GB1594253A - Recovery of a metal from articles containing it - Google Patents

Recovery of a metal from articles containing it Download PDF

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Publication number
GB1594253A
GB1594253A GB44569/79A GB4456979A GB1594253A GB 1594253 A GB1594253 A GB 1594253A GB 44569/79 A GB44569/79 A GB 44569/79A GB 4456979 A GB4456979 A GB 4456979A GB 1594253 A GB1594253 A GB 1594253A
Authority
GB
United Kingdom
Prior art keywords
tin
tinning
articles
metal
alloy
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
GB44569/79A
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.)
Crown Packaging UK Ltd
Original Assignee
Metal Box PLC
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 Metal Box PLC filed Critical Metal Box PLC
Priority to GB44569/79A priority Critical patent/GB1594253A/en
Publication of GB1594253A publication Critical patent/GB1594253A/en
Expired legal-status Critical Current

Links

Classifications

    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22BPRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B25/00Obtaining tin
    • C22B25/06Obtaining tin from scrap, especially tin scrap
    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02PCLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00Technologies related to metal processing
    • Y02P10/20Recycling

Description

(54) IMPROVEMENTS RELATING TO THE RECOVERY OF A METAL FROM ARTICLES CONTAINING IT (71) We, METAL Box LIMITED of Queens House, Forbury Road, Reading RGl 3JH, a British company, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to a method of recovering a metal from articles containing it, and more particularly to a method of detinning articles plated with tin or tin-based alloys, such as for example tin cans and other containers, for the purpose of recovering tin from such articles (e.g. by electrodeposition), and also the base metal of such articles which have been so plated.The invention also includes within its scope tin and such base metal when recovered by the said method, as well as articles from which tin or tin alloys, applied in the course of their manufacture, e.g. as lubricants, have been removed by the said method as part of the manufacturing process of such articles.
The high price of tin makes it desirable to provide a speedy and economical method for recovering tin from articles plated with tin or tin-based alloys, when such articles or the said tin or alloys of such articles are no longer required. Moreover tin or tin-based alloys are often applied as lubricant during the drawing and wall-ironing of two-piece cans. The latter are generally made of steel, lacquered inside and printed outside so that the protective tin layer is no longer required.
Alternatively or additionally the purpose of a de-tinning operation may be to recover the base metal, e.g. steel, from such articles.
In the complete specification of our British patent specification No. 1 537670 there is described and claimed a method of detinning an article which is plated with tin or a tin-based alloy (followed, if desired, by the recovery of the tin by electrodeposition), by forming a stagnate from the tin recovered from the article, the method comprising exposing the article to a heated solution comprising, dissolved in a solvent, an alkali and an anthraquinone or a derivative thereof, the solvent and the anthraquinone or derivative thereof, being such that the said anthraquinone or derivative thereof and the said stannate are soluble in the solvent.
The present invention relates to an improvement in, or modification of, the aforesaid method.
It has been found that the problem of removal of iron/tin alloy layers can be overcome by the addition of complexing agents to the de-tinning medium. Thus, according to the invention, a method of detinning a steel based article which is plated with tin or a tin-based alloy and includes an iron/tin alloy layer, comprises exposing the articles to a heated liquid medium comprising an anthraquinone de-tinning agent, an alkali and an iron complexing agent.
The complexing agent may suitably be E.D.T.A. with triethanolamlno. It is believed that the complexing agent reacts with, so as to remove, the hydrous iron oxide formed early in the de-alloying operation from the residual alloy remaining on the surface which would otherwise be masked Sy the iron oxide, the presence of which appears to prevent the access of de-tinning solution to the residual alloy. The use of a complexing agent for the iron speeds the rate of alloy removal.
The preferred anthraquinone de-tinning agent is sodium anthraquinone-2-sulphonate. Preferably the concentration of alkali, usually caustic soda, in the de-tinning solution is at least 5% w/v.
We have carried out experiments in accordance with the invention, using samples cut from D100/50 plate (viz. tinplate nominally coated with 11.2 g/m2 of tin on one side and 5.6 g/m2 on the other) immersed in various de-tinning solutions, containing sodium an thraquinone-2-sulphonate at a concentration of 1.5 g/l, progress of the de-tinning reaction was followed using a Stereoscan/X-ray analyser unit, since alloy dissolution is difficult to follow, whereas the removal of free tin can be followed with the naked eye. The addition of a mixture of 0.025S, w/v E.D.T.A., disodium salt and 0.025S, w/v triethanolamine was found to lead to a 30'E,, reduction in the time required to remove all tin from the sample. The use of excess complexing agent did not appear to reduce the de-tinning time.
The speed of alloy removal has been found to be dependent on the alkali concentration and this is preferably in excess of 5S, w/v.
Thus the time required to de-tin and de-alloy a sample in 3% caustic soda using 1S sodium anthraquinone-2-sulphonate at a temperature of 90"C was 45 minutes. Using 10% caustic soda and the same conditions, the time was reduced to 15 minutes. However, in the latter case some quinone remained undissolved.
The rate of de-tinning achieved by the method according to the present invention is believed to be enhanced by agitation of the liquid medium in or by an agitation device.
Thus the method according to the present invention is preferably carried out in an agitation device in the form of a rotating drum which is inclined to the horizontal, similar for example to a conventional cement mixer, but modified so as to allow the introduction thereinto and removal therefrom of hot fluid reagents and other media for reacting with the tin as aforesaid, as well as for rinsing and any other additional subsidiary operations which may be required in the course of the de-tinning operation.
Articles to be de-tinned are continuously agitated together with the solution or liquid medium in the drum. This agitation and the collisions of the articles (which, where appropriate, have been comminuted, e.g. shredded, in a suitable shredder) with themselves and with the walls of the drum tends to increase the rate of de-tinning. Such agitation also provides for good aeration of the solution or liquid medium which is particularly desirable where sodium anthraquinone-2-sulphonate is the de-tinning agent.
It will also be appreciated that, in he same way as in the method described and claimed in our aforesaid patent No. 1 537670, the recovery of the tin may be performed by electrodeposition.
WHAT WE CLAIM IS: 1. A method of de-tinning a steel-based article which is plated with tin or a tin-based alloy and includes an iron/tin alloy layer, said method comprising exposing the article to a heated liquid medium comprising an anthraquinone de-tinning agent, an alkali and an iron complexing agent.
2. A method according to Claim 1, wherein said iron complexing agent comprises E.D.T.A. with triethanolamine.
3. A method according to Claim I or Claim 2, wherein said anthraquinone detinning agent is sodium anthraquinone-2sulphonate.
4. A method according to any one of the preceding claims, wherein said alkali is caustic soda.
5. A method according to any one of the preceding claims, wherein the concentration of said alkali in the de-tinning solution or liquid medium is at least 5% w/v.
6. A method according to Claim 5, wherein the concentration of said alkali is 10% w/v.
7. A method according to any one of the preceding claims, wherein the temperature of said solution or liquid medium is 90on.
8. A method according to any one of the preceding claims, wherein said solution or liquid medium is aerated.
9. A method according to any one of the preceding claims, wherein said solution or liquid medium is agitated in or by an agitation device.
10. A method according to Claim 9, wherein said agitation device comprises a rotating drum inclined to the horizontal.
Il. A method of recovering from an article comprising a base metal plated with tin or a tin-based alloy, the tin or the tin and the said base metal, said method comprising the steps of de-tinning the article by a method according to any one of the preceding claims and of recovering the tin by electrodeposition.
12. A method according to Claim 11, wherein said base metal is steel and both the steel and the tin are recovered.
13. A method according to Claim 1 and substantially as hereinbefore described.
14. An article which has been de-tinned by a method according to any one of Claims 1 to 10 or Claim 13 or in the course of a method according to Claim 11 or Claim 12.
15. A steel can body being an article according to Claim 14.
16. Tin and/or a said base metal when recovered by a method according to Claim

Claims (1)

11 or Claim 12.
17. Steel when recovered by a method according to Claim 11 or Claim 12.
GB44569/79A 1978-01-16 1978-01-16 Recovery of a metal from articles containing it Expired GB1594253A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB44569/79A GB1594253A (en) 1978-01-16 1978-01-16 Recovery of a metal from articles containing it

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB44569/79A GB1594253A (en) 1978-01-16 1978-01-16 Recovery of a metal from articles containing it

Publications (1)

Publication Number Publication Date
GB1594253A true GB1594253A (en) 1981-07-30

Family

ID=10433902

Family Applications (1)

Application Number Title Priority Date Filing Date
GB44569/79A Expired GB1594253A (en) 1978-01-16 1978-01-16 Recovery of a metal from articles containing it

Country Status (1)

Country Link
GB (1) GB1594253A (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6045686A (en) * 1997-03-18 2000-04-04 The University Of Connecticut Method and apparatus for electrochemical delacquering and detinning
US6290835B1 (en) 2000-02-07 2001-09-18 Rd Chemical Company Treatment of waste from printed circuit board production for recovery of tin and environmentally safe disposal
CN101104940B (en) * 2007-04-19 2010-05-19 华中师范大学 Preparation for gold electrode with nano-pore structure by electrochemistry alloying/dealloying method
CN103820602A (en) * 2013-11-25 2014-05-28 江苏科技大学 Low-carbon steel detinning method

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6045686A (en) * 1997-03-18 2000-04-04 The University Of Connecticut Method and apparatus for electrochemical delacquering and detinning
US6290835B1 (en) 2000-02-07 2001-09-18 Rd Chemical Company Treatment of waste from printed circuit board production for recovery of tin and environmentally safe disposal
CN101104940B (en) * 2007-04-19 2010-05-19 华中师范大学 Preparation for gold electrode with nano-pore structure by electrochemistry alloying/dealloying method
CN103820602A (en) * 2013-11-25 2014-05-28 江苏科技大学 Low-carbon steel detinning method
CN103820602B (en) * 2013-11-25 2015-06-17 江苏科技大学 Low-carbon steel detinning method

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