulfate ion to iron ion is adjusted, and then in a closed container. It is a method of reacting at a temperature of 120 to 180 ° C. This method is a production method aiming at shortening the reaction time by advancing the reaction under high temperature and high pressure, but still requires a reaction time of 0.8 to 1.5 hours.
  • ferric trioxide Fe 2 O 3
  • Fe 2 (SO 4 ) 3 ferric sulfate
  • a method for producing an iron-based flocculant that is partially neutralized with ferric oxide is disclosed.
  • this method consists of two steps, a step of dissolving ferric trioxide in sulfuric acid and a step of partially neutralizing the produced ferric sulfate, the manufacturing process becomes complicated and the polyferric sulfate solution is efficiently prepared.
  • it is required to keep the mixture heated to 100 ° C. for about 3 hours to allow the reaction to proceed.
  • Patent Document 1 Japanese Patent Application Laid-Open No. 51-17516
  • Patent Document 2 Japanese Patent No. 3379204
  • Patent Document 3 Japanese Patent No. 2741137
  • the patent applicant manufactures and sells the iron-based inorganic polymer flocculant "Polytetsu" (registered trademark), and its total iron concentration is approximately 11.0 to 12.5% ("normal product"). (Called). Iron-based inorganic polymer flocculants have high coagulation ability and dehydration property if the total iron concentration is high. Therefore, in recent years, iron-based inorganic polymer flocculants having a total iron concentration of 12.5 or more are "high-concentration products”. Has been manufactured and sold as. However, even when a flocculant having a high total iron concentration is produced, the total iron concentration is limited to about 12.7% (less than 13%) at most in relation to the above-mentioned problem that the production time becomes long. It was not possible to produce a ferric polysulfate solution of 13.0% or more as a commercial product.
  • the concentration in the present invention is intended to mean all the weight% except where noted that the molar concentration, [T-Fe] has a weight percentage of total iron, [SO 4 2-] sulfate ion It shall represent the weight concentration of.
  • the total iron concentration means a concentration including not only iron dissolved in the raw material but also iron existing in the raw material liquid as a solid (powder or the like) without being dissolved.
  • Even iron-based powder present in the raw material solution contributes to the production reaction of the ferric polysulfate solution, so it is rational to include iron-based components that are not dissolved in the raw material solution in the iron concentration. is there.
  • the concentration is indicated by the total iron concentration, but it is natural that all the iron is dissolved.
  • the present invention has been made to solve these problems, and an object of the present invention is to provide a production method capable of producing a ferric polysulfate solution having a high total iron concentration in a short time as compared with a conventional product. is there.
  • a method for producing an iron-based flocculant containing a polyferric sulfate solution which comprises reacting a ferric sulfate and a raw material liquid containing sulfuric acid satisfying the following conditions in a closed container under high temperature and high pressure conditions.
  • the molar ratio of total iron and sulfate ion SO 4 2- / T-Fe
  • SO 4 2- sulfate ion
  • [SO 4 2-] is 35 wt%
  • the method for producing an iron-based flocculant according to the following (2) which comprises further adding nitric acid or nitrite as a catalyst into a closed container.
  • the ultra-high-concentration iron-based flocculant of the present invention is characterized in that it has a higher concentration than the high-concentration iron-based flocculant commercially available by the applicant of the present invention, and has high flocculation ability and dehydration. have.
  • the water content is less than that of a normal product, the product transportation cost can be reduced.
  • the production time which required 10 hours or more in the conventional method, can be significantly shortened, and the iron-based flocculant can be efficiently produced. Can be done.
  • an inorganic flocculant inorganic flocculant.
  • suspended particles and colloidal particles in sludge are agglomerated with a flocculant and dehydrated for solid-liquid separation.
  • the surface of suspended particles and colloidal particles in sewage sludge is usually negatively charged, and is in a stable state due to repulsive force and hydration due to the surface charge.
  • the aggregating agent is a drug having an action of adsorbing on the surface of these particles to neutralize the surface charge and weakening the repulsive force between the particles to cause agglomeration.
  • the iron-based flocculant is a typical inorganic flocculant, and positively charged iron ions neutralize the negative charge on the surface of suspended substances such as suspended particles and colloidal particles to perform a flocculant action. .. Therefore, the iron-based flocculant always has an agglutinating action in the presence of iron ions, but if the iron ion concentration is high, the agglutinating ability of the suspended substance is increased, so that the amount of the flocculant added can be small. Further, in order for the iron ions in the flocculant to be stably present, a certain amount of negative ions must be present. In the case of iron-based flocculants, sulfate ions usually play this role. If the amount of negative ions has an appropriate molar ratio with the amount of iron ions, the iron-based flocculant will be stable, but if the amount of negative ions is excessive or insufficient, it will become unstable and precipitate as crystals. ..
  • the relationship between the total iron concentration and the sulfate ion concentration of the raw material liquid to be added is within a specific range. It is to be set to the thing.
  • the invention in all the molar ratio of iron and sulfate ion (SO 4 2- / T-Fe ) is a specific value or more, by the sulfate ion concentration [SO 4 2-] is to the following specific values, the prior art
  • the reaction can be completed in a short time that cannot be predicted from the above, and the produced ferric sulfate solution has an ultra-high total iron concentration ([T-Fe]) that cannot be produced by conventional techniques. It achieves the exceptionally remarkable effect of being able to be manufactured.
  • the present invention is characterized in that a raw material liquid containing ferrous sulfate and sulfuric acid satisfying the following conditions are reacted under high temperature and high pressure conditions.
  • a raw material liquid containing ferrous sulfate and sulfuric acid satisfying the following conditions are reacted under high temperature and high pressure conditions.
  • the molar ratio of total iron and sulfate ion SO 4 2- / T-Fe
  • [SO 4 2-] is 35 wt%
  • the total iron concentration of ferrous sulfate and the ion concentration of sulfate have such a relationship, it is possible to obtain an ultra-high concentration ferrous sulfate solution in a short time without generating ridges. , A new finding found by the present inventors.
  • Patent Document 1 High temperature and high pressure reaction
  • the method described in Patent Document 1 is a conventional manufacturing method carried out by the present inventors. In this method, it is considered that the reaction proceeds under normal temperature and pressure in which the three phases of the solid phase, the liquid phase, and the gas phase are interrelated with each other. This is because, while the reaction proceeds, because generation and NO x odor tan gases from NO x is kantoku. However, in the method of the present invention, NO x odor the autoclave was opened was not kantoku after the reaction. Therefore, in the high-temperature high-pressure reaction of the present invention, when a solid material FeSO 4 ⁇ 7H 2 O are related solid and liquid phases that progresses dissolved to oxidation in sulfuric acid solution reaction proceeds Guess.
  • reaction temperature and pressure It is necessary to adjust the temperature inside the container to the range of 100 to 150 ° C. If the reaction temperature is less than 100 ° C., the oxidation reaction of ferrous sulfate does not proceed sufficiently. In addition, it has been confirmed that yellow ridges remain when the temperature exceeds 150 ° C., and these ridges have been found to be Fe (OH) SO 4 by X-ray analysis. Although specific experimental data are omitted, the present inventors have confirmed that the reaction proceeds more effectively as the reaction pressure increases. This can be said to be natural when the reaction mechanism of the high-temperature and high-pressure reaction described above is taken into consideration. Therefore, the reaction pressure of the present invention may be set to realistic conditions in consideration of the manufacturing cost and the like, and the reaction pressure may be 0.3 MPa or more.
  • catalyst It is preferable to use a catalyst in order to accelerate the reaction for producing the above-mentioned ferric sulfate solution.
  • Preferred catalysts for accelerating the reaction include nitric acid and nitrite, and examples of nitrite include sodium salt and potassium salt of nitrite.
  • Nitric acid is preferable from the viewpoint of the function of promoting the reaction and the cost.
  • the inventors of the present invention set the reaction temperature to 110 ° C., the reaction pressure to 0.30 MPa, and the reaction time to 10 minutes as the reaction conditions of high temperature and high pressure, and various raw material solutions containing ferrous sulfate and sulfuric acid were used. The concentration was adjusted to be. Nitric acid was added to this as a catalyst to carry out a high-temperature and high-pressure reaction. Then, it was examined whether or not the palace was generated after the reaction time had elapsed. [Experiment 2]
  • the reaction temperature is set to 120 ° C.
  • the reaction pressure is set to 10.00 MPa
  • the reaction time is set to 10 minutes so that the raw material liquid containing ferrous sulfate and sulfuric acid has various concentrations. It was adjusted. Nitric acid was added to this as a catalyst to carry out a high-temperature and high-pressure reaction. Then, it was examined whether or not the palace was generated after the reaction time had elapsed.
  • Tables 1 and 2 summarize the experimental results of whether or not a burial is generated. It was found that the reaction temperature of Experiment 1 at 110 ° C. and the reaction pressure of 0.30 MPa was exactly the same as that of Experiment 2 at 120 ° C. and 10.00 MPa. .. That is, the results in Tables 1 and 2 are common to Experiment 1 and Experiment 2.
  • Total iron concentration shown in Table 1 [T-Fe] and in the case of total sulfuric acid concentration [SO 4 2-] is intended to ferric polysulfate solution was formed without Tono was formed, the present invention It is an embodiment. Further, in the case shown in Table 2, the occurrence of burrs was confirmed, which is a comparative example of the present invention.
  • FIG. 1 Specific area A summary of these results is shown in FIG.
  • the area occupied by the circle in the figure is the area where the ferric polysulfate solution was formed without forming the ridge.
  • This is an area defined by the present invention, and will be referred to as a "specific area” below.
  • Shows white ⁇ mark included in the specific area [T-Fe], [SO 4 2-] is the raw material composition of an embodiment of the present invention. By reacting this composition under high temperature and high pressure conditions, a reddish brown solution of ferric polysulfate could be obtained.
  • a comparative example of the present invention is one in which the reaction is carried out under high temperature and high pressure using the raw material composition indicated by the ⁇ mark on the outside of the specific region.
  • the present inventors have decided to specify this specific region from the following two equations.
  • the upper limit of this region can be a weight concentration of sulfate [SO 4 2-] is set to 35 wt% or less.
  • the lower limit of this region can be defined by a diagonal straight line rising to the right.
  • the oblique straight line, the straight line indicating the relationship between the molar ratio of total iron and sulfate ion (SO 4 2- / T-Fe ) is 1.2 or more, the vertical and horizontal axes and the weight concentration of sulfate ion all It is written by converting it into a figure showing the weight concentration of iron.
  • [T-Fe] and a specific area regarding feed composition of [SO 4 2-] is a region which can be generated in the ferric polysulfate solution stably at high temperature and pressure conditions Shown.
  • the samples of (15.0: 32.0) and (15.0: 34.0) are all samples in which no ridges are generated. These samples were kept in three environments of (i) 50 ° C. in a dryer, (ii) about 20 ° C. in a laboratory, and (iii) 10 ° C. in an incubator, and changes were observed after one month. As a result, (i) the ridges were observed only in the sample kept at 50 ° C in the dryer (15.0: 34.0).
  • reaction time The production method according to the prior art described in Patent Document 1 is a method of oxidizing ferrous sulfate at normal temperature and pressure, and even if a catalyst, an oxidizing agent, etc. are devised, the total iron concentration ([T-Fe]) is at most. However, only about 12.5% of the solution was obtained, and the reaction time was 16 hours or more. In the present invention, the reaction time has been significantly shortened by adopting the high temperature and high pressure method. In the example shown in FIG. 1, the reaction was completed within 30 minutes in all the samples from the high concentration solution having a total iron concentration of 12.5% to the ultra-high concentration solution having a total iron concentration of 16%. It goes without saying that the reaction time depends on the total iron concentration.
  • the reaction is completed in 7.5 minutes when the total iron concentration is 12.5%, and the reaction is completed within 30 minutes even when the total iron concentration is 16%. ing.
  • the completion of the reaction was determined by measuring the concentration of ferrous iron in the sample solution. Being able to carry out the reaction in such a short time is a remarkably remarkable effect that cannot be predicted by the prior art.
  • sample A is a sample having the same total iron concentration as that produced in the prior art over a period of 16 hours or more.
  • sample B is a sample produced in the present invention having an ultra-high total iron concentration.
  • the colored water of acrylic paint is used as the liquid to be treated, and the amount of sample B added is reduced so that the total amount of iron of sample A and sample B to be added is the same, that is, the aggregation ability by iron ions is the same.
  • the cohesive ability of both was compared.
  • the conditions of the agglutination test are shown in Table 4.
  • sample B Since sample B has an ultra-high concentration, the amount of addition thereof can be reduced by 32% as compared with sample A when the agglutination ability is equivalent to that of sample A. Also, in the case of Sample B, due to the low [SO 4 2-] As shown in Table 1, it is possible to suppress the PH lowering of the liquid to be treated after the flocculation treatment, Therefore, it added for neutralization The amount of caustic soda added could be reduced by 47% as compared with the case of using sample A.
  • the sample B having an ultra-high concentration had a higher ability to form flocs and a faster settling rate of flocs.
  • the sample B has the same amount of iron as the sample A, the sample B has a higher aggregation ability.
  • sample B is more polymerized and is advantageous for cross-linking adsorption of flocs. This is supported by the fact that the ultra-high concentration sample of sample B has a higher liquid viscosity than sample A.
  • the coagulant used in the treatment of wastewater such as sewage since the coagulant having high coagulation performance can be produced in a short time, it can be widely used in the field of wastewater treatment.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Hydrology & Water Resources (AREA)
  • Engineering & Computer Science (AREA)
  • Environmental & Geological Engineering (AREA)
  • Water Supply & Treatment (AREA)
  • Separation Of Suspended Particles By Flocculating Agents (AREA)
  • Inorganic Compounds Of Heavy Metals (AREA)
PCT/JP2020/036337 2019-09-30 2020-09-25 高濃度鉄系凝集剤とその製造方法 Ceased WO2021065732A1 (ja)

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CN202080068376.XA CN114466824B (zh) 2019-09-30 2020-09-25 高浓度铁系絮凝剂及其生产方法
MYPI2022001348A MY209506A (en) 2019-09-30 2020-09-25 High-concentration iron-based flocculant, and method for producing same
KR1020227014081A KR20220069092A (ko) 2019-09-30 2020-09-25 고농도 철계 응집제와 그 제조 방법

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JP2003104728A (ja) * 2001-09-28 2003-04-09 Nittetsu Mining Co Ltd 含鉄硫酸溶液の処理方法
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JP2018008837A (ja) * 2016-07-12 2018-01-18 日鉄鉱業株式会社 ポリ硫酸第二鉄の製造方法及び汚泥焼却炉用固結抑制剤

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US5766566A (en) * 1994-02-03 1998-06-16 Kemira Pigments Oy Process for preparing ferric sulfate
JP2003104728A (ja) * 2001-09-28 2003-04-09 Nittetsu Mining Co Ltd 含鉄硫酸溶液の処理方法
CN104071853A (zh) * 2014-07-17 2014-10-01 广西平果锋华科技有限公司 利用废硫酸和硫酸亚铁氧气加压生产聚合硫酸铁的方法
JP2018008837A (ja) * 2016-07-12 2018-01-18 日鉄鉱業株式会社 ポリ硫酸第二鉄の製造方法及び汚泥焼却炉用固結抑制剤

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JP2021053580A (ja) 2021-04-08
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KR20220069092A (ko) 2022-05-26
CN114466824A (zh) 2022-05-10
TWI880961B (zh) 2025-04-21
TW202122146A (zh) 2021-06-16
CN114466824B (zh) 2025-06-20

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