EP0077041A1 - Verfahren zur Ergänzung von Reinigerlösungen - Google Patents

Verfahren zur Ergänzung von Reinigerlösungen Download PDF

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Publication number
EP0077041A1
EP0077041A1 EP82109310A EP82109310A EP0077041A1 EP 0077041 A1 EP0077041 A1 EP 0077041A1 EP 82109310 A EP82109310 A EP 82109310A EP 82109310 A EP82109310 A EP 82109310A EP 0077041 A1 EP0077041 A1 EP 0077041A1
Authority
EP
European Patent Office
Prior art keywords
acid
temperature
solution
fluoride ion
fluoride
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.)
Withdrawn
Application number
EP82109310A
Other languages
German (de)
English (en)
French (fr)
Inventor
Richard Andrew Beck
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.)
GEA Group AG
Continentale Parker Ste
Continentale Parker SA
Original Assignee
Metallgesellschaft AG
Continentale Parker Ste
Continentale Parker SA
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 Metallgesellschaft AG, Continentale Parker Ste, Continentale Parker SA filed Critical Metallgesellschaft AG
Publication of EP0077041A1 publication Critical patent/EP0077041A1/de
Withdrawn legal-status Critical Current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
    • C23G1/02—Cleaning or pickling metallic material with solutions or molten salts with acid solutions
    • C23G1/12—Light metals
    • C23G1/125—Light metals aluminium

Definitions

  • the invention relates to a method for supplementing cleaning solutions in the cleaning of aluminum surfaces with acidic aqueous solutions containing fluoride ions, in which the fluoride ion content is measured and supplemented with fluoride ions and acid.
  • Aluminum objects e.g. Aluminum cans can be cleaned by contact with an aqueous solution containing fluoride ions.
  • aqueous solution containing fluoride ions contain e.g. Fluoride ions and sulfuric acid (GB-PS 1 454 974).
  • control methods are carried out by keeping the temperature of the treatment bath at a constant value by means of suitable heating and / or cooling systems, and both the fluoride ion content and the acid content by measuring the content of free fluoride ions or the pH value and supplementing it with fluoride and acid, depending on the deviation from the respective setpoint.
  • the known methods have the disadvantage in common that a precise indication of the amounts of chemicals to be added requires a constant temperature of the treatment bath, a requirement which is usually not given.
  • the conventional metering of the supplementary chemicals to a target value based on a measured actual value often leads to an overdose of the chemicals to be supplemented, since the concentration balance between the supplemental solution and the treatment solution supplied in practice is often of the order of several minutes.
  • the object of the invention is to provide a method for supplementing cleaning solutions which avoids the disadvantages of the known methods, is simple to carry out and does not require a high outlay on equipment Lich.
  • the object is achieved by designing the method of the type mentioned at the outset in accordance with the invention in such a way that the metering of the quantity of chemicals is regulated as a function of the deviation from the automatically corrected setpoint of the fluoride ion concentration and required for constant pickling removal.
  • the inventive method comprises device parts for measuring the F luoridionengehaltes, parts of the device for measuring the temperature of the detergent solution as well as correction elements (override Means) on to the value in terms of fluoride ion content as a function of or compensate for change in the detected temperature - in each case based on a predetermined Temperature value - to change.
  • the device parts for measuring the fluoride ion content of the cleaning solution are expediently connected to a device for generating a signal in the event of a deviation from the predetermined value.
  • An optical display for example in the form of a pointer instrument, is suitable for this.
  • the device parts for measuring the temperature and - if necessary. Deviations from the target value that occur - for adaptation contains elements for applying a signal to the display instrument. The result of this is that a fluoride ion content is displayed which, depending on the type of temperature deviation, is higher or lower than the actual fluoride ion content.
  • the temperature-corrected value obtained in this way ultimately controls the dosage of the supplementary solution and ensures constant removal of the pickling.
  • the fluoride ion content shown on the display device would be about twice as high as the value actually present in the cleaning solution. In practical terms, this means that when the temperature of the cleaning solution rises by 10 ° C, the fluoride ion content actually measured is reduced to about half as a result of the regulation. If the temperature drops by 10 ° C below the target temperature, a correspondingly reduced content of fluoride ions would be indicated, but this is increased accordingly by the control.
  • the amount of acid required to supplement the cleaning solution can be determined as a function of a separate acid measurement, for example by means of a conductivity or pH measurement.
  • the acid is added without a separate acid measurement, but in conjunction with the fluoride ion addition by means of a metering device, which is also controlled by measuring the fluoride ion content of the cleaning solution.
  • a certain relationship between fluoride ion supplementation and acid supplementation is determined and set on the basis of empirical values or by preliminary tests.
  • the Dösiervoriques can be used for the fluoride ion-containing solution at a certain flow rate during a time-b deviation from the A of the measured fluoride ion content from the desired value is dependent, and are operated at the same time a Do Siervoriques for acid for a period of time, which is in a predetermined relation to the running time of the metering device for fluorine dosing, in motion.
  • a coupled acid supplement which is controlled solely by the fluoride ion content of the cleaning solution, is associated under normal operating conditions with deviations in the acid supplement of at most 5%.
  • the control device provides a safety circuit which ensures the addition of acid at predetermined time intervals, even if no fluoride ions are added. This means that if sufficient acid is added as a result of the usual addition, the safety circuit does not operate.
  • the safety circuit starts the metering for acid from time to time so long that the acid content is at an appropriate level.
  • the time after which the safety circuit is activated can be determined in a very simple manner by experiments. It generally depends on the normal loss of detergent solution, the free acidity of the detergent solution, the concentration of the make-up solution for acid and the metering capacity of the metering device for the acid.
  • fluoride ions are also optionally coupled therewith acid at a predetermined delivery rate of the metering devices in A b-dependence of the determined metered fluoride ion content of the cleaning solution for a certain period.
  • a metering device for the solution containing fluoride ions, a metering device for the acid and a device for measuring the fluoride ion content of the cleaning solution are also provided here.
  • the electronic circuit used in the method according to the invention has a variable circuit which gives a pulse duty factor (mark / space ratio) and is connected to a clock generator.
  • the time interval at which the metering devices are started can be selected by the clock generator.
  • the measuring device is expediently installed at a point at which the cleaning solution which is directly in use is obtained. That is, in the preferred cleaning by spraying, the measuring device is advantageously connected to the pipelines connected to the circulation pumps.
  • the running time of the cyclically switched metering devices is expediently chosen such that they meter about half the time of a cycle interval during normal operation of the cleaning system. With a cycle time of 4 minutes, their running time would be about 2 minutes.
  • the delivery rate of the dosing devices must be adapted to the need for a supplementary solution.
  • control device can be connected to an additional device which prevents the metering devices from being controlled as a result of operational malfunctions with an unusually short or long runtime within a supplementary cycle.
  • This abnormal operating condition can. are indicated by warning indicators.
  • the use of such power keys has the disadvantage that they can lead to incorrect displays as a result of loss of electrolyte solution. This can be remedied if the power key has a container for the electro-hydroxide solution, which is connected to an additional warning electrode. It is coupled to the reference electrode and arranged in the electrolyte solution container in such a way that it emits a warning signal as soon as the level of the electrolyte drops below a certain level.
  • Such a current key accordingly has a container for the electrolyte and reference or warning electrodes immersed in the electrolyte.
  • the lowest part of the warning electrode is in a position above that at which the reference electrode becomes ineffective. Under normal operating conditions there is electrical contact between the warning and reference electrodes. If the electrolyte level in the container drops below a certain level, the warning electrode no longer dips into the electrolyte. The thus changing potential difference between the reference and warning electrodes triggers a warning signal which can be implemented in any way, for example acoustically or optically.
  • the electrolyte used in the power key is usually an aqueous potassium chloride solution.
  • the warning electrode can e.g. consist of a stainless steel rod.
  • a calomel electrode is usually used as the reference electrode.
  • An electrode 1 responsive to fluoride ions is immersed in a treatment bath 2 and connected to a reference electrode 3 (calomel electrode) by a conventional circuit 4.
  • the reference electrode 3 is immersed in an aqueous potassium chloride electrolyl solution, which is located in a container 6.
  • a tube 7 ends in a ceramic porous stopper 8, which in turn is immersed in the treatment bath 2.
  • a rod-shaped warning electrode 9 made of stainless steel is fixed in the electrolyte solution 5 in such a way that its lower end ends above the level of the upper edge of the reference electrode 3.
  • An electrical connection between reference electrode 3 and warning electrode 9 is indicated by device parts 10. These include a suitable warning device which operates when the potential difference between the electrodes 3 and 9 is undesirably exceeded.
  • the cleaning solution usually has a temperature of 30 to 70 ° C, a pH below 3, usually between 1 and 2.5, in particular 1.5, and a free fluoride ion content of 0.05 to 10, preferably 0.1 up to 5 and in particular from 0.8 mg / l.
  • a cleaning solution can be easily done with hydrofluoric acid or other fluoride ion-providing substances and sulfuric acid, if necessary with the additional use of surfactant. It is used for the usual spray cleaning of, for example, aluminum cans.
  • the fluoride ion content and the temperature are continuously monitored.
  • the temperature is shown as a digital display, the temperature-corrected fluoride ion content is shown by an indicator, as explained above.
  • a supplementary operation is started every 4 minutes by means of a clock and a mark / space ratio circuit, whereby, in order to keep the fluoride ion content constant, a pump for supplying fluoride-containing supplementary solution in a predetermined manner for a time dependent on the position depends on the display device, is activated. At the same time, a second pump adds sulfuric acid during a time that is in a predetermined ratio to the addition period of the fluoride ion addition.

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)
  • Cleaning By Liquid Or Steam (AREA)
  • Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
EP82109310A 1981-10-09 1982-10-08 Verfahren zur Ergänzung von Reinigerlösungen Withdrawn EP0077041A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8130529 1981-10-09
GB8130529 1981-10-09

Publications (1)

Publication Number Publication Date
EP0077041A1 true EP0077041A1 (de) 1983-04-20

Family

ID=10525053

Family Applications (1)

Application Number Title Priority Date Filing Date
EP82109310A Withdrawn EP0077041A1 (de) 1981-10-09 1982-10-08 Verfahren zur Ergänzung von Reinigerlösungen

Country Status (7)

Country Link
EP (1) EP0077041A1 (xx)
JP (1) JPS5881980A (xx)
AU (1) AU8910382A (xx)
BR (1) BR8205926A (xx)
DE (1) DE3237553A1 (xx)
GB (1) GB2107359B (xx)
ZA (1) ZA827263B (xx)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002079545A1 (en) * 2001-03-30 2002-10-10 Alcan International Limited Method of controlling a chemical cleaning line for aluminum strip

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090229995A1 (en) * 2008-03-14 2009-09-17 Eci Technology, Inc. Analysis of fluoride at low concentrations in acidic processing solutions
CN110484750A (zh) * 2019-08-21 2019-11-22 陕西美泰节能科技有限公司 一种铝合金碎料再利用装置及加工工艺

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1454974A (en) * 1974-02-14 1976-11-10 Amchem Prod Processes for cleaning aluminium
US4124407A (en) * 1975-08-25 1978-11-07 Amchem Products, Inc. Method for cleaning aluminum at low temperatures

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5035033A (xx) * 1973-08-02 1975-04-03
JPS5355307A (en) * 1976-10-29 1978-05-19 Yoshio Asahi Detergent for aluminum

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1454974A (en) * 1974-02-14 1976-11-10 Amchem Prod Processes for cleaning aluminium
US4124407A (en) * 1975-08-25 1978-11-07 Amchem Products, Inc. Method for cleaning aluminum at low temperatures

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002079545A1 (en) * 2001-03-30 2002-10-10 Alcan International Limited Method of controlling a chemical cleaning line for aluminum strip
US6524391B2 (en) 2001-03-30 2003-02-25 Alcan International Limited Method for automatically controlling a chemical cleaning stage of a metal strip cleaning line
US6595222B2 (en) 2001-03-30 2003-07-22 Alcan International Limited Chemical cleaning apparatus for cleaning metal strip

Also Published As

Publication number Publication date
GB2107359A (en) 1983-04-27
GB2107359B (en) 1986-01-22
JPS5881980A (ja) 1983-05-17
BR8205926A (pt) 1983-09-06
AU8910382A (en) 1983-04-14
DE3237553A1 (de) 1983-05-05
ZA827263B (en) 1984-05-30

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Effective date: 19831004

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Inventor name: BECK, RICHARD ANDREW