EP0087166A1 - Procédé pour la régénération électrolytique des solutions de décapage usées à base d'acide sulfurique - Google Patents

Procédé pour la régénération électrolytique des solutions de décapage usées à base d'acide sulfurique Download PDF

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Publication number
EP0087166A1
EP0087166A1 EP83101720A EP83101720A EP0087166A1 EP 0087166 A1 EP0087166 A1 EP 0087166A1 EP 83101720 A EP83101720 A EP 83101720A EP 83101720 A EP83101720 A EP 83101720A EP 0087166 A1 EP0087166 A1 EP 0087166A1
Authority
EP
European Patent Office
Prior art keywords
sulfuric acid
cathode
acid pickling
catholyte
spaces
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
EP83101720A
Other languages
German (de)
English (en)
Inventor
Hans-Jürgen Dr. Heimgard
Hans-Jürgen Simon
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.)
Keramchemie GmbH
Original Assignee
Keramchemie GmbH
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 Keramchemie GmbH filed Critical Keramchemie GmbH
Publication of EP0087166A1 publication Critical patent/EP0087166A1/fr
Ceased legal-status Critical Current

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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
    • 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
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
    • C25C1/00—Electrolytic production, recovery or refining of metals by electrolysis of solutions
    • C25C1/06—Electrolytic production, recovery or refining of metals by electrolysis of solutions or iron group metals, refractory metals or manganese

Definitions

  • the invention relates to a method for the electrolytic regeneration of spent sulfuric acid pickling liquid according to the preamble of claim 1.
  • a process for the reprocessing of spent sulfuric acid pickling liquid in which the iron sulfate is partially removed from the spent sulfuric acid pickling liquid by crystallization and is normally fed to a landfill. Only the free sulfuric acid is recovered.
  • a process according to this reaction equation for the regeneration of spent sulfuric acid pickling liquid which contains at most a content of about 100 g sulfuric acid / 1 and at least 25 g iron oxide / 1, is known from DE-OS 24 56 058.
  • the spent sulfuric acid pickling liquid is adjusted to an ammonium sulfate, magnesium sulfate and / or alkali metal sulfate concentration of 0.5-1.0 mol / 1 by adding salts.
  • This spent sulfuric acid pickling liquid in the row then flows through all the cathode spaces of an electrolysis device constructed from a plurality of electrolysis cells which are arranged in cascade behind one another, in which the anode spaces are separated by diaphragms from the cathode spaces assigned to them.
  • the iron content of the sulfuric acid pickling liquid is exhausted to a value of 7-15 g iron ions / l.
  • This sulfuric acid pickling liquid is then conveyed back into the anode compartment of the first electrolysis cell and flows through this and the further anode compartments in a direction identical to the flow maintained in the cathode compartments.
  • the current density based on the area of the diaphragm is kept at a value of 15-22 A / dm 2 and the working temperature of the electrolysis is kept at a value of 70 ° C.-30 ° C.
  • Hydroxide precipitation leads to considerable disruptions in the operational process. With the cascade-like arrangement of the individual electrolysis cells, there is only a very low flow rate. A flow rate that is too low, however, results in poor mixing in the electrode spaces and thus concentration layers. In addition, liquid mass transfer in free fall is prone to failure in practice. The relatively high current density causes excessive iron growth on the edges and unevenness of the cathode due to peak discharge, which also leads to malfunctions. In addition, an undesirable evolution of hydrogen appears even more.
  • the invention has for its object to provide a method for the electrolytic regeneration of spent sulfuric acid pickling liquid according to the preamble of claim 1, which can be carried out both technically and economically.
  • the proposed process sequence enables the electrolysis device to be designed in a structurally simple manner. A concentration gradation in the individual electrolysis cells is thus omitted, so that discontinuous operation is possible without any particular expenditure of time for starting up.
  • By metering in the spent sulfuric acid pickling liquid in the catholyte it is easy to set such a stable pH that silting up due to hydroxide precipitation no longer occurs.
  • By pumping the catholyte around flow velocities can be achieved which ensure thorough mixing in the cathode compartments and exclude concentration stratification.
  • the content of additional electrolytes is low, so that no blockages occur due to the solubility products of the salts present being exceeded. Growth of iron and undesirably strong hydrogen evolution are avoided.
  • the feature of claim 2 ensures that the addition of the additional electrolyte, if necessary at all, has a direct effect on the electrolysis cells.
  • the invention is based on a in a drawing tion explained in more detail in a simplified manner.
  • an electrolysis container 1 in which, in this exemplary embodiment, six so-called anode pockets 2 are inserted next to one another in a fixed manner, leaving gaps, each of which has an anode space 3 for receiving anodes 4.
  • only one anode 4 is arranged in each of the two outer anode pockets 2, while the four inner anode pockets 2 each hold two anodes 4.
  • These anodes 4 are connected in a manner known per se via a line 5 to the positive pole of a voltage source.
  • the side walls of the anode pockets 2 running parallel to the anodes 4 are formed by sealingly inserted diaphragms 6, the two outer anode pockets 2 having only one side wall designed in this way.
  • cathodes 7 are arranged as sheets, the entire space outside of the anode pocket 2 being designated as the cathode space 8.
  • This cathode space 8 is formed by the cathode spaces of the individual electrolysis cells which are not separate from one another. All cathodes 7 are connected via a line 9 to the negative pole of a voltage source.
  • four pipelines 10, 11 are connected to both longitudinal sides of the electrolyzing container 1, which lead to a common pipe string 12.
  • a pump 13 is inserted, by means of which the liquid located in the cathode chamber 8, the catholyte, is pumped around and thus circulated.
  • the tubing string 12 passes through a heating and cooling device 14 known per se, by means of which the temperature of the catholyte can be kept at a predetermined value of 75 ° C.-100 ° C.
  • a pipeline 16 which receives a metering pump 17 and is connected to a reservoir 18, opens into the tubing string 12 between the electrolyzing tank 1 and the pump 13.
  • This storage container 18 receives used sulfuric acid pickling liquid, which is fed to it via a pipe 19 with a metering pump 20 from a sulfuric acid pickling system 21 with a downstream washing container 22.
  • the pickling unit 21 receives the sulfuric acid pickling liquid via a pipe 23 from a storage container 24, which in turn is in flow communication with the individual anode compartments 3 of the anode pockets 2 via a pipe 25 with branch pieces 26.
  • the catholyte When the electrolysis device is operating, the catholyte is pumped through the pump 13 in the circuit simultaneously and in parallel through the cathode space 8 or the cathode spaces of the individual electrolysis lines of the electrolysis container 1, which are not particularly separated from one another.
  • the sulfuric acid pickling liquid which contains a maximum of 90 g sulfuric acid / l and at least 40 g iron ions / l, is metered into the catholyte continuously or in batches via the metering pump 17.
  • the catholyte After it has been heated or cooled to a predetermined temperature and the additional electrolyte concentration likewise set has been set, the catholyte enters the cathode space 8 or the cathode spaces of the individual electrolysis cells through the pipelines 10, through which it flows simultaneously and in parallel.
  • the catholyte emerging from the cathode compartment 8 or the cathode compartments of the individual electrolysis cells only contains a small amount of free sulfuric acid; its residual iron concentration is 10 - 30 g iron ions / l.
  • the regenerated sulfuric acid pickling liquid is withdrawn from the anode compartments 3 in the free overflow via the branch pieces 26 and fed to the reservoir 24 via the pipeline 25.
  • the cathodes 7 are replaced.
  • the water loss occurring in the electrolysis process can be compensated for by metering in rinsing water from the rinsing tank 22 via line 27 with a metering pump 28 into the storage tank 24.
  • a fresh water line 29 is connected to the rinsing container 22 itself.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Mechanical Engineering (AREA)
  • Electrolytic Production Of Metals (AREA)
  • Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
EP83101720A 1982-02-24 1983-02-23 Procédé pour la régénération électrolytique des solutions de décapage usées à base d'acide sulfurique Ceased EP0087166A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19823206538 DE3206538C2 (de) 1982-02-24 1982-02-24 Verfahren zur elektrolytischen Regenerierung von verbrauchter Schwefelsäure-Beizflüssigkeit
DE3206538 1982-02-24

Publications (1)

Publication Number Publication Date
EP0087166A1 true EP0087166A1 (fr) 1983-08-31

Family

ID=6156530

Family Applications (1)

Application Number Title Priority Date Filing Date
EP83101720A Ceased EP0087166A1 (fr) 1982-02-24 1983-02-23 Procédé pour la régénération électrolytique des solutions de décapage usées à base d'acide sulfurique

Country Status (2)

Country Link
EP (1) EP0087166A1 (fr)
DE (1) DE3206538C2 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19850524A1 (de) * 1998-11-03 2000-05-04 Eilenburger Elektrolyse & Umwelttechnik Gmbh Nitratfreies Recycling-Beizverfahren für Edelstähle
DE19850525A1 (de) * 1998-11-03 2000-05-04 Eilenburger Elektrolyse & Umwelttechnik Gmbh Verfahren zum elektrochemischen Regenerieren von Schwefelsäure-Eisen-III-sulfat-Beizlösungen für Edelstähle

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19521132C1 (de) * 1995-06-09 1996-10-17 Poligrat Holding Gmbh Verfahren zum Entmetallisieren von hochsauren Bädern und Verwendung dieses Verfahrens beim Elektropolieren von Edelstahloberflächen

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE459377A (fr) *
US3072545A (en) * 1961-11-20 1963-01-08 Ionics Electroplating of metals
DE1571728A1 (de) * 1966-10-01 1970-12-17 Duerkes Dipl Chem Dr Karl Verfahren zur Regenerierung und/oder Aufbereitung sowie Reinigung von Beizbaedern,Wasch- und Spuelfluessigkeiten,galvanischen Baedern und Abwaessern
FR2252422A1 (fr) * 1973-11-27 1975-06-20 Licencia Talalmanyokat

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE459377A (fr) *
US3072545A (en) * 1961-11-20 1963-01-08 Ionics Electroplating of metals
DE1571728A1 (de) * 1966-10-01 1970-12-17 Duerkes Dipl Chem Dr Karl Verfahren zur Regenerierung und/oder Aufbereitung sowie Reinigung von Beizbaedern,Wasch- und Spuelfluessigkeiten,galvanischen Baedern und Abwaessern
FR2252422A1 (fr) * 1973-11-27 1975-06-20 Licencia Talalmanyokat

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19850524A1 (de) * 1998-11-03 2000-05-04 Eilenburger Elektrolyse & Umwelttechnik Gmbh Nitratfreies Recycling-Beizverfahren für Edelstähle
DE19850525A1 (de) * 1998-11-03 2000-05-04 Eilenburger Elektrolyse & Umwelttechnik Gmbh Verfahren zum elektrochemischen Regenerieren von Schwefelsäure-Eisen-III-sulfat-Beizlösungen für Edelstähle
DE19850524C2 (de) * 1998-11-03 2002-04-04 Eilenburger Elektrolyse & Umwelttechnik Gmbh Nitratfreies Recycling-Beizverfahren für Edelstähle

Also Published As

Publication number Publication date
DE3206538A1 (de) 1983-09-01
DE3206538C2 (de) 1984-04-12

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PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

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Effective date: 19831219

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Effective date: 19850915

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Inventor name: SIMON, HANS-JUERGEN

Inventor name: HEIMGARD, HANS-JUERGEN, DR.