WO2023148516A1 - Procédé de récupération d'acide fluorhydrique libre et combiné à partir d'un bain de décapage d'acier inoxydable - Google Patents
Procédé de récupération d'acide fluorhydrique libre et combiné à partir d'un bain de décapage d'acier inoxydable Download PDFInfo
- Publication number
- WO2023148516A1 WO2023148516A1 PCT/IB2022/050884 IB2022050884W WO2023148516A1 WO 2023148516 A1 WO2023148516 A1 WO 2023148516A1 IB 2022050884 W IB2022050884 W IB 2022050884W WO 2023148516 A1 WO2023148516 A1 WO 2023148516A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- pickling
- process according
- metal
- hydrofluoric acid
- free
- Prior art date
Links
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 title claims abstract description 76
- 238000000034 method Methods 0.000 title claims abstract description 44
- 238000005554 pickling Methods 0.000 title claims abstract description 42
- 230000008569 process Effects 0.000 title claims abstract description 35
- 229910001220 stainless steel Inorganic materials 0.000 title claims abstract description 11
- 239000010935 stainless steel Substances 0.000 title claims abstract description 9
- 238000011084 recovery Methods 0.000 title claims description 11
- 229910052751 metal Inorganic materials 0.000 claims abstract description 24
- 239000002184 metal Substances 0.000 claims abstract description 24
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 33
- 238000006243 chemical reaction Methods 0.000 claims description 22
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 21
- 239000000126 substance Substances 0.000 claims description 9
- 230000009467 reduction Effects 0.000 claims description 8
- 229910000831 Steel Inorganic materials 0.000 claims description 7
- 229910052742 iron Inorganic materials 0.000 claims description 7
- 239000010959 steel Substances 0.000 claims description 7
- DWAQJAXMDSEUJJ-UHFFFAOYSA-M Sodium bisulfite Chemical compound [Na+].OS([O-])=O DWAQJAXMDSEUJJ-UHFFFAOYSA-M 0.000 claims description 6
- 238000007254 oxidation reaction Methods 0.000 claims description 6
- 229910045601 alloy Inorganic materials 0.000 claims description 5
- 239000000956 alloy Substances 0.000 claims description 5
- 230000003647 oxidation Effects 0.000 claims description 5
- 239000000843 powder Substances 0.000 claims description 5
- 239000003638 chemical reducing agent Substances 0.000 claims description 4
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 3
- 229910052739 hydrogen Inorganic materials 0.000 claims description 3
- 239000001257 hydrogen Substances 0.000 claims description 3
- 238000001914 filtration Methods 0.000 claims description 2
- 238000011144 upstream manufacturing Methods 0.000 claims description 2
- 239000007787 solid Substances 0.000 claims 3
- 239000007788 liquid Substances 0.000 claims 2
- 230000008901 benefit Effects 0.000 abstract description 7
- 230000007613 environmental effect Effects 0.000 abstract description 6
- QPJSUIGXIBEQAC-UHFFFAOYSA-N n-(2,4-dichloro-5-propan-2-yloxyphenyl)acetamide Chemical compound CC(C)OC1=CC(NC(C)=O)=C(Cl)C=C1Cl QPJSUIGXIBEQAC-UHFFFAOYSA-N 0.000 description 25
- 239000002253 acid Substances 0.000 description 18
- 150000007513 acids Chemical class 0.000 description 12
- 239000000463 material Substances 0.000 description 10
- 239000000203 mixture Substances 0.000 description 10
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 9
- 238000006722 reduction reaction Methods 0.000 description 9
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 6
- 239000010410 layer Substances 0.000 description 6
- 150000002739 metals Chemical class 0.000 description 6
- 229910052804 chromium Inorganic materials 0.000 description 5
- 239000011651 chromium Substances 0.000 description 5
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 description 5
- 229910000359 iron(II) sulfate Inorganic materials 0.000 description 5
- 229910052759 nickel Inorganic materials 0.000 description 5
- 150000003839 salts Chemical class 0.000 description 5
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 4
- 229910021564 Chromium(III) fluoride Inorganic materials 0.000 description 4
- -1 Fe2+ ions Chemical class 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 4
- 229910052799 carbon Inorganic materials 0.000 description 4
- 239000002245 particle Substances 0.000 description 4
- 230000035484 reaction time Effects 0.000 description 4
- 239000011347 resin Substances 0.000 description 4
- 229920005989 resin Polymers 0.000 description 4
- 238000011282 treatment Methods 0.000 description 4
- FTBATIJJKIIOTP-UHFFFAOYSA-K trifluorochromium Chemical compound F[Cr](F)F FTBATIJJKIIOTP-UHFFFAOYSA-K 0.000 description 4
- 239000002699 waste material Substances 0.000 description 4
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 3
- MUBZPKHOEPUJKR-UHFFFAOYSA-N Oxalic acid Chemical compound OC(=O)C(O)=O MUBZPKHOEPUJKR-UHFFFAOYSA-N 0.000 description 3
- 239000004743 Polypropylene Substances 0.000 description 3
- 150000002222 fluorine compounds Chemical class 0.000 description 3
- SHXXPRJOPFJRHA-UHFFFAOYSA-K iron(iii) fluoride Chemical compound F[Fe](F)F SHXXPRJOPFJRHA-UHFFFAOYSA-K 0.000 description 3
- 229910021645 metal ion Inorganic materials 0.000 description 3
- JZMJDSHXVKJFKW-UHFFFAOYSA-M methyl sulfate(1-) Chemical compound COS([O-])(=O)=O JZMJDSHXVKJFKW-UHFFFAOYSA-M 0.000 description 3
- 229920001155 polypropylene Polymers 0.000 description 3
- 150000003467 sulfuric acid derivatives Chemical class 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- 229910001339 C alloy Inorganic materials 0.000 description 2
- 229910000640 Fe alloy Inorganic materials 0.000 description 2
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 2
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 description 2
- 238000009825 accumulation Methods 0.000 description 2
- 229910001430 chromium ion Inorganic materials 0.000 description 2
- 238000005260 corrosion Methods 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000007654 immersion Methods 0.000 description 2
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 2
- 229910052749 magnesium Inorganic materials 0.000 description 2
- BDAGIHXWWSANSR-UHFFFAOYSA-N methanoic acid Natural products OC=O BDAGIHXWWSANSR-UHFFFAOYSA-N 0.000 description 2
- LGQLOGILCSXPEA-UHFFFAOYSA-L nickel sulfate Chemical compound [Ni+2].[O-]S([O-])(=O)=O LGQLOGILCSXPEA-UHFFFAOYSA-L 0.000 description 2
- 229910000363 nickel(II) sulfate Inorganic materials 0.000 description 2
- 238000002161 passivation Methods 0.000 description 2
- 239000012071 phase Substances 0.000 description 2
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 2
- 238000000746 purification Methods 0.000 description 2
- 230000000717 retained effect Effects 0.000 description 2
- WBHQBSYUUJJSRZ-UHFFFAOYSA-M sodium bisulfate Chemical compound [Na+].OS([O-])(=O)=O WBHQBSYUUJJSRZ-UHFFFAOYSA-M 0.000 description 2
- 229910000342 sodium bisulfate Inorganic materials 0.000 description 2
- 229910052725 zinc Inorganic materials 0.000 description 2
- OSWFIVFLDKOXQC-UHFFFAOYSA-N 4-(3-methoxyphenyl)aniline Chemical compound COC1=CC=CC(C=2C=CC(N)=CC=2)=C1 OSWFIVFLDKOXQC-UHFFFAOYSA-N 0.000 description 1
- CIWBSHSKHKDKBQ-JLAZNSOCSA-N Ascorbic acid Natural products OC[C@H](O)[C@H]1OC(=O)C(O)=C1O CIWBSHSKHKDKBQ-JLAZNSOCSA-N 0.000 description 1
- 229910000975 Carbon steel Inorganic materials 0.000 description 1
- 229910001018 Cast iron Inorganic materials 0.000 description 1
- 229910002555 FeNi Inorganic materials 0.000 description 1
- PXGOKWXKJXAPGV-UHFFFAOYSA-N Fluorine Chemical compound FF PXGOKWXKJXAPGV-UHFFFAOYSA-N 0.000 description 1
- 229910021626 Tin(II) chloride Inorganic materials 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 230000001464 adherent effect Effects 0.000 description 1
- 150000001299 aldehydes Chemical class 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 235000010323 ascorbic acid Nutrition 0.000 description 1
- 229960005070 ascorbic acid Drugs 0.000 description 1
- 239000011668 ascorbic acid Substances 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 229910052797 bismuth Inorganic materials 0.000 description 1
- 239000004202 carbamide Substances 0.000 description 1
- 235000013877 carbamide Nutrition 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 230000003197 catalytic effect Effects 0.000 description 1
- 239000013043 chemical agent Substances 0.000 description 1
- 238000005097 cold rolling Methods 0.000 description 1
- 239000000356 contaminant Substances 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 150000004673 fluoride salts Chemical class 0.000 description 1
- 239000011737 fluorine Substances 0.000 description 1
- 229910052731 fluorine Inorganic materials 0.000 description 1
- 235000019253 formic acid Nutrition 0.000 description 1
- 239000013505 freshwater Substances 0.000 description 1
- 239000008187 granular material Substances 0.000 description 1
- 239000003112 inhibitor Substances 0.000 description 1
- 150000002576 ketones Chemical class 0.000 description 1
- TYQCGQRIZGCHNB-JLAZNSOCSA-N l-ascorbic acid Chemical compound OC[C@H](O)[C@H]1OC(O)=C(O)C1=O TYQCGQRIZGCHNB-JLAZNSOCSA-N 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 238000010002 mechanical finishing Methods 0.000 description 1
- 238000010907 mechanical stirring Methods 0.000 description 1
- 229910001512 metal fluoride Inorganic materials 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 238000006386 neutralization reaction Methods 0.000 description 1
- 230000003472 neutralizing effect Effects 0.000 description 1
- 235000006408 oxalic acid Nutrition 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 238000010422 painting Methods 0.000 description 1
- 229910052763 palladium Inorganic materials 0.000 description 1
- ACVYVLVWPXVTIT-UHFFFAOYSA-N phosphinic acid Chemical class O[PH2]=O ACVYVLVWPXVTIT-UHFFFAOYSA-N 0.000 description 1
- 150000003017 phosphorus Chemical class 0.000 description 1
- 238000007747 plating Methods 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 230000001376 precipitating effect Effects 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- 239000002893 slag Substances 0.000 description 1
- 239000010802 sludge Substances 0.000 description 1
- LSNNMFCWUKXFEE-UHFFFAOYSA-L sulfite Chemical class [O-]S([O-])=O LSNNMFCWUKXFEE-UHFFFAOYSA-L 0.000 description 1
- 239000002344 surface layer Substances 0.000 description 1
- 239000004094 surface-active agent Substances 0.000 description 1
- AXZWODMDQAVCJE-UHFFFAOYSA-L tin(II) chloride (anhydrous) Chemical compound [Cl-].[Cl-].[Sn+2] AXZWODMDQAVCJE-UHFFFAOYSA-L 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
- C23G1/00—Cleaning or pickling metallic material with solutions or molten salts
- C23G1/36—Regeneration of waste pickling liquors
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
- C23G1/00—Cleaning or pickling metallic material with solutions or molten salts
- C23G1/02—Cleaning or pickling metallic material with solutions or molten salts with acid solutions
- C23G1/08—Iron or steel
- C23G1/086—Iron or steel solutions containing HF
Definitions
- the present invention relates to a process for recovering, with high yields, the hydrofluoric acid remaining inside spent the pickling baths used during the metal processing, such as the stainless steel processing, allowing it to be reused with obvious economic and environmental advantages.
- the pickling is a chemical operation carried out to remove surface layers of a material by means of acid or base solutions.
- this treatment When performed on metallic materials, this treatment is able to remove the layer of surface oxide or other contaminants, also with the purpose of making the surface suitable for further processing. In fact, after the pickling the exposed surface becomes “porous" and allows for possible bonding with another material. Furthermore, the outer layer of the material is thus cleaned of possible unwanted residues such as, for example, rust formed by hot-rolled steel products, surfactants or other chemicals, and rolling flakes.
- the pickling is one of the commonly used methods to prepare the steel surfaces on which further cold rolling or mechanical finishing is to be performed.
- the pickling operation is carried out by immersing the material to be treated in tanks containing acid solutions at high temperature.
- acid solutions such as hydrochloric, sulfuric, phosphoric, nitric and/or hydrofluoric acids, also in mixture with each other, are used.
- Corrosion inhibitors can also be introduced into the pickling solutions in order to limit the attack of the acids at the level of the "bare" metal portions, i.e. those areas deprived of the oxide layer more quickly than others.
- the pickling Since the pickling leaves the metal surface completely clean and exposed, it is usually followed by further treatments adapted to cover it and protect its integrity, which depend on the type of material and the required finish. For example, some operations that can be carried out after the pickling process are the passivation, chrome plating, anodic oxidation and painting.
- the stainless steels are materials characterized by greater resistance to the oxidation and corrosion, especially in humid air or fresh water, than the so-called "carbon steels". Such capability is mainly due to almost the absence of carbon (less than 0.07%) and the concomitant presence of chromium inside the alloy. The latter, in fact, is able to be "passivated” i.e., to cover itself with a thin and adherent layer of oxides that superficially protects the underlying material from the action of the oxygen and possible other external chemical agents.
- Austenitic steels Chromium is accompanied by Nickel and the standard alloy is called 18/8 since it contains 18% Chromium and 8% Nickel.
- Ferritic steels only Chromium is present in amounts from 11% to 30%. In both cases the rolled or forged products have a strong dark layer of oxides that must be chemically removed to obtain the classic light gray color, Such operation is known as pickling.
- the pickling of a stainless steel provides for the use of strong acid solutions, in order to remove the surface oxides present on its surface, such as slag, dust, iron rust, welding oxides, as well as to remove from the surface the possible layer of steel depleted in chromium due to the alterations suffered by the steel itself during processing. This operation will be followed by a passivation process that will restore in a uniform manner the protective film of oxides.
- ARU Acid Recovery Units
- the recoverable free acids are H 2 SO 4 and HF
- ARU Acid Retard Resin
- the second phase of the process is started, which involves the introduction of counter-current water in order to free the acids held by the inside of the chromatographic resin (ARR) and return them to the pickling tank.
- the volumes of spent solution entering the ARU system from the first step and the volumes of counter-current water from the second step are equivalent.
- Bonded fluorides 58.2 g/L it follows that the maximum recovery achievable by applying only the ARU system will be:
- an object of the present invention to provide a process for recovering the hydrofluoric acid from the pickling baths that produces high yields in recovering hydrofluoric acid and allows it to be reused, even inside the same pickling system.
- a further object of the invention is to recover and recycle the hydrofluoric acid present in a pickling solution containing high concentrations of metal fluoride salts.
- Object of the present invention is a process which allows for recovering the hydrofluoric acid from the pickling bath solutions, particularly for the pickling of metals, preferably stainless steel, including the hydrofluoric acid bound to the Me +3 forms present.
- pickling bath solutions is meant to denote the liquid phase that fills the tanks in which the materials, that are to undergo the pickling treatment, are immersed. As previously described, said solutions must be periodically replaced due to the accumulation of metal ions that form salts/complexes with the acids present, making the process progressively less efficient.
- Object of the present invention is a process which allows for reducing the economic and environmental costs of using and disposing of such pickling solutions thanks to an efficient recovery of the hydrofluoric acid dissolved therein and enabling its subsequent possible recycling,
- the process of the present invention has to be employed upstream of the ARU system and is based on the possibility to free hydrofluoric acid (HF) from its salified/complexed forms with the metal ions, and in particular from the FeF 3 , form.
- HF hydrofluoric acid
- hydrofluoric acid occurs thanks to the use of a strongly reducing chemical system.
- said system may comprise the use of different chemicals and/or modes:
- organic reducing agents such as oxalic acid, formic acid, ascorbic acid, urea, aldehydes and ketones etc.;
- hypophosphites and phosphorus derivatives 4. hypophosphites and phosphorus derivatives; 4. catalytic reducing agents (H 2 catalyzed with Palladium, Platinum, Nickel);
- metal-based or bimetal-based sacrificial anodes such as Fe, Zn, Bi. Ca, Sr, Mg, Ni, in combination or not with carbon.
- the reducing system is based on the use of NaHSOj (1); a practical example of this aspect is given, for illustrative and non-limiting purposes, in the Experimental Section below (Example 1).
- the reducing system is constituted by a hydrogen electrolytic cell (3).
- the reducing system is based on the use of metal-based sacrificial anodes (4), a practical example of this aspect is given, for illustrative and non-limiting purpose, in the Experimental Section below (Example 2).
- Said metal-based sacrificial anodes may be, according to the present invention, a special mixture of metals (Me 0 ), such as Fe, Zn, Bi, Ca, Mg and Ni, also combined with the carbon, which undergo an oxidation reaction in acid environment, then allowing the reduction of the iron present in the pickling bath from Fe 3+ to Fe 2+ , resulting in the breakdown of the FeFj complex and the formation of FeSO 4 .
- metals Fe 0
- metal sacrificial anode an assembly of one or more metals to form an alloy with the carbon, such as the cast iron, iron/ carbon alloy.
- Said sacrificial anode may be in the form of flakes or powder of the metal itself, its particle size only affecting the process times.
- the sacrificial anode is constituted by an alloy (Fe/C or FeNi/C, 95% purity) in the powder state, average particle size between 50 and 500 pm.
- the reaction takes place inside a special reactor made of polypropylene (PP) and equipped with a mixer, thanks to the use of a cell in which the sacrificial anode or the hydrogen electrolytic generator are housed, if present, at a temperature between 20 and 50°C, preferably between 30 and 40°C.
- PP polypropylene
- the reaction time required for the conversion of FeF 3 to HF depends on the type of reducing reaction and, in the case of the sacrificial anode, on the particle size of the metal mixture, According to a particular aspect of the present invention, said mixture is in powder form and the reaction time is between 1 and 4 hours.
- the reaction occurring inside the reactor comprises the following two main steps, sequentially; a. Me 0 + H 2 SO 4 MeSO 4 + H 2 oxidation of the metal from Me 0 to Me 2+ b. 2FeF 3 + H 2 + 2H 2 SO 4 2FeSO 4 + 6HF
- a stoichiometric amount of H 2 SO 4 must be added from outside, adding to the sulfuric acid already present in the pickling bath solution.
- Said added amount of H 2 SO 4 is between 5% and 11% by weight to the total volume of the solution introduced into the reactor, depending on the reduction method selected.
- reaction completion can be verified experimentally by using an instrument capable of reading the redox potential of the solution once all the Fe' 3 has been converted to Fe +2 .
- a mechanical filtration is performed on a column filter filled with inert material (e.g., polypropylene granules).
- the solution in which the conversion from Fe +3 to Fe +2 has taken place is sent to the ARU system where, thanks to the presence of the chromatographic resin (ARR), the free acids present can be retained and separated from the metallic salts and finally, thanks to the water introduced in counter-current as previously described, reintroduced into the pickling tanks.
- ARU chromatographic resin
- the process of the present invention allows for the conversion of Fe +3 to Fe 4-2 , resulting in the release of HF but at the expense of the simultaneous formation of FeSO 4 , thereby reducing, as a result, the amount of sulfuric acid that can be re-uptaken in the subsequent step through the ARU system and that must be rebalanced.
- the yields obtained downstream of the ARU system used after the conversion process to free hydrofluoric acid of the present invention are equal to 81,2% with respect to HF, compared to a recovery yield of hydrofluoric acid of, at most, 37.5% according to the known technique, as described above.
- the process of the present invention therefore allows to achieve significant economic advantages, which reside mainly in the possibility of reusing a greater amount of hydrofluoric acid, thus lowering its living costs as well as those related to the difficulty of its management and storage.
- the percentage of HF recovered and reusable thanks to the process of the invention increases, as a matter of fact and as already stated above, from about 37,5% achieved with the use of the ARU system alone to 81.22% thanks to the present invention.
- the economic saving is sufficiently high to absorb, without being significantly affected, the costs, however low, related to the purchase of the mixture of metals to be used for the conversion process from Fe +3 to Fe +2 .
- the present invention also results in considerable benefits from the environmental point of view, thanks to the consequent reduction of all the problems generated by its management and disposal.
- Fe +3 (FeFa) 40 g/L (corresponding to F" 40.7 g/L)
- the reaction bath is kept under mechanical stirring and we proceed to the immersion of a pre- weighed sacrificial anode (Me 0 ) constituted by a iron/carbon alloy, of which 95% iron.
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
Abstract
La présente invention concerne un procédé de récupération, avec des rendements élevés, de l'acide fluorhydrique restant à l'intérieur des bains de décapage utilisés pendant le traitement de métal, tel que le traitement de l'acier inoxydable, ce qui permet de réutiliser l'acide fluorhydrique avec des avantages économiques et environnementaux évidents.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
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PCT/IB2022/050884 WO2023148516A1 (fr) | 2022-02-02 | 2022-02-02 | Procédé de récupération d'acide fluorhydrique libre et combiné à partir d'un bain de décapage d'acier inoxydable |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
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PCT/IB2022/050884 WO2023148516A1 (fr) | 2022-02-02 | 2022-02-02 | Procédé de récupération d'acide fluorhydrique libre et combiné à partir d'un bain de décapage d'acier inoxydable |
Publications (1)
Publication Number | Publication Date |
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WO2023148516A1 true WO2023148516A1 (fr) | 2023-08-10 |
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Family Applications (1)
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PCT/IB2022/050884 WO2023148516A1 (fr) | 2022-02-02 | 2022-02-02 | Procédé de récupération d'acide fluorhydrique libre et combiné à partir d'un bain de décapage d'acier inoxydable |
Country Status (1)
Country | Link |
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WO (1) | WO2023148516A1 (fr) |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1993002227A1 (fr) * | 1991-07-15 | 1993-02-04 | Eco-Tec Limited | Procede et dispositif de traitement de solutions acides contenant du fluorure |
IT1290947B1 (it) * | 1997-02-25 | 1998-12-14 | Sviluppo Materiali Spa | Metodo e dispositivo per il decapaggio di prodotti in lega metallica in assenza di acido nitrico e per il recupero di soluzioni esauste |
-
2022
- 2022-02-02 WO PCT/IB2022/050884 patent/WO2023148516A1/fr active Application Filing
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1993002227A1 (fr) * | 1991-07-15 | 1993-02-04 | Eco-Tec Limited | Procede et dispositif de traitement de solutions acides contenant du fluorure |
IT1290947B1 (it) * | 1997-02-25 | 1998-12-14 | Sviluppo Materiali Spa | Metodo e dispositivo per il decapaggio di prodotti in lega metallica in assenza di acido nitrico e per il recupero di soluzioni esauste |
Non-Patent Citations (1)
Title |
---|
REGEL-ROSOCKA ET AL: "A review on methods of regeneration of spent pickling solutions from steel processing", JOURNAL OF HAZARDOUS MATERIALS, ELSEVIER, AMSTERDAM, NL, vol. 177, no. 1-3, 15 May 2010 (2010-05-15), pages 57 - 69, XP026928925, ISSN: 0304-3894, [retrieved on 20091216], DOI: 10.1016/J.JHAZMAT.2009.12.043 * |
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