WO2010052123A1 - Composition de liquide ionique pour l’élimination de la calamine - Google Patents

Composition de liquide ionique pour l’élimination de la calamine Download PDF

Info

Publication number
WO2010052123A1
WO2010052123A1 PCT/EP2009/063706 EP2009063706W WO2010052123A1 WO 2010052123 A1 WO2010052123 A1 WO 2010052123A1 EP 2009063706 W EP2009063706 W EP 2009063706W WO 2010052123 A1 WO2010052123 A1 WO 2010052123A1
Authority
WO
WIPO (PCT)
Prior art keywords
metal
lewis
ionic liquid
oxidation state
component
Prior art date
Application number
PCT/EP2009/063706
Other languages
English (en)
Inventor
Ramon Bacardit
Paolo Giordani
Mauro Rigamonti
Dennis Bankmann
Maria Del Mar Combarros Gracia
Original Assignee
Henkel Ag & Co. Kgaa
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Henkel Ag & Co. Kgaa filed Critical Henkel Ag & Co. Kgaa
Publication of WO2010052123A1 publication Critical patent/WO2010052123A1/fr

Links

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
    • C23G5/00—Cleaning or de-greasing metallic material by other methods; Apparatus for cleaning or de-greasing metallic material with organic solvents
    • 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
    • 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
    • C23G1/28—Cleaning or pickling metallic material with solutions or molten salts with molten salts

Definitions

  • the present invention refers to a composition comprising an ionic liquid (IL) for the conditioning and/or pickling of oxide scale on metal parts as well as to a process for the removal of oxide scale on metal parts, wherein the metal part is brought into contact with a composition comprising an ionic liquid (IL1 ) composed of
  • component (b) one or more Lewis-acidic inorganic metal salts, wherein at least one Lewis-acidic inorganic metal salt according to component (b) comprises a metal cation with an oxidation state more positive than the lowest accessible positive oxidation state of the metal element itself.
  • metal parts that are at least partially composed of steel and/or stainless steel are preferred in a conditioning and/or pickling process as described herein.
  • the present invention encompasses metal parts, especially sheets, coils, wires, rods and preformed parts that have been treated in a process for the removal of oxide scale according to this invention.
  • the present invention relates to the field of metal surface treatment, particularly the treatment of thermally created oxide layers, such as those occurring in hot processing of metals into strip and wire. These oxides must be removed from the finished metal product. According to industrial standards the finished metal product has to be metallic bright with almost no residues of oxides on the metal surface. Especially, the removal of thermal oxide scale on forgeable metals, e.g. various types of steel, is a major aspect of the underlying invention.
  • Chemical oxide removal (“pickling") systems are typically aqueous and consist of a strong acid, an oxidizing agent and a complexing agent.
  • a typical, simple yet hazardous system uses a mixture of concentrated nitric acid and concentrated hydrofluoric acid.
  • Various combinations of acids and oxidizing agents have been used in the past.
  • Current state-of-the-art systems rely on the presence of at least some amount of fluoride or hazardous hydrofluoric acid in the mixture.
  • Oxide conditioning can be achieved thermally or by chemical modification of the oxide scale.
  • Thermal treatment using high temperature gradients may cause cracking of closed oxide layers allowing the pickling agent to penetrate the scale more readily.
  • Chemical modification of the scale involves oxidation or reduction of the part of the oxides present in the scale.
  • Oxidative treatment by means of a "conditioning step” is typically conducted in a bath of molten sodium nitrate with sodium hydroxide as a flux agent at around 500 0 C.
  • Such systems are commercially available under the brand name Kolene ® (Shoemaker, R. H. (1982), "Metal purification by molten salt process", Metalurgia y Electricidad 46, 44-6, 49-50).
  • Reductive conditioning is also conducted in a molten salt bath, but employs sodium hydride as a reducing agent instead of the sodium nitrate oxidizing agent.
  • sodium hydride as a reducing agent instead of the sodium nitrate oxidizing agent.
  • a de-scaling process for metal parts is disclosed in GB1221694.
  • Both molten salt technologies require furnaces and substantial safety measures due to the highly reactive and caustic nature of the chemicals used. Furthermore, these processes consume significant energy for heating the bath to flux. They also produce caustic sludges and quenching parts from molten salt baths creates toxic and caustic steam.
  • a further example of oxidative treatment uses permanganate in methanol.
  • Methanol is a toxic, volatile and flammable organic solvent and permanganate is a strong oxidizing agent with the ability to produce toxic Cr(VI) species from chromium(lll) oxide present in oxide scale of stainless steel metal parts.
  • compositions exist for pickling baths in a process for pickling martensitic or ferhtic stainless steel disclosed in the German Application DE10160318, wherein the stainless steel is placed in contact with a pickling solution which has a temperature in the range 15 to 29 0 C and contains 50 to 120 g/l of free sulfuric acid, 5 to 40 g/l of free HF and 5 to 40 g/l of Fe(III) ions.
  • pickling solution which has a temperature in the range 15 to 29 0 C and contains 50 to 120 g/l of free sulfuric acid, 5 to 40 g/l of free HF and 5 to 40 g/l of Fe(III) ions.
  • Cleanox ® Hex AG & Co. KGaA, Germany
  • the present invention by virtue of the compositions described, relates to the field of non-aqueous solvents containing organic salts. These are well known in the art and are usually referred to as molten salts, ionic liquids or deep eutectic solvents, depending on their precise nature. Reviews on ionic liquids can be found in the concurrent literature (Wasserborg, Peter / Welton, Thomas (Eds.), "Ionic Liquids in Synthesis", 2007, Wiley-VCH, Weinheim; J. Dupont et al, Chem. Rev. 2002, 102, 3667)
  • deep eutectic solvent refers to a mixture of at least two components which do not form discrete new compounds, but show a very low temperature eutectic point in their phase diagram.
  • ionic liquids can be prepared by combination of an organic salt with a Lewis-basic anion and a Lewis-acidic inorganic material, thus forming new ionic liquid compounds with complex anions (Wasserscheid, Peter / Welton, Thomas (Eds.), "Ionic Liquids in Synthesis", 2007, Wiley-VCH, Weinheim; J. Dupont et al, Chem. Rev. 2002, 102, 3667).
  • ionic liquids based on choline chloride and inorganic Lewis- acidic metal salts wherein the molar ratio of the the Lewis-acidic metal salt to the quarternary ammonium compound is at least 1 : 1 are disclosed for the reprocessing of an oxidized transition metal catalyst in powdered form.
  • the problem to be solved according to this invention consists in establishing a composition comprising an ionic liquid suitable for the conditioning of oxide scale on metal parts, especially of oxide scale on various types of steel, together with an aqueous process for the removal of such oxide scale.
  • a further problem to be solved consists in establishing a composition comprising an ionic liquid that is also suitable for the removal of oxide scale on metal parts, especially of oxide scale on various types of steel.
  • steel according to this invention includes all forgeable iron-based materials, but also all highly alloyed metallic materials in which the element iron (Fe) is the major metallic elemental constituent. This definition also includes those iron-based materials that are generically referred to as stainless steels. A list of the technically most important stainless steels, together with the material Nos., identifications and alloy components, as well as the mechanical and chemical properties thereof are given in Ullmanns Encyklopadie der ischen Chemie, 4 th Edition, Vol. 22, pp. 106-112 and in German Industrial Standard DIN 17440, July 1985. Stainless steels are iron-based alloys containing at least 10% chromium. The formation of chromium oxide on the material surface imparts to the stainless steels the corrosion-resistant character thereof.
  • Stainless steels may be sub-divided into the following families: austenitic steels, ferhtic steels, martensitic steels, precipitation hardened steels and duplex steels. These groups differ in the physical and mechanical properties thereof, as well as in corrosion resistance, as a result of the various alloying constituents.
  • Austenitic stainless steels are listed as stainless steels of the 200 and 300 Series. They are the most widely employed stainless steels and represent 65 to 85% of the stainless steel market. They are chemically characterised by a chromium content of > 17% and a nickel content of > 8%. They have a cubic face-centered structure and are outstandingly ductile and weldable.
  • Type UNS S 30400 Type 304
  • Modifications include S 32100 (stabilized with titanium) and S 34700 (stabilized with niobium). Alloys having higher contents of chromium, nickel or molybdenum are available and provide increased corrosion resistance. Examples are S 31600, S 31700, S 30900 and S 31000.
  • the 200 Series of austenitic stainless steels has, on the other hand, a reduced nickel content and contains manganese instead.
  • ionic liquid corresponds to salts with a relatively low melting point and low viscosity.
  • IL ionic liquid
  • RTIL room temperature ionic liquid
  • Ionic liquids can be stable up to temperatures of 500 0 C. As a medium they can provide excellent solubility for numerous organic, inorganic and polymeric substances. Further notable characteristic of ionic liquids are their non- measurable vapor pressure and the non-flammable nature of most members of the family of ionic liquids.
  • conditioning and pickling constitute process steps in an overall process for the removal of oxide scale on metal parts.
  • the compact oxide film covering the surface of the metal part has to be altered in contact with the composition comprising an ionic liquid by means of physical and chemical attack in a way that the subsequent pickling of the metal part is rendered more efficient yielding an almost complete removal of oxide scale.
  • a composition suitable for conditioning might as well be suitable for the pickling of oxide scale on metal parts. Consequently, the conditioning of the compact oxide film and the pickling of the oxide scale on the metal part might be accomplished in one process step provided that the composition comprising an ionic-liquid acts as a markedly effective pickling agent as well.
  • compositions comprising an ionic liquid (IL) composed of
  • organic salts as a source of Lewis-basic anions, wherein the organic salts are selected from halides and/or pseudohalides of mono- or polyfunctional ammonium, iminium, imidazolium, pyrazolinium, pyridinium, phosphonium and/or sulfonium compounds,
  • component (b) one or more Lewis-acidic inorganic metal salts selected from halides and pseudohalides, wherein at least one Lewis-acidic inorganic metal salt according to component (b) comprises a metal cation with an oxidation state more positive than the lowest accessible positive oxidation state of the metal element itself, wherein the conditioning and/or pickling composition comprises a molar ratio of metal cations of components (b) to Lewis-basic anions that originate from components (a) that is less than 1 : 1.
  • oxidation state is defined by the corresponding IUPAC Rule 1-5.5.2.1 ("Nomenclature of Inorganic Chemistry - Recommendations 1990", Blackwell: Oxford, 1990) and thereby defines the hypothetical charge an atom might be imagined to have when electrons are counted in accordance with the electronegativity of the respective elements that assemble the molecule or salt, while the element with the higher electronegativity gathers all the electrons shared with elements that are less electronegative.
  • the lowest accessible positive oxidation state means the lowest common positive oxidation state of a metal element that is listed in the "Periodic Table of the Elements” by Fluck, E. and Heumann, K. G. (Wiley-VCH, 4 th Edition, 2007).
  • Lewis-basic anions of component (a) react with at least one of the Lewis-acidic inorganic metal salt of component (b) thereby forming an ionic liquid (IL) that comprises anionic metal complexes, while the overall molar concentration of Lewis-basic anions that possibly originate from component (a) organic salts exceeds the molar concentration of metal cations of component (b) Lewis-acidic inorganic metal salts. Therefore, an excess of organic salt as a source of Lewis-basic anions dissolved within the ionic liquid is established which strongly affects the conditioning and pickling properties of the composition according to this invention. Nevertheless, a certain amount of Lewis-acidic metal salts according to component (b) within the compositions is preferred.
  • compositions with a molar ratio of metal cations of components (b) to Lewis-basic anions that originate from components (a) that is less than 1 : 100 yield from a technical point of view unacceptable minor results in conditioning and pickling of oxide scale on metal parts.
  • the molar ratio of metal cations of components (b) to Lewis-basic anions that originate from components (a) is not less than 1 : 10 to deploy a considerable conditioning or removal of oxide scale.
  • those organic salts as a source of Lewis-basic anions are selected that do not have hydrogen atoms being bonded to the cationoid heteroatoms selected from nitrogen, phosphorus and/or sulfur of the above-mentioned halides and/or pseudohalides of component (a).
  • thermal decomposition reactions of the ionic liquid at elevated temperatures can be avoided.
  • Lewis-basic anions of component (a) that contribute to the formation of the ionic liquid (IL) of the conditioning and/or pickling composition are according to the Lewis concept electron donors.
  • Those electron donors are selected preferably from chloride, bromide, fluoride, dicyanamide and/or thiocyanate, most preferably chloride.
  • Lewis-acidic inorganic metal salts of component (b) that compose the ionic liquid (IL) of the conditioning and/or pickling composition are according to the Lewis concept electron acceptors.
  • Lewis-acidic metal salts according to component (b) are of use where the metal can exist in two reasonably stable, distinct oxidations states greater than zero, thus salts like AICI3 and ZnC ⁇ are found to be unsuitable.
  • Metals with just one oxidation state greater than zero and which may be described as an oxidizing agent, will likely deposit in elemental form by electroless plating on suitable substrates, which contradicts the purpose of the invention to provide a clean, bare surface of the base alloy of the treated metal part.
  • a preferred inorganic salt used in the design and construction of the preferred conditioning and/or pickling composition herein described will be incapable of oxidizing chromium(lll) to toxic chromium(VI) compounds.
  • those electron acceptors are preferred wherein the metal with an oxidation state more positive than the lowest accessible positive oxidation state of the metal element itself is selected from those metal cations that have a standard reduction potential with respect to their metal cations in their lowest accessible positive oxidation state in the ionic liquid (IL) higher than at least one standard reduction potential of the major metallic elemental constituent of the metal part to be treated with respect to any oxidation state of its metal cations in an ionic liquid (IL2) that differs from the ionic liquid (IL) according to this invention only in that the component (b) Lewis-acidic metal salts comprise the metal cations in their lowest accessible positive oxidation state only.
  • the standard reduction potential E°(Me n+ /Me m+ ) of a redox couple Me n+ (iL)/Me m+ (iL) in the ionic liquid (IL), wherein Me n V) originates from the at least one component (b) Lewis-acidic metal salt with an oxidation state of the metal cation higher than the lowest accessible oxidation state of the metal itself, is defined as the half cell potential of the following electrochemical reaction (1 ) versus the half cell potential of the standard hydrogen electrode (SHE), wherein all thermodynamic concentrations of the metal species equal to 1 :
  • n being an integer number of at least 1 and m being zero or an integer number of at least 1 , wherein n is greater than m.
  • the preferred electron acceptors according to the invention are based on metal cations of a Lewis-acidic metal salt of component (b) wherein the following condition is fulfilled:
  • IL ionic liquid according to the composition of the invention
  • IL2 ionic liquid that differs from the ionic liquid (IL) according to this invention only in that the component (b) Lewis-acidic metal salts comprise the metal cations in their lowest accessible positive oxidation state only.
  • the oxidizing action is high enough to enable the release of metal ions from the metal part to be treated and thus to remove oxide scale.
  • Me n+ metal cation of the at least one component (b) Lewis-acidic inorganic metal salt with an oxidation state more positive than the lowest accessible oxidation state of the metal element itself;
  • IL ionic liquid according to the invention;
  • Pt inert platinum electrode;
  • Me x+ metal cations of the major elemental constituent of the metal to be treated
  • IL2 ionic liquid that differs from the ionic liquid (IL) according to this invention only in that the component (b) Lewis-acidic metal salts comprise the metal cations in their lowest accessible positive oxidation state only; and Me 0 : metal electrode of the major elemental constituent of the metal.
  • the cell voltage of this electrochemical measurement sequence (3) imposes a cathodic current in the half cell Me n+ ( i L) (Pt), more preferably a cathodic current and an absolute value of the cell voltage of more than 50 mV and less than 1500 mV, more preferably less than 1000 mV.
  • conditioning and/or pickling compositions comprising a ionic liquid, wherein the at least one component (b) Lewis-acidic inorganic metal salt with an oxidation state of the metal cation more positive than the lowest accessible positive oxidation state of the metal element itself is selected from bromides, chlorides, fluorides, dicyanamides and/or thiocyanates of iron, cobalt, nickel, tin, vanadium, titanium, lead, cerium and/or manganese.
  • the oxidizing action of the component (b) Lewis-acidic metal salts does not produce chromium(VI) compounds that might be released from the metallic substrate and/or the chromium(lll) containing oxide scale on the metal part.
  • the ionic liquid is composed of component (b) Lewis- acidic metal salts comprising a metal cation with an oxidation state more positive than the lowest accessible positive oxidation state of the metal element itself that are selected from those metal cations that do not possess any standard reduction potential with respect to a lower positive oxidation state of this metal element in the ionic liquid (IL) that is higher than the standard reduction potential of the redox couple Cr +I "/Cr +Vl in an ionic liquid (IL2) that differs from the ionic liquid (IL) according to this invention only in that the component (b) Lewis-acidic metal salts comprise the metal cations in their lowest accessible positive oxidation state only.
  • component (b) Lewis-acidic metal salts comprise the metal cations in their lowest accessible positive oxidation state only.
  • the conditioning and/or pickling composition according to this invention preferably comprises component (b) Lewis-acidic metal salts with an oxidation state of the metal cations more positive than the lowest accessible positive oxidation state of the metal element itself, wherein the metal cations are further selected from those metal cations that have at least one standard reduction potential with respect to a lower positive oxidation state of this metal element in the ionic liquid (IL) that is higher than the standard reduction potential of this metal element in this lower positive oxidation state with respect to its metallic state in an ionic liquid (IL3) that differs from the ionic liquid (IL) only in that the component (b) Lewis-acidic metal salts comprise the metal cations in the lower positive oxidation state only.
  • component (b) Lewis-acidic metal salts comprise the metal cations in the lower positive oxidation state only.
  • the at least one component (b) Lewis-acidic metal salt with an oxidation state of the metal cation more positive than the lowest accessible positive oxidation state of the metal element itself is selected from iron(lll)halides, more preferably iron(lll)chloride and most preferably non-hydrated iron(lll)chloride.
  • any organic cation that does not carry interfering functional groups may be used in such a composition, if it allows for a suitably low melting point of the mixture of the components (a) and (b), i.e. below the decomposition temperature of the organic parts and below the desired processing temperature.
  • functional groups with protic reactivity such as alcohols and carboxylic acids are not preferred compounds as they inhibit the performance in respect to the present invention.
  • an organic material that is oxidizable due to its structure or functionality i.e.
  • thiols, aldehydes are less preferred, since they possibly decrease the oxidizing action of the at least one component (b) Lewis-acidic metal salt within the ionic liquid (IL) according to this invention comprising metal cations in a higher positive oxidation state than the lowest accessible positive oxidation state of the respective metal itself.
  • the chemical structure of the organic cations of components (a) is not strictly limited by the scope of this invention, optimum results in the conditioning and pickling of oxide scale on metal surfaces are obtained for compounds of component (a) wherein the organic salts that also act as a source of Lewis-basic anions, are constituted by organic cations with a monofunctional ammonium, iminium, imidazolium, pyrazolinium and/or pyridinium structure, most preferably with a monofunctional imidazolium structure according to the general formula (I): wherein R 1 and R 2 are independently from each other selected from branched or linear alkyl or hydroxyalkyl groups with not more than 10 carbon atoms, preferably not more than 6 carbon atoms, or from alkoxylates with not more than 6, preferably not more than 4 repeating units, preferably propoxylates and ethoxylates; wherein R 3 , R 4 and R 5 are independently from each other selected from hydrogen atoms, branched or linear alkyl or
  • the conditioning of the oxide scale that in turn consists mainly in altering the strength and porosity of the compact oxide film on the metal part is more efficiently accomplished.
  • those imidazolium cations according to the general structure (I) are even more favorable, wherein R 3 , R 4 and R 5 are hydrogen atoms and R 1 and R 2 are independently from each other selected from a linear or branched alkyl group with not more than 10 carbon atoms, more preferably less than 4 and most preferably not more than two carbon atoms.
  • Another aspect of this invention consist in a process for the removal of oxide scale on metal parts by means of conditioning and/or pickling, wherein the metal part is brought into contact with a composition comprising an ionic liquid (IL1 ) composed of
  • component (b) one or more Lewis-acidic inorganic metal salts, wherein at least one Lewis-acidic inorganic metal salt according to component (b) comprises a metal cation with an oxidation state more positive than the lowest accessible positive oxidation state of the metal element itself.
  • the conditioning and/or pickling performance of the composition used in the process according to this invention can be further improved with an ionic liquid (IL1 ) composed of organic salts of halides and/or pseudohalides as a source of inorganic Lewis-basic anions according to component (a).
  • IL1 ionic liquid
  • the organic cations that correspond to the inorganic Lewis-basic anions of component (a) are preferably selected from cations of mono- or polyfunctional ammonium, iminium, imidazolium, pyrazolinium, pyridinium, phosphonium and/or sulfonium compounds in order to constitute ionic liquids with a melting point of not more than 100 0 C when combined with Lewis-acidic inorganic metal salts according to component (b).
  • monofunctional ammonium, iminium, imidazolium, pyrazolinium and/or pyridinium compounds are most preferred, especially monofunctional imidazolium compounds.
  • component (a) of the composition used in the process according to this invention correspond to the above-defined specified embodiments of the conditioning and/or pickling composition comprising the ionic liquid (IL).
  • component (b) composing the ionic liquid (IL1 ) of the composition used in a conditioning and/or pickling process those Lewis-acidic metal salts with an oxidation state of the metal cation more positive than the lowest accessible positive oxidation state of the metal element itself are preferred, wherein the metal cations of the metal salt have a standard reduction potential with respect to their metal cations in their lowest accessible positive oxidation state in the ionic liquid (IL1 ) higher than at least one standard reduction potential of the metal to be treated with respect to any oxidation state of its metal cations in an ionic liquid (IL2) that differs from the ionic liquid (IL1 ) only in that the component (b) Lewis-acidic metal salts comprise the metal cations in their lowest accessible positive oxidation state only.
  • the oxidizing action of the component (b) Lewis-acidic metal salts does not produce chromium(VI) compounds that might be released from the metallic substrate and/or the chromium(lll) containing oxide scale on the metal part.
  • the ionic liquid (IL1 ) is composed of component (b) Lewis-acidic metal salts comprising a metal cation with an oxidation state more positive than the lowest accessible positive oxidation state of the metal element itself that are selected from those metal cations that do not possess any standard reduction potential with respect to a lower positive oxidation state of this metal element in the ionic liquid (IL1 ) that is higher than the standard reduction potential of the redox couple Cr +I "/Cr +Vl in an ionic liquid (IL2) that differs from the ionic liquid (IL1 ) according to this invention only in that the component (b) Lewis-acidic metal salts comprise the metal cations in their lowest accessible positive oxidation state only.
  • the ionic liquid (IL1 ) of the conditioning and/or pickling composition preferably contains component (b) Lewis-acidic metal salts with an oxidation state of the metal cations more positive than the lowest accessible positive oxidation state of the metal element itself, wherein the metal cations are further selected from those metal cations that have at least one standard reduction potential with respect to a lower positive oxidation state of this metal element in the ionic liquid (IL1 ) that is higher than the standard reduction potential of this metal element in this lower positive oxidation state with respect to its metallic state in an ionic liquid (IL3) that differs from the ionic liquid (IL1 ) only in that the component (b) Lewis-acidic metal salts comprise the metal cations in the lower positive oxidation state only.
  • component (b) Lewis-acidic metal salts comprise the metal cations in the lower positive oxidation state only.
  • compositions comprising the ionic liquid (IL1 )
  • the Lewis-acidic inorganic metal salts according to component (b) of the composition are selected from halides and/or pseudohalides such as chlorides, bromides, fluorides, dicyanamides and/or thiocyanates of iron, cobalt, nickel, tin, vanadium, titanium, lead, cerium and/or manganese.
  • Lewis-acidic metal salts according to component (b) for the conditioning and pickling of various types of steel and/or stainless steel are selected from iron(lll)halides while the equivalent fluorides preferably do not constitute the major species according to component (b) but might as well be present in a mixture of component (b) Lewis-acidic metal salts, more preferably non-hydrated iron(lll)halides and most preferred is non-hydrated iron(lll)chloride.
  • the conditioning and/or pickling process according to this invention yields optimum results for compositions comprising a ionic liquid (IL1 ), wherein the molar ratio of metal cations of components (b) to Lewis-basic anions that originate from components (a) is less than 1 : 1 , but not less than 1 : 100, preferably not less than 1 : 10.
  • Those ionic liquid compositions (IL1 ) are preferred in a process for the removal of oxide scale as they contain a molar excess of Lewis-basic anions that originate from component (a) with respect to the Lewis-acidic metal salt according to component (b).
  • a certain minimum amount of Lewis-acidic metal salts according to component (b) is from a technical point of view preferred in order to provide a considerable conditioning and/or pickling of oxide scale.
  • compositions comprising a ionic liquid (IL1 ) and wherein no subsequent aqueous pickling step is applied to the metal part
  • IL1 ionic liquid
  • those compositions are preferred wherein the molar ratio of metal cations of components (b) to Lewis-basic anions that originate from components (a) is not less than 1 : 10, more preferably not less 1 : 5, but less than 9 : 10, more preferably less than 4 : 5.
  • compositions comprising an ionic liquid that were used in a conditioning and/or pickling process according to this invention tolerate small amounts of water and acids without any detrimental effect for the removal of oxide scale on the treated metal specimens.
  • a process for conditioning and/or pickling of metal parts covered with a compact oxide layer the use of compositions with less than 5 wt.-%, preferably less than 2 wt.-% acids and/or water is favored.
  • composition used in the process according to this invention may additionally contain auxiliary components (c) selected from flux agents, chelating agents, surfactants or dispersing agents, fillers, thixotropic compounds and/or corrosion inhibitors.
  • auxiliary components (c) selected from flux agents, chelating agents, surfactants or dispersing agents, fillers, thixotropic compounds and/or corrosion inhibitors.
  • Flux agents as auxiliary components (c) aid in lowering the melting point of the composition realizing in this way stable low temperature conditioning and pickling bathes that account for minimum energy consumption and prolonged bath lifetime.
  • Chelating agents according to this invention do neither belong to the definition given for component (a) organic salts nor to the definition of component (b) Lewis- acidic metal salt according to the ionic liquid (IL1 ).
  • a preferred flux agent in a process according to this invention is urea.
  • Chelating agents as auxiliary components (c) aid in complexing metal cations in order to improve solubility of the metal ions dissolved during the conditioning and/or pickling treatment of the specimens. Chelating agents used in aqueous media are well known to the person skilled in the art and can as well be used according to this invention.
  • Chelating agents according to this invention do neither belong to the definition given for component (a) organic salts nor to the definition of component (b) Lewis-acidic metal salts according to the ionic liquid (IL1 ).
  • preferred chelating agents are selected from EDTA, rhodanite and/or amines.
  • Surfactants or dispersing agents as auxiliary components (c) may be added to aid in improving effectiveness of the conditioning and/or pickling process on oiled substrates as well as in dispersing solid oxide scale released from the specimens during the conditioning and/or pickling process.
  • auxiliary components (c) may be added to aid in improving effectiveness of the conditioning and/or pickling process on oiled substrates as well as in dispersing solid oxide scale released from the specimens during the conditioning and/or pickling process.
  • perfluorinated anionic surfactants or non-ionic surfactants belonging to alkoxylated alcohol derivatives are preferred as dispersing agents.
  • Fillers as well as thixotropic compounds as auxiliary components (c) impart heightened viscosity to the composition used in the process according to this invention and thereby allow the alignment of the viscosity of the mixture and the application of the composition as a paste or as a thin adherent film to the metal part to be treated.
  • Such fillers are well known to the person skilled in the art, but have to be selected from inorganic particulate matter that does not dissolve in the composition comprising the ionic liquid.
  • Thixotropic compounds as auxiliary components (c) of the composition used in a process according to this invention are preferably selected from particulate silica, particulate aluminum oxide or particulate matter with a non-spherical shape and a preferred particle size with regard to the longest dimension of no more than 50 ⁇ m, more preferably of no more than 10 ⁇ m, i.e. clay minerals and mica.
  • organic polymeric substances that are non-functional ized and non-soluble in the ionic-liquid and thus form colloidal solutions of the polymeric material are preferred as thixotropic compounds.
  • Corrosion inhibitors are compounds that act to prevent corrosion, i.e. etching of the base alloy of the treated specimen during the conditioning or pickling process. They serve to amplify the reactivity difference towards the conditioning/pickling agent between base alloy and scale.
  • Typical corrosion inhibitors are for example amino alcohols, phosphoric acid esters, thiourea derivatives.
  • auxiliary components (c) are present in a composition used in a process for the conditioning and/or pickling of oxide scale according to this invention
  • the composition contains (i) 50-95 wt. -% of the ionic liquid composed of the components (a) and (b) (ii) 0.1 -50 wt.-% of the auxiliary components (c) selected from flux agents, chelating agents, surfactants or dispersing agents, fillers, thixotropic compounds and/or corrosion inhibitors, wherein the overall amount of components (a) and (b) and the auxiliary components (c) adds up to at least 95 wt.-%.
  • the residual amount of the composition that adds up to 100 wt.-% consists of acids and/or water.
  • auxiliary components (c) are preferably present in the composition in an amount of
  • the oxidizing action of the conditioning and/or pickling bath has to be monitored and kept at a certain level.
  • a molar fraction of Lewis-acidic inorganic metal salts according to component (b) with an oxidation state of the metal higher than the lowest accessible positive oxidation state of the metal element itself to the overall amount of components (b) of not less than 50 %, preferably not less than 80 % and more preferably not less than 90 %.
  • the depletion state of a conditioning and/or bath may be determined by taking aliquots and titrating with standard methods for content in iron(ll) and iron(lll).
  • Preferred oxidizing agents according to this invention that are used to align the composition of the bath are those ones that are incapable of oxidizing Cr(III) to Cr(VI), most preferably hydrogen peroxide and/or oxygen.
  • electrolytic oxidation may be applied to return the Lewis-acidic metal salt of component (b) to its higher oxidation state. Electrolytic treatment consumes energy, but much less than required for the maintenance of conditioning baths in prior art using molten salt baths that have to be permanently heated in a furnace.
  • the composition used in the conditioning and/or pickling process according to this invention can be applied to the metal part or metal specimen with conventional industrial coating techniques such as immersing, spraying, wiping and squeegee and/or roller applications.
  • the application by means of immersing the metal part in a bath of the composition comprising the ionic liquid (IL1 ) is preferred.
  • the bath is agitated, by mechanical stirring or injection of air or an inert gas, wherein the relative humidity is preferably less than 10 %, most preferably less than 5 %.
  • auxiliary components are preferably excluded in spray applications of the composition comprising the ionic liquid (IL1 ).
  • flux agents may be especially useful in spray applications to prevent from crystallization of the ionic liquid.
  • the temperature of the composition comprising an ionic liquid (IL1 ) used in a conditioning and/or pickling process according to this invention can be determined by several factors and will usually be chosen so that the conditioning and/or pickling composition is liquid and maintains a suitable viscosity. Increased working temperatures can be employed to speed up the conditioning and pickling process.
  • the temperature may be chosen to exceed the boiling point of water under the prevailing conditions, typically around 100 0 C, to continuously drive off humidity from the conditioning and/or pickling composition in open vessels, thus maintaining a high level of dryness.
  • vacuum may be applied to achieve drying at lower temperatures.
  • the treated metal specimens are removed and rinsed, preferably at high pressure, with tap or deionized water to remove residuals from conditioning and/or pickling composition and to wash off oxide scale flakes.
  • the good water solubility of the conditioning and/or pickling composition comprising the ionic liquid (IL1 ) allows for efficient removal by water rinse.
  • a conditioning and pickling process according to this invention is preferably a two- step process that consists in contacting the metal part to be treated with a conditioning composition comprising an ionic liquid (IL1 ) and subsequently with or without intermediate rinsing step in treating the conditioned metal part with an aqueous pickling solution.
  • a conditioning composition comprising an ionic liquid (IL1 ) and subsequently with or without intermediate rinsing step in treating the conditioned metal part with an aqueous pickling solution.
  • Such an aqueous pickling solution preferably contains iron(lll) ions, sulfuric acid and hydrofluoric acid.
  • iron(lll) ions for such a pickling solution the following amounts are especially preferred: a) 50 to 120 g/l of free sulfuric acid, b) 5 to 40 g/l of free HF and c) 5 to 40 g/l of Fe(III) ions.
  • Further similar embodiments of aqueous pickling solutions are given within the Patent Applications WO 1999/031296, US 6,210,558 which are herewith enclosed by reference.
  • Another preferred aqueous pickling solution for a two-step process may comprise: a) 2 to 100 g/l of one or more strong acids selected from sulfuric acid, phosphoric acid, and hydrochloric acid, or mixtures thereof b) of one or more oxidizing agents containing a peroxo-group, more preferably 1 to 30 g/l of hydrogen peroxide, c) 50 to 300 mmoles per liter of complex fluoride ions of elements of B, Si, Ti and/or Zr.
  • the two-step process is conducted without an intermediate rinsing step.
  • the intermediate rinsing step in the two-step conditioning and pickling process may be omitted.
  • a metal part is encompassed that has been treated according to a conditioning and/or pickling process as described herein.
  • Typical metal parts that have been treated in a process according to this invention are preferably steel metal parts that due to their production process accrue with a compact thermal oxide layer such as sheets and coils after hot- and cold-rolling, drawn wires and wire rods.
  • the conditioning or pickling process according to this invention may be applied to more complex structures, e.g. to oxide formed in welding seams, on larger or preformed parts.
  • the treated metal part is at least partially composed of stainless steel.
  • the conditioning and/or pickling composition used in a process according to the present invention exhibits the following advantages: 1. low hazard classifications such as irritant or harmful on constituents as compared to fluorous pickling systems, with hydrofluoric acid classified as corrosive and very toxic
  • the described invention therefore represents a significant improvement relative to existing conditioning baths in the prior art, which require capital investment of special furnaces, high energy requirements for temperature in excess of 500 0 C, handling of dangerous and strongly corrosive materials, processing of caustic dust, sterna and sludges, or employ flammable, volatile toxic solvents in the presence of strong oxidizing agents.
  • compositions comprising an ionic liquid that reveals adequate pickling properties and thus can be used in a one-step process for the removal of oxide scale on metal parts.
  • pickling baths known in the prior art that are based on compositions that contain strong acids (e.g. hydrofluoric acid) can be replaced with the less hazardous compositions based on ionic liquids according to this invention.
  • Preparation example P1 lron(lll)chloride (anhydrous form) and 1 -ethyl-3-methylimidazolium chloride (Abbr.: emimCI; BASF AG, Germany) were weighed in a 2:3 w/w ratio and mixed in an open vessel at room temperature by mechanical agitation until a brown liquid was formed.
  • An AISI 304 non-annealed stainless steel wire piece was immersed in a stirred bath of an ionic liquid composition according to the preparation example P1 at 80 0 C for 15min.
  • the rod was removed from the bath, rinsed with Dl water and subsequently treated in a Cleanox ® 352 bath (Henkel AG & Co. KGaA, Germany) for 10 min.
  • the rod was rinsed with Dl water and blowdried.
  • the rod was completely pickled (>90% of the surface is metallic bright).
  • Table 1 resumes the effect of conditioning with an ionic liquid composition according to the preparation example P1 on different types of steel compared to a one-step process in which the conditioning step is omitted and which solely relies on the aqueous pickling step accomplished with a Cleanox ® 352 bath.
  • the organic salt according to component (a) was 1 - hydroxyethyl-3-methylimidazolium chloride (C5) and choline chloride (C6) while component (b) was still non-hydrated iron(lll)chloride and the molar ratio of metal cations of component (b) to chloride ions that possibly originate from the respective organic salt according to component (a) was kept according to example P1.
  • Example P1 A used bath according to Example P1 was subjected to air bubbling at 100 0 C for 2 hours. The amount of contained Fe 2+ after treatment was found by redox titration to be reduced from 2.7 % Fe 2+ (relative to Fe 3+ ) to 1.5% Fe 2+ , thus proving the concept of re-establishing the oxidizing action of the ionic liquid composition by means of air injection.
  • a used bath according to Example P1 of total weight of 230 g was treated with 12ml_ of 30% aqueous hydrogen peroxide solution at room temperature and then agitated mechanically while heating at 120 0 C to evaporate water from the mixture.
  • the amount of contained Fe 2+ after treatment was found by redox titration to be reduced from approx. 18 % Fe 2+ (relative to Fe 3+ ) to 10 % Fe 2+ , thus proving the concept of re-establishing the oxidizing action of the ionic liquid composition by means of adding an oxidizing agent.

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

Cette invention concerne une composition comprenant un liquide ionique (LI) pour le traitement et/ou le décapage de la calamine sur des pièces métalliques. L’invention concerne aussi un procédé d’élimination de la calamine sur les pièces métalliques. La pièce métallique est mise en contact avec une composition comprenant un liquide ionique (LI1) composé de (a) au moins un sel organique comme source d’anions inorganiques basiques selon Lewis, et (b) un ou plusieurs sels métalliques inorganiques acides selon Lewis. Au moins un sel métallique inorganique acide selon Lewis du composant (b) comprend un cation métallique dont l’état d’oxydation est plus positif que l’état d’oxydation positif le plus bas possible de l’élément métallique lui-même. Par conséquent, les pièces métalliques, en particulier les feuilles, bobines, fils, tiges et pièces préformées ayant été traitées par un procédé selon l’invention, entrent dans la portée de celle-ci. De préférence, dans un procédé de traitement et/ou de décapage selon l’invention, on utilisera des pièces métalliques au moins partiellement composées d’acier et/ou d’acier inoxydable.
PCT/EP2009/063706 2008-11-05 2009-10-20 Composition de liquide ionique pour l’élimination de la calamine WO2010052123A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US11147308P 2008-11-05 2008-11-05
US61/111,473 2008-11-05

Publications (1)

Publication Number Publication Date
WO2010052123A1 true WO2010052123A1 (fr) 2010-05-14

Family

ID=41510618

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2009/063706 WO2010052123A1 (fr) 2008-11-05 2009-10-20 Composition de liquide ionique pour l’élimination de la calamine

Country Status (1)

Country Link
WO (1) WO2010052123A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114829682A (zh) * 2019-11-21 2022-07-29 株式会社Posco 用于酸洗不锈钢的离子液体和通过使用其酸洗不锈钢的方法

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5731101A (en) * 1996-07-22 1998-03-24 Akzo Nobel Nv Low temperature ionic liquids
WO1999019288A1 (fr) * 1997-10-13 1999-04-22 Quest International B.V. Ameliorations propres aux reactions de friedel et crafts ou liees a ces reactions
WO2000056700A1 (fr) * 1999-03-24 2000-09-28 University Of Leicester Liquides ioniques
WO2001081353A1 (fr) * 2000-04-26 2001-11-01 Atofina Liquides ioniques derives d'acides de lewis a base de titane, niobium, tantale, etain ou antimoine, et leurs applications
WO2002026381A2 (fr) * 2000-09-27 2002-04-04 Scionix Limited Liquides ioniques et leur utilisation
US20060090777A1 (en) * 2004-11-01 2006-05-04 Hecht Stacie E Multiphase cleaning compositions having ionic liquid phase
WO2006088737A2 (fr) * 2005-02-14 2006-08-24 Small Robert J Nettoyage d'un semi-conducteur
WO2007093574A2 (fr) * 2006-02-15 2007-08-23 Akzo Nobel N.V. Procede d'electrodeposition de metaux utilisant des liquides ioniques
WO2007147222A2 (fr) * 2006-06-21 2007-12-27 Katholieke Universiteit Leuven Nouveaux liquides ioniques

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5731101A (en) * 1996-07-22 1998-03-24 Akzo Nobel Nv Low temperature ionic liquids
WO1999019288A1 (fr) * 1997-10-13 1999-04-22 Quest International B.V. Ameliorations propres aux reactions de friedel et crafts ou liees a ces reactions
WO2000056700A1 (fr) * 1999-03-24 2000-09-28 University Of Leicester Liquides ioniques
WO2001081353A1 (fr) * 2000-04-26 2001-11-01 Atofina Liquides ioniques derives d'acides de lewis a base de titane, niobium, tantale, etain ou antimoine, et leurs applications
WO2002026381A2 (fr) * 2000-09-27 2002-04-04 Scionix Limited Liquides ioniques et leur utilisation
US20060090777A1 (en) * 2004-11-01 2006-05-04 Hecht Stacie E Multiphase cleaning compositions having ionic liquid phase
WO2006088737A2 (fr) * 2005-02-14 2006-08-24 Small Robert J Nettoyage d'un semi-conducteur
WO2007093574A2 (fr) * 2006-02-15 2007-08-23 Akzo Nobel N.V. Procede d'electrodeposition de metaux utilisant des liquides ioniques
WO2007147222A2 (fr) * 2006-06-21 2007-12-27 Katholieke Universiteit Leuven Nouveaux liquides ioniques

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
HOLBREY J D ET AL: "IONIC LIQUIDS", CLEAN PRODUCTS AND PROCESSES, SPRINGER, BERLIN, DE, vol. 1, 1 January 1999 (1999-01-01), pages 223 - 236, XP001000207, ISSN: 1435-2974 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114829682A (zh) * 2019-11-21 2022-07-29 株式会社Posco 用于酸洗不锈钢的离子液体和通过使用其酸洗不锈钢的方法
EP4056737A4 (fr) * 2019-11-21 2023-01-11 Posco Liquide ionique pour décapage d'acier inoxydable et procédé de décapage d'acier inoxydable en utilisant celui-ci

Similar Documents

Publication Publication Date Title
JP3655635B2 (ja) 金属表面に化成皮膜を付与する方法およびそのための溶液
Smith* Deep eutectic solvents (DESs) and the metal finishing industry: where are they now?
JP5130226B2 (ja) 亜鉛または亜鉛合金表面を有する加工部品を不動態化するための水性反応溶液及び方法
CN109402702B (zh) 一种铝合金阳极氧化工艺封闭后除灰剂及其制备方法
CN108914106B (zh) 一种镀锌板表面钝化自填充处理液及其应用
JP2009131949A (ja) 金属製品の電解加工用電解液
JP2947695B2 (ja) アルミニウム系金属の酸性洗浄水溶液及びその洗浄方法
CN101278075B (zh) 含过氧化氢和螯合羧酸的磷化液
BR112018075934B1 (pt) Método e fundente para galvanização a quente
Kityk et al. Electropolishing of two kinds of bronze in a deep eutectic solvent (Ethaline)
JPH07122152B2 (ja) アルミニウム用酸性洗浄液
JP5586614B2 (ja) ステンレス鋼の表面処理方法
CN107740022B (zh) 一种热浸镀锌铝镁合金助镀剂
CA1046387A (fr) Methode et compose pour le nettoyage de la surface de metaux ferreux
Tang et al. Electrochemical dissolution and recovery of tin from printed circuit board in methane–sulfonic acid solution
US20030121568A1 (en) Brightening/passivating metal surfaces without hazard from emissions of oxides of nitrogen
WO2010052123A1 (fr) Composition de liquide ionique pour l’élimination de la calamine
Bučko et al. A review of the electrochemical corrosion of metals in choline chloride based deep eutectic solvents
US6669786B2 (en) Self-healing non-chromate coatings for aluminum and aluminum alloys
EP1242651B1 (fr) Brillantage/passivation de surfaces metalliques sans risques d'emissions d'oxydes d'azote
Hazzazi et al. Passivation and cl induced depassivation of Cu-Ag alloys in borate buffer solutions
KR101715618B1 (ko) 탈청용 금속 표면처리제
JP2007321219A (ja) 電解リン酸塩化成処理を用いた潤滑処理方法
JP4119949B2 (ja) ニッケルめっき皮膜の後処理剤
CA2458305A1 (fr) Procede electrolytique et compositions de decapage de depot autocatalytique de nickel

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 09740309

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 09740309

Country of ref document: EP

Kind code of ref document: A1