CA2884787A1 - Processing of iron oxide containing chloride - Google Patents
Processing of iron oxide containing chloride Download PDFInfo
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- CA2884787A1 CA2884787A1 CA2884787A CA2884787A CA2884787A1 CA 2884787 A1 CA2884787 A1 CA 2884787A1 CA 2884787 A CA2884787 A CA 2884787A CA 2884787 A CA2884787 A CA 2884787A CA 2884787 A1 CA2884787 A1 CA 2884787A1
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- Prior art keywords
- iron oxide
- solution
- iron
- fe2o3
- chloride
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- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 title claims abstract description 196
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 title claims abstract description 44
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 claims abstract description 55
- 238000002386 leaching Methods 0.000 claims abstract description 47
- 238000000034 method Methods 0.000 claims abstract description 47
- 239000000243 solution Substances 0.000 claims abstract description 46
- 239000003637 basic solution Substances 0.000 claims abstract description 24
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical group Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims abstract description 21
- FBAFATDZDUQKNH-UHFFFAOYSA-M iron chloride Chemical compound [Cl-].[Fe] FBAFATDZDUQKNH-UHFFFAOYSA-M 0.000 claims abstract description 15
- LIKBJVNGSGBSGK-UHFFFAOYSA-N iron(3+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[Fe+3].[Fe+3] LIKBJVNGSGBSGK-UHFFFAOYSA-N 0.000 claims abstract description 10
- 230000009467 reduction Effects 0.000 claims abstract description 10
- 230000007062 hydrolysis Effects 0.000 claims abstract description 6
- 238000006460 hydrolysis reaction Methods 0.000 claims abstract description 6
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 21
- 238000005554 pickling Methods 0.000 claims description 17
- 239000007788 liquid Substances 0.000 claims description 15
- 239000007787 solid Substances 0.000 claims description 12
- 239000000203 mixture Substances 0.000 claims description 11
- 230000008929 regeneration Effects 0.000 claims description 9
- 238000011069 regeneration method Methods 0.000 claims description 9
- 238000000926 separation method Methods 0.000 claims description 9
- 239000002253 acid Substances 0.000 claims description 8
- 238000001027 hydrothermal synthesis Methods 0.000 claims description 7
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 5
- 229910000831 Steel Inorganic materials 0.000 claims description 4
- 229910052801 chlorine Inorganic materials 0.000 claims description 4
- 239000010959 steel Substances 0.000 claims description 4
- 229910052742 iron Inorganic materials 0.000 claims description 3
- 239000000463 material Substances 0.000 claims description 3
- 239000002585 base Substances 0.000 claims description 2
- 230000001464 adherent effect Effects 0.000 abstract description 11
- 235000013980 iron oxide Nutrition 0.000 description 83
- 239000007921 spray Substances 0.000 description 8
- 239000000460 chlorine Substances 0.000 description 6
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 4
- VBMVTYDPPZVILR-UHFFFAOYSA-N iron(2+);oxygen(2-) Chemical class [O-2].[Fe+2] VBMVTYDPPZVILR-UHFFFAOYSA-N 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- 238000007669 thermal treatment Methods 0.000 description 3
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- 150000001805 chlorine compounds Chemical class 0.000 description 2
- 230000003292 diminished effect Effects 0.000 description 2
- 239000008187 granular material Substances 0.000 description 2
- 239000005431 greenhouse gas Substances 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000012256 powdered iron Substances 0.000 description 2
- 230000001172 regenerating effect Effects 0.000 description 2
- 239000011780 sodium chloride Substances 0.000 description 2
- NGNBDVOYPDDBFK-UHFFFAOYSA-N 2-[2,4-di(pentan-2-yl)phenoxy]acetyl chloride Chemical compound CCCC(C)C1=CC=C(OCC(Cl)=O)C(C(C)CCC)=C1 NGNBDVOYPDDBFK-UHFFFAOYSA-N 0.000 description 1
- 238000004438 BET method Methods 0.000 description 1
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- 239000012080 ambient air Substances 0.000 description 1
- 238000000137 annealing Methods 0.000 description 1
- -1 chlorine ions Chemical class 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 239000000112 cooling gas Substances 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 239000002803 fossil fuel Substances 0.000 description 1
- 239000002737 fuel gas Substances 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 239000001307 helium Substances 0.000 description 1
- 229910052734 helium Inorganic materials 0.000 description 1
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 1
- 238000007131 hydrochloric acid regeneration reaction Methods 0.000 description 1
- 239000003317 industrial substance Substances 0.000 description 1
- 239000003041 laboratory chemical Substances 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 238000004806 packaging method and process Methods 0.000 description 1
- 238000005453 pelletization Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 239000008237 rinsing water Substances 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 229910001415 sodium ion Inorganic materials 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 238000005979 thermal decomposition reaction Methods 0.000 description 1
- 238000004876 x-ray fluorescence Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G49/00—Compounds of iron
- C01G49/02—Oxides; Hydroxides
- C01G49/06—Ferric oxide [Fe2O3]
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/12—Surface area
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/80—Compositional purity
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Compounds Of Iron (AREA)
- Processing Of Solid Wastes (AREA)
Abstract
In a method for processing iron(III) oxide (Fe2O3) obtained from a solution containing iron chloride by means of a hydrolysis step with a reduction of chloride groups (Cl-) adhering to the iron(III) oxide, the aim of the invention is to create a solution that makes it possible to remove adherent chloride from the iron(III) oxide obtained by means of the hydrolysis step in the processing of a solution containing iron chloride and at the same time to maintain a high specific surface area of the iron oxide. Said aim is achieved in that the iron oxide (Fe2O3) is treated in a leaching stage (2) with a basic solution (3) having a pH value > 7, preferably > 8.
Description
' =
Processing of Iron Oxide Containing Chloride The invention concerns a method for processing iron(III) oxide obtained from a solution containing iron chloride by means of a hydrolysis step with a reduction of chloride groups adhering to the iron(III) oxide.
The invention further concerns the use of the method for processing pickling liquor.
Pickling is a process step frequently used in the production of steel- or iron-containing products.
Acids and acid mixtures, especially hydrochloric acid and sulfuric acid, are used as pickling medium. The method involving pickling with hydrochloric acid or with mixtures containing hydrochloric acid is frequently and readily used due to the quality of final products that can be achieved but also due to the capacity of the pickling solution for regeneration. The acid acts to dissolve the oxide layers or scale layers that form on the steel or metal surface during previous processes such as rolling, annealing, etc. During pickling, scale which contains iron oxide reacts with the acid that is used, forming iron chloride and water. During the pickling process, acid is consumed until the solution becomes saturated with iron chloride. This necessitates a continuous supply of hydrochloric acid to the pickling process. The use of spray roasting systems (Ruther or Woodhall-Duckham method) or fluidized bed systems for regenerating pickling liquor has therefore become standard practice.
With sufficient quality, the powdered iron oxide that forms as a secondary product during regeneration of the pickling liquor is a marketable product. However, regenerated iron oxide with even small fractions of residual chloride exhibits highly unfavorable corrosion behavior in relation to metallic materials across a broad temperature range. Moreover, small residual chloride concentrations interfere with the magnetic and mechanical properties of ferritic materials in which regenerated iron oxide is used as a raw material. In addition to a low residual chloride concentration, a high specific surface area of the regenerated iron chloride is a further essential quality feature for the industrial (re)usability of regenerated iron oxide.
WO 2008/070885 A2 discloses a method for reducing the chloride concentration of iron oxides containing chloride while at the same time achieving a sufficiently large specific surface area of the regenerated iron oxide. In a hydrochloric acid regeneration system that functions according to the spray roasting principle, the acid- and iron chloride-containing pickling liquor to be regenerated is preconcentrated and then sprayed into a reactor from the top, after which circulation is generated in the reactor using one or more burner(s) disposed on the sides of the reactor, and the temperature in the reactor is maintained at approximately 550 C, thereby oxidizing the iron chloride in a roasting process to form powdered iron oxide.
Below the burner level, superheated steam is then injected via a tangential infeed line in the cone region of the reactor and reacts with the chlorides still adhering to the surface of the iron oxide, forming gaseous hydrochloric acid, with the chloride concentration of the iron oxide that is discharged the reactor having a chloride percentage by weight of less than 0.15 wt%.
Ambient air is then injected below the burner level to cool the iron oxide in order to prevent shrinkage of the specific surface area of the iron oxide.
EP 0 850 881 Al discloses a method for reducing the chloride concentration of iron oxides containing chloride while at the same time achieving a sufficiently large specific surface area of the regenerated iron oxide. In a spray roaster, the iron chloride-containing pickling liquor is sprayed into a reaction chamber which is heated in the area of the burner level to approximately 650 C and to which fuel gases are supplied, and the solution is thermally decomposed in said reaction chamber to form iron oxide granulate and hydrochloric acid gas. Below the burner level, the spray roasted iron oxide granulate is cooled in a cooling zone to temperatures below 450 C
by introducing cooling gases, and is discharged by means of a discharge device arranged at the
Processing of Iron Oxide Containing Chloride The invention concerns a method for processing iron(III) oxide obtained from a solution containing iron chloride by means of a hydrolysis step with a reduction of chloride groups adhering to the iron(III) oxide.
The invention further concerns the use of the method for processing pickling liquor.
Pickling is a process step frequently used in the production of steel- or iron-containing products.
Acids and acid mixtures, especially hydrochloric acid and sulfuric acid, are used as pickling medium. The method involving pickling with hydrochloric acid or with mixtures containing hydrochloric acid is frequently and readily used due to the quality of final products that can be achieved but also due to the capacity of the pickling solution for regeneration. The acid acts to dissolve the oxide layers or scale layers that form on the steel or metal surface during previous processes such as rolling, annealing, etc. During pickling, scale which contains iron oxide reacts with the acid that is used, forming iron chloride and water. During the pickling process, acid is consumed until the solution becomes saturated with iron chloride. This necessitates a continuous supply of hydrochloric acid to the pickling process. The use of spray roasting systems (Ruther or Woodhall-Duckham method) or fluidized bed systems for regenerating pickling liquor has therefore become standard practice.
With sufficient quality, the powdered iron oxide that forms as a secondary product during regeneration of the pickling liquor is a marketable product. However, regenerated iron oxide with even small fractions of residual chloride exhibits highly unfavorable corrosion behavior in relation to metallic materials across a broad temperature range. Moreover, small residual chloride concentrations interfere with the magnetic and mechanical properties of ferritic materials in which regenerated iron oxide is used as a raw material. In addition to a low residual chloride concentration, a high specific surface area of the regenerated iron chloride is a further essential quality feature for the industrial (re)usability of regenerated iron oxide.
WO 2008/070885 A2 discloses a method for reducing the chloride concentration of iron oxides containing chloride while at the same time achieving a sufficiently large specific surface area of the regenerated iron oxide. In a hydrochloric acid regeneration system that functions according to the spray roasting principle, the acid- and iron chloride-containing pickling liquor to be regenerated is preconcentrated and then sprayed into a reactor from the top, after which circulation is generated in the reactor using one or more burner(s) disposed on the sides of the reactor, and the temperature in the reactor is maintained at approximately 550 C, thereby oxidizing the iron chloride in a roasting process to form powdered iron oxide.
Below the burner level, superheated steam is then injected via a tangential infeed line in the cone region of the reactor and reacts with the chlorides still adhering to the surface of the iron oxide, forming gaseous hydrochloric acid, with the chloride concentration of the iron oxide that is discharged the reactor having a chloride percentage by weight of less than 0.15 wt%.
Ambient air is then injected below the burner level to cool the iron oxide in order to prevent shrinkage of the specific surface area of the iron oxide.
EP 0 850 881 Al discloses a method for reducing the chloride concentration of iron oxides containing chloride while at the same time achieving a sufficiently large specific surface area of the regenerated iron oxide. In a spray roaster, the iron chloride-containing pickling liquor is sprayed into a reaction chamber which is heated in the area of the burner level to approximately 650 C and to which fuel gases are supplied, and the solution is thermally decomposed in said reaction chamber to form iron oxide granulate and hydrochloric acid gas. Below the burner level, the spray roasted iron oxide granulate is cooled in a cooling zone to temperatures below 450 C
by introducing cooling gases, and is discharged by means of a discharge device arranged at the
2 =
= lower end of the spray roaster, and then conducted across a bed to which superheated steam is applied, wherein the iron oxide that is regenerated following the application of superheated steam has a residual chloride concentration of less than 500 ppm and a specific surface area greater than 3.5 m2/g.
Common to the prior art methods described is that the roasting process used for regenerating or regeneration of the iron oxide is energy intensive, and the energy required to power the thermal decomposition is supplied by fossil fuels, so that a corresponding quantity of greenhouse gases is produced. Moreover, the specific surface area and the chloride concentration of the iron oxide and/or the amount of chloride adhering to the iron oxide are substantially dependent on the temperature of the roasting reaction in the reactor. At routine roasting temperatures of less than 800 C, only an improvable, insufficient reduction of the chloride concentration of the iron oxide and/or the chloride adherent to the iron oxide is obtained. Sufficient reduction of the chloride concentration and/or of the chloride adherent to the iron oxide first occurs at temperatures of between 800 and 1000 C. However, thermal treatment at such high temperatures results in a decrease in the specific surface area of the iron oxide which is negative for the subsequent industrial use of the iron oxides. Moreover, systems in which iron oxide can be annealed at such high temperatures of up to 1000 C and then cooled are technically complex.
The object of the invention is therefore to devise a solution that will make it possible to remove adherent chloride from iron(III) oxide which is obtained by means of a hydrothermal method in the processing of a solution containing iron chloride, and at the same time to maintain a high specific surface area of the iron oxide.
In a method of the type described in detail in the introductory part, this object is attained according to the invention in that the iron oxide (Fe203) is treated in a leaching stage with a basic solution having a pH value of > 7, preferably > 8.
= lower end of the spray roaster, and then conducted across a bed to which superheated steam is applied, wherein the iron oxide that is regenerated following the application of superheated steam has a residual chloride concentration of less than 500 ppm and a specific surface area greater than 3.5 m2/g.
Common to the prior art methods described is that the roasting process used for regenerating or regeneration of the iron oxide is energy intensive, and the energy required to power the thermal decomposition is supplied by fossil fuels, so that a corresponding quantity of greenhouse gases is produced. Moreover, the specific surface area and the chloride concentration of the iron oxide and/or the amount of chloride adhering to the iron oxide are substantially dependent on the temperature of the roasting reaction in the reactor. At routine roasting temperatures of less than 800 C, only an improvable, insufficient reduction of the chloride concentration of the iron oxide and/or the chloride adherent to the iron oxide is obtained. Sufficient reduction of the chloride concentration and/or of the chloride adherent to the iron oxide first occurs at temperatures of between 800 and 1000 C. However, thermal treatment at such high temperatures results in a decrease in the specific surface area of the iron oxide which is negative for the subsequent industrial use of the iron oxides. Moreover, systems in which iron oxide can be annealed at such high temperatures of up to 1000 C and then cooled are technically complex.
The object of the invention is therefore to devise a solution that will make it possible to remove adherent chloride from iron(III) oxide which is obtained by means of a hydrothermal method in the processing of a solution containing iron chloride, and at the same time to maintain a high specific surface area of the iron oxide.
In a method of the type described in detail in the introductory part, this object is attained according to the invention in that the iron oxide (Fe203) is treated in a leaching stage with a basic solution having a pH value of > 7, preferably > 8.
3 = This object is likewise attained according to the invention by the use of a method according to claim 14.
By treating the obtained iron oxide according to the invention in a leaching stage with a basic solution having a pH value of greater than 7, preferably greater than 8, the chlorides adherent to the iron oxide are bound by at least one component of the basic solution, so that an effective reduction in the chloride concentration of the iron oxide (Fe203) or in the chloride still adherent to the respective iron oxide particles or the adherent chlorine ions is achieved. However, treatment with the basic solution has no effect on the specific surface area of the iron oxide produced by means of a hydrothermal process, so that the specific surface area of the regenerated iron oxide that is present at the start of the leaching step in the leaching stage is maintained and preserved. The method according to the invention has substantially lower energy requirements as compared with spray roasting methods known in the art which achieve similar chloride reductions at temperatures of between 800 and 1000 C, and therefore the greenhouse gas emissions produced during the regeneration process as a whole can be reduced significantly. In general, with the solutions according to the invention, adherent chloride is detached from iron(III) oxide obtained by means of a hydrothermal process during the processing of a solution containing iron chloride, and at the same time, a high specific surface area of the iron oxide is obtained or maintained. With the solutions according to the invention, methods are provided by which the chloride concentration (Cl) in iron oxide (Fe203) produced by means of a hydrothermal process is reduced or diminished in an environmentally safe and energy saving manner by mixing or treating the iron oxide with a solution that increases the pH
value.
In an advantageous manner, the solution containing iron chloride, for example a solution containing hydrochloric acid, which forms during pickling of an object made of a material that contains iron, in particular steel, with hydrochloric acid as the pickling liquor, is subjected for its regeneration to a hydrolysis step during treatment in a thermal treatment stage, resulting in
By treating the obtained iron oxide according to the invention in a leaching stage with a basic solution having a pH value of greater than 7, preferably greater than 8, the chlorides adherent to the iron oxide are bound by at least one component of the basic solution, so that an effective reduction in the chloride concentration of the iron oxide (Fe203) or in the chloride still adherent to the respective iron oxide particles or the adherent chlorine ions is achieved. However, treatment with the basic solution has no effect on the specific surface area of the iron oxide produced by means of a hydrothermal process, so that the specific surface area of the regenerated iron oxide that is present at the start of the leaching step in the leaching stage is maintained and preserved. The method according to the invention has substantially lower energy requirements as compared with spray roasting methods known in the art which achieve similar chloride reductions at temperatures of between 800 and 1000 C, and therefore the greenhouse gas emissions produced during the regeneration process as a whole can be reduced significantly. In general, with the solutions according to the invention, adherent chloride is detached from iron(III) oxide obtained by means of a hydrothermal process during the processing of a solution containing iron chloride, and at the same time, a high specific surface area of the iron oxide is obtained or maintained. With the solutions according to the invention, methods are provided by which the chloride concentration (Cl) in iron oxide (Fe203) produced by means of a hydrothermal process is reduced or diminished in an environmentally safe and energy saving manner by mixing or treating the iron oxide with a solution that increases the pH
value.
In an advantageous manner, the solution containing iron chloride, for example a solution containing hydrochloric acid, which forms during pickling of an object made of a material that contains iron, in particular steel, with hydrochloric acid as the pickling liquor, is subjected for its regeneration to a hydrolysis step during treatment in a thermal treatment stage, resulting in
4 the iron(III) oxide to be further processed. The invention embodiment is therefore further characterized in that the iron oxide (Fe203) to be treated with the basic solution is produced hydrothermally, preferably by means of an acid regeneration process carried out within a temperature range of 130-190 C, in particular by means of a hydrothermal process. In particular, this is carried out by means of a hydrothermal process with/in a corresponding system. The thermal treatment stage is thus a component of an acid regeneration process, preferably a spray roasting process or a fluidized bed process having a corresponding spray roasting system or fluidized bed system.
The reduction in the chloride concentration of the iron oxide (Fe203) containing chloride or in the chloride still adherent to the respective iron oxide particles is expediently carried out at pressures of 0 to 100 bar. The invention therefore further provides that the iron oxide (Fe203) is treated in a leaching step of the leaching stage at a pressure of between 0 and 100 bar.
It is further expedient according to the embodiment of the invention that the iron oxide (Fe203) is treated in a leaching step of the leaching stage at a temperature of between 0 and 300 C. This temperature range can be achieved with an acceptable level of energy consumption, and ensures that the specific surface area of the iron oxide does not change.
Although in principle it is sufficient for the success of the method according to the invention to establish a pH value of greater than 7 in the leaching stage, the method can be carried out particularly effectively if the iron oxide (Fe203) is treated in the leaching stage with a basic solution having a pH value of between 11 and 14, which likewise characterizes the embodiment of the invention.
It is likewise particularly advantageous if, according to a further embodiment of the invention, the iron oxide (Fe203) is treated in the leaching stage at a temperature of between 10 and 80 C
and/or at ambient pressure.
In the execution of the method, it can be provided that, after the basic solution is added to the chloride-containing iron oxide (Fe203) and after the chloride concentration of the or on the iron oxide (Fe203) has been reduced/diminished, an oxide/leaching solution mixture results, which contains both "dechlorinated" iron oxide (Fe203) and a basic solution. This is then fed to a solid-liquid separation unit in which the "dechlorinated" iron oxide (Fe203) and the basic solution are separated from the oxide-leaching solution mixture. The separated "dechlorinated" iron oxide (Fe203) can be rinsed with rinsing water and the separated basic solution can be returned to the leaching stage.
The invention therefore further provides that the iron oxide (Fe203)/solution mixture is separated, in particular mechanically, in a solid-liquid separation stage that follows the leaching stage, into an iron oxide-containing solid portion and a solution-containing liquid portion.
It is also expedient for the recovery of the chloride if the solid-liquid separation stage comprises a rinsing treatment of the solid portion using a rinsing medium, which is likewise provided by the invention. Additional residues are also rinsed out of the iron oxide.
To use the basic solution efficiently, the invention also provides that the solution-containing liquid portion is returned at least partially to the leaching stage.
The invention is further characterized in that surplus basic solution and/or a portion of the iron oxide (Fe203)/solution mixture that forms in the leaching stage is removed from the leaching stage as discharge water by means of an overflow device.
In particular, a further development of the invention is also characterized in that the iron oxide (Fe203) of the iron oxide-containing solid portion has a chloride adherence (Cl) of 0.18 wt%, in particular 15 wt%. The residual chloride concentration of the regenerated iron oxide is therefore low enough for industrial applications.
It is further advantageous for the invention for both the chlorinated iron oxide (Fe203) supplied to the leaching stage and the "dechlorinated" iron oxide (Fe203) to have a BET
surface area of more than 15 m2/g. An iron chloride thus regenerated not only has a sufficiently low residual chloride fraction, but also has a sufficiently high specific surface area for industrial applications, so that it is a marketable product that meets industrial requirements. In a further embodiment, the invention is therefore characterized in that the iron oxide (Fe203) of the iron oxide-containing solid portion has a specific BET surface area of > 15 m2/g, in particular of 20-30 m2/g, preferably of 22-26 m2/g, and also in that the specific BET surface area of the iron oxide (Fe203) passes through the leaching stage unchanged.
Finally, in a further advantageous embodiment, the invention provides that a leaching solution having an alkaline or alkaline-earth base, in particular sodium hydroxide solution (NaOH) is used as the basic solution. Sodium hydroxide solution is one of the most widely used laboratory and industrial chemicals, and due to its industrial mass production is available as a cost-effective basic solution.
In the following, the invention will be described by way of example in reference to a drawing.
The drawing shows =
Fig 1 a schematic representation of a block diagram of a method according to the invention.
In the embodiment example shown, in a first process stage 1, iron oxide (Fe203) is produced by means of one or more process step(s) comprising a hydrolysis step from a solution containing iron chloride, said solution being obtained, for example, from the pickling of steel using hydrochloric acid, wherein the iron oxide contains chloride groups (Cl) and therefore chloride ions on an order of magnitude greater than 0.15 wt%, generally on an order of magnitude of approximately 0.55 wt%, and a specific BET surface area of more than 15 m2/g.
In a subsequent leaching stage 2, a basic solution 3 or leaching solution having a pH value greater than 8 is added to the iron oxide (Fe203). Said solution is preferably sodium hydroxide solution (NaOH). The sodium ions (Nat) react with the chloride ions (Cr), which become detached from the iron oxide (Fe203), resulting in a reduction in the chloride concentration of the iron oxide (Fe203) containing chloride or in the chloride still adherent to the respective iron oxide particles or in the adherent chloride ions. This is achieved without any significant change, in particular without a reduction in the specific (BET) surface area of the iron oxide (Fe203).
Surplus basic solution or leaching solution and/or a portion of the iron oxide (Fe203)/solution mixture 5 that forms in leaching stage 2 is discharged via an overflow device 4 as discharge water. The iron oxide (Fe203)/solution mixture 5 obtained in leaching stage 2, which contains both "dechlorinated" iron oxide (Fe203) and sodium chloride (NaCl)-containing solution or leaching solution that has formed, for example, is fed to a subsequent solid-liquid separation stage 6. The "dechlorinated" iron oxide (Fe203) that is discharged from leaching stage 2 still has a BET surface area of more than 15 m2/g.
In solid-liquid separation stage 6, the "dechlorinated" iron oxide (Fe203) is separated from iron oxide (Fe203)/solution mixture 5 as an iron oxide-containing solid portion (8), and basic solution or leaching solution is separated out as a solution- or leaching solution-containing liquid portion =(7). The separated "dechlorinated" iron oxide (Fe203) or the iron oxide-containing solid portion can be rinsed in solid-liquid separation stage 6 with a rinsing medium, for example water. The separated solution- or leaching solution-containing liquid portion is returned as basic solution or leaching solution to the leaching stage, as indicated by reference sign 7. In the iron oxide-containing solid portion 8 which is discharged from solid-liquid separation stage 6, the separated, "dechlorinated" and optionally rinsed iron oxide (Fe203) has a chloride concentration of less than 0.18 wt%, even of less than 0.15 wt%, and still has a specific (BET) surface area of more than 15 m2/g.
The iron oxide-containing solid portion 8 is fed for final processing to one or more additional process stage(s), denoted together by reference sign 9. The further processing steps of process stage(s) 9 comprise drying and/or packaging and/or pelletizing the obtained iron oxide (Fe203).
The iron oxide (Fe203) recovered or obtained according to the embodiment has a concentration of chloride ions (Cl) of 0.13 to 0.17 wt% and a specific BET surface area of 22-26 m2/g. The chlorine or chlorine ion concentration (CV) is determined in the dry sample by means of MatrixPro x-ray fluorescence analysis (model number 2.699) as a bed sample in a helium atmosphere. The Q+ method specific to the device is used for analysis. The specific surface area is measured using the BET method by means of gas adsorption.
The reduction in the chloride concentration of the iron oxide (Fe203) containing chloride or in the chloride still adherent to the respective iron oxide particles is expediently carried out at pressures of 0 to 100 bar. The invention therefore further provides that the iron oxide (Fe203) is treated in a leaching step of the leaching stage at a pressure of between 0 and 100 bar.
It is further expedient according to the embodiment of the invention that the iron oxide (Fe203) is treated in a leaching step of the leaching stage at a temperature of between 0 and 300 C. This temperature range can be achieved with an acceptable level of energy consumption, and ensures that the specific surface area of the iron oxide does not change.
Although in principle it is sufficient for the success of the method according to the invention to establish a pH value of greater than 7 in the leaching stage, the method can be carried out particularly effectively if the iron oxide (Fe203) is treated in the leaching stage with a basic solution having a pH value of between 11 and 14, which likewise characterizes the embodiment of the invention.
It is likewise particularly advantageous if, according to a further embodiment of the invention, the iron oxide (Fe203) is treated in the leaching stage at a temperature of between 10 and 80 C
and/or at ambient pressure.
In the execution of the method, it can be provided that, after the basic solution is added to the chloride-containing iron oxide (Fe203) and after the chloride concentration of the or on the iron oxide (Fe203) has been reduced/diminished, an oxide/leaching solution mixture results, which contains both "dechlorinated" iron oxide (Fe203) and a basic solution. This is then fed to a solid-liquid separation unit in which the "dechlorinated" iron oxide (Fe203) and the basic solution are separated from the oxide-leaching solution mixture. The separated "dechlorinated" iron oxide (Fe203) can be rinsed with rinsing water and the separated basic solution can be returned to the leaching stage.
The invention therefore further provides that the iron oxide (Fe203)/solution mixture is separated, in particular mechanically, in a solid-liquid separation stage that follows the leaching stage, into an iron oxide-containing solid portion and a solution-containing liquid portion.
It is also expedient for the recovery of the chloride if the solid-liquid separation stage comprises a rinsing treatment of the solid portion using a rinsing medium, which is likewise provided by the invention. Additional residues are also rinsed out of the iron oxide.
To use the basic solution efficiently, the invention also provides that the solution-containing liquid portion is returned at least partially to the leaching stage.
The invention is further characterized in that surplus basic solution and/or a portion of the iron oxide (Fe203)/solution mixture that forms in the leaching stage is removed from the leaching stage as discharge water by means of an overflow device.
In particular, a further development of the invention is also characterized in that the iron oxide (Fe203) of the iron oxide-containing solid portion has a chloride adherence (Cl) of 0.18 wt%, in particular 15 wt%. The residual chloride concentration of the regenerated iron oxide is therefore low enough for industrial applications.
It is further advantageous for the invention for both the chlorinated iron oxide (Fe203) supplied to the leaching stage and the "dechlorinated" iron oxide (Fe203) to have a BET
surface area of more than 15 m2/g. An iron chloride thus regenerated not only has a sufficiently low residual chloride fraction, but also has a sufficiently high specific surface area for industrial applications, so that it is a marketable product that meets industrial requirements. In a further embodiment, the invention is therefore characterized in that the iron oxide (Fe203) of the iron oxide-containing solid portion has a specific BET surface area of > 15 m2/g, in particular of 20-30 m2/g, preferably of 22-26 m2/g, and also in that the specific BET surface area of the iron oxide (Fe203) passes through the leaching stage unchanged.
Finally, in a further advantageous embodiment, the invention provides that a leaching solution having an alkaline or alkaline-earth base, in particular sodium hydroxide solution (NaOH) is used as the basic solution. Sodium hydroxide solution is one of the most widely used laboratory and industrial chemicals, and due to its industrial mass production is available as a cost-effective basic solution.
In the following, the invention will be described by way of example in reference to a drawing.
The drawing shows =
Fig 1 a schematic representation of a block diagram of a method according to the invention.
In the embodiment example shown, in a first process stage 1, iron oxide (Fe203) is produced by means of one or more process step(s) comprising a hydrolysis step from a solution containing iron chloride, said solution being obtained, for example, from the pickling of steel using hydrochloric acid, wherein the iron oxide contains chloride groups (Cl) and therefore chloride ions on an order of magnitude greater than 0.15 wt%, generally on an order of magnitude of approximately 0.55 wt%, and a specific BET surface area of more than 15 m2/g.
In a subsequent leaching stage 2, a basic solution 3 or leaching solution having a pH value greater than 8 is added to the iron oxide (Fe203). Said solution is preferably sodium hydroxide solution (NaOH). The sodium ions (Nat) react with the chloride ions (Cr), which become detached from the iron oxide (Fe203), resulting in a reduction in the chloride concentration of the iron oxide (Fe203) containing chloride or in the chloride still adherent to the respective iron oxide particles or in the adherent chloride ions. This is achieved without any significant change, in particular without a reduction in the specific (BET) surface area of the iron oxide (Fe203).
Surplus basic solution or leaching solution and/or a portion of the iron oxide (Fe203)/solution mixture 5 that forms in leaching stage 2 is discharged via an overflow device 4 as discharge water. The iron oxide (Fe203)/solution mixture 5 obtained in leaching stage 2, which contains both "dechlorinated" iron oxide (Fe203) and sodium chloride (NaCl)-containing solution or leaching solution that has formed, for example, is fed to a subsequent solid-liquid separation stage 6. The "dechlorinated" iron oxide (Fe203) that is discharged from leaching stage 2 still has a BET surface area of more than 15 m2/g.
In solid-liquid separation stage 6, the "dechlorinated" iron oxide (Fe203) is separated from iron oxide (Fe203)/solution mixture 5 as an iron oxide-containing solid portion (8), and basic solution or leaching solution is separated out as a solution- or leaching solution-containing liquid portion =(7). The separated "dechlorinated" iron oxide (Fe203) or the iron oxide-containing solid portion can be rinsed in solid-liquid separation stage 6 with a rinsing medium, for example water. The separated solution- or leaching solution-containing liquid portion is returned as basic solution or leaching solution to the leaching stage, as indicated by reference sign 7. In the iron oxide-containing solid portion 8 which is discharged from solid-liquid separation stage 6, the separated, "dechlorinated" and optionally rinsed iron oxide (Fe203) has a chloride concentration of less than 0.18 wt%, even of less than 0.15 wt%, and still has a specific (BET) surface area of more than 15 m2/g.
The iron oxide-containing solid portion 8 is fed for final processing to one or more additional process stage(s), denoted together by reference sign 9. The further processing steps of process stage(s) 9 comprise drying and/or packaging and/or pelletizing the obtained iron oxide (Fe203).
The iron oxide (Fe203) recovered or obtained according to the embodiment has a concentration of chloride ions (Cl) of 0.13 to 0.17 wt% and a specific BET surface area of 22-26 m2/g. The chlorine or chlorine ion concentration (CV) is determined in the dry sample by means of MatrixPro x-ray fluorescence analysis (model number 2.699) as a bed sample in a helium atmosphere. The Q+ method specific to the device is used for analysis. The specific surface area is measured using the BET method by means of gas adsorption.
Claims (13)
1. A method for processing iron(III) oxide (Fe2O3) obtained from a solution containing iron chloride by means of a hydrolysis step with a reduction of chloride groups (Cl-) adhering to the iron(III) oxide, wherein the iron oxide (Fe2O3) is processed in a leaching stage (2) with a basic solution (3) having a pH value of > 7, preferably of > 8, characterized in that the iron oxide (Fe2O3) to be treated with the basic solution (3) is produced hydrothermally by means of an acid regeneration process, in particular a hydrothermal process, carried out in a temperature range of 130-190°C.
2. The method according to claim 1, characterized in that the iron oxide (Fe2O3) is treated in a leaching step of the leaching stage (2) at a pressure of between 0 and 100 bar, preferably at ambient pressure.
3. The method according to claim 1 or 2, characterized in that the iron oxide (Fe2O3) is treated in a leaching step of the leaching stage (2) at a temperature of between 0 and 300°C, preferably between 10 and 80°C.
4. The method according to any one of the preceding claims, characterized in that the iron oxide (Fe2O3) is treated in the leaching stage (2) with a basic solution (3) having a pH
value of between 11 and 14.
value of between 11 and 14.
5. The method according to any one of the preceding claims, characterized in that the iron oxide (Fe2O3)/solution mixture (5) obtained in the leaching stage (2) is separated, in particular mechanically, in a solid-liquid separation stage (6) that follows the leaching stage (2) into an iron oxide-containing solid portion (8) and a solution-containing liquid portion (7).
6. The method according to claim 5, characterized in that the solid-liquid separation stage (6) comprises a rinsing treatment of the solid portion with a rinsing medium.
7. The method according to claim 5 or 6, characterized in that the solution-containing liquid portion (7) is returned at least partially to the leaching stage (2).
8. The method according to any one of claims 5 to 7, characterized in that surplus basic solution (3) and/or a portion of the iron oxide (Fe2O3)/solution mixture (5) that forms in the leaching stage (2) is removed from the leaching stage (2) as discharge water via an overflow device (4).
9. The method according to any one of claims 5 to 8, characterized in that the iron oxide (Fe2O3) of the iron oxide-containing solid portion (8) has a chloride adherence (Cl-) of <=
0.18 wt% Cl, in particular of <= 15 wt% Cl.
0.18 wt% Cl, in particular of <= 15 wt% Cl.
10. The method according to any one of claims 5 to 9, characterized in that the iron oxide (Fe2O3) of the solid portion containing iron oxide (8) has a specific BET
surface area of >
15 m2/g, in particular of 20-30 m2/g, preferably of 22-26 m2/g.
surface area of >
15 m2/g, in particular of 20-30 m2/g, preferably of 22-26 m2/g.
11. The method according to any one of the preceding claims, characterized in that the specific BET surface area of the iron oxide (Fe2O3) passes through the leaching stage (2) unchanged.
12. The method according to any one of the preceding claims, characterized in that a leaching solution having an alkaline-earth base, in particular sodium hydroxide solution (NaOH), is used as the basic solution (3).
13. The use of the method according to any one of the preceding claims for processing pickling liquor that accumulates in the regeneration of iron-containing material, in particular steel, during pickling.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE102011083863A DE102011083863A1 (en) | 2011-09-30 | 2011-09-30 | Preparation of chloride-containing iron oxide |
| DE102011083863.5 | 2011-09-30 | ||
| PCT/EP2012/069326 WO2013045692A1 (en) | 2011-09-30 | 2012-10-01 | Processing of iron oxide containing chloride |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2884787A1 true CA2884787A1 (en) | 2013-04-04 |
| CA2884787C CA2884787C (en) | 2017-11-07 |
Family
ID=47002855
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA2884787A Expired - Fee Related CA2884787C (en) | 2011-09-30 | 2012-10-01 | Processing of iron oxide containing chloride |
Country Status (3)
| Country | Link |
|---|---|
| CA (1) | CA2884787C (en) |
| DE (1) | DE102011083863A1 (en) |
| WO (1) | WO2013045692A1 (en) |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9150428B2 (en) | 2011-06-03 | 2015-10-06 | Orbite Aluminae Inc. | Methods for separating iron ions from aluminum ions |
| US9260767B2 (en) | 2011-03-18 | 2016-02-16 | Orbite Technologies Inc. | Processes for recovering rare earth elements from aluminum-bearing materials |
| US9290828B2 (en) | 2012-07-12 | 2016-03-22 | Orbite Technologies Inc. | Processes for preparing titanium oxide and various other products |
| US9353425B2 (en) | 2012-09-26 | 2016-05-31 | Orbite Technologies Inc. | Processes for preparing alumina and magnesium chloride by HCl leaching of various materials |
| US9382600B2 (en) | 2011-09-16 | 2016-07-05 | Orbite Technologies Inc. | Processes for preparing alumina and various other products |
| US9410227B2 (en) | 2011-05-04 | 2016-08-09 | Orbite Technologies Inc. | Processes for recovering rare earth elements from various ores |
| US9534274B2 (en) | 2012-11-14 | 2017-01-03 | Orbite Technologies Inc. | Methods for purifying aluminium ions |
| US9556500B2 (en) | 2012-01-10 | 2017-01-31 | Orbite Technologies Inc. | Processes for treating red mud |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| RU2735608C1 (en) * | 2020-02-06 | 2020-11-05 | Хажмухамед Харабиевич Этуев | Method of obtaining iron (iii) oxide fe2o3 from aqueous solutions of salts |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4434968A1 (en) * | 1994-09-30 | 1996-04-04 | Bayer Ag | Highly transparent, red iron oxide pigments, processes for their production and their use |
| DE59609577D1 (en) | 1996-12-27 | 2002-09-26 | Michael Johann Ruthner | Method and device for producing iron oxides from hydrochloric acid solutions containing iron chloride |
| DE502006008730D1 (en) * | 2006-12-01 | 2011-02-24 | Ruthner Michael Johann | Process for producing iron powder or steel powder from iron oxide powder by oxidation and reduction |
| AT9645U1 (en) | 2006-12-12 | 2008-01-15 | Gerhard Dr Frithum | METHOD FOR INCREASING THE SPECIFIC SURFACE OF IRON OXIDES FROM SPRAYING ESTABLISHMENTS |
-
2011
- 2011-09-30 DE DE102011083863A patent/DE102011083863A1/en not_active Withdrawn
-
2012
- 2012-10-01 CA CA2884787A patent/CA2884787C/en not_active Expired - Fee Related
- 2012-10-01 WO PCT/EP2012/069326 patent/WO2013045692A1/en active Application Filing
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9260767B2 (en) | 2011-03-18 | 2016-02-16 | Orbite Technologies Inc. | Processes for recovering rare earth elements from aluminum-bearing materials |
| US9945009B2 (en) | 2011-03-18 | 2018-04-17 | Orbite Technologies Inc. | Processes for recovering rare earth elements from aluminum-bearing materials |
| US9410227B2 (en) | 2011-05-04 | 2016-08-09 | Orbite Technologies Inc. | Processes for recovering rare earth elements from various ores |
| US9150428B2 (en) | 2011-06-03 | 2015-10-06 | Orbite Aluminae Inc. | Methods for separating iron ions from aluminum ions |
| US9382600B2 (en) | 2011-09-16 | 2016-07-05 | Orbite Technologies Inc. | Processes for preparing alumina and various other products |
| US10174402B2 (en) | 2011-09-16 | 2019-01-08 | Orbite Technologies Inc. | Processes for preparing alumina and various other products |
| US9556500B2 (en) | 2012-01-10 | 2017-01-31 | Orbite Technologies Inc. | Processes for treating red mud |
| US9290828B2 (en) | 2012-07-12 | 2016-03-22 | Orbite Technologies Inc. | Processes for preparing titanium oxide and various other products |
| US9353425B2 (en) | 2012-09-26 | 2016-05-31 | Orbite Technologies Inc. | Processes for preparing alumina and magnesium chloride by HCl leaching of various materials |
| US9534274B2 (en) | 2012-11-14 | 2017-01-03 | Orbite Technologies Inc. | Methods for purifying aluminium ions |
Also Published As
| Publication number | Publication date |
|---|---|
| WO2013045692A1 (en) | 2013-04-04 |
| DE102011083863A1 (en) | 2013-04-04 |
| CA2884787C (en) | 2017-11-07 |
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