WO2021187553A1 - High-concentration iron-based flocculant and method for producing same - Google Patents
High-concentration iron-based flocculant and method for producing same Download PDFInfo
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- WO2021187553A1 WO2021187553A1 PCT/JP2021/011030 JP2021011030W WO2021187553A1 WO 2021187553 A1 WO2021187553 A1 WO 2021187553A1 JP 2021011030 W JP2021011030 W JP 2021011030W WO 2021187553 A1 WO2021187553 A1 WO 2021187553A1
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- iron
- ferric polysulfate
- concentration
- producing
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- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 title claims abstract description 212
- 229910052742 iron Inorganic materials 0.000 title claims abstract description 104
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 45
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N iron oxide Inorganic materials [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 claims abstract description 72
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims abstract description 44
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 claims abstract description 24
- 238000007254 oxidation reaction Methods 0.000 claims abstract description 20
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 13
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 13
- 239000001301 oxygen Substances 0.000 claims abstract description 13
- 239000007789 gas Substances 0.000 claims abstract description 12
- 239000000843 powder Substances 0.000 claims abstract description 4
- 239000002994 raw material Substances 0.000 claims description 34
- 239000003054 catalyst Substances 0.000 claims description 19
- SZVJSHCCFOBDDC-UHFFFAOYSA-N iron(II,III) oxide Inorganic materials O=[Fe]O[Fe]O[Fe]=O SZVJSHCCFOBDDC-UHFFFAOYSA-N 0.000 claims description 17
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical group O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims description 7
- 229910017604 nitric acid Inorganic materials 0.000 claims description 7
- 238000000034 method Methods 0.000 abstract description 10
- 239000010802 sludge Substances 0.000 abstract description 5
- NDLPOXTZKUMGOV-UHFFFAOYSA-N oxo(oxoferriooxy)iron hydrate Chemical compound O.O=[Fe]O[Fe]=O NDLPOXTZKUMGOV-UHFFFAOYSA-N 0.000 abstract description 4
- 239000000463 material Substances 0.000 abstract description 2
- 230000016615 flocculation Effects 0.000 abstract 1
- 238000005189 flocculation Methods 0.000 abstract 1
- 238000006243 chemical reaction Methods 0.000 description 37
- -1 iron ion Chemical class 0.000 description 31
- 239000002002 slurry Substances 0.000 description 28
- 239000000243 solution Substances 0.000 description 27
- 235000013980 iron oxide Nutrition 0.000 description 26
- RUTXIHLAWFEWGM-UHFFFAOYSA-H iron(3+) sulfate Chemical compound [Fe+3].[Fe+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O RUTXIHLAWFEWGM-UHFFFAOYSA-H 0.000 description 14
- 229910000360 iron(III) sulfate Inorganic materials 0.000 description 14
- 239000000047 product Substances 0.000 description 14
- 230000000052 comparative effect Effects 0.000 description 11
- 230000003647 oxidation Effects 0.000 description 11
- 239000012071 phase Substances 0.000 description 10
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 description 9
- LIKBJVNGSGBSGK-UHFFFAOYSA-N iron(3+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[Fe+3].[Fe+3] LIKBJVNGSGBSGK-UHFFFAOYSA-N 0.000 description 7
- 229910000359 iron(II) sulfate Inorganic materials 0.000 description 7
- 239000007800 oxidant agent Substances 0.000 description 7
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 description 6
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 6
- 235000003891 ferrous sulphate Nutrition 0.000 description 6
- 239000011790 ferrous sulphate Substances 0.000 description 6
- 229910052595 hematite Inorganic materials 0.000 description 6
- 239000011019 hematite Substances 0.000 description 6
- 238000004090 dissolution Methods 0.000 description 5
- 230000035484 reaction time Effects 0.000 description 5
- 230000002776 aggregation Effects 0.000 description 4
- 239000000701 coagulant Substances 0.000 description 4
- 150000002500 ions Chemical class 0.000 description 4
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 239000010801 sewage sludge Substances 0.000 description 4
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 3
- VTLYFUHAOXGGBS-UHFFFAOYSA-N Fe3+ Chemical compound [Fe+3] VTLYFUHAOXGGBS-UHFFFAOYSA-N 0.000 description 3
- 229910001882 dioxygen Inorganic materials 0.000 description 3
- 229910000358 iron sulfate Inorganic materials 0.000 description 3
- 230000001590 oxidative effect Effects 0.000 description 3
- 238000004065 wastewater treatment Methods 0.000 description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- 238000003723 Smelting Methods 0.000 description 2
- 238000005054 agglomeration Methods 0.000 description 2
- 238000004220 aggregation Methods 0.000 description 2
- 239000006227 byproduct Substances 0.000 description 2
- 230000015271 coagulation Effects 0.000 description 2
- 238000005345 coagulation Methods 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 239000000706 filtrate Substances 0.000 description 2
- 238000001914 filtration Methods 0.000 description 2
- VBMVTYDPPZVILR-UHFFFAOYSA-N iron(2+);oxygen(2-) Chemical class [O-2].[Fe+2] VBMVTYDPPZVILR-UHFFFAOYSA-N 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- FGIUAXJPYTZDNR-UHFFFAOYSA-N potassium nitrate Chemical compound [K+].[O-][N+]([O-])=O FGIUAXJPYTZDNR-UHFFFAOYSA-N 0.000 description 2
- 239000010865 sewage Substances 0.000 description 2
- LPXPTNMVRIOKMN-UHFFFAOYSA-M sodium nitrite Chemical compound [Na+].[O-]N=O LPXPTNMVRIOKMN-UHFFFAOYSA-M 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 1
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 239000000460 chlorine Substances 0.000 description 1
- 229910052801 chlorine Inorganic materials 0.000 description 1
- 238000009264 composting Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 150000002506 iron compounds Chemical class 0.000 description 1
- GDPKWKCLDUOTMP-UHFFFAOYSA-B iron(3+);dihydroxide;pentasulfate Chemical compound [OH-].[OH-].[Fe+3].[Fe+3].[Fe+3].[Fe+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O GDPKWKCLDUOTMP-UHFFFAOYSA-B 0.000 description 1
- 230000005389 magnetism Effects 0.000 description 1
- 235000010333 potassium nitrate Nutrition 0.000 description 1
- 239000004323 potassium nitrate Substances 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- 239000002893 slag Substances 0.000 description 1
- 235000010288 sodium nitrite Nutrition 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 230000002195 synergetic effect Effects 0.000 description 1
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 1
- 239000012808 vapor phase Substances 0.000 description 1
- 239000002351 wastewater Substances 0.000 description 1
Images
Classifications
-
- 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
-
- 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
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G49/00—Compounds of iron
- C01G49/14—Sulfates
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Definitions
- the present invention relates to a high-concentration iron-based flocculant used for wastewater treatment and a method for producing the same.
- Sewage sludge is coagulated with various coagulants and then dehydrated and landfilled.
- Ferric polysulfate is a typical inorganic coagulant used for coagulation of sewage sludge. It is widely used both in Japan and overseas because it is less corrosive and does not easily damage wastewater treatment facilities, and because it does not contain chlorine, it is effective for recycling such as composting sewage sludge cake.
- ferrous sulfate Fe (SO 4 ), 7H 2 O
- Fe (SO 4 ), 7H 2 O ferrous sulfate
- ferrous sulfate is a by-product obtained in the titanium oxide production process, its supply is not stable, and therefore, an alternative material to ferrous sulfate has been sought as a raw material for producing polyferric sulfate.
- iron oxides such as magnetite and wustite are by-products generated in the copper smelting process and are naturally produced as ores.
- technological development for producing polyferric sulfate using iron oxide is also being carried out.
- the following two techniques have been published as a method for producing a ferric sulfate solution using iron oxide as an iron-based raw material and using an autoclave.
- the method for producing an iron-based inorganic flocculant described in Patent Document 1 uses iron oxide (magnetite) as an iron-based raw material, adjusts the molar ratio of sulfate ion to iron ion, and then 120 to 180 in a closed container. This is a method of dissolving iron oxide by reacting at a temperature of ° C. Then, an oxidizing agent is added to obtain an iron sulfate solution.
- This method is a production method aiming at shortening the reaction time by advancing the reaction under high temperature and high pressure, but a ferric polysulfate solution having a high total iron concentration has not been obtained.
- Patent Document 2 describes that water, sulfuric acid, oxygen, and iron oxide (magnetite, hematite) are introduced into a pressure vessel to produce a ferric sulfate solution under high temperature and high pressure conditions.
- iron oxide is dissolved using a large amount of sulfuric acid, it is an iron sulfate solution that is produced, and the polyferric sulfate solution that is the object of the present invention cannot be obtained.
- iron oxide is dissolved in sulfuric acid to generate divalent or trivalent iron ions, which are then oxidized with an oxidizing agent to produce an iron sulfate solution, which is used as an iron-based flocculant. That is, and the reaction proceeds in a closed container at high temperature and high pressure to promote the dissolution of iron oxide in sulfuric acid.
- iron oxide is difficult to dissolve in sulfuric acid and takes a long time to dissolve, in the prior art, iron oxide was dissolved using a large amount of sulfuric acid even under high temperature and high pressure conditions. Therefore, the reaction product was an aqueous solution of ferric sulfate.
- Ferric sulfate produced by the prior art has a chemical formula of Fe 2 (SO 4 ) 3 , and when used as a flocculant, 3 mol of sulfate ion is generated for every 2 mol of iron ion.
- sulfate ions are not involved in sludge aggregation, they remain in the drainage. The treatment cost of this residual sulfate ion has become a big problem. This is because it costs a lot of money to neutralize this.
- the chemical formula of ferric polysulfate produced in the present invention is as follows.
- the fact that less sulfate ions are generated is one of the excellent features of the ferric polysulfate solution as an inorganic flocculant. Since it is necessary to treat a large amount of sewage sludge, it is a great merit in sewage treatment that the treatment cost of residual sulfate ions is low.
- iron oxide which is easily and inexpensively available as compared with ferrous sulfate, is used as an iron-based raw material, and a ferric polysulfate solution having a high total iron concentration and a high sludge agglomeration ability is used at high temperature and high pressure. It is an object of the present invention to provide a method for efficiently producing under conditions in a short time.
- the method for producing ferric polysulfate of the present invention comprises the following technical means.
- a method for producing polyferric sulfate using iron oxide as an iron-based raw material in which the molar ratio of sulfate ions to total iron is adjusted to be less than 1.5 in a closed container.
- a method for producing ferric polysulfate which comprises adding iron powder and a sulfuric acid solution, replacing the gas phase in a closed container with oxygen, and then performing an oxidation reaction under high temperature and high pressure conditions.
- concentration indications adopted in the present invention mean% by weight unless it is clearly stated that the concentration is molar concentration.
- [T-Fe] represents the weight concentration of total iron
- [SO 4 2- ] represents the weight concentration of sulfate ions.
- 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. be. In the column of Examples, the ferric sulfate solution produced was indicated by the total iron concentration, but all the iron was dissolved.
- FIG. 1 is a flow chart of an autoclave which is a manufacturing apparatus.
- FIG. 2 shows the relationship between the concentration of the input raw material and the concentration of the produced slurry.
- ⁇ indicates the composition of the added raw material, and ⁇ indicates the composition of ferric polysulfate produced in Examples 1 to 4.
- the method for producing ferric polysulfate in the present invention is a production method including the following production steps using the production apparatus outlined in FIG. (1) Sulfuric acid, water, and iron oxide are put into a closed container. (2) The air in the closed container is replaced with oxygen, and nitric acid is added as a catalyst if necessary. (3) Keep the temperature in the closed container at 100 ° C. or higher and the pressure at 0.3 MPa or higher, and stir for 1 to 4 hours. (4) After completion of the reaction, the obtained solution is cooled and filtered to remove the insoluble residue. It has been confirmed that this insoluble residue is mainly iron oxide added as a raw material.
- iron oxide is used as an iron-based raw material.
- iron oxide is a general term for iron oxides, and ferrous oxide, ferric oxide, and triiron tetroxide are known to have different compositions depending on the number of oxidations.
- Ferrous oxide is iron (II) oxide (FeO) known as ustite
- ferric oxide is iron (III) oxide (Fe 2 O 3 ) known as hematite or mughemite, tritetraoxide.
- Iron is iron oxide (II, III) and is known as magnetite.
- Magnetite is an iron compound that is easily available as a raw material because it is abundantly contained in slag in the copper smelting process and abundantly in natural ores.
- the present invention it is preferable to set the molar ratio of sulfate ion to total iron (sulfate ion / total iron) of the iron oxide and sulfuric acid solution to be put into a closed container as a raw material to less than 1.5.
- a ferric polysulfate solution cannot be produced.
- the inventors of the present invention are empirically aware that the target ferric sulfate solution cannot be produced unless the molar ratio is set to less than 1.5.
- reaction temperature and pressure The temperature inside the container is preferably adjusted to 100 ° C. or higher. If the reaction temperature is less than 100 ° C., the dissolution of iron oxide and the oxidation reaction do not proceed sufficiently.
- the reaction pressure of the present invention may be set to realistic conditions in consideration of manufacturing cost and the like, and generally, the reaction pressure may be 0.3 MPa or more. When the reaction is carried out at 0.2 MPa, a relatively large amount of residue consisting of a compound of iron and sulfuric acid is generated, so that it is contained in the recovered rate of the produced ferric polysulfate solution and in ferric polysulfate. It is not preferable because the total iron concentration decreases.
- the oxidation catalyst can be put into the closed container together with the reaction raw material.
- the oxidation reaction in the reaction in a closed container, the oxidation reaction is promoted by oxygen substituting the gas phase to improve the reaction rate, and ferric polysulfate having a high total iron concentration is produced.
- the oxidation catalyst is contained in the oxygen-substituted closed container, it is preferable because the oxidation of divalent iron ions dissolved in sulfuric acid can be further promoted and the production efficiency of ferric polysulfate can be improved.
- the oxidation catalyst may be any catalyst having an action of oxidizing dissolved divalent iron ions. Examples thereof include sodium nitrite and potassium nitrate, but it is most preferable to use nitric acid as the catalyst because it is considered that it also functions as an oxidizing agent in addition to acting as an oxidation catalyst.
- the inventors of the present invention presume that, in the present invention, the reason why a high concentration of ferric polysulfate, which cannot be achieved by the prior art, can be efficiently produced in a short time is as follows. However, the technical interpretation of the present invention is not bound by this conjecture.
- the iron oxide raw material is dissolved in a high-temperature and high-pressure sulfuric acid solution in a pressure vessel to form a solution containing divalent and trivalent iron ions, and this solution is prepared. After taking it out of the pressure vessel, an oxidizing agent was added to oxidize the remaining divalent iron ions to produce a ferric polysulfate solution (Patent Document 1).
- the oxygen gas in the closed container immediately acts as an oxidant on the divalent iron ions eluted in the closed container, so that the divalent iron ions are precipitated as an iron / sulfuric acid compound. It was possible to prevent and efficiently form a high concentration of ferric polysulfate. This is a technical finding newly discovered by the present inventors, and the present invention has been made based on this finding.
- Example 1 In a closed container with a content of 1 L, 221 g of magnetite and sulfuric acid were added so that the molar ratio of SO 4 2- ion / iron ion was 1.3, and 2.7 g of nitric acid was added as a catalyst. Close the closed container, replace the gas phase part in the closed container with oxygen, use the heater and oxygen cylinder equipped in the closed container, set the temperature of the slurry to 130 ° C, and the pressure of the gas phase part in the closed container. The temperature was raised and increased to 1.0 MPa, and the reaction was carried out for 1 hour. During the reaction, the temperature and pressure of the gas phase portion in the closed container were maintained at 130 ° C. and 1.0 MPa.
- the slurry was separated from the closed container and the slurry was cooled. The end point of the reaction was determined by measuring the concentration of ferrous iron contained in the cooled slurry. Then, the slurry was filtered to obtain a product of ferric polysulfate.
- the obtained ferric polysulfate had a high total iron concentration (T-Fe) of 15.9%.
- the divalent iron ion concentration (Fe 2+ ) was less than 0.01%, and all iron ions were oxidized to trivalent ions.
- the sulfate ion concentration was 36.7%, and the SO 4 2- / T-Fe molar ratio was 1.34.
- the proportion of iron distributed from the raw material to the product (iron solubility) was 91.9%.
- the residue was magnetite. Since the divalent iron ion concentration (Fe 2+ ) was less than 0.01%, it can be seen that the reaction for producing ferric polysulfate was completed within 1 hour. Moreover, since the SO 4 2- / T-Fe molar ratio is 1.34, which is smaller than 1.5, it can be seen that ferric polysulfate is formed.
- Example 2 (Reaction tank gas phase pressure: 0.3 MPa) The reaction was carried out under the same conditions as in Example 1 except that the pressure of the gas phase portion in the closed container was 0.3 MPa and the reaction time was 2 hours, and the obtained slurry was cooled. The end point of the reaction was determined by measuring the concentration of ferrous iron contained in the cooled slurry. Then, the slurry was filtered to obtain a product of ferric polysulfate.
- the obtained ferric polysulfate had a high total iron concentration (T-Fe) of 14.7%.
- the divalent iron ion concentration (Fe 2+ ) was less than 0.01%, and all iron ions were oxidized to trivalent ions.
- the sulfate ion concentration was 37.5% and the SO 4 2- / T-Fe molar ratio was 1.48.
- the proportion of iron distributed from the raw material to the product (iron solubility) was 84.5%.
- the residue was magnetite. Since the divalent iron ion concentration (Fe 2+ ) was less than 0.01%, it can be seen that the reaction for producing ferric polysulfate was completed within 2 hours. Moreover, since the SO 4 2- / T-Fe molar ratio is 1.48, which is smaller than 1.5, it can be seen that ferric polysulfate is formed.
- Example 3 Low iron concentration raw material Except for the fact that 298 g of magnetite with an iron concentration of 52.1% and sulfuric acid were added to a closed container with a content of 1 L so that the molar ratio of SO 4 2- ion / iron ion was 1.3, and the reaction time was set to 4 hours. , The reaction was carried out under the same conditions as in Example 1, and the obtained slurry was cooled. The end point of the reaction was determined by measuring the concentration of ferrous iron contained in the cooled slurry. Then, the slurry was filtered to obtain a product of ferric polysulfate.
- the obtained ferric sulfate had a high total iron concentration (T-Fe) of 16.3%.
- the divalent iron ion concentration (Fe 2+ ) was less than 0.01%, and all iron ions were oxidized to trivalent ions.
- the sulfate ion concentration was 40.3% and the SO 4 2- / T-Fe molar ratio was 1.44.
- the proportion of iron distributed from the raw material to the product (iron solubility) was 83.6%.
- the residue was magnetite. Since the divalent iron ion concentration (Fe 2+ ) was less than 0.01%, it can be seen that the reaction for producing ferric polysulfate was completed within 4 hours. Moreover, since the SO 4 2- / T-Fe molar ratio is 1.44, which is smaller than 1.5, it can be seen that ferric polysulfate is formed.
- Example 4 (Wustite) Example 1 except that 210 g of wustite (iron concentration: 74.2%) and sulfuric acid were added to a closed container with a content of 1 L so that the molar ratio of SO 4 2- ion / iron ion was 1.3. The reaction was carried out under the same conditions, and the obtained slurry was cooled. The end point of the reaction was determined by measuring the concentration of ferrous iron contained in the cooled slurry. Then, the slurry was filtered to obtain a product of ferric polysulfate.
- the obtained ferric sulfate had a high total iron concentration (T-Fe) of 14.6%.
- the divalent iron ion concentration (Fe 2+ ) was less than 0.01%, and all iron ions were oxidized to trivalent ions.
- the sulfate ion concentration was 37.2%, and the SO 4 2- / T-Fe molar ratio was 1.48.
- the proportion of iron distributed from the raw material to the product (iron solubility) was 84.1%.
- the residues were wustite, magnetite and hematite. Since the divalent iron ion concentration (Fe 2+ ) was less than 0.01%, it can be seen that the reaction for producing ferric polysulfate was completed within 1 hour.
- the SO 4 2- / T-Fe molar ratio is 1.48, which is smaller than 1.5, it can be seen that ferric polysulfate is formed.
- the -Fe molar ratio was 1.36.
- the proportion of iron distributed from the raw material to the product was 76.1%.
- the residue was zomolnokite (Szomolnokite (Fe (SO 4 ) (H 2 O))).
- Comparative Example 2 The reaction was carried out under the same conditions as in Comparative Example 1 except that 2.7 g of nitric acid as a catalyst was added to the slurry before the temperature was raised, and the obtained slurry was cooled. When the concentration of ferric iron contained in the cooled slurry was measured, it was confirmed that ferric iron remained, so after filtering the slurry, 33.5 g of hydrogen peroxide was added to the filtrate. , A product of ferric polysulfate was obtained by completing the oxidation of ferric ferrous.
- the total iron concentration (T-Fe) of the obtained ferric sulfate was 13.7%, the divalent iron ion concentration (Fe 2+ ) was less than 0.01%, the sulfate ion concentration was 34.7%, and SO 4 2- / T.
- the -Fe molar ratio was 1.47.
- the proportion of iron distributed from the raw material to the product (iron solubility) was 72.4%.
- the residue was iron hydroxide sulfate (Fe (SO 4 ) 2 H).
- Table 1 summarizes the iron raw materials, reaction conditions, and the characteristics of the ferric polysulfate produced for Examples 1 to 4 and Comparative Examples 1 and 2.
- the reactions were completed within 1 to 4 hours, respectively, but in Comparative Examples 1 and 2, the oxidation reaction was not completed even if the mixture was held at high temperature and high pressure for 4 hours, and the divalent iron remained unoxidized. It had been done. Therefore, a hydrogen peroxide solution was added to oxidize all the divalent iron remaining in the slurry to ferric iron. Therefore, the characteristics of the products in Comparative Examples 1 and 2 represent the characteristics of the products after the oxidation reaction is completed by additionally adding H 2 O 2.
- ferric polysulfate in the present invention when the air in the closed container is replaced with oxygen gas, ferric polysulfate having a high sludge aggregation ability can be efficiently used in a short time. It can be seen that the remarkable effect of being able to be produced is achieved.
- 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)
- Environmental & Geological Engineering (AREA)
- Engineering & Computer Science (AREA)
- Hydrology & Water Resources (AREA)
- Water Supply & Treatment (AREA)
- Life Sciences & Earth Sciences (AREA)
- Inorganic Compounds Of Heavy Metals (AREA)
- Separation Of Suspended Particles By Flocculating Agents (AREA)
- Compounds Of Iron (AREA)
- Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
Abstract
A method for producing polyferric sulfate, the method comprising adding a ferric oxide powder and a sulfuric acid solution into a sealed container, substituting the gas phase in the sealed container with oxygen, and causing an oxidation reaction to occur in a high-temperature, high-pressure condition. Provided is a method for efficiently producing, in a short period of time under a high-temperature, high-pressure condition, a polyferric sulfate solution having a high total-iron concentration and a high sludge flocculation ability, by using a ferric oxide as an iron-based material.
Description
本発明は、排水処理に使用される高濃度の鉄系凝集剤及びその製造方法に関する。
The present invention relates to a high-concentration iron-based flocculant used for wastewater treatment and a method for producing the same.
下水汚泥は各種凝集剤を用いて凝集処理した後に脱水し埋め立てられるが、ポリ硫酸第二鉄は、下水汚泥の凝集処理に使用される代表的な無機凝集剤である。腐食性が少ないので排水処理施設を痛めにくい、塩素を含まないので下水汚泥ケーキのコンポスト化等の再資源化に有効である等の特徴があるため、国内外を問わず広く使用されている。
Sewage sludge is coagulated with various coagulants and then dehydrated and landfilled. Ferric polysulfate is a typical inorganic coagulant used for coagulation of sewage sludge. It is widely used both in Japan and overseas because it is less corrosive and does not easily damage wastewater treatment facilities, and because it does not contain chlorine, it is effective for recycling such as composting sewage sludge cake.
鉄系無機凝集剤としてポリ硫酸第二鉄を製造するにあたっては、一般には、硫酸第一鉄（Fe（SO4）・7H2O）が鉄系の製造原料として用いられていることが多い。しかし、硫酸第一鉄は、酸化チタン製造工程で得られる副産物であるが供給が安定していないため、ポリ硫酸第二鉄製造原料として硫酸第一鉄に代わる代替材料が求められていた。
一方、マグネタイトやウスタイト等の酸化鉄は、銅の製錬工程で発生する副産物であるほか、鉱石として天然に産出するものである。このように、硫酸第一鉄に比較して入手が容易であるため、酸化鉄を用いてポリ硫酸第二鉄を製造しようとする技術開発も行われている。 In producing ferric polysulfate as an iron-based inorganic flocculant, ferrous sulfate (Fe (SO 4 ), 7H 2 O) is often used as an iron-based production raw material. However, although ferrous sulfate is a by-product obtained in the titanium oxide production process, its supply is not stable, and therefore, an alternative material to ferrous sulfate has been sought as a raw material for producing polyferric sulfate.
On the other hand, iron oxides such as magnetite and wustite are by-products generated in the copper smelting process and are naturally produced as ores. As described above, since it is easier to obtain than ferrous sulfate, technological development for producing polyferric sulfate using iron oxide is also being carried out.
一方、マグネタイトやウスタイト等の酸化鉄は、銅の製錬工程で発生する副産物であるほか、鉱石として天然に産出するものである。このように、硫酸第一鉄に比較して入手が容易であるため、酸化鉄を用いてポリ硫酸第二鉄を製造しようとする技術開発も行われている。 In producing ferric polysulfate as an iron-based inorganic flocculant, ferrous sulfate (Fe (SO 4 ), 7H 2 O) is often used as an iron-based production raw material. However, although ferrous sulfate is a by-product obtained in the titanium oxide production process, its supply is not stable, and therefore, an alternative material to ferrous sulfate has been sought as a raw material for producing polyferric sulfate.
On the other hand, iron oxides such as magnetite and wustite are by-products generated in the copper smelting process and are naturally produced as ores. As described above, since it is easier to obtain than ferrous sulfate, technological development for producing polyferric sulfate using iron oxide is also being carried out.
酸化鉄を鉄系原料としてオートクレーブを用いて硫酸第二鉄溶液を製造する方法として、次の２つの技術が公開されている。
特許文献１に記載された鉄系無機凝集剤の製造方法は、鉄系原料として酸化鉄（マグネタイト）を使用し、硫酸イオンと鉄イオンのモル比を調整した後に、密閉容器中で１２０～１８０℃の温度で反応させて酸化鉄を溶解させる方法である。その後、酸化剤を添加して硫酸鉄溶液を得ている。この方法は高温高圧下で反応を進めることにより反応時間の短縮化を目指す製造方法であるが、全鉄濃度が高いポリ硫酸第二鉄溶液は得られていなかった。 The following two techniques have been published as a method for producing a ferric sulfate solution using iron oxide as an iron-based raw material and using an autoclave.
The method for producing an iron-based inorganic flocculant described in Patent Document 1 uses iron oxide (magnetite) as an iron-based raw material, adjusts the molar ratio of sulfate ion to iron ion, and then 120 to 180 in a closed container. This is a method of dissolving iron oxide by reacting at a temperature of ° C. Then, an oxidizing agent is added to obtain an iron sulfate solution. This method is a production method aiming at shortening the reaction time by advancing the reaction under high temperature and high pressure, but a ferric polysulfate solution having a high total iron concentration has not been obtained.
特許文献１に記載された鉄系無機凝集剤の製造方法は、鉄系原料として酸化鉄（マグネタイト）を使用し、硫酸イオンと鉄イオンのモル比を調整した後に、密閉容器中で１２０～１８０℃の温度で反応させて酸化鉄を溶解させる方法である。その後、酸化剤を添加して硫酸鉄溶液を得ている。この方法は高温高圧下で反応を進めることにより反応時間の短縮化を目指す製造方法であるが、全鉄濃度が高いポリ硫酸第二鉄溶液は得られていなかった。 The following two techniques have been published as a method for producing a ferric sulfate solution using iron oxide as an iron-based raw material and using an autoclave.
The method for producing an iron-based inorganic flocculant described in Patent Document 1 uses iron oxide (magnetite) as an iron-based raw material, adjusts the molar ratio of sulfate ion to iron ion, and then 120 to 180 in a closed container. This is a method of dissolving iron oxide by reacting at a temperature of ° C. Then, an oxidizing agent is added to obtain an iron sulfate solution. This method is a production method aiming at shortening the reaction time by advancing the reaction under high temperature and high pressure, but a ferric polysulfate solution having a high total iron concentration has not been obtained.
特許文献２には、圧力容器内に水、硫酸、酸素、および酸化鉄（マグネタイト、ヘマタイト）を導入し、高温高圧条件下で硫酸第二鉄溶液を製造することが記載されている。この製造方法では、大量の硫酸を使用して酸化鉄を溶解しているので製造されるのは硫酸鉄溶液であり、本発明の目的とするポリ硫酸第二鉄溶液を得ることはできない。
Patent Document 2 describes that water, sulfuric acid, oxygen, and iron oxide (magnetite, hematite) are introduced into a pressure vessel to produce a ferric sulfate solution under high temperature and high pressure conditions. In this production method, since iron oxide is dissolved using a large amount of sulfuric acid, it is an iron sulfate solution that is produced, and the polyferric sulfate solution that is the object of the present invention cannot be obtained.
これらの従来技術によれば、次の技術は当業者には知られていた技術であるといえる。すなわち、酸化鉄を硫酸で溶解して二価や三価の鉄イオンを生成し、その後に酸化剤を用いてこれを酸化して硫酸鉄溶液を製造し、これを鉄系凝集剤として利用すること、および、酸化鉄が硫酸に溶解することを促進するために高温高圧の密閉容器内で反応を進めること、である。しかし、酸化鉄は硫酸に溶解しにくく溶解に長時間を要するので、従来技術においては、高温高圧条件下であっても多量の硫酸を用いて酸化鉄を溶解していた。このため、反応生成物は硫酸第二鉄水溶液であった。
According to these conventional techniques, it can be said that the following techniques are known to those skilled in the art. That is, iron oxide is dissolved in sulfuric acid to generate divalent or trivalent iron ions, which are then oxidized with an oxidizing agent to produce an iron sulfate solution, which is used as an iron-based flocculant. That is, and the reaction proceeds in a closed container at high temperature and high pressure to promote the dissolution of iron oxide in sulfuric acid. However, since iron oxide is difficult to dissolve in sulfuric acid and takes a long time to dissolve, in the prior art, iron oxide was dissolved using a large amount of sulfuric acid even under high temperature and high pressure conditions. Therefore, the reaction product was an aqueous solution of ferric sulfate.
従来技術で製造される硫酸第二鉄は化学式がFe2(SO4)3であり、凝集剤として使用した場合には鉄イオン２モルに対して硫酸イオンが３モル発生する。しかし、硫酸イオンは汚泥の凝集に関与しないので、排液中に残留してしまう。この残留した硫酸イオンの処理コストが大きな問題となっている。これを中和するために多額のコストがかかるからである。
Ferric sulfate produced by the prior art has a chemical formula of Fe 2 (SO 4 ) 3 , and when used as a flocculant, 3 mol of sulfate ion is generated for every 2 mol of iron ion. However, since sulfate ions are not involved in sludge aggregation, they remain in the drainage. The treatment cost of this residual sulfate ion has become a big problem. This is because it costs a lot of money to neutralize this.
これに対し、本発明で生産するポリ硫酸第二鉄の化学式は次に示すものである。硫酸イオンの発生の少ないことが、無機系凝集剤としてポリ硫酸第二鉄溶液が有する優れた特徴の1つである。下水汚泥は大量に処理する必要があるため、残留する硫酸イオンの処理コストが小さくて済むことは、下水処理において大きなメリットとなる。
［Fe2(OH)n（SO4）3－n/2］m (０＜n≦２, mは自然数) 式（１） On the other hand, the chemical formula of ferric polysulfate produced in the present invention is as follows. The fact that less sulfate ions are generated is one of the excellent features of the ferric polysulfate solution as an inorganic flocculant. Since it is necessary to treat a large amount of sewage sludge, it is a great merit in sewage treatment that the treatment cost of residual sulfate ions is low.
[Fe 2 (OH) n (SO 4 ) 3- n / 2] m (0 <n ≤ 2, m is a natural number) Equation (1)
［Fe2(OH)n（SO4）3－n/2］m (０＜n≦２, mは自然数) 式（１） On the other hand, the chemical formula of ferric polysulfate produced in the present invention is as follows. The fact that less sulfate ions are generated is one of the excellent features of the ferric polysulfate solution as an inorganic flocculant. Since it is necessary to treat a large amount of sewage sludge, it is a great merit in sewage treatment that the treatment cost of residual sulfate ions is low.
[Fe 2 (OH) n (SO 4 ) 3- n / 2] m (0 <n ≤ 2, m is a natural number) Equation (1)
本発明は、硫酸第一鉄に比較して容易に安価で入手できる酸化鉄を鉄系原料として用い、全鉄濃度が高くて汚泥の凝集能力が高いポリ硫酸第二鉄溶液を、高温高圧の条件下に於いて短時間で効率的に製造する方法を提供することを目的とする。
In the present invention, iron oxide, which is easily and inexpensively available as compared with ferrous sulfate, is used as an iron-based raw material, and a ferric polysulfate solution having a high total iron concentration and a high sludge agglomeration ability is used at high temperature and high pressure. It is an object of the present invention to provide a method for efficiently producing under conditions in a short time.
これらの課題を解決するため、本発明のポリ硫酸第二鉄の製造方法は、次の技術的手段から構成されるものである。
（１）鉄系原料として酸化鉄を用いてポリ硫酸第二鉄を製造する方法であって、密閉容器内に、硫酸イオンと全鉄のモル比が１．５未満となるように調整した酸化鉄粉末と硫酸溶液を投入し、密閉容器内の気相を酸素に置換した後、高温高圧条件下で酸化反応を行うことからなるポリ硫酸第二鉄の製造方法。
（２）鉄系原料としてマグネタイト又はウスタイトを用いる（１）に記載のポリ硫酸第二鉄の製造方法。
（３）更に触媒を添加する（１）または（２）に記載のポリ硫酸第二鉄の製造方法。
（４）前記触媒が硝酸であることを特徴とする（３）に記載のポリ硫酸第二鉄の製造方法。
（５）前記高温高圧条件が、圧力０．３ＭＰａ以上、温度が１００℃以上である（１）～（４）のいずれかに記載のポリ硫酸第二鉄の製造方法。
（６）全鉄濃度が１４．５％以上の高濃度のポリ硫酸第二鉄を製造する（１）～（５）のいずれかに記載のポリ硫酸第二鉄の製造方法。
（７）前記ポリ硫酸第二鉄の製造を4時間以内に完了させる（６）のポリ硫酸第二鉄の製造方法。 In order to solve these problems, the method for producing ferric polysulfate of the present invention comprises the following technical means.
(1) A method for producing polyferric sulfate using iron oxide as an iron-based raw material, in which the molar ratio of sulfate ions to total iron is adjusted to be less than 1.5 in a closed container. A method for producing ferric polysulfate, which comprises adding iron powder and a sulfuric acid solution, replacing the gas phase in a closed container with oxygen, and then performing an oxidation reaction under high temperature and high pressure conditions.
(2) The method for producing ferric polysulfate according to (1), which uses magnetite or wustite as an iron-based raw material.
(3) The method for producing ferric polysulfate according to (1) or (2), wherein a catalyst is further added.
(4) The method for producing ferric polysulfate according to (3), wherein the catalyst is nitric acid.
(5) The method for producing ferric polysulfate according to any one of (1) to (4), wherein the high temperature and high pressure conditions are a pressure of 0.3 MPa or more and a temperature of 100 ° C. or more.
(6) The method for producing ferric polysulfate according to any one of (1) to (5), which produces ferric polysulfate having a total iron concentration of 14.5% or more.
(7) The method for producing ferric polysulfate according to (6), which completes the production of ferric polysulfate within 4 hours.
（１）鉄系原料として酸化鉄を用いてポリ硫酸第二鉄を製造する方法であって、密閉容器内に、硫酸イオンと全鉄のモル比が１．５未満となるように調整した酸化鉄粉末と硫酸溶液を投入し、密閉容器内の気相を酸素に置換した後、高温高圧条件下で酸化反応を行うことからなるポリ硫酸第二鉄の製造方法。
（２）鉄系原料としてマグネタイト又はウスタイトを用いる（１）に記載のポリ硫酸第二鉄の製造方法。
（３）更に触媒を添加する（１）または（２）に記載のポリ硫酸第二鉄の製造方法。
（４）前記触媒が硝酸であることを特徴とする（３）に記載のポリ硫酸第二鉄の製造方法。
（５）前記高温高圧条件が、圧力０．３ＭＰａ以上、温度が１００℃以上である（１）～（４）のいずれかに記載のポリ硫酸第二鉄の製造方法。
（６）全鉄濃度が１４．５％以上の高濃度のポリ硫酸第二鉄を製造する（１）～（５）のいずれかに記載のポリ硫酸第二鉄の製造方法。
（７）前記ポリ硫酸第二鉄の製造を4時間以内に完了させる（６）のポリ硫酸第二鉄の製造方法。 In order to solve these problems, the method for producing ferric polysulfate of the present invention comprises the following technical means.
(1) A method for producing polyferric sulfate using iron oxide as an iron-based raw material, in which the molar ratio of sulfate ions to total iron is adjusted to be less than 1.5 in a closed container. A method for producing ferric polysulfate, which comprises adding iron powder and a sulfuric acid solution, replacing the gas phase in a closed container with oxygen, and then performing an oxidation reaction under high temperature and high pressure conditions.
(2) The method for producing ferric polysulfate according to (1), which uses magnetite or wustite as an iron-based raw material.
(3) The method for producing ferric polysulfate according to (1) or (2), wherein a catalyst is further added.
(4) The method for producing ferric polysulfate according to (3), wherein the catalyst is nitric acid.
(5) The method for producing ferric polysulfate according to any one of (1) to (4), wherein the high temperature and high pressure conditions are a pressure of 0.3 MPa or more and a temperature of 100 ° C. or more.
(6) The method for producing ferric polysulfate according to any one of (1) to (5), which produces ferric polysulfate having a total iron concentration of 14.5% or more.
(7) The method for producing ferric polysulfate according to (6), which completes the production of ferric polysulfate within 4 hours.
本発明において採用する濃度表示は、モル濃度であることを明記する場合以外は全て重量％を意味するものである。[T-Fe ]は全鉄の重量濃度、[SO4
2-]は硫酸イオンの重量濃度を表すものとする。
ここで全鉄濃度とは、原料中に溶解している鉄ばかりでなく、溶解することなく固体（粉体等）として原料液中に存在する鉄を含めた濃度であることを意味する。原料液中に存在する鉄系粉末であっても、ポリ硫酸第二鉄溶液の製造反応に寄与するので、原料液中に溶解していない鉄系成分も鉄の濃度に含めることが合理的である。
なお、実施例の欄において、製造されたポリ硫酸第二鉄溶液について、全鉄濃度で濃度表示をしているが、鉄はすべて溶解していた。 All the concentration indications adopted in the present invention mean% by weight unless it is clearly stated that the concentration is molar concentration. [T-Fe] represents the weight concentration of total iron, and [SO 4 2- ] represents the weight concentration of sulfate ions.
Here, 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. be.
In the column of Examples, the ferric sulfate solution produced was indicated by the total iron concentration, but all the iron was dissolved.
ここで全鉄濃度とは、原料中に溶解している鉄ばかりでなく、溶解することなく固体（粉体等）として原料液中に存在する鉄を含めた濃度であることを意味する。原料液中に存在する鉄系粉末であっても、ポリ硫酸第二鉄溶液の製造反応に寄与するので、原料液中に溶解していない鉄系成分も鉄の濃度に含めることが合理的である。
なお、実施例の欄において、製造されたポリ硫酸第二鉄溶液について、全鉄濃度で濃度表示をしているが、鉄はすべて溶解していた。 All the concentration indications adopted in the present invention mean% by weight unless it is clearly stated that the concentration is molar concentration. [T-Fe] represents the weight concentration of total iron, and [SO 4 2- ] represents the weight concentration of sulfate ions.
Here, 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. be.
In the column of Examples, the ferric sulfate solution produced was indicated by the total iron concentration, but all the iron was dissolved.
本発明の製造方法を採用することにより、入手が容易な酸化鉄を鉄系原料として用い、全鉄濃度が高くて汚泥の凝集能力が高いポリ硫酸第二鉄溶液を、高温高圧の条件下に於いて短時間で効率的に製造することが可能となった。
By adopting the production method of the present invention, easily available iron oxide is used as an iron-based raw material, and a ferric polysulfate solution having a high total iron concentration and a high sludge agglomeration ability is prepared under high temperature and high pressure conditions. It has become possible to efficiently manufacture in a short time.
（製造工程）
本発明におけるポリ硫酸第二鉄の製造方法は、図１に概要を示す製造装置を用いて、次の製造工程を含む製造方法である。
（１）密閉容器内に硫酸と水、酸化鉄を投入する。
（２）密閉容器内の空気を酸素に置換し、必要に応じて触媒として硝酸を添加する。
（３）密閉容器内の温度を１００℃以上、圧力を０．３ＭＰａ以上に保ち、１～４時間撹拌する。
（４）反応終了後に得られた溶液を冷却し、濾過を行い不溶残渣を除去する。この不溶残渣は、主に原料として投入した酸化鉄であることが確認されている。 (Manufacturing process)
The method for producing ferric polysulfate in the present invention is a production method including the following production steps using the production apparatus outlined in FIG.
(1) Sulfuric acid, water, and iron oxide are put into a closed container.
(2) The air in the closed container is replaced with oxygen, and nitric acid is added as a catalyst if necessary.
(3) Keep the temperature in the closed container at 100 ° C. or higher and the pressure at 0.3 MPa or higher, and stir for 1 to 4 hours.
(4) After completion of the reaction, the obtained solution is cooled and filtered to remove the insoluble residue. It has been confirmed that this insoluble residue is mainly iron oxide added as a raw material.
本発明におけるポリ硫酸第二鉄の製造方法は、図１に概要を示す製造装置を用いて、次の製造工程を含む製造方法である。
（１）密閉容器内に硫酸と水、酸化鉄を投入する。
（２）密閉容器内の空気を酸素に置換し、必要に応じて触媒として硝酸を添加する。
（３）密閉容器内の温度を１００℃以上、圧力を０．３ＭＰａ以上に保ち、１～４時間撹拌する。
（４）反応終了後に得られた溶液を冷却し、濾過を行い不溶残渣を除去する。この不溶残渣は、主に原料として投入した酸化鉄であることが確認されている。 (Manufacturing process)
The method for producing ferric polysulfate in the present invention is a production method including the following production steps using the production apparatus outlined in FIG.
(1) Sulfuric acid, water, and iron oxide are put into a closed container.
(2) The air in the closed container is replaced with oxygen, and nitric acid is added as a catalyst if necessary.
(3) Keep the temperature in the closed container at 100 ° C. or higher and the pressure at 0.3 MPa or higher, and stir for 1 to 4 hours.
(4) After completion of the reaction, the obtained solution is cooled and filtered to remove the insoluble residue. It has been confirmed that this insoluble residue is mainly iron oxide added as a raw material.
（酸化鉄）
本願発明で鉄系原料として使用するのは酸化鉄である。ここで、酸化鉄は鉄の酸化物の総称であり、酸化数に応じて酸化第一鉄、酸化第二鉄、四酸化三鉄が組成の異なるものとして知られている。
酸化第一鉄は、酸化鉄（II）（FeO）でウスタイトとして知られ、酸化第二鉄は、酸化鉄（III）（Fe2O3）でヘマタイトないしはマグへマイトとして知られ、四酸化三鉄は、酸化鉄（II、III）でマグネタイトとして知られている。
マグネタイトは、銅製錬過程のスラグ中に多く含まれ、天然の鉱石中に多く含まれるので原料として入手しやすい鉄化合物である。また、磁性を有するため磁力選鉱により精鉱を得やすいという特徴を有する。また、ウスタイトは、発火性のある常温常圧で黒色の固体であり、ヘマタイトないしマグへマイトは、錆の主要成分でもある。いずれも、鉱石として採取される。
本発明では、マグネタイトとウスタイトについて実施例を示すが、ヘマタイトないしマグへマイトについての実施例はない。しかし、前記した特許文献２では、マグネタイトとヘマタイトについて、高温高圧下で硫酸に溶解して硫酸第二鉄溶液を製造している。
このため、本発明のポリ硫酸第二鉄の製造方法は、鉄原料として酸化鉄一般に適用できることは、技術的には明らかである。 (iron oxide)
In the present invention, iron oxide is used as an iron-based raw material. Here, iron oxide is a general term for iron oxides, and ferrous oxide, ferric oxide, and triiron tetroxide are known to have different compositions depending on the number of oxidations.
Ferrous oxide is iron (II) oxide (FeO) known as ustite, and ferric oxide is iron (III) oxide (Fe 2 O 3 ) known as hematite or mughemite, tritetraoxide. Iron is iron oxide (II, III) and is known as magnetite.
Magnetite is an iron compound that is easily available as a raw material because it is abundantly contained in slag in the copper smelting process and abundantly in natural ores. Further, since it has magnetism, it has a feature that it is easy to obtain a concentrate by magnetic dressing. Wüstite is a flammable, normal temperature and pressure black solid, and hematite or mughemite is also a major component of rust. Both are collected as ores.
In the present invention, examples are shown for magnetite and wustite, but there are no examples for hematite or mughemite. However, in Patent Document 2 described above, magnetite and hematite are dissolved in sulfuric acid under high temperature and high pressure to produce a ferric sulfate solution.
Therefore, it is technically clear that the method for producing ferric polysulfate of the present invention can be generally applied to iron oxide as an iron raw material.
本願発明で鉄系原料として使用するのは酸化鉄である。ここで、酸化鉄は鉄の酸化物の総称であり、酸化数に応じて酸化第一鉄、酸化第二鉄、四酸化三鉄が組成の異なるものとして知られている。
酸化第一鉄は、酸化鉄（II）（FeO）でウスタイトとして知られ、酸化第二鉄は、酸化鉄（III）（Fe2O3）でヘマタイトないしはマグへマイトとして知られ、四酸化三鉄は、酸化鉄（II、III）でマグネタイトとして知られている。
マグネタイトは、銅製錬過程のスラグ中に多く含まれ、天然の鉱石中に多く含まれるので原料として入手しやすい鉄化合物である。また、磁性を有するため磁力選鉱により精鉱を得やすいという特徴を有する。また、ウスタイトは、発火性のある常温常圧で黒色の固体であり、ヘマタイトないしマグへマイトは、錆の主要成分でもある。いずれも、鉱石として採取される。
本発明では、マグネタイトとウスタイトについて実施例を示すが、ヘマタイトないしマグへマイトについての実施例はない。しかし、前記した特許文献２では、マグネタイトとヘマタイトについて、高温高圧下で硫酸に溶解して硫酸第二鉄溶液を製造している。
このため、本発明のポリ硫酸第二鉄の製造方法は、鉄原料として酸化鉄一般に適用できることは、技術的には明らかである。 (iron oxide)
In the present invention, iron oxide is used as an iron-based raw material. Here, iron oxide is a general term for iron oxides, and ferrous oxide, ferric oxide, and triiron tetroxide are known to have different compositions depending on the number of oxidations.
Ferrous oxide is iron (II) oxide (FeO) known as ustite, and ferric oxide is iron (III) oxide (Fe 2 O 3 ) known as hematite or mughemite, tritetraoxide. Iron is iron oxide (II, III) and is known as magnetite.
Magnetite is an iron compound that is easily available as a raw material because it is abundantly contained in slag in the copper smelting process and abundantly in natural ores. Further, since it has magnetism, it has a feature that it is easy to obtain a concentrate by magnetic dressing. Wüstite is a flammable, normal temperature and pressure black solid, and hematite or mughemite is also a major component of rust. Both are collected as ores.
In the present invention, examples are shown for magnetite and wustite, but there are no examples for hematite or mughemite. However, in Patent Document 2 described above, magnetite and hematite are dissolved in sulfuric acid under high temperature and high pressure to produce a ferric sulfate solution.
Therefore, it is technically clear that the method for producing ferric polysulfate of the present invention can be generally applied to iron oxide as an iron raw material.
（硫酸イオンと全鉄のモル比）
本発明においては、原料として密閉容器中に投入する酸化鉄と硫酸溶液の、硫酸イオンと全鉄のモル比（硫酸イオン／全鉄）を１．５未満に設定することが好ましい。
従来技術において行われてきたように、酸化鉄の溶解を優先するために大量の硫酸を投入する場合には、ポリ硫酸第二鉄溶液を製造することができない。本発明の発明者らは、前記モル比を１．５未満に設定しないと、目的とするポリ硫酸第二鉄溶液が製造できないことを、経験上承知している。 (Mole ratio of sulfate ion to total iron)
In the present invention, it is preferable to set the molar ratio of sulfate ion to total iron (sulfate ion / total iron) of the iron oxide and sulfuric acid solution to be put into a closed container as a raw material to less than 1.5.
As has been done in the prior art, when a large amount of sulfuric acid is added in order to prioritize the dissolution of iron oxide, a ferric polysulfate solution cannot be produced. The inventors of the present invention are empirically aware that the target ferric sulfate solution cannot be produced unless the molar ratio is set to less than 1.5.
本発明においては、原料として密閉容器中に投入する酸化鉄と硫酸溶液の、硫酸イオンと全鉄のモル比（硫酸イオン／全鉄）を１．５未満に設定することが好ましい。
従来技術において行われてきたように、酸化鉄の溶解を優先するために大量の硫酸を投入する場合には、ポリ硫酸第二鉄溶液を製造することができない。本発明の発明者らは、前記モル比を１．５未満に設定しないと、目的とするポリ硫酸第二鉄溶液が製造できないことを、経験上承知している。 (Mole ratio of sulfate ion to total iron)
In the present invention, it is preferable to set the molar ratio of sulfate ion to total iron (sulfate ion / total iron) of the iron oxide and sulfuric acid solution to be put into a closed container as a raw material to less than 1.5.
As has been done in the prior art, when a large amount of sulfuric acid is added in order to prioritize the dissolution of iron oxide, a ferric polysulfate solution cannot be produced. The inventors of the present invention are empirically aware that the target ferric sulfate solution cannot be produced unless the molar ratio is set to less than 1.5.
（反応温度と圧力）
容器内の温度は１００℃以上に調整することが好ましい。
反応温度が１００℃に満たないと酸化鉄の溶解と酸化反応が十分に進行しない。
本発明の反応圧力は、製造コスト等を考慮して現実的な条件を設定すればよく、一般的には反応圧力が０．３ＭＰａ以上であればよい。０．２ＭＰａで反応させた場合には、鉄と硫酸の化合物からなる残渣が比較的多く発生するため、製造されるポリ硫酸第二鉄溶液の回収率やポリ硫酸第二鉄中に含有される全鉄濃度が低下してしまい好ましくはない。 (Reaction temperature and pressure)
The temperature inside the container is preferably adjusted to 100 ° C. or higher.
If the reaction temperature is less than 100 ° C., the dissolution of iron oxide and the oxidation reaction do not proceed sufficiently.
The reaction pressure of the present invention may be set to realistic conditions in consideration of manufacturing cost and the like, and generally, the reaction pressure may be 0.3 MPa or more. When the reaction is carried out at 0.2 MPa, a relatively large amount of residue consisting of a compound of iron and sulfuric acid is generated, so that it is contained in the recovered rate of the produced ferric polysulfate solution and in ferric polysulfate. It is not preferable because the total iron concentration decreases.
容器内の温度は１００℃以上に調整することが好ましい。
反応温度が１００℃に満たないと酸化鉄の溶解と酸化反応が十分に進行しない。
本発明の反応圧力は、製造コスト等を考慮して現実的な条件を設定すればよく、一般的には反応圧力が０．３ＭＰａ以上であればよい。０．２ＭＰａで反応させた場合には、鉄と硫酸の化合物からなる残渣が比較的多く発生するため、製造されるポリ硫酸第二鉄溶液の回収率やポリ硫酸第二鉄中に含有される全鉄濃度が低下してしまい好ましくはない。 (Reaction temperature and pressure)
The temperature inside the container is preferably adjusted to 100 ° C. or higher.
If the reaction temperature is less than 100 ° C., the dissolution of iron oxide and the oxidation reaction do not proceed sufficiently.
The reaction pressure of the present invention may be set to realistic conditions in consideration of manufacturing cost and the like, and generally, the reaction pressure may be 0.3 MPa or more. When the reaction is carried out at 0.2 MPa, a relatively large amount of residue consisting of a compound of iron and sulfuric acid is generated, so that it is contained in the recovered rate of the produced ferric polysulfate solution and in ferric polysulfate. It is not preferable because the total iron concentration decreases.
（酸化触媒）
本発明においては、密閉容器内に反応原料とともに酸化触媒を投入することができる。
本発明では、密閉容器内での反応において、気相を置換した酸素によって酸化反応を促進し、反応速度を向上させ、全鉄濃度の高いポリ硫酸第二鉄を製造している。また、酸素置換した密閉容器中に酸化触媒があれば、硫酸に溶解した二価の鉄イオンの酸化をさらに促進して、ポリ硫酸第二鉄の生成効率を向上させることができるので好ましい。
酸化触媒としては、溶解した二価の鉄イオンを酸化する作用を有する触媒であれば何でもよい。亜硝酸ソーダ、硝酸カリウム等が挙げられるが、酸化触媒としての作用の他、酸化剤としても機能すると考えられるという点から、触媒としては硝酸を使用することが最も好ましい。 (Oxidation catalyst)
In the present invention, the oxidation catalyst can be put into the closed container together with the reaction raw material.
In the present invention, in the reaction in a closed container, the oxidation reaction is promoted by oxygen substituting the gas phase to improve the reaction rate, and ferric polysulfate having a high total iron concentration is produced. Further, if the oxidation catalyst is contained in the oxygen-substituted closed container, it is preferable because the oxidation of divalent iron ions dissolved in sulfuric acid can be further promoted and the production efficiency of ferric polysulfate can be improved.
The oxidation catalyst may be any catalyst having an action of oxidizing dissolved divalent iron ions. Examples thereof include sodium nitrite and potassium nitrate, but it is most preferable to use nitric acid as the catalyst because it is considered that it also functions as an oxidizing agent in addition to acting as an oxidation catalyst.
本発明においては、密閉容器内に反応原料とともに酸化触媒を投入することができる。
本発明では、密閉容器内での反応において、気相を置換した酸素によって酸化反応を促進し、反応速度を向上させ、全鉄濃度の高いポリ硫酸第二鉄を製造している。また、酸素置換した密閉容器中に酸化触媒があれば、硫酸に溶解した二価の鉄イオンの酸化をさらに促進して、ポリ硫酸第二鉄の生成効率を向上させることができるので好ましい。
酸化触媒としては、溶解した二価の鉄イオンを酸化する作用を有する触媒であれば何でもよい。亜硝酸ソーダ、硝酸カリウム等が挙げられるが、酸化触媒としての作用の他、酸化剤としても機能すると考えられるという点から、触媒としては硝酸を使用することが最も好ましい。 (Oxidation catalyst)
In the present invention, the oxidation catalyst can be put into the closed container together with the reaction raw material.
In the present invention, in the reaction in a closed container, the oxidation reaction is promoted by oxygen substituting the gas phase to improve the reaction rate, and ferric polysulfate having a high total iron concentration is produced. Further, if the oxidation catalyst is contained in the oxygen-substituted closed container, it is preferable because the oxidation of divalent iron ions dissolved in sulfuric acid can be further promoted and the production efficiency of ferric polysulfate can be improved.
The oxidation catalyst may be any catalyst having an action of oxidizing dissolved divalent iron ions. Examples thereof include sodium nitrite and potassium nitrate, but it is most preferable to use nitric acid as the catalyst because it is considered that it also functions as an oxidizing agent in addition to acting as an oxidation catalyst.
（溶解と酸化反応）
密閉容器中の高温高圧条件下で鉄系原料の溶解と二価の鉄イオンの酸化反応が開始すると、気相部分の酸素が酸化剤として作用する。また、原料液中に酸化触媒があれば触媒として作用するし、酸化触媒が硝酸であれば酸化剤としても作用する。
酸素置換と触媒添加を併用した場合、高温高圧条件下での酸素と触媒との相乗的効果により、従来の技術知見では予測のできなかった高濃度のポリ硫酸第二鉄溶液が形成されることができる。 (Dissolution and oxidation reaction)
When the dissolution of the iron-based raw material and the oxidation reaction of divalent iron ions are started under the high temperature and high pressure conditions in the closed container, oxygen in the vapor phase portion acts as an oxidant. Further, if the raw material liquid contains an oxidation catalyst, it acts as a catalyst, and if the oxidation catalyst is nitric acid, it also acts as an oxidizing agent.
When oxygen substitution and catalyst addition are used together, a high-concentration ferric sulfate solution that could not be predicted by conventional technical knowledge is formed due to the synergistic effect of oxygen and the catalyst under high temperature and high pressure conditions. Can be done.
密閉容器中の高温高圧条件下で鉄系原料の溶解と二価の鉄イオンの酸化反応が開始すると、気相部分の酸素が酸化剤として作用する。また、原料液中に酸化触媒があれば触媒として作用するし、酸化触媒が硝酸であれば酸化剤としても作用する。
酸素置換と触媒添加を併用した場合、高温高圧条件下での酸素と触媒との相乗的効果により、従来の技術知見では予測のできなかった高濃度のポリ硫酸第二鉄溶液が形成されることができる。 (Dissolution and oxidation reaction)
When the dissolution of the iron-based raw material and the oxidation reaction of divalent iron ions are started under the high temperature and high pressure conditions in the closed container, oxygen in the vapor phase portion acts as an oxidant. Further, if the raw material liquid contains an oxidation catalyst, it acts as a catalyst, and if the oxidation catalyst is nitric acid, it also acts as an oxidizing agent.
When oxygen substitution and catalyst addition are used together, a high-concentration ferric sulfate solution that could not be predicted by conventional technical knowledge is formed due to the synergistic effect of oxygen and the catalyst under high temperature and high pressure conditions. Can be done.
本発明の発明者らは、本発明では、従来技術では達成できない高濃度のポリ硫酸第二鉄を短時間で効率的に製造できる理由を、次のとおりのものと推測している。しかし、本発明の技術的な解釈は、この推測には何ら拘束されるものではない。
従来技術における硫酸第二鉄の製造方法では、酸化鉄原料は、圧力容器中で高温高圧の硫酸溶液中で溶解して二価と三価の鉄イオンを含有する溶液を形成し、この溶液を圧力容器から取り出した後に酸化剤を添加し、残存していた二価の鉄イオンを酸化してポリ硫酸第二鉄溶液を製造していた（特許文献１）。しかし、この方法では、圧力容器中で形成された二価の鉄イオンの一部が硫酸と反応して鉄・硫酸化合物を形成して反応溶液から析出してしまっていた。
本発明では、密閉容器中で溶出した二価の鉄イオンに対し、当該密閉容器内にある酸素ガスが直ちに酸化剤として作用するので、二価の鉄イオンが鉄・硫酸化合物として析出することを防ぎ、高濃度のポリ硫酸第二鉄を効率的に形成することが可能になった。
これは、本発明者らが新たに見出した技術知見であり、本発明はこの知見に基づいてなされたものである。 The inventors of the present invention presume that, in the present invention, the reason why a high concentration of ferric polysulfate, which cannot be achieved by the prior art, can be efficiently produced in a short time is as follows. However, the technical interpretation of the present invention is not bound by this conjecture.
In the method for producing ferric sulfate in the prior art, the iron oxide raw material is dissolved in a high-temperature and high-pressure sulfuric acid solution in a pressure vessel to form a solution containing divalent and trivalent iron ions, and this solution is prepared. After taking it out of the pressure vessel, an oxidizing agent was added to oxidize the remaining divalent iron ions to produce a ferric polysulfate solution (Patent Document 1). However, in this method, a part of the divalent iron ions formed in the pressure vessel react with sulfuric acid to form an iron / sulfuric acid compound, which is precipitated from the reaction solution.
In the present invention, the oxygen gas in the closed container immediately acts as an oxidant on the divalent iron ions eluted in the closed container, so that the divalent iron ions are precipitated as an iron / sulfuric acid compound. It was possible to prevent and efficiently form a high concentration of ferric polysulfate.
This is a technical finding newly discovered by the present inventors, and the present invention has been made based on this finding.
従来技術における硫酸第二鉄の製造方法では、酸化鉄原料は、圧力容器中で高温高圧の硫酸溶液中で溶解して二価と三価の鉄イオンを含有する溶液を形成し、この溶液を圧力容器から取り出した後に酸化剤を添加し、残存していた二価の鉄イオンを酸化してポリ硫酸第二鉄溶液を製造していた（特許文献１）。しかし、この方法では、圧力容器中で形成された二価の鉄イオンの一部が硫酸と反応して鉄・硫酸化合物を形成して反応溶液から析出してしまっていた。
本発明では、密閉容器中で溶出した二価の鉄イオンに対し、当該密閉容器内にある酸素ガスが直ちに酸化剤として作用するので、二価の鉄イオンが鉄・硫酸化合物として析出することを防ぎ、高濃度のポリ硫酸第二鉄を効率的に形成することが可能になった。
これは、本発明者らが新たに見出した技術知見であり、本発明はこの知見に基づいてなされたものである。 The inventors of the present invention presume that, in the present invention, the reason why a high concentration of ferric polysulfate, which cannot be achieved by the prior art, can be efficiently produced in a short time is as follows. However, the technical interpretation of the present invention is not bound by this conjecture.
In the method for producing ferric sulfate in the prior art, the iron oxide raw material is dissolved in a high-temperature and high-pressure sulfuric acid solution in a pressure vessel to form a solution containing divalent and trivalent iron ions, and this solution is prepared. After taking it out of the pressure vessel, an oxidizing agent was added to oxidize the remaining divalent iron ions to produce a ferric polysulfate solution (Patent Document 1). However, in this method, a part of the divalent iron ions formed in the pressure vessel react with sulfuric acid to form an iron / sulfuric acid compound, which is precipitated from the reaction solution.
In the present invention, the oxygen gas in the closed container immediately acts as an oxidant on the divalent iron ions eluted in the closed container, so that the divalent iron ions are precipitated as an iron / sulfuric acid compound. It was possible to prevent and efficiently form a high concentration of ferric polysulfate.
This is a technical finding newly discovered by the present inventors, and the present invention has been made based on this finding.
［実施例１］
内容量1Lの密閉容器にマグネタイトを221ｇと、硫酸とをSO4 2-イオン／鉄イオンのモル比が1.3となるように投入し、触媒として硝酸を2.7g投入した。密閉容器を閉じ、前記密閉容器内の気相部分を酸素に置換し、前記密閉容器に装備されているヒーターと酸素ボンベを用い、スラリーの温度を130℃、密閉容器内の気相部分の圧力を1.0MPaまで昇温・昇圧し、1時間反応を行った。なお、反応中は、密閉容器内の気相部分の温度・圧力を130℃、1.0MPaに保持した。反応時間１時間が経過した後、密閉容器中からスラリーを分取し、スラリーを冷却した。
冷却したスラリーに含有されている二価鉄の濃度を測定することにより、反応の終点を判断した。その後、スラリーの濾過を行い、ポリ硫酸第二鉄の製品を得た。 [Example 1]
In a closed container with a content of 1 L, 221 g of magnetite and sulfuric acid were added so that the molar ratio of SO 4 2- ion / iron ion was 1.3, and 2.7 g of nitric acid was added as a catalyst. Close the closed container, replace the gas phase part in the closed container with oxygen, use the heater and oxygen cylinder equipped in the closed container, set the temperature of the slurry to 130 ° C, and the pressure of the gas phase part in the closed container. The temperature was raised and increased to 1.0 MPa, and the reaction was carried out for 1 hour. During the reaction, the temperature and pressure of the gas phase portion in the closed container were maintained at 130 ° C. and 1.0 MPa. After the reaction time of 1 hour had elapsed, the slurry was separated from the closed container and the slurry was cooled.
The end point of the reaction was determined by measuring the concentration of ferrous iron contained in the cooled slurry. Then, the slurry was filtered to obtain a product of ferric polysulfate.
内容量1Lの密閉容器にマグネタイトを221ｇと、硫酸とをSO4 2-イオン／鉄イオンのモル比が1.3となるように投入し、触媒として硝酸を2.7g投入した。密閉容器を閉じ、前記密閉容器内の気相部分を酸素に置換し、前記密閉容器に装備されているヒーターと酸素ボンベを用い、スラリーの温度を130℃、密閉容器内の気相部分の圧力を1.0MPaまで昇温・昇圧し、1時間反応を行った。なお、反応中は、密閉容器内の気相部分の温度・圧力を130℃、1.0MPaに保持した。反応時間１時間が経過した後、密閉容器中からスラリーを分取し、スラリーを冷却した。
冷却したスラリーに含有されている二価鉄の濃度を測定することにより、反応の終点を判断した。その後、スラリーの濾過を行い、ポリ硫酸第二鉄の製品を得た。 [Example 1]
In a closed container with a content of 1 L, 221 g of magnetite and sulfuric acid were added so that the molar ratio of SO 4 2- ion / iron ion was 1.3, and 2.7 g of nitric acid was added as a catalyst. Close the closed container, replace the gas phase part in the closed container with oxygen, use the heater and oxygen cylinder equipped in the closed container, set the temperature of the slurry to 130 ° C, and the pressure of the gas phase part in the closed container. The temperature was raised and increased to 1.0 MPa, and the reaction was carried out for 1 hour. During the reaction, the temperature and pressure of the gas phase portion in the closed container were maintained at 130 ° C. and 1.0 MPa. After the reaction time of 1 hour had elapsed, the slurry was separated from the closed container and the slurry was cooled.
The end point of the reaction was determined by measuring the concentration of ferrous iron contained in the cooled slurry. Then, the slurry was filtered to obtain a product of ferric polysulfate.
得られたポリ硫酸第二鉄は、全鉄濃度(T-Fe)が15.9%と高濃度のものであった。また、二価の鉄イオン濃度(Fe2+)が0.01%未満であり、鉄イオンは全て酸化されて三価のイオンになっていた。硫酸イオン濃度は36.7%、SO4
2-/T-Feモル比は1.34であった。原料から製品へ分配された鉄の割合（鉄溶解率）は91.9％であった。また、残渣はマグネタイトであった。
二価の鉄イオン濃度(Fe2+)が0.01%未満であったので、ポリ硫酸第二鉄の生成反応は１時間以内に完了していたことが分かる。また、SO4 2-/T-Feモル比が1.34であり、1.5より小さい値であるので、ポリ硫酸第二鉄が形成されていることが分かる。 The obtained ferric polysulfate had a high total iron concentration (T-Fe) of 15.9%. In addition, the divalent iron ion concentration (Fe 2+ ) was less than 0.01%, and all iron ions were oxidized to trivalent ions. The sulfate ion concentration was 36.7%, and the SO 4 2- / T-Fe molar ratio was 1.34. The proportion of iron distributed from the raw material to the product (iron solubility) was 91.9%. The residue was magnetite.
Since the divalent iron ion concentration (Fe 2+ ) was less than 0.01%, it can be seen that the reaction for producing ferric polysulfate was completed within 1 hour. Moreover, since the SO 4 2- / T-Fe molar ratio is 1.34, which is smaller than 1.5, it can be seen that ferric polysulfate is formed.
二価の鉄イオン濃度(Fe2+)が0.01%未満であったので、ポリ硫酸第二鉄の生成反応は１時間以内に完了していたことが分かる。また、SO4 2-/T-Feモル比が1.34であり、1.5より小さい値であるので、ポリ硫酸第二鉄が形成されていることが分かる。 The obtained ferric polysulfate had a high total iron concentration (T-Fe) of 15.9%. In addition, the divalent iron ion concentration (Fe 2+ ) was less than 0.01%, and all iron ions were oxidized to trivalent ions. The sulfate ion concentration was 36.7%, and the SO 4 2- / T-Fe molar ratio was 1.34. The proportion of iron distributed from the raw material to the product (iron solubility) was 91.9%. The residue was magnetite.
Since the divalent iron ion concentration (Fe 2+ ) was less than 0.01%, it can be seen that the reaction for producing ferric polysulfate was completed within 1 hour. Moreover, since the SO 4 2- / T-Fe molar ratio is 1.34, which is smaller than 1.5, it can be seen that ferric polysulfate is formed.
［実施例２］(反応槽気相圧力：0.3MPa)
密閉容器内の気相部分の圧力を0.3MPa、反応時間を2時間とした以外は、実施例1と同一の条件で反応を行い、得られたスラリーを冷却した。
冷却したスラリーに含有されている二価鉄の濃度を測定することにより、反応の終点を判断した。その後、スラリーの濾過を行い、ポリ硫酸第二鉄の製品を得た。 [Example 2] (Reaction tank gas phase pressure: 0.3 MPa)
The reaction was carried out under the same conditions as in Example 1 except that the pressure of the gas phase portion in the closed container was 0.3 MPa and the reaction time was 2 hours, and the obtained slurry was cooled.
The end point of the reaction was determined by measuring the concentration of ferrous iron contained in the cooled slurry. Then, the slurry was filtered to obtain a product of ferric polysulfate.
密閉容器内の気相部分の圧力を0.3MPa、反応時間を2時間とした以外は、実施例1と同一の条件で反応を行い、得られたスラリーを冷却した。
冷却したスラリーに含有されている二価鉄の濃度を測定することにより、反応の終点を判断した。その後、スラリーの濾過を行い、ポリ硫酸第二鉄の製品を得た。 [Example 2] (Reaction tank gas phase pressure: 0.3 MPa)
The reaction was carried out under the same conditions as in Example 1 except that the pressure of the gas phase portion in the closed container was 0.3 MPa and the reaction time was 2 hours, and the obtained slurry was cooled.
The end point of the reaction was determined by measuring the concentration of ferrous iron contained in the cooled slurry. Then, the slurry was filtered to obtain a product of ferric polysulfate.
得られたポリ硫酸第二鉄は、全鉄濃度(T-Fe)が14.7%と高濃度のものであった。また、二価の鉄イオン濃度(Fe2+)が0.01%未満であり、鉄イオンは全て酸化されて三価のイオンになっていた。硫酸イオン濃度は37.5%、SO4
2-/T-Feモル比は1.48であった。原料から製品へ分配された鉄の割合（鉄溶解率）は84.5％であった。また、残渣はマグネタイトであった。
二価の鉄イオン濃度(Fe2+)が0.01%未満であったので、ポリ硫酸第二鉄の生成反応は2時間以内に完了していたことが分かる。また、SO4 2-/T-Feモル比が1.48であり、1.5より小さい値であるので、ポリ硫酸第二鉄が形成されていることが分かる。 The obtained ferric polysulfate had a high total iron concentration (T-Fe) of 14.7%. In addition, the divalent iron ion concentration (Fe 2+ ) was less than 0.01%, and all iron ions were oxidized to trivalent ions. The sulfate ion concentration was 37.5% and the SO 4 2- / T-Fe molar ratio was 1.48. The proportion of iron distributed from the raw material to the product (iron solubility) was 84.5%. The residue was magnetite.
Since the divalent iron ion concentration (Fe 2+ ) was less than 0.01%, it can be seen that the reaction for producing ferric polysulfate was completed within 2 hours. Moreover, since the SO 4 2- / T-Fe molar ratio is 1.48, which is smaller than 1.5, it can be seen that ferric polysulfate is formed.
二価の鉄イオン濃度(Fe2+)が0.01%未満であったので、ポリ硫酸第二鉄の生成反応は2時間以内に完了していたことが分かる。また、SO4 2-/T-Feモル比が1.48であり、1.5より小さい値であるので、ポリ硫酸第二鉄が形成されていることが分かる。 The obtained ferric polysulfate had a high total iron concentration (T-Fe) of 14.7%. In addition, the divalent iron ion concentration (Fe 2+ ) was less than 0.01%, and all iron ions were oxidized to trivalent ions. The sulfate ion concentration was 37.5% and the SO 4 2- / T-Fe molar ratio was 1.48. The proportion of iron distributed from the raw material to the product (iron solubility) was 84.5%. The residue was magnetite.
Since the divalent iron ion concentration (Fe 2+ ) was less than 0.01%, it can be seen that the reaction for producing ferric polysulfate was completed within 2 hours. Moreover, since the SO 4 2- / T-Fe molar ratio is 1.48, which is smaller than 1.5, it can be seen that ferric polysulfate is formed.
［実施例３］(低鉄濃度原料)
内容量1Lの密閉容器に鉄濃度が52.1%のマグネタイトを298ｇと、硫酸とをSO4 2-イオン／鉄イオンのモル比が1.3となるように投入し、反応時間を4時間とした以外は、実施例1と同一の条件で反応を行い、得られたスラリーを冷却した。
冷却したスラリーに含有されている二価鉄の濃度を測定することにより、反応の終点を判断した。その後、スラリーの濾過を行い、ポリ硫酸第二鉄の製品を得た。 [Example 3] (Low iron concentration raw material)
Except for the fact that 298 g of magnetite with an iron concentration of 52.1% and sulfuric acid were added to a closed container with a content of 1 L so that the molar ratio of SO 4 2- ion / iron ion was 1.3, and the reaction time was set to 4 hours. , The reaction was carried out under the same conditions as in Example 1, and the obtained slurry was cooled.
The end point of the reaction was determined by measuring the concentration of ferrous iron contained in the cooled slurry. Then, the slurry was filtered to obtain a product of ferric polysulfate.
内容量1Lの密閉容器に鉄濃度が52.1%のマグネタイトを298ｇと、硫酸とをSO4 2-イオン／鉄イオンのモル比が1.3となるように投入し、反応時間を4時間とした以外は、実施例1と同一の条件で反応を行い、得られたスラリーを冷却した。
冷却したスラリーに含有されている二価鉄の濃度を測定することにより、反応の終点を判断した。その後、スラリーの濾過を行い、ポリ硫酸第二鉄の製品を得た。 [Example 3] (Low iron concentration raw material)
Except for the fact that 298 g of magnetite with an iron concentration of 52.1% and sulfuric acid were added to a closed container with a content of 1 L so that the molar ratio of SO 4 2- ion / iron ion was 1.3, and the reaction time was set to 4 hours. , The reaction was carried out under the same conditions as in Example 1, and the obtained slurry was cooled.
The end point of the reaction was determined by measuring the concentration of ferrous iron contained in the cooled slurry. Then, the slurry was filtered to obtain a product of ferric polysulfate.
得られたポリ硫酸第二鉄は、全鉄濃度(T-Fe)が16.3%と高濃度のものであった。また、二価の鉄イオン濃度(Fe2+)が0.01%未満であり、鉄イオンは全て酸化されて三価のイオンになっていた。硫酸イオン濃度は40.3%、SO4
2-/T-Feモル比は1.44であった。原料から製品へ分配された鉄の割合（鉄溶解率）は83.6％であった。また、残渣はマグネタイトであった。
二価の鉄イオン濃度(Fe2+)が0.01%未満であったので、ポリ硫酸第二鉄の生成反応は4時間以内に完了していたことが分かる。また、SO4 2-/T-Feモル比が1.44であり、1.5より小さい値であるので、ポリ硫酸第二鉄が形成されていることが分かる。 The obtained ferric sulfate had a high total iron concentration (T-Fe) of 16.3%. In addition, the divalent iron ion concentration (Fe 2+ ) was less than 0.01%, and all iron ions were oxidized to trivalent ions. The sulfate ion concentration was 40.3% and the SO 4 2- / T-Fe molar ratio was 1.44. The proportion of iron distributed from the raw material to the product (iron solubility) was 83.6%. The residue was magnetite.
Since the divalent iron ion concentration (Fe 2+ ) was less than 0.01%, it can be seen that the reaction for producing ferric polysulfate was completed within 4 hours. Moreover, since the SO 4 2- / T-Fe molar ratio is 1.44, which is smaller than 1.5, it can be seen that ferric polysulfate is formed.
二価の鉄イオン濃度(Fe2+)が0.01%未満であったので、ポリ硫酸第二鉄の生成反応は4時間以内に完了していたことが分かる。また、SO4 2-/T-Feモル比が1.44であり、1.5より小さい値であるので、ポリ硫酸第二鉄が形成されていることが分かる。 The obtained ferric sulfate had a high total iron concentration (T-Fe) of 16.3%. In addition, the divalent iron ion concentration (Fe 2+ ) was less than 0.01%, and all iron ions were oxidized to trivalent ions. The sulfate ion concentration was 40.3% and the SO 4 2- / T-Fe molar ratio was 1.44. The proportion of iron distributed from the raw material to the product (iron solubility) was 83.6%. The residue was magnetite.
Since the divalent iron ion concentration (Fe 2+ ) was less than 0.01%, it can be seen that the reaction for producing ferric polysulfate was completed within 4 hours. Moreover, since the SO 4 2- / T-Fe molar ratio is 1.44, which is smaller than 1.5, it can be seen that ferric polysulfate is formed.
［実施例４］(ウスタイト)
内容量1Lの密閉容器にウスタイト(鉄濃度：74.2%)を210ｇと、硫酸とをSO4 2-イオン／鉄イオンのモル比が1.3となるように投入しとした以外は、実施例1と同一の条件で反応を行い、得られたスラリーを冷却した。
冷却したスラリーに含有されている二価鉄の濃度を測定することにより、反応の終点を判断した。その後、スラリーの濾過を行い、ポリ硫酸第二鉄の製品を得た。 [Example 4] (Wustite)
Example 1 except that 210 g of wustite (iron concentration: 74.2%) and sulfuric acid were added to a closed container with a content of 1 L so that the molar ratio of SO 4 2- ion / iron ion was 1.3. The reaction was carried out under the same conditions, and the obtained slurry was cooled.
The end point of the reaction was determined by measuring the concentration of ferrous iron contained in the cooled slurry. Then, the slurry was filtered to obtain a product of ferric polysulfate.
内容量1Lの密閉容器にウスタイト(鉄濃度：74.2%)を210ｇと、硫酸とをSO4 2-イオン／鉄イオンのモル比が1.3となるように投入しとした以外は、実施例1と同一の条件で反応を行い、得られたスラリーを冷却した。
冷却したスラリーに含有されている二価鉄の濃度を測定することにより、反応の終点を判断した。その後、スラリーの濾過を行い、ポリ硫酸第二鉄の製品を得た。 [Example 4] (Wustite)
Example 1 except that 210 g of wustite (iron concentration: 74.2%) and sulfuric acid were added to a closed container with a content of 1 L so that the molar ratio of SO 4 2- ion / iron ion was 1.3. The reaction was carried out under the same conditions, and the obtained slurry was cooled.
The end point of the reaction was determined by measuring the concentration of ferrous iron contained in the cooled slurry. Then, the slurry was filtered to obtain a product of ferric polysulfate.
得られたポリ硫酸第二鉄は、全鉄濃度(T-Fe)が14.6%と高濃度のものであった。また、二価の鉄イオン濃度(Fe2+)が0.01%未満であり、鉄イオンは全て酸化されて三価のイオンになっていた。硫酸イオン濃度は37.2%、SO4
2-/T-Feモル比は1.48であった。原料から製品へ分配された鉄の割合（鉄溶解率）は84.1％であった。また、残渣はウスタイト、マグネタイト、ヘマタイトであった。
二価の鉄イオン濃度(Fe2+)が0.01%未満であったので、ポリ硫酸第二鉄の生成反応は１時間以内に完了していたことが分かる。また、SO4 2-/T-Feモル比が1.48であり、1.5より小さい値であるので、ポリ硫酸第二鉄が形成されていることが分かる。 The obtained ferric sulfate had a high total iron concentration (T-Fe) of 14.6%. In addition, the divalent iron ion concentration (Fe 2+ ) was less than 0.01%, and all iron ions were oxidized to trivalent ions. The sulfate ion concentration was 37.2%, and the SO 4 2- / T-Fe molar ratio was 1.48. The proportion of iron distributed from the raw material to the product (iron solubility) was 84.1%. The residues were wustite, magnetite and hematite.
Since the divalent iron ion concentration (Fe 2+ ) was less than 0.01%, it can be seen that the reaction for producing ferric polysulfate was completed within 1 hour. Moreover, since the SO 4 2- / T-Fe molar ratio is 1.48, which is smaller than 1.5, it can be seen that ferric polysulfate is formed.
二価の鉄イオン濃度(Fe2+)が0.01%未満であったので、ポリ硫酸第二鉄の生成反応は１時間以内に完了していたことが分かる。また、SO4 2-/T-Feモル比が1.48であり、1.5より小さい値であるので、ポリ硫酸第二鉄が形成されていることが分かる。 The obtained ferric sulfate had a high total iron concentration (T-Fe) of 14.6%. In addition, the divalent iron ion concentration (Fe 2+ ) was less than 0.01%, and all iron ions were oxidized to trivalent ions. The sulfate ion concentration was 37.2%, and the SO 4 2- / T-Fe molar ratio was 1.48. The proportion of iron distributed from the raw material to the product (iron solubility) was 84.1%. The residues were wustite, magnetite and hematite.
Since the divalent iron ion concentration (Fe 2+ ) was less than 0.01%, it can be seen that the reaction for producing ferric polysulfate was completed within 1 hour. Moreover, since the SO 4 2- / T-Fe molar ratio is 1.48, which is smaller than 1.5, it can be seen that ferric polysulfate is formed.
［比較例１］
内容量1Lの密閉容器にマグネタイトを221ｇと、硫酸とをSO4 2-イオン／鉄イオンのモル比が1.3となるように投入した。密閉容器内の気相を酸素に置換することなく、気相は空気のままに保持して密閉容器を閉じ、前記密閉容器に装備されているヒーターを用い、スラリーの温度を130℃まで昇温し、４時間反応を行った。なお、反応中は、密閉容器内の温度を130℃に保持し、蒸気圧（約０．２MPa）によって圧力を保持した。
反応時間４時間が経過した後、密閉容器中からスラリーを分取し、スラリーを冷却した。 [Comparative Example 1]
221 g of magnetite and sulfuric acid were added to a closed container having a content of 1 L so that the molar ratio of SO 4 2- ion / iron ion was 1.3. Without replacing the gas phase in the closed container with oxygen, the gas phase is kept as air, the closed container is closed, and the temperature of the slurry is raised to 130 ° C. using the heater equipped in the closed container. Then, the reaction was carried out for 4 hours. During the reaction, the temperature inside the closed container was maintained at 130 ° C., and the pressure was maintained by vapor pressure (about 0.2 MPa).
After the reaction time of 4 hours had elapsed, the slurry was separated from the closed container and the slurry was cooled.
内容量1Lの密閉容器にマグネタイトを221ｇと、硫酸とをSO4 2-イオン／鉄イオンのモル比が1.3となるように投入した。密閉容器内の気相を酸素に置換することなく、気相は空気のままに保持して密閉容器を閉じ、前記密閉容器に装備されているヒーターを用い、スラリーの温度を130℃まで昇温し、４時間反応を行った。なお、反応中は、密閉容器内の温度を130℃に保持し、蒸気圧（約０．２MPa）によって圧力を保持した。
反応時間４時間が経過した後、密閉容器中からスラリーを分取し、スラリーを冷却した。 [Comparative Example 1]
221 g of magnetite and sulfuric acid were added to a closed container having a content of 1 L so that the molar ratio of SO 4 2- ion / iron ion was 1.3. Without replacing the gas phase in the closed container with oxygen, the gas phase is kept as air, the closed container is closed, and the temperature of the slurry is raised to 130 ° C. using the heater equipped in the closed container. Then, the reaction was carried out for 4 hours. During the reaction, the temperature inside the closed container was maintained at 130 ° C., and the pressure was maintained by vapor pressure (about 0.2 MPa).
After the reaction time of 4 hours had elapsed, the slurry was separated from the closed container and the slurry was cooled.
冷却したスラリーに含有されている二価鉄の濃度を測定したところ、二価鉄が残存していることを確認した。このため、４時間反応を継続したにもかかわらず、ポリ硫酸第二鉄の生成反応は完了していなかった。反応を完了するため、スラリーを濾過した後、ろ液に対して過酸化水素を41.7g添加し、二価鉄の酸化を完了することでポリ硫酸第二鉄の製品を得た。
得られたポリ硫酸第二鉄の全鉄濃度(T-Fe)は14.2%、二価の鉄イオン濃度(Fe2+)が0.01%未満、硫酸イオン濃度は33.3%、SO4 2-/T-Feモル比は1.36であった。原料から製品へ分配された鉄の割合（鉄溶解率）は76.1％であった。また、残渣はゾモルノカイト（Szomolnokite（Fe(SO4)(H2O)））であった。 When the concentration of ferrous iron contained in the cooled slurry was measured, it was confirmed that divalent iron remained. Therefore, although the reaction was continued for 4 hours, the reaction for producing ferric polysulfate was not completed. To complete the reaction, after filtering the slurry, 41.7 g of hydrogen peroxide was added to the filtrate to complete the oxidation of ferric ferrous sulfate to obtain a product of ferric polysulfate.
The total iron concentration (T-Fe) of the obtained ferric sulfate was 14.2%, the divalent iron ion concentration (Fe 2+ ) was less than 0.01%, the sulfate ion concentration was 33.3%, and SO 4 2- / T. The -Fe molar ratio was 1.36. The proportion of iron distributed from the raw material to the product (iron solubility) was 76.1%. The residue was zomolnokite (Szomolnokite (Fe (SO 4 ) (H 2 O))).
得られたポリ硫酸第二鉄の全鉄濃度(T-Fe)は14.2%、二価の鉄イオン濃度(Fe2+)が0.01%未満、硫酸イオン濃度は33.3%、SO4 2-/T-Feモル比は1.36であった。原料から製品へ分配された鉄の割合（鉄溶解率）は76.1％であった。また、残渣はゾモルノカイト（Szomolnokite（Fe(SO4)(H2O)））であった。 When the concentration of ferrous iron contained in the cooled slurry was measured, it was confirmed that divalent iron remained. Therefore, although the reaction was continued for 4 hours, the reaction for producing ferric polysulfate was not completed. To complete the reaction, after filtering the slurry, 41.7 g of hydrogen peroxide was added to the filtrate to complete the oxidation of ferric ferrous sulfate to obtain a product of ferric polysulfate.
The total iron concentration (T-Fe) of the obtained ferric sulfate was 14.2%, the divalent iron ion concentration (Fe 2+ ) was less than 0.01%, the sulfate ion concentration was 33.3%, and SO 4 2- / T. The -Fe molar ratio was 1.36. The proportion of iron distributed from the raw material to the product (iron solubility) was 76.1%. The residue was zomolnokite (Szomolnokite (Fe (SO 4 ) (H 2 O))).
［比較例２］
昇温前のスラリーに触媒としての硝酸を2.7g投入した以外は比較例１と同一の条件で反応を行い、得られたスラリーを冷却した。
冷却したスラリーに含有されている二価鉄の濃度を測定したところ、二価鉄が残存していることを確認したため、スラリーを濾過した後、ろ液に対して過酸化水素を33.5g添加し、二価鉄の酸化を完了することでポリ硫酸第二鉄の製品を得た。
得られたポリ硫酸第二鉄の全鉄濃度(T-Fe)は13.7%、二価の鉄イオン濃度(Fe2+)が0.01%未満、硫酸イオン濃度は34.7%、SO4 2-/T-Feモル比は1.47であった。原料から製品へ分配された鉄の割合（鉄溶解率）は72.4％であった。また、残渣は水酸化鉄硫酸塩（Iron hydroxide sulfate（Fe(SO4)2H））であった。 [Comparative Example 2]
The reaction was carried out under the same conditions as in Comparative Example 1 except that 2.7 g of nitric acid as a catalyst was added to the slurry before the temperature was raised, and the obtained slurry was cooled.
When the concentration of ferric iron contained in the cooled slurry was measured, it was confirmed that ferric iron remained, so after filtering the slurry, 33.5 g of hydrogen peroxide was added to the filtrate. , A product of ferric polysulfate was obtained by completing the oxidation of ferric ferrous.
The total iron concentration (T-Fe) of the obtained ferric sulfate was 13.7%, the divalent iron ion concentration (Fe 2+ ) was less than 0.01%, the sulfate ion concentration was 34.7%, and SO 4 2- / T. The -Fe molar ratio was 1.47. The proportion of iron distributed from the raw material to the product (iron solubility) was 72.4%. The residue was iron hydroxide sulfate (Fe (SO 4 ) 2 H).
昇温前のスラリーに触媒としての硝酸を2.7g投入した以外は比較例１と同一の条件で反応を行い、得られたスラリーを冷却した。
冷却したスラリーに含有されている二価鉄の濃度を測定したところ、二価鉄が残存していることを確認したため、スラリーを濾過した後、ろ液に対して過酸化水素を33.5g添加し、二価鉄の酸化を完了することでポリ硫酸第二鉄の製品を得た。
得られたポリ硫酸第二鉄の全鉄濃度(T-Fe)は13.7%、二価の鉄イオン濃度(Fe2+)が0.01%未満、硫酸イオン濃度は34.7%、SO4 2-/T-Feモル比は1.47であった。原料から製品へ分配された鉄の割合（鉄溶解率）は72.4％であった。また、残渣は水酸化鉄硫酸塩（Iron hydroxide sulfate（Fe(SO4)2H））であった。 [Comparative Example 2]
The reaction was carried out under the same conditions as in Comparative Example 1 except that 2.7 g of nitric acid as a catalyst was added to the slurry before the temperature was raised, and the obtained slurry was cooled.
When the concentration of ferric iron contained in the cooled slurry was measured, it was confirmed that ferric iron remained, so after filtering the slurry, 33.5 g of hydrogen peroxide was added to the filtrate. , A product of ferric polysulfate was obtained by completing the oxidation of ferric ferrous.
The total iron concentration (T-Fe) of the obtained ferric sulfate was 13.7%, the divalent iron ion concentration (Fe 2+ ) was less than 0.01%, the sulfate ion concentration was 34.7%, and SO 4 2- / T. The -Fe molar ratio was 1.47. The proportion of iron distributed from the raw material to the product (iron solubility) was 72.4%. The residue was iron hydroxide sulfate (Fe (SO 4 ) 2 H).
実施例１～４と比較例１、２について、鉄原料、反応条件および生成されたポリ硫酸第二鉄の特性をまとめると表１の通りとなる。
実施例１～４において反応はそれぞれ１～４時間以内で完了したが、比較例１、２では高温高圧に４時間保持しても酸化反応が完了せず、二価鉄が酸化されずに残ってしまっていた。そこで、スラリーに残存する二価鉄を全て三価鉄に酸化するために過酸化水素水を添加した。
このため、比較例１、２における生成物の特性は、いずれも、追加的にH2O2を添加して酸化反応を完了させた後の生成物の特性を表す。 Table 1 summarizes the iron raw materials, reaction conditions, and the characteristics of the ferric polysulfate produced for Examples 1 to 4 and Comparative Examples 1 and 2.
In Examples 1 to 4, the reactions were completed within 1 to 4 hours, respectively, but in Comparative Examples 1 and 2, the oxidation reaction was not completed even if the mixture was held at high temperature and high pressure for 4 hours, and the divalent iron remained unoxidized. It had been done. Therefore, a hydrogen peroxide solution was added to oxidize all the divalent iron remaining in the slurry to ferric iron.
Therefore, the characteristics of the products in Comparative Examples 1 and 2 represent the characteristics of the products after the oxidation reaction is completed by additionally adding H 2 O 2.
実施例１～４において反応はそれぞれ１～４時間以内で完了したが、比較例１、２では高温高圧に４時間保持しても酸化反応が完了せず、二価鉄が酸化されずに残ってしまっていた。そこで、スラリーに残存する二価鉄を全て三価鉄に酸化するために過酸化水素水を添加した。
このため、比較例１、２における生成物の特性は、いずれも、追加的にH2O2を添加して酸化反応を完了させた後の生成物の特性を表す。 Table 1 summarizes the iron raw materials, reaction conditions, and the characteristics of the ferric polysulfate produced for Examples 1 to 4 and Comparative Examples 1 and 2.
In Examples 1 to 4, the reactions were completed within 1 to 4 hours, respectively, but in Comparative Examples 1 and 2, the oxidation reaction was not completed even if the mixture was held at high temperature and high pressure for 4 hours, and the divalent iron remained unoxidized. It had been done. Therefore, a hydrogen peroxide solution was added to oxidize all the divalent iron remaining in the slurry to ferric iron.
Therefore, the characteristics of the products in Comparative Examples 1 and 2 represent the characteristics of the products after the oxidation reaction is completed by additionally adding H 2 O 2.
実施例１～４と比較例１、２で製造されたいずれのスラリーにおいても、SO4
2-／Fe比が１．５未満であるので、ポリ硫酸第二鉄が生成されていることがわかる。
しかし、実施例１～４におけるスラリーは、密閉容器内の酸素ガスの作用を受け、全鉄濃度が14.6～16.3％と高濃度のポリ硫酸第二鉄を製造することができた。この特性は、比較例１、２のスラリーと比較するまでもなく、無機凝集剤としては従来技術では得られなかった優れた特性である。
また、ポリ硫酸第二鉄の生成が効率的に行われていることは、実施例１および４では１時間以内に、密閉容器内の圧力を0.3MPaとした実施例２では２時間以内、低鉄濃度の原料を使用した実施例３においても４時間以内に反応が完了していることから確認できる。 Since the SO 4 2- / Fe ratio is less than 1.5 in both the slurries produced in Examples 1 to 4 and Comparative Examples 1 and 2, it can be seen that ferric polysulfate is produced. ..
However, the slurries in Examples 1 to 4 were affected by the action of oxygen gas in the closed container, and ferric polysulfate having a high total iron concentration of 14.6-16.3% could be produced. It is not necessary to compare this property with the slurries of Comparative Examples 1 and 2, and it is an excellent property that could not be obtained by the prior art as an inorganic flocculant.
Further, the efficient production of ferric polysulfate was low within 1 hour in Examples 1 and 4 and within 2 hours in Example 2 in which the pressure in the closed container was 0.3 MPa. It can be confirmed from the fact that the reaction was completed within 4 hours also in Example 3 using the raw material having an iron concentration.
しかし、実施例１～４におけるスラリーは、密閉容器内の酸素ガスの作用を受け、全鉄濃度が14.6～16.3％と高濃度のポリ硫酸第二鉄を製造することができた。この特性は、比較例１、２のスラリーと比較するまでもなく、無機凝集剤としては従来技術では得られなかった優れた特性である。
また、ポリ硫酸第二鉄の生成が効率的に行われていることは、実施例１および４では１時間以内に、密閉容器内の圧力を0.3MPaとした実施例２では２時間以内、低鉄濃度の原料を使用した実施例３においても４時間以内に反応が完了していることから確認できる。 Since the SO 4 2- / Fe ratio is less than 1.5 in both the slurries produced in Examples 1 to 4 and Comparative Examples 1 and 2, it can be seen that ferric polysulfate is produced. ..
However, the slurries in Examples 1 to 4 were affected by the action of oxygen gas in the closed container, and ferric polysulfate having a high total iron concentration of 14.6-16.3% could be produced. It is not necessary to compare this property with the slurries of Comparative Examples 1 and 2, and it is an excellent property that could not be obtained by the prior art as an inorganic flocculant.
Further, the efficient production of ferric polysulfate was low within 1 hour in Examples 1 and 4 and within 2 hours in Example 2 in which the pressure in the closed container was 0.3 MPa. It can be confirmed from the fact that the reaction was completed within 4 hours also in Example 3 using the raw material having an iron concentration.
これに対して、比較例１、２の製造条件では、本発明の特徴である短時間で効率的なポリ硫酸第二鉄の製造を実現できないことが明らかとなった。
すなわち、比較例１、２においては、高温高圧条件下でポリ硫酸第二鉄の生成反応を４時間継続したにもかかわらず、二価鉄が酸化されずに残存したため、これを全て三価鉄に酸化するために過酸化水素水の添加が必要であった。
また、比較的大量の不溶性残渣が発生してしまい、効率的なポリ硫酸第二鉄の生成が行われていない。このことは、比較例１、２においては、鉄溶解率が低いことが示すように、ポリ硫酸第二鉄に取り込まれなかった鉄の多くが不溶性残渣として析出している。このことからも、本発明において密閉容器内の気相を酸素に置換することの技術的な意義が明らかとなる。 On the other hand, it was clarified that under the production conditions of Comparative Examples 1 and 2, efficient production of ferric polysulfate, which is a feature of the present invention, cannot be realized in a short time.
That is, in Comparative Examples 1 and 2, although the reaction for producing ferric polysulfate was continued for 4 hours under high temperature and high pressure conditions, ferric divalent iron remained without being oxidized. It was necessary to add hydrogen peroxide solution to oxidize the iron.
In addition, a relatively large amount of insoluble residue is generated, and efficient ferric sulfate is not produced. This means that in Comparative Examples 1 and 2, most of the iron that was not incorporated into ferric polysulfate was precipitated as an insoluble residue, as shown by the low iron solubility. From this, the technical significance of substituting the gas phase in the closed container with oxygen in the present invention becomes clear.
すなわち、比較例１、２においては、高温高圧条件下でポリ硫酸第二鉄の生成反応を４時間継続したにもかかわらず、二価鉄が酸化されずに残存したため、これを全て三価鉄に酸化するために過酸化水素水の添加が必要であった。
また、比較的大量の不溶性残渣が発生してしまい、効率的なポリ硫酸第二鉄の生成が行われていない。このことは、比較例１、２においては、鉄溶解率が低いことが示すように、ポリ硫酸第二鉄に取り込まれなかった鉄の多くが不溶性残渣として析出している。このことからも、本発明において密閉容器内の気相を酸素に置換することの技術的な意義が明らかとなる。 On the other hand, it was clarified that under the production conditions of Comparative Examples 1 and 2, efficient production of ferric polysulfate, which is a feature of the present invention, cannot be realized in a short time.
That is, in Comparative Examples 1 and 2, although the reaction for producing ferric polysulfate was continued for 4 hours under high temperature and high pressure conditions, ferric divalent iron remained without being oxidized. It was necessary to add hydrogen peroxide solution to oxidize the iron.
In addition, a relatively large amount of insoluble residue is generated, and efficient ferric sulfate is not produced. This means that in Comparative Examples 1 and 2, most of the iron that was not incorporated into ferric polysulfate was precipitated as an insoluble residue, as shown by the low iron solubility. From this, the technical significance of substituting the gas phase in the closed container with oxygen in the present invention becomes clear.
以上の結果より、本発明におけるポリ硫酸第二鉄の製造方法においては、密閉容器内の空気を酸素ガスに置換した場合に、汚泥の凝集能力が高いポリ硫酸第二鉄を短時間で効率的に製造することができるという顕著な効果が達成されることが分かる。
From the above results, in the method for producing ferric polysulfate in the present invention, when the air in the closed container is replaced with oxygen gas, ferric polysulfate having a high sludge aggregation ability can be efficiently used in a short time. It can be seen that the remarkable effect of being able to be produced is achieved.
下水等の廃水処理において利用する凝集剤に関し、凝集性能の高い凝集剤を短時間で製造できるので、排水処理の分野において広く利用することができる。
Regarding 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.
Claims (7)
- 鉄系原料として酸化鉄を用いてポリ硫酸第二鉄を製造する方法であって、
密閉容器内に硫酸イオンと全鉄のモル比が１．５未満となるように調整した酸化鉄粉末と硫酸溶液を投入し、
前記密閉容器内の気相を酸素に置換した後、高温高圧条件下で酸化反応を行うこと、からなることを特徴とするポリ硫酸第二鉄の製造方法。 A method for producing ferric polysulfate using iron oxide as an iron-based raw material.
Put iron oxide powder and sulfuric acid solution adjusted so that the molar ratio of sulfate ion to total iron is less than 1.5 in a closed container.
A method for producing ferric polysulfate, which comprises replacing the gas phase in the closed container with oxygen and then carrying out an oxidation reaction under high temperature and high pressure conditions. - 前記鉄系原料としてマグネタイト又はウスタイトを用いることを特徴とする請求項１に記載のポリ硫酸第二鉄の製造方法。 The method for producing ferric polysulfate according to claim 1, wherein magnetite or wustite is used as the iron-based raw material.
- 更に触媒を添加することを特徴とする請求項１または２に記載のポリ硫酸第二鉄の製造方法。 The method for producing ferric polysulfate according to claim 1 or 2, wherein a catalyst is further added.
- 前記触媒が硝酸であることを特徴とする請求項３に記載のポリ硫酸第二鉄の製造方法。 The method for producing ferric polysulfate according to claim 3, wherein the catalyst is nitric acid.
- 前記高温高圧条件が、圧力０．３ＭＰａ以上、温度が１００℃以上であることを特徴とする請求項１～４のいずれかに記載のポリ硫酸第二鉄の製造方法。 The method for producing ferric polysulfate according to any one of claims 1 to 4, wherein the high-temperature and high-pressure conditions are a pressure of 0.3 MPa or more and a temperature of 100 ° C. or higher.
- 全鉄濃度が１４．５%以上の高濃度のポリ硫酸第二鉄を製造することを特徴とする請求項１～５のいずれかに記載のポリ硫酸第二鉄の製造方法。 The method for producing ferric polysulfate according to any one of claims 1 to 5, wherein a high concentration of ferric polysulfate having a total iron concentration of 14.5% or more is produced.
- 前記ポリ硫酸第二鉄の製造を4時間以内に完了させることを特徴とする請求項６に記載のポリ硫酸第二鉄の製造方法。
The method for producing ferric polysulfate according to claim 6, wherein the production of ferric polysulfate is completed within 4 hours.
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| US4814158A (en) * | 1988-01-28 | 1989-03-21 | Fini Enterprises, Inc. | Process for making liquid ferric sulfate |
| JPH11292545A (en) * | 1998-04-02 | 1999-10-26 | Sugita Seisen:Kk | Method to efficiently produce iron(iii) polysulfate |
| KR20020086450A (en) * | 2002-10-28 | 2002-11-18 | 박경호 | manufacturing method of ploy ferric sulfate |
| US8658124B1 (en) * | 2012-04-04 | 2014-02-25 | Ronald L. Horne | Process for the manufacturing of ferric sulfate |
| WO2019077302A1 (en) * | 2017-10-18 | 2019-04-25 | Industrial Chemicals Group Limited | Polyferric sulphate solution |
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| CN1031699C (en) * | 1991-10-25 | 1996-05-01 | 北京科技大学 | Process for producing high specific gravity ferric sulfate polymer |
| CN1076914A (en) * | 1992-08-31 | 1993-10-06 | 山东建筑工程学院 | The production technique of bodied ferric sulfate and device |
| JP3379204B2 (en) | 1994-04-06 | 2003-02-24 | 王子製紙株式会社 | Method for producing iron-based inorganic coagulant |
| CN1109027A (en) * | 1994-11-30 | 1995-09-27 | 华南理工大学 | Production of iron polysulfate |
| CN104355336A (en) * | 2014-10-17 | 2015-02-18 | 陕西华陆化工环保有限公司 | Method of utilizing ferrous sulfate waste residue to prepare polymeric ferric sulfate |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US4814158A (en) * | 1988-01-28 | 1989-03-21 | Fini Enterprises, Inc. | Process for making liquid ferric sulfate |
| JPH11292545A (en) * | 1998-04-02 | 1999-10-26 | Sugita Seisen:Kk | Method to efficiently produce iron(iii) polysulfate |
| KR20020086450A (en) * | 2002-10-28 | 2002-11-18 | 박경호 | manufacturing method of ploy ferric sulfate |
| US8658124B1 (en) * | 2012-04-04 | 2014-02-25 | Ronald L. Horne | Process for the manufacturing of ferric sulfate |
| WO2019077302A1 (en) * | 2017-10-18 | 2019-04-25 | Industrial Chemicals Group Limited | Polyferric sulphate solution |
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