EP0654546A1 - Beizverfahren und Einrichtung - Google Patents

Beizverfahren und Einrichtung Download PDF

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Publication number
EP0654546A1
EP0654546A1 EP94203432A EP94203432A EP0654546A1 EP 0654546 A1 EP0654546 A1 EP 0654546A1 EP 94203432 A EP94203432 A EP 94203432A EP 94203432 A EP94203432 A EP 94203432A EP 0654546 A1 EP0654546 A1 EP 0654546A1
Authority
EP
European Patent Office
Prior art keywords
pickling
iron
medium
crystallization
bath
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Withdrawn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
EP94203432A
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English (en)
French (fr)
Inventor
Piet De Vries
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.)
Individual
Original Assignee
Individual
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 Individual filed Critical Individual
Publication of EP0654546A1 publication Critical patent/EP0654546A1/de
Withdrawn legal-status Critical Current

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    • 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 present invention relates to a method for pickling iron and steel products in an acid solution, wherein rust and possible mill scale are removed.
  • the iron content of the pickling medium hereby increases gradually.
  • the pickling action of the pickling medium has practically ceased. At that moment the pickling medium must be refreshed.
  • the pickling medium itself has an environmental impact even after neutralization.
  • the pickling medium contains valuable components which are lost as a result of neutralization.
  • the present invention is based on the insight that a pickling medium regains its pickling action when the iron content of the pickling medium is further increased to generally above 150 g iron/l, whereby it also becomes worthwhile to separate iron salts, such as iron chloride, formed by means of crystallization.
  • the pickling action is maintained or even improved when compared to the use of a pickling medium with an iron content lower than 75 g/l, and a valuable crystallization product results with a comparatively small content of contaminants, while the treated pickling medium can be re-used.
  • the iron content of the pickling medium generally lies above 150 g iron/l, it is further recommended to work with a pickling medium with an iron content lying above 175 g/l. Under practical conditions the iron concentration will generally lie in the range of 180 to 250 g/l, more preferably between 190 and 210 g/l. A pickling medium is thus provided with a pickling action equal to or even greater than that of a pickling medium which works with an iron content smaller than 75 g/l.
  • the pickling medium is subjected to crystallization conditions by cooling generally to a temperature below 2°C, more preferably to below 0°C. This results in iron chloride crystals and the iron content falls to about 100 g/l.
  • the concentrated acid can be chosen from hydrochloric acid, sulphuric acid and phosphoric acid. The use of sulphuric acid and phosphoric acid is herein preferred because re-dissolution of the iron chloride crystals is further inhibited.
  • Crystallization can be further enhanced by performing crystallization under the influence of ultrasonic sound (more than 20,000 Hz, in general between 0.1 - 100 MHz depending on the crystal structure).
  • ultrasonic sound more than 20,000 Hz, in general between 0.1 - 100 MHz depending on the crystal structure.
  • the present invention further relates to a pickling installation for performing the method according to the invention, which pickling installation comprises
  • the pickling is performed at a temperature generally in the order of 20-50°C and crystallization is performed after cooling, it is recommended for reasons of heat economy that the feed line and the recirculation line are in heat-exchanging contact.
  • figures 1-3 each show a schematic view of a pickling installation according to the invention.
  • Figure 1 shows an installation 1 for pickling steel and iron products, wherein for instance 2-3 kg iron/ton product is removed.
  • the installation 1 comprises a pickling bath 4 with a content of for instance 60,000 l.
  • the pickling bath contains a pickling medium with an iron content of roughly 175-210 g/l, a hydrochloric acid content of about 30-60 g/l (pH ⁇ 1), while the temperature amounts to around 40°C.
  • Pickling medium is continuously drained via a feed line 5 to a crystallization unit 6, wherein an intermediate tank 7 is arranged in feed line 5.
  • the crystallization unit 6 is manufactured from stainless steel and protected against corrosion by means of the circuit 8, an anode 9 of which is immersed in the pickling medium 10 for treating.
  • the crystallization unit is provided with cooling means 11 with which the pickling medium 10 is cooled to below 0°C.
  • a stirring gear 12 By means of a stirring gear 12 a circulation is maintained in crystallization unit 6.
  • the medium is guided via a line 13 through a solid/liquid separator 14 in which formed iron chloride crystals are separated and removed via discharge line 15.
  • Pickling medium with iron removed is returned via recirculation line 16 to pickling bath 4. This pickling medium contains about 160 g/l iron.
  • the same construction elements are designated with the same reference numerals.
  • the crystallization unit 6 is also provided with a line 17 with which concentrated acid (for instance hydrochloric acid) is supplied from a tank 18 to crystallization unit 6. Cooling thereby only need take place for crystallization to a temperature of around 0°C, while the iron content of the pickling medium returned via the recirculation line 16 to pickling bath 4 has an iron content of only 100 g/l.
  • the crystallization unit 6 is likewise embodied with means 19 for externally radiating ultrasonic sound, whereby germing is greatly enhanced and therewith crystallization.
  • the liquid/solid separator now takes the form of a centrifuge 20, the rotating drum 21 of which is scraped with a knife 22 and the solids removed via discharge line 15.
  • the iron chloride has a moisture content far below 60%, such as 10-30%, and in a practical embodiment 18%. This further contains iron chloride (50%), zinc (60 ppm) and other metals (less than 25 ppm). This material is very suitable for use as flocculant in water treatment plants.
  • the recirculation line 16 is further provided with a heat-exchanging part 23, whereby heat-exchanging contact is possible in the intermediate tank 7, whereby pickling medium for treatment is cooled and treated pickling medium is heated and the heat economy thereby greatly improves.
  • a belt filter is used instead of a centrifuge, wherein the iron chloride crystals are washed with concentrated hydrochloric acid (33%).
  • the washed clean iron chloride crystals can be discharged as such or further refined.
  • the washing liquid is returned to the pickling bath (optionally after prior heat exchanging in heat exchanger 7).
  • the washed clean iron chloride crystals can be further refined to for instance iron(III)chloride of commercial quality.
  • the washed clean crystals are placed into a dissolving tank to which water is added.
  • the heat of solution is provided by heat exchanging with the solution leaving the pickling bath.
  • Iron(III)chloride of commercial quality is formed in a concentration of 140 g iron/l.

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)
EP94203432A 1993-11-24 1994-11-24 Beizverfahren und Einrichtung Withdrawn EP0654546A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NL9302035 1993-11-24
NL9302035A NL9302035A (nl) 1993-11-24 1993-11-24 Beitswerkwijze en een inrichting daarvoor.

Publications (1)

Publication Number Publication Date
EP0654546A1 true EP0654546A1 (de) 1995-05-24

Family

ID=19863180

Family Applications (1)

Application Number Title Priority Date Filing Date
EP94203432A Withdrawn EP0654546A1 (de) 1993-11-24 1994-11-24 Beizverfahren und Einrichtung

Country Status (2)

Country Link
EP (1) EP0654546A1 (de)
NL (1) NL9302035A (de)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2003035934A1 (en) * 2001-10-25 2003-05-01 Eco-Tec Limited Process and apparatus for recovery of peroxide containing pickling solutions
CN103063501A (zh) * 2011-10-24 2013-04-24 上海宝钢工业检测公司 钢材酸浸试验腐蚀集成装置
CN103063501B (zh) * 2011-10-24 2016-12-14 上海宝钢工业检测公司 钢材酸浸试验腐蚀集成装置
CN106676558A (zh) * 2017-01-05 2017-05-17 宝钢工程技术集团有限公司 一种溶液循环过滤装置及方法

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR997963A (fr) * 1945-09-14 1952-01-14 Colin & Cie Procédé de régénération des bains chlorhydriques de décapage des métaux et alliages
FR1234930A (fr) * 1958-08-29 1960-07-01 Procédé de récupération de lessives résiduelles de décapage contenant un sel de fer
WO1981002026A1 (en) * 1980-01-18 1981-07-23 Boliden Ab A method of regenerating pickling bath solutions
CS234724B1 (cs) * 1983-12-28 1985-04-16 Pavel Schwarzrock Způsob regenerace mořící kyselinové lázně pro moření antikorozních ocelí
WO1986005523A1 (en) * 1985-03-19 1986-09-25 Korrosionsforskning Ab Method for pickling iron or steel objects
DE3521632A1 (de) * 1985-06-15 1986-12-18 Metallgesellschaft Ag, 6000 Frankfurt Verfahren zum behandeln einer eisenchlorid und salzsaeure enthaltenden waessrigen loesung
US5057290A (en) * 1990-04-23 1991-10-15 Peterson Joseph C Process and apparatus for the low temperature recovery of ferrous chloride from spent hydrochloric acid pickle liquors

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB877066A (en) * 1959-04-30 1961-09-13 Kestner Evaporator And Enginee Process for the treatment of pickle bath liquor

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR997963A (fr) * 1945-09-14 1952-01-14 Colin & Cie Procédé de régénération des bains chlorhydriques de décapage des métaux et alliages
FR1234930A (fr) * 1958-08-29 1960-07-01 Procédé de récupération de lessives résiduelles de décapage contenant un sel de fer
WO1981002026A1 (en) * 1980-01-18 1981-07-23 Boliden Ab A method of regenerating pickling bath solutions
CS234724B1 (cs) * 1983-12-28 1985-04-16 Pavel Schwarzrock Způsob regenerace mořící kyselinové lázně pro moření antikorozních ocelí
WO1986005523A1 (en) * 1985-03-19 1986-09-25 Korrosionsforskning Ab Method for pickling iron or steel objects
DE3521632A1 (de) * 1985-06-15 1986-12-18 Metallgesellschaft Ag, 6000 Frankfurt Verfahren zum behandeln einer eisenchlorid und salzsaeure enthaltenden waessrigen loesung
US5057290A (en) * 1990-04-23 1991-10-15 Peterson Joseph C Process and apparatus for the low temperature recovery of ferrous chloride from spent hydrochloric acid pickle liquors

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
CHEMICAL ABSTRACTS, vol. 107, no. 14, 5 October 1987, Columbus, Ohio, US; abstract no. 119313x, SCHWARZROCK: "Regeneration of acid bath in pickling steel" page 231; *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2003035934A1 (en) * 2001-10-25 2003-05-01 Eco-Tec Limited Process and apparatus for recovery of peroxide containing pickling solutions
CN103063501A (zh) * 2011-10-24 2013-04-24 上海宝钢工业检测公司 钢材酸浸试验腐蚀集成装置
CN103063501B (zh) * 2011-10-24 2016-12-14 上海宝钢工业检测公司 钢材酸浸试验腐蚀集成装置
CN106676558A (zh) * 2017-01-05 2017-05-17 宝钢工程技术集团有限公司 一种溶液循环过滤装置及方法

Also Published As

Publication number Publication date
NL9302035A (nl) 1995-06-16

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