WO2010143033A1 - Procédé de récupération de solutions alcalines - Google Patents

Procédé de récupération de solutions alcalines Download PDF

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Publication number
WO2010143033A1
WO2010143033A1 PCT/IB2010/001015 IB2010001015W WO2010143033A1 WO 2010143033 A1 WO2010143033 A1 WO 2010143033A1 IB 2010001015 W IB2010001015 W IB 2010001015W WO 2010143033 A1 WO2010143033 A1 WO 2010143033A1
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WO
WIPO (PCT)
Prior art keywords
solution
aluminium
process according
potash
soda
Prior art date
Legal status (The legal status 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 status listed.)
Ceased
Application number
PCT/IB2010/001015
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English (en)
Inventor
Franco Falcone
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Cie Srl
Original Assignee
Cie Srl
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 Cie Srl filed Critical Cie Srl
Publication of WO2010143033A1 publication Critical patent/WO2010143033A1/fr
Anticipated expiration legal-status Critical
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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
    • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
    • C23F1/00—Etching metallic material by chemical means
    • C23F1/46—Regeneration of etching compositions
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES, PROFILES OR LIKE SEMI-MANUFACTURED PRODUCTS OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
    • B21C35/00—Removing work or waste from extruding presses; Drawing-off extruded work; Cleaning dies, ducts, containers, or mandrels for metal extruding
    • B21C35/06—Cleaning dies, ducts, containers or mandrels
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
    • C01D1/00—Oxides or hydroxides of sodium, potassium or alkali metals in general
    • C01D1/04—Hydroxides
    • C01D1/20—Preparation by reacting oxides or hydroxides with alkali metal salts
    • C01D1/22—Preparation by reacting oxides or hydroxides with alkali metal salts with carbonates or bicarbonates
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
    • C01D1/00—Oxides or hydroxides of sodium, potassium or alkali metals in general
    • C01D1/04—Hydroxides
    • C01D1/28—Purification; Separation
    • C01D1/32—Purification; Separation by absorption or precipitation
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
    • C01D7/00—Carbonates of sodium, potassium or alkali metals in general
    • C01D7/07—Preparation from the hydroxides
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
    • C01F7/00—Compounds of aluminium
    • C01F7/02—Aluminium oxide; Aluminium hydroxide; Aluminates
    • C01F7/04—Preparation of alkali metal aluminates; Aluminium oxide or hydroxide therefrom
    • C01F7/14—Aluminium oxide or hydroxide from alkali metal aluminates
    • C01F7/141—Aluminium oxide or hydroxide from alkali metal aluminates from aqueous aluminate solutions by neutralisation with an acidic agent
    • C01F7/142—Aluminium oxide or hydroxide from alkali metal aluminates from aqueous aluminate solutions by neutralisation with an acidic agent with carbon dioxide
    • 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
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/141—Feedstock

Definitions

  • the present invention concerns a process for the treatment and recovery of alkaline solutions, in particular solutions based on caustic soda or caustic potash, used in aluminium pickling reactions.
  • Metalworking processes provide a number of obligatory stages necessary to make the metal suitable for the subsequent work processes or the subsequent surface treatments.
  • a very important stage in metal and metal alloy work processes is represented, for example, by chemical pickling which, again by way of example, promotes adhesion and long-term strength of glues and paints.
  • Said process provides compression of the starting materials, after heating which facilitates the modelling thereof, inside a cylinder or die terminating in a shaped hole which gives the material the desired form.
  • the section thus obtained after extrusion undergoes further finishing and, if necessary, painting, before it is put on the market.
  • the extrusion of aluminium profiles therefore combines one of the basic techniques of industrial processing with one of the materials, aluminium, most universally widespread in the production of articles of all types, from simple saucepans to very complicated components of jet engines.
  • the extrusion of aluminium sections constitutes the first step in the production of numerous daily-used articles, including saucepans, as mentioned above, tin cans and door and window frames commonly used in homes.
  • the process of extrusion of metals involves the use of dies suitable for giving the metal the desired form. Once the programmed extruded parts have been obtained, the residue left inside the channels of the extrusion die must be eliminated before performing the next extrusion operation.
  • the die is immersed in a bath, also called pickling bath.
  • the operating principle of this bath in the case of aluminium, is based on the chemical reaction which occurs between metallic aluminium and NaOH (sodium hydroxide or caustic soda) or KOH (potassium hydroxide or caustic potash) in an aqueous solution.
  • NaOH sodium hydroxide or caustic soda
  • KOH potassium hydroxide or caustic potash
  • the soda or the potash react with the aluminium and form NaAIO 2 or KAIO 2 with the formation of gaseous hydrogen.
  • the aluminium accumulated in the die dissolves and the die is cleaned and is ready to be used again.
  • the free soda or potash is consumed and its concentration decreases.
  • the spent soda solution is diluted with water, in a ratio of approximately 1 :100. This causes the precipitation of AI(OH) 3 which is partially filtered and removed while the remaining solution can be re-used, even though it contains dissolved quantities of AI(OH) 3 which can interfere, especially if re-use is repeated.
  • the soda or potash solution obtained from the above-mentioned recovery process is very diluted and cannot be used as it is but must be concentrated by means of evaporation, with considerable costs due to the required energy consumption.
  • the diluted solution can be concentrated by means of a process of reverse osmosis, but also in this case the costs are high and the results uncertain due to the presence of traces of aluminium which are dangerous as they can cause collapse of the osmotic membranes.
  • the spent soda or potash solution can be chemically transformed (3.2) via the addition of carbon dioxide (CO 2 ).
  • the chemical reactions involved provide transformation of the residual soda (NaOH) or potash (KOH) into sodium carbonate (Na 2 CO 3 ) or potassium carbonate (K 2 CO 3 ) with formation of water, and likewise the transformation of NaAIO 2 or KAIO 2 (which forms by reaction between soda or potash and aluminium) into sodium carbonate (Na 2 CO 3 ) or potassium carbonate (K 2 CO 3 ) and aluminium hydroxide (AI(OH) 3 ) which precipitates and can be filtered and removed.
  • NaAIO 2 or KAIO 2 which forms by reaction between soda or potash and aluminium
  • the object of the present invention is to provide a process for the recovery of spent alkaline baths or solutions coming from aluminium pickling reactions, in particular from the treatment of extrusion dies used in the extrusion of aluminium, which allows recovery of the solutions with consequent re-use of the same.
  • a further object of the present invention is to provide a process for the recovery of spent alkaline baths or solutions coming from aluminium pickling reactions, in particular from the treatment of extrusion dies used in the extrusion of aluminium, which does not provide the substantial correction, integration or concentration of the solution recovered.
  • a further object of the invention is to provide a process for the recovery of spent alkaline baths or solutions coming from aluminium pickling reactions, in particular from the treatment of extrusion dies used in the extrusion of aluminium, which is economically advantageous and which involves a significant economic advantage throughout the extrusion process.
  • a further object of the present invention is to provide a process for the recovery of spent alkaline baths or solutions coming from aluminium pickling reactions, in particular from the treatment of extrusion dies used in the extrusion of aluminium, which is simple, does not require the use of particular reagents and can be performed parallel to any extrusion process.
  • a further object of the present invention is use of the above-mentioned process, for recovery of the spent alkaline baths or solutions coming from aluminium pickling reactions, in particular from the treatment of extrusion dies used in the extrusion of aluminium.
  • the process comprises a first phase of: a) treatment of the spent bath or soda or potash solution with carbon dioxide (CO2), obtaining a first precipitate and a first solution, b) treatment of said first solution with oxides and/or hydroxides of divalent metals, obtaining a second precipitate and a second solution.
  • CO2 carbon dioxide
  • said second solution thus obtained is directly used in the processes in the previous points 1,2,3,4, without the need to be concentrated, corrected or in any way modified.
  • phase a when conducted on spent soda or potash solutions coming from the above-mentioned treatments, provides the following chemical reactions:
  • phase b) when said oxides and/or hydroxides of divalent metals are chosen like CaO and/or Ca(OH) 2 , said phase b) provides the following chemical reactions:
  • the calcium carbonate (CaCO 3 ) is obtained in the form of a precipitate (called second precipitate), which is removed by filtration, while the resulting solution (called second solution), is re-used as it is being rich in soda or potash.
  • second precipitate a precipitate
  • This process has considerable advantages with respect to the processes in the known art.
  • a further advantage is represented by the fact that, operating according to the process subject of the present invention, all the AI(OH) 3 forming during phase a) of said process is removed by filtration or in any case by separation, since it is a precipitate (first precipitate). As the solution does not undergo dilutions, there is no risk of a part of said Al hydroxide re-dissolving or remaining directly in solution and therefore remaining, even only partially, present in said first solution.
  • the spent starting solution can advantageously be optionally diluted with water up to a ratio of 1 :1.
  • This dilution can be advantageous because it is an aid for avoiding the precipitation of Na 2 CO 3 or KCO 3 in crystallised form during the reaction in the above-mentioned stage a). If said dilution is performed, the solution resulting from stage b), and therefore the final solution, will undergo an optional concentration phase c) which will occur, for example, by evaporation, until reaching the desired soda or potash concentration for re-use of the solution.
  • Said optional evaporation stage, and relative preceding optional dilution stage does not involve the drawbacks due to the dilution when performed according to the methods described above and commonly employed in the known art.
  • a dilution ratio does not exceed 1 :1 and, consequently, also any possible phase of concentration of the final solution is very simple, rapid and with practically nonexistent added costs.
  • a further advantage is represented by the fact that, even if said optional stage of dilution of the starting solution and said optional phase of concentration of the final solution (or said second solution) is performed, any dilution is in a ratio of 1 :1 and all the aluminium hydroxide (AI(OH) 3 ) will remain in the form of a precipitate and can therefore be completely removed.
  • the dilution is such as to guarantee that all the AI(OH) 3 formed is removed in the form of a solid precipitate.
  • phase of filtering of AI(OH) 3 (which precipitates completely) can advantageously be performed by means of a belt, rotating drum, centrifuge or bag filter.
  • the pure hydroxide which is thus obtained is advantageously used as a second raw material since it is free of other contaminants.
  • the soda regeneration phase is performed by reaction of the solution containing Na 2 CO 3 with CaO or with Ca(OH) 2 , according to the following reactions:
  • the starting concentration in Na 2 CO 3 is between 5 and 25%, while the quantity of CaO used for each Kg of Na 2 CO 3 is 0.528 Kg.
  • the reaction temperature is between 40 and 100 0 C and the reaction time can vary between 10 minutes and 3 hours.
  • the solution of caustic soda thus regenerated will have a concentration of between approximately 2.5% and
  • the final solution can be concentrated to the desired value (between 5 and 30%), for example by means of steam or hot water concentrator in heat pump or multi-stage evaporators.
  • the soda solution thus recovered can be for example stored in a metal, PVC, PP, fibreglass or SS silo.
  • the titre of the solution can be controlled for example by means of acidimetric titration.
  • the controls highlight the following residues: Al 10-1000 ppm, Ca 10-300 ppm.
  • phase of filtering of AI(OH) 3 (which precipitates completely) can advantageously be performed by means of a belt, rotating drum, press, centrifuge or bag filter.
  • the pure hydroxide which is thus obtained is advantageously used as a second raw material since it is free of other contaminants.
  • the potash regeneration phase is performed by reaction of the solution containing K 2 CO 3 with CaO or with Ca(OH) 2 , according to the following reactions:
  • the starting concentration in K 2 CO 3 is between 5 and 25%, while the quantity of CaO used for each Kg of K 2 CO 3 is 0.40 Kg.
  • the reaction temperature is between 40 and 10O 0 C and the reaction time can vary between 10 minutes and 3 hours.
  • the solution of caustic potash thus regenerated will have a concentration of between approximately 2.5% and 15%.
  • the final solution can be concentrated to the desired value
  • the potash solution thus recovered can be stored, for example, in a metal, PVC, PP, fibreglass or SS silo.
  • the titre of the solution can be controlled for example by means of acidimetric titration.
  • the controls highlight the following residues: Al 10-1000 ppm, Ca 10-300 ppm.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Inorganic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • General Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Geology (AREA)
  • Separation Using Semi-Permeable Membranes (AREA)
  • Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)

Abstract

L'invention concerne un procédé de récupération de bains ou de solutions alcalines utilisées, en particulier de solutions usées de soude (NaOH) ou de potasse (KOH) issues de réactions de décapage chimique d'aluminium, en particulier de traitement de filières d'extrusion utilisées dans l'extrusion de l'aluminium, qui comprend une première phase de a) traitement d'un bain ou d'une solution de soude utilisée avec du dioxyde de carbone (CO2), pour obtenir un premier précipité et une première solution, b) traitement de ladite première solution avec des oxydes et/ou des hydroxydes de métaux divalents, pour obtenir un deuxième précipité et une deuxième solution de soude (NaOH) ou de potasse (KOH) qui peut être réutilisée sans autre traitement.
PCT/IB2010/001015 2009-06-12 2010-05-04 Procédé de récupération de solutions alcalines Ceased WO2010143033A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
ITMI2009A001043A IT1398512B1 (it) 2009-06-12 2009-06-12 Procedimento per il recupero di soluzioni alcaline
ITMI2009A001043 2009-06-12

Publications (1)

Publication Number Publication Date
WO2010143033A1 true WO2010143033A1 (fr) 2010-12-16

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PCT/IB2010/001015 Ceased WO2010143033A1 (fr) 2009-06-12 2010-05-04 Procédé de récupération de solutions alcalines

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WO (1) WO2010143033A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105585179A (zh) * 2016-03-08 2016-05-18 华南理工大学 一种铝型材厂脱模废液回收利用方法

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3607482A (en) * 1969-08-11 1971-09-21 Wilson & Co Process of regeneration of metal treating solutions
DE2738134B1 (de) * 1977-08-24 1979-02-08 Vaw Ver Aluminium Werke Ag Verfahren zur Reinigung von verduennten Natronlaugen
DE19703348A1 (de) * 1997-01-30 1998-08-06 Klaus Dipl Ing Klein Verfahren zur Rückgewinnung alkalischer Beizlösungen
CN1287186A (zh) * 1999-09-06 2001-03-14 谭红卫 化铣加工后废碱液及沉渣处理技术
EP1932948A1 (fr) * 2006-12-07 2008-06-18 Italtecno S.R.L. Appareil et procédé pour la récupération de soude caustique de solutions caustiques

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3607482A (en) * 1969-08-11 1971-09-21 Wilson & Co Process of regeneration of metal treating solutions
DE2738134B1 (de) * 1977-08-24 1979-02-08 Vaw Ver Aluminium Werke Ag Verfahren zur Reinigung von verduennten Natronlaugen
DE19703348A1 (de) * 1997-01-30 1998-08-06 Klaus Dipl Ing Klein Verfahren zur Rückgewinnung alkalischer Beizlösungen
CN1287186A (zh) * 1999-09-06 2001-03-14 谭红卫 化铣加工后废碱液及沉渣处理技术
EP1932948A1 (fr) * 2006-12-07 2008-06-18 Italtecno S.R.L. Appareil et procédé pour la récupération de soude caustique de solutions caustiques

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105585179A (zh) * 2016-03-08 2016-05-18 华南理工大学 一种铝型材厂脱模废液回收利用方法
CN105585179B (zh) * 2016-03-08 2018-07-10 华南理工大学 一种铝型材厂脱模废液回收利用方法

Also Published As

Publication number Publication date
IT1398512B1 (it) 2013-03-01
ITMI20091043A1 (it) 2010-12-13

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