EP0035804B1 - Process for regenerating pickling solutions containing zrf6 - Google Patents

Process for regenerating pickling solutions containing zrf6 Download PDF

Info

Publication number
EP0035804B1
EP0035804B1 EP81200113A EP81200113A EP0035804B1 EP 0035804 B1 EP0035804 B1 EP 0035804B1 EP 81200113 A EP81200113 A EP 81200113A EP 81200113 A EP81200113 A EP 81200113A EP 0035804 B1 EP0035804 B1 EP 0035804B1
Authority
EP
European Patent Office
Prior art keywords
pickle
zrf
process according
naoh
hno
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.)
Expired
Application number
EP81200113A
Other languages
German (de)
French (fr)
Other versions
EP0035804A1 (en
Inventor
Wolfgang Fennemann
Jürgen Haldorn
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
Original Assignee
Metallgesellschaft AG
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 filed Critical Metallgesellschaft AG
Publication of EP0035804A1 publication Critical patent/EP0035804A1/en
Application granted granted Critical
Publication of EP0035804B1 publication Critical patent/EP0035804B1/en
Expired legal-status Critical Current

Links

Images

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

Definitions

  • the invention relates to a process for the regeneration of ZrF 4- containing HF-HNO 3 pickling solutions by precipitation of ZrF 4 in the form of Na 2 ZrF 6 and separation of the precipitated Na 2 ZrF 6 and addition of HF, HNO 3 and possibly H 2 O.
  • NaF is a relatively expensive precipitant.
  • the process is also sensitive to overdosing or underdosing of the precipitant. If the residual NaF content is too high after the regeneration is over due to an overdosing of the precipitant, precipitation of Na 2 ZrF 6 is already initiated there when it is returned to the pickling bath, as a result of which the pickling process is impaired. For safety reasons, zirconium can only be precipitated in the regenerated pickling solution to a content of 3 to 7 g / l in the known processes.
  • under-dosing forms gel-like NaZrF 5 ⁇ H 2 O, which is difficult to filter.
  • the invention has for its object to propose a method of the type mentioned, which is less complex and easier to use and in which the disadvantages described are avoided.
  • the used pickling solution is first heated to above 40 ° C. and then dissolved NaOH is added and that after cooling to below 20 ° C. the precipitated Na 2 ZrF 6 is separated off by filtration.
  • HNO 3 before the precipitation and HF and possibly H 2 0 after the separation are added.
  • NaOH is preferably added at a temperature of 50 to 60 ° C.
  • the removal is expediently carried out at a temperature of -20 to + 10 ° C.
  • the NaOH addition is preferably dimensioned such that the completely regenerated pickling solution has a Na content of 1 to 3 g / l and a Zr content of 1.5 to 2.5 g / l.
  • the Na content in the completely regenerated pickling solution is preferably set to 1.5 to 2.5 g / l.
  • the process can be carried out in such a way that continuously removed pickling solution is withdrawn from a pickling plant and is continuously fed back to the pickling plant after regeneration.
  • the pickling solution contents of HF, HNO 3 and Na can be measured continuously and the measured values can be used for automatic control of the addition of NaOH, HNO 3 and HF and, if necessary, H 2 0.
  • the heating and cooling of the pickling solution is carried out with a circulating heat transfer medium having a suitable boiling temperature.
  • NaOH is about 12 times as soluble as NaF, it can be added in solution without significantly disturbing the water balance.
  • the expenditure of NaOH + H F for the regeneration of a certain amount of pickling solution is nevertheless only about 50% of the costs compared to the addition of NaF according to the known process.
  • the addition of NaOH as a solution makes dosing easier.
  • the heating of the used pickling solution according to the invention has the purpose of avoiding the formation of NaZrF 5 .H 2 O. It has been found that this gel-like compound, which is therefore difficult to filter, does not form, regardless of a sufficient dosage with NaOH, if the precipitation is initiated at an elevated temperature.
  • the necessary heating and cooling of the pickling solution can be carried out with a minimum of energy if the amount of heat extracted from the pickling agent stream during cooling is used for heating, whereby a heat transfer medium circuit with a heat pump can be used for the required temperature increase.
  • the used pickling solution is fed into the heat exchanger 5 by means of the pump 3 via the line 2, after 3 HNO 3 had been added beforehand.
  • the pickling solution is heated to above 40 ° C., then the precipitant NaOH is fed in at 6 and the precipitation of the ZrF 4 is initiated.
  • the pickling solution then reaches the heat exchanger 8 via the line 7, where it is cooled to below 20 ° C. and the precipitation is completed.
  • the pickling solution is then fed via line 9 to the filter 10, from which the precipitated Na 2 ZrF 6 is removed at 11.
  • the pickling solution is then fed via line 13 to H 2 0 at 15 and HF at 16 into heat exchanger 14, where it is brought back to the pickling bath temperature and then fed back to the pickling bath via line 17.
  • the circuit of the heat transfer medium essentially consists of the compressor 18 and the lines 19, 20 and 21. From the heat exchanger 8, vaporous heat transfer medium is sucked off, compressed in the compressor 18 and liquefied after cooling in the heat exchangers 5 and 14 before it is again via a throttle point is introduced into the heat exchanger 8, where it evaporates again while absorbing heat.

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)
  • Separation Using Semi-Permeable Membranes (AREA)
  • Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
  • Inorganic Compounds Of Heavy Metals (AREA)

Description

Die Erfindung bezieht sich auf ein Verfahren zum Regenerieren von ZrF4 enthaltenden HF-HNO3-Beizlösungen durch Ausfällen von ZrF4 in Form von Na2ZrF6 und Abtrennen des ausgefällten Na2ZrF6 sowie Ergänzung von HF, HNO3 und ggfs. H2O.The invention relates to a process for the regeneration of ZrF 4- containing HF-HNO 3 pickling solutions by precipitation of ZrF 4 in the form of Na 2 ZrF 6 and separation of the precipitated Na 2 ZrF 6 and addition of HF, HNO 3 and possibly H 2 O.

Ein derartiges Verfahren ist aus der US-PS Nr. 4105469 bekanntgeworden. Dabei wird ZrF4 aus der verbrauchten Beizlösung durch Zugabe von kristallinem NaF als Na2ZrFe ausgefällt und durch Filtrieren abgetrennt. Damit sind zwar die Nachteile der früheren Verfahren überwunden, wonach die verbrauchten Beizlösungen neutralisiert und unter Verlust des Zirkoniumgehaltes deponiert wurden, das bekannte Verfahren selbst ist jedoch noch verhältnismässig aufwendig und schwierig in der Handhabung.Such a method has become known from US Patent No. 4105469. ZrF 4 is precipitated from the used pickling solution by adding crystalline NaF as Na 2 ZrF e and separated off by filtration. This overcomes the disadvantages of the earlier methods, according to which the used pickling solutions were neutralized and deposited with loss of the zirconium content, but the known method itself is still relatively complex and difficult to handle.

Die Zugabe des Fällungsmittels muss wegen der geringen Wasserlöslichkeit von NaF in kristalliner Form erfolgen, wodurch eine exakte Dosierung insbesondere bei einer kontinuierlichen Regeneration erschwert wird. Bei einer Zugabe in gelöster Form würde die Beizlösung zu stark verdünnt und es müsste nach der eigentlichen Regeneration noch eine Abtrennung des überschüssigen Wassers durchgeführt werden. Hinzu kommt, dass NaF ein verhältnismässig teueres Fällungsmittel ist.Due to the low water solubility of NaF, the precipitant must be added in crystalline form, which makes exact dosing difficult, particularly in the case of continuous regeneration. If it were added in dissolved form, the pickling solution would be diluted too much and the excess water would have to be removed after the actual regeneration. In addition, NaF is a relatively expensive precipitant.

Das Verfahren ist ausserdem empfindlich gegen eine Über- oder Unterdosierung des Fällungsmittels. Ist der Restgehalt an NaF nach Abschluss der Regeneration infolge einer Überdosierung des Fällungsmittels zu hoch, so wird bei der Rückführung in das Beizbad bereits dort eine Ausfällung von Na2ZrF6 eingeleitet, wodurch der Beizvorgang beeinträchtigt wird. Aus Sicherheitsgründen kann bei den bekannten Verfahren Zirkonium nur bis auf einen Gehalt von 3 bis 7 g/I in der regenerierten Beizlösung ausgefällt werden.The process is also sensitive to overdosing or underdosing of the precipitant. If the residual NaF content is too high after the regeneration is over due to an overdosing of the precipitant, precipitation of Na 2 ZrF 6 is already initiated there when it is returned to the pickling bath, as a result of which the pickling process is impaired. For safety reasons, zirconium can only be precipitated in the regenerated pickling solution to a content of 3 to 7 g / l in the known processes.

Bei einer Unterdosierung dagegen bildet sich gelartiges NaZrF5·H2O, was schwierig zu filtrieren ist.On the other hand, under-dosing forms gel-like NaZrF 5 · H 2 O, which is difficult to filter.

Der Erfindung liegt die Aufgabe zugrunde, ein Verfahren der eingangs genannten Art vorzuschlagen, das weniger aufwendig und leichter zu handhaben ist und bei dem die geschilderten Nachteile vermieden werden.The invention has for its object to propose a method of the type mentioned, which is less complex and easier to use and in which the disadvantages described are avoided.

Zur Lösung dieser Aufgabe ist erfindungsgemäss vorgesehen, dass die verbrauchte Beizlösung zunächst auf über 40° C erwärmt und dann gelöstes NaOH zugegeben wird und dass nach einer Abkühlung auf unter 20° C das ausgefällte Na2ZrF6 durch Filtrieren abgetrennt wird. In weiterer Ausbildung des Erfindungsgedankens ist vorgesehen, dass HNO3 vor der Fällung und HF sowie ggfs. H20 nach der Abtrennung ergänzt werden. Vorzugsweise erfolgt die Zugabe von NaOH bei einer Temperatur von 50 bis 60° C. Die Abtrennung wird zweckmässigerweise bei einer Temperatur von -20 bis +10° C durchgeführt. Vorzugsweise wird die NaOH-Zugabe so bemessen, dass die fertig regenerierte Beizlösung einen Na-Gehalt von 1 bis 3 g/I und einen Zr-Gehalt von 1,5 bis 2,5 g/I aufweist. Vorzugsweise wird der Na-Gehalt in der fertig regenerierten Beizlösung auf 1,5 bis 2,5 g/I eingestellt.To achieve this object it is provided according to the invention that the used pickling solution is first heated to above 40 ° C. and then dissolved NaOH is added and that after cooling to below 20 ° C. the precipitated Na 2 ZrF 6 is separated off by filtration. In a further development of the inventive concept it is provided that HNO 3 before the precipitation and HF and possibly H 2 0 after the separation are added. NaOH is preferably added at a temperature of 50 to 60 ° C. The removal is expediently carried out at a temperature of -20 to + 10 ° C. The NaOH addition is preferably dimensioned such that the completely regenerated pickling solution has a Na content of 1 to 3 g / l and a Zr content of 1.5 to 2.5 g / l. The Na content in the completely regenerated pickling solution is preferably set to 1.5 to 2.5 g / l.

Das Verfahren kann in der Weise durchgeführt werden, dass aus einer Beizanlage kontinuierlich verbrauchte Beizlösung abgezogen und nach dem Regenerieren kontinuierlich der Beizanlage wieder zugeführt wird. Dabei können die Gehalte der Beizlösung an HF, HNO3 und Na kontinuierlich gemessen und die Messwerte zur automatischen Regelung der Zugabe von NaOH, HNO3 und HF sowie ggfs. H20 herangezogen werden. Schliesslich ist vorgesehen, dass die Erwärmung und Abkühlung der Beizlösung mit einem im Kreislauf geführten Wärmeträgermittel geeigneter Siedetemperatur durchgeführt wird.The process can be carried out in such a way that continuously removed pickling solution is withdrawn from a pickling plant and is continuously fed back to the pickling plant after regeneration. The pickling solution contents of HF, HNO 3 and Na can be measured continuously and the measured values can be used for automatic control of the addition of NaOH, HNO 3 and HF and, if necessary, H 2 0. Finally, it is envisaged that the heating and cooling of the pickling solution is carried out with a circulating heat transfer medium having a suitable boiling temperature.

Bei dem erfindungsgemässen Verfahren laufen folgende Reaktionen in der verbrauchten Beizlösung ab:

  • 1) NaOH + HF NaF + H20
  • 2) ZrF4 + 2NaF → Na2ZrF6
In the process according to the invention, the following reactions take place in the used pickling solution:
  • 1) NaOH + HF NaF + H 2 0
  • 2) ZrF 4 + 2NaF → Na 2 ZrF 6

Da NaOH etwa 12mal so gut löslich ist wie NaF, kann es in gelöster Form zugegeben werden, ohne dass die Wasserbilanz nennenswert gestört wird. Bei dem erfindungsgemässen Verfahren wird zwar eine bestimmte Menge HFfür die Bildung von NaF verbraucht, der Aufwand an NaOH + H F zur Regenerierung einer bestimmten Menge Beizlösung beträgt aber trotzdem nur etwa 50% der Kosten verglichen mit der Zugabe von NaF nach dem bekannten Verfahren. Ausserdem wird durch die Zugabe von NaOH als Lösung die Dosierung erleichtert.Since NaOH is about 12 times as soluble as NaF, it can be added in solution without significantly disturbing the water balance. In the process according to the invention, although a certain amount of HF is used for the formation of NaF, the expenditure of NaOH + H F for the regeneration of a certain amount of pickling solution is nevertheless only about 50% of the costs compared to the addition of NaF according to the known process. In addition, the addition of NaOH as a solution makes dosing easier.

Mit dem Verbrauch an H F ist ein weiterer Vorteil verbunden. Da die Löslichkeit von Na2ZrF6 mit fallendem HF-Gehalt sinkt, wird die Ausfällung noch weiter verbessert, als es allein durch die vorgesehene Abkühlung möglich ist. Weiterhin wird die Löslichkeit von Na2ZrE6 durch den HNO3-Gehalt beeinflusst: Sie nimmt mit steigender HN03-Konzentration ab. Aus diesen Gründen ist es wichtig, dass das Aufkonzentrieren mit HNO3 vor der Zugabe des Fällungsmittels und das Aufkonzentrieren mit HF nach dem Filtrieren durchgeführt wird.Another advantage is associated with the consumption of HF. Since the solubility of Na 2 ZrF 6 decreases with a falling HF content, the precipitation is further improved than is possible only by the intended cooling. Furthermore, the solubility of Na 2 ZrE 6 is influenced by the HNO 3 content: it decreases with increasing HN0 3 concentration. For these reasons it is important that the concentration with HNO 3 is carried out before the addition of the precipitant and the concentration with HF after the filtration.

Die erfindungsgemässe Erwärmung der verbrauchten Beizlösung hat den Zweck, die Bildung von NaZrF5· H2O zu vermeiden. Es wurde nämlich festgestellt, dass sich diese gelartige und daher schlecht zu filtrierende Verbindung unabhängig von einer ausreichenden Dosierung mit NaOH nicht bildet, wenn die Ausfällung bei erhöhter Temperatur eingeleitet wird.The heating of the used pickling solution according to the invention has the purpose of avoiding the formation of NaZrF 5 .H 2 O. It has been found that this gel-like compound, which is therefore difficult to filter, does not form, regardless of a sufficient dosage with NaOH, if the precipitation is initiated at an elevated temperature.

Die erfindungsgemässe Kühlung nach Zugabe des Fällungsmittels hat den Zweck, die Löslichkeit des Na2ZrF6 zu vermindern, eine weitgehende Zr-Ausfällung zu erreichen und ein kristallines, gut entwässerbares Na2ZrFe-Salz zu erzeugen. Während ohne genaue Einhaltung der erfindungsgemässen Temperaturen nach einer standardisierten Filtermethode der Filterkuchen noch 50 bis 60% anhaftende Feuchte enthielt und nicht reproduzierbare Filterleistungen von 10 bis 140 kg Salz pro Stunde und Quadratmeter Filterfläche ermittelt wurden, betrugen diese Werte nach dem erfindungsgemässen Verfahren:

  • ca. 20% Feuchte
  • 350 bis 400 kg Salz pro Stunde und Quadratmeter Filterfläche.
The cooling according to the invention after the addition of the precipitating agent has the purpose of reducing the solubility of the Na 2 ZrF 6, of achieving extensive Zr precipitation and of producing a crystalline, readily dewaterable Na 2 ZrF e salt. While without exact adherence to the temperatures according to the invention, the filter cake still contained 50 to 60% adhering moisture according to a standardized filter method and did not reproduce filter capacities of 10 to 140 kg salt per hour and square meter filter area were determined, these values were according to the inventive method:
  • approx. 20% moisture
  • 350 to 400 kg of salt per hour and square meter of filter area.

Durch das Zusammenwirken aller erfindungsgemässen Massnahmen ist ein Verfahren geschaffen worden, das trotz zusätzlichem HF-Verbrauch erheblich kostengünstiger und in der Handhabung wesentlich einfacher ist, als das bekannte Verfahren. Es erlaubt eine Ausfällung bis auf einen Zirkoniumrest von 1 bis 2,5 g/I in der regenerierten Beizlösung und eignet sich sehr gut für eine kontinuierliche Arbeitsweise. Die Abtrennung des gefällten Na2ZrF6 ist einfach und führt zu einem gut entwässerten Salz, welches mit relativ geringem Aufwand in bekannter Weise getrocknet und anderen Verwendungszwecken zugeführt werden kann. Da es keine besonderen Schwierigkeiten bereitet, die Gehalte der Beizlösung an HF, HNO3 und Na kontinuierlich zu messen, kann das Verfahren bei Anwendung entsprechender Mess- und Regeleinrichtungen - die nicht Gegenstand der vorliegenden Erfindung sind―auch in einer vollautomatisch arbeitenden Anlage durchgeführt werden.Through the interaction of all measures according to the invention, a method has been created which, despite additional HF consumption, is considerably less expensive and much easier to handle than the known method. It allows precipitation down to a zirconium residue of 1 to 2.5 g / l in the regenerated pickling solution and is very suitable for continuous operation. The separation of the precipitated Na 2 ZrF 6 is simple and leads to a well-dewatered salt which can be dried in a known manner and used for other purposes with relatively little effort. Since it is not particularly difficult to continuously measure the HF, HNO 3 and Na content of the pickling solution, the method can also be carried out in a fully automated system if appropriate measuring and control devices are used - which are not the subject of the present invention.

Die notwendige Erwärmung und Abkühlung der Beizlösung kann dabei mit einem Minimum an Energieaufwand durchgeführt werden, wenn die dem Beizmittelstrom bei der Abkühlung entzogene Wärmemenge für die Erwärmung eingesetzt wird, wobei für die erforderliche Temperaturerhöhung ein Wärmeträgermittelkreislauf mit Wärmepumpe eingesetzt werden kann.The necessary heating and cooling of the pickling solution can be carried out with a minimum of energy if the amount of heat extracted from the pickling agent stream during cooling is used for heating, whereby a heat transfer medium circuit with a heat pump can be used for the required temperature increase.

Weitere Einzelheiten werden anhand des in Fig. 1 dargestellten Ausführungsbeispiels für eine kontinuierliche Regenerierung der Beizlösung erläutert.Further details are explained on the basis of the exemplary embodiment shown in FIG. 1 for a continuous regeneration of the pickling solution.

Aus dem Beizbad 1 wird die verbrauchte Beizlösung mittels Pumpe 3 über die Leitung 2 in den Wärmetauscher 5 geleitet, nachdem vorher noch bei 4 HNO3 ergänzt wurde. Im Wärmetauscher 5 wird die Beizlösung auf über 40° C erwärmt, danach bei 6 das Fällungsmittel NaOH zugeführt und die Fällung des ZrF4 eingeleitet. Über die Leitung 7 gelangt dann die Beizlösung in den Wärmetauscher 8, wo sie auf unter 20° C abgekühlt und die Fällung abgeschlossen wird. Anschliessend wird die Beizlösung über die Leitung 9 dem Filter 10 zugeführt, aus dem das ausgefällte Na2ZrF6 bei 11 abgeführt wird. Mittels Pumpe 12 wird dann die Beizlösung über die Leitung 13 nach Ergänzung von H20 bei 15 und HF bei 16 in den Wärmetauscher 14 geleitet, wo sie wieder auf die Beizbadtemperatur gebracht und dann über die Leitung 17 dem Beizbad wieder zugeführt wird. Der Kreislauf des Wärmeträgermittels besteht im wesentlichen aus dem Verdichter 18 sowie den Leitungen 19, 20 und 21. Aus dem Wärmetauscher 8 wird dampfförmiges Wärmeträgermittel abgesaugt, im Verdichter 18 komprimiert und nach Abkühlung in den Wärmetauschern 5 und 14 verflüssigt, bevor es über eine Drosselstelle wieder in den Wärmetauscher 8 eingeleitet wird, wo es unter Wärmeaufnahme erneut verdampft.From the pickling bath 1, the used pickling solution is fed into the heat exchanger 5 by means of the pump 3 via the line 2, after 3 HNO 3 had been added beforehand. In the heat exchanger 5, the pickling solution is heated to above 40 ° C., then the precipitant NaOH is fed in at 6 and the precipitation of the ZrF 4 is initiated. The pickling solution then reaches the heat exchanger 8 via the line 7, where it is cooled to below 20 ° C. and the precipitation is completed. The pickling solution is then fed via line 9 to the filter 10, from which the precipitated Na 2 ZrF 6 is removed at 11. By means of pump 12, the pickling solution is then fed via line 13 to H 2 0 at 15 and HF at 16 into heat exchanger 14, where it is brought back to the pickling bath temperature and then fed back to the pickling bath via line 17. The circuit of the heat transfer medium essentially consists of the compressor 18 and the lines 19, 20 and 21. From the heat exchanger 8, vaporous heat transfer medium is sucked off, compressed in the compressor 18 and liquefied after cooling in the heat exchangers 5 and 14 before it is again via a throttle point is introduced into the heat exchanger 8, where it evaporates again while absorbing heat.

Claims (9)

1. A process of regenerating an HF-HN03 pickle which contains ZrF4, wherein ZrF4 is precipitated as Na2ZrFe, the precipitated Na2ZrF6 is removed, and HF, HNO3 and, if required, H2O are made up, characterized in that the spent pickel is first heated above 40° C, dissolved NaOH is then added to the pickle, which is subsequently cooled below 20° C, whereafter precipitated Na2ZrFe is removed by filtration.
2. A process according to claim 1, characterized in that HNO3 is made up before the precipitation, and H F and, if required, H2O are made up after the removal of the precipitate.
3. A process according to claim 1 or 2, characterized in that NaOH is added to the pickle when the latter is at a temperature of 50 to 60° C.
4. Process according to any of claims 1 to 3, characterized in that the precipitate is removed from the pickle when the latter is at a temperature of -20 to +10° C.
5. A process according to any of claims 1 to 4, characterized in that NaOH is added in such an amount that the regenerated pickle contains 1 to 3 g of sodium/I and 1.5 to 2.5 g of zirconium/I.
6. A process according to claim 5, characterized in that the regenerated pickle is adjusted to contain 1.5 to 2.5 g of sodium/I.
7. A process according to any of claims 1 to 6, characterized in that spent pickle is continuously withdrawn from a pickling plant and regenerated pickle is continuously supplied to the pickling plant.
8. A process according to claim 7, characterized in that the contents of HF, HNO3 and Na in the pickle are continuously measured and the addition of NaOH, HNO3 and HF and, if required, H2O is automatically controlled in dependence on the measured contents.
9. A process according to any of claims 1 to 8, characterized in that the pickle is heated and cooled by means of a circulating heat transfer fluid which has a suitable boiling point.
EP81200113A 1980-03-11 1981-01-30 Process for regenerating pickling solutions containing zrf6 Expired EP0035804B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19803009265 DE3009265A1 (en) 1980-03-11 1980-03-11 METHOD FOR REGENERATING ZRF (DOWN ARROW) 4 (ARROW DOWN) CONTAINING SOLUTIONS
DE3009265 1980-03-11

Publications (2)

Publication Number Publication Date
EP0035804A1 EP0035804A1 (en) 1981-09-16
EP0035804B1 true EP0035804B1 (en) 1983-09-21

Family

ID=6096846

Family Applications (1)

Application Number Title Priority Date Filing Date
EP81200113A Expired EP0035804B1 (en) 1980-03-11 1981-01-30 Process for regenerating pickling solutions containing zrf6

Country Status (4)

Country Link
US (1) US4330342A (en)
EP (1) EP0035804B1 (en)
JP (1) JPS56136983A (en)
DE (2) DE3009265A1 (en)

Families Citing this family (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4572824A (en) * 1984-11-01 1986-02-25 General Electric Company Process for recovery of zirconium and acid from spent etching solutions
DE58900366D1 (en) * 1988-02-24 1991-11-21 Metallgesellschaft Ag METHOD FOR REGENERATING ZRF4 CONTAINING SOLUTIONS.
US4943419A (en) * 1988-05-24 1990-07-24 Megy Joseph A Process for recovering alkali metal titanium fluoride salts from titanium pickle acid baths
US5076884A (en) * 1990-07-19 1991-12-31 Westinghouse Electric Corp. Process of precipitating zirconium or hafnium from spent pickling solutions
US5082523A (en) * 1990-11-19 1992-01-21 Westinghouse Electric Corp. Process of regenerating spent HF-HNO3 pickle acid containing (ZrF6-2
US5232460A (en) * 1991-07-12 1993-08-03 W. R. Grace & Co.-Conn. System and process for recycling aqueous cleaners
US5256313A (en) * 1992-12-21 1993-10-26 Heritage Environmental Services, Inc. System and process for treatment of cyanide-containing waste
FR2729676B1 (en) * 1995-01-24 1997-04-11 Zircotube METHOD AND DEVICE FOR REGENERATING A USED SOLUTION FOR STRIPPING ZIRCONIUM ALLOY ELEMENTS
GB2350543B (en) * 1999-05-29 2001-05-09 Graham Edward Burden Tine mountings for agricultural equipment
MY161542A (en) * 2011-04-08 2017-04-28 Shinetsu Chemical Co Preparation of complex fluoride and complex fluoride phosphor

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2828547A1 (en) * 1978-06-29 1980-01-03 Didier Werke Ag Metal pickling bath compsn. control - using sample treated to form ppte. monitored by turbidity meter controlling supply of fresh pickling liq. to bath

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2812237A (en) * 1952-01-31 1957-11-05 Horizons Titanium Corp Preparation of alkali metal fluotitanates
US2743160A (en) * 1952-01-31 1956-04-24 Wainer Eugene Preparation of alkali metal double fluorides of zirconium and hafnium
US3048503A (en) * 1958-06-19 1962-08-07 Crucible Steel Co America Pickling apparatus and method
US4105469A (en) * 1977-02-11 1978-08-08 Teledyne Industries, Inc. Process for regenerating a pickle acid bath

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2828547A1 (en) * 1978-06-29 1980-01-03 Didier Werke Ag Metal pickling bath compsn. control - using sample treated to form ppte. monitored by turbidity meter controlling supply of fresh pickling liq. to bath

Also Published As

Publication number Publication date
US4330342A (en) 1982-05-18
JPS6254195B2 (en) 1987-11-13
EP0035804A1 (en) 1981-09-16
JPS56136983A (en) 1981-10-26
DE3009265A1 (en) 1981-09-24
DE3160900D1 (en) 1983-10-27

Similar Documents

Publication Publication Date Title
EP0035804B1 (en) Process for regenerating pickling solutions containing zrf6
DE1467019B2 (en) Process for the production of finely divided silica by reacting alkali silicate solutions with acid solutions
DE2210106A1 (en) Process for the selective extraction of metalhones from aqueous solutions
WO2009083234A1 (en) Removal of silicon from brine
DE2526297C3 (en) Method and device for obtaining sugar crystals from a sugar solution
DE2321804C3 (en) Device for washing ice crystals through direct contact with a coolant
DE2147507A1 (en) Process for the production of metal fluorides and metal fluoride mixtures which do not contain oxygen
EP0112500B1 (en) Process for producing crystals containing plutonium dioxide
EP0176126B1 (en) Apparatus and process for treating pickling and etching solutions
DE3428788C2 (en) Process for the continuous production of low-fluoride tantalum or niobium pentoxides
EP0331231B1 (en) Process for regenerating pickling solutions containing zrf4
DE2022571A1 (en) Method and device for the transfer of substances between a liquid and a granular material
DE3200518C2 (en)
DE60002370T2 (en) System for heat transfer in a reactor for the conversion of UF6 into uranium oxide
EP0445516B1 (en) Process and apparatus for the production of silver nitrate
DE1608737C3 (en) Process for enriching lithium isotopes according to the countercurrent principle
DE2348804A1 (en) METHOD OF REMOVING FISSION PRODUCTS FROM COOLANT FROM NUCLEAR REACTOR PLANTS
DE509044C (en) Recovery of hydrogen chloride gas from aqueous solutions containing it by heating with sulfuric acid in a circuit
DE2649906C3 (en)
DE707573C (en) Wood saccharification process
DE1919428C (en) Vacuum separator for metal refining
DE1567436C (en) Method for the regeneration of heavy serving as a moderator of a nuclear reactor
DE4132728C2 (en) Process for concentrating a low-concentration plutonium nitrate solution
DE1592525C (en) Process and device for the production of titanium tetraiodide
EP0183678A2 (en) Process for the final treatment of molasses or vinasses, and apparatus for carrying out this process

Legal Events

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

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Designated state(s): AT BE CH DE FR GB IT LU NL SE

17P Request for examination filed

Effective date: 19811126

ITF It: translation for a ep patent filed

Owner name: STUDIO JAUMANN

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Designated state(s): DE FR IT SE

REF Corresponds to:

Ref document number: 3160900

Country of ref document: DE

Date of ref document: 19831027

ET Fr: translation filed
PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 19841226

Year of fee payment: 5

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: SE

Payment date: 19841231

Year of fee payment: 5

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 19850220

Year of fee payment: 5

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: SE

Effective date: 19890131

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19890929

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Effective date: 19891003

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

EUG Se: european patent has lapsed

Ref document number: 81200113.9

Effective date: 19891205