US1719649A - Pickling and cleaning of metal - Google Patents

Description

252 COMPOSITIONS. i i i l i i fei ned July 2, 1929. 1,719,649 UNITED STATES PATENT OFFICE.

GEORGE D. CHAMBERLAIN, OF ASHLAND, KENTUCKY, ASSIGNOR TO R. T. VANDERIBILT COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF YORK.

PICKLING AND CLEANING OF METAL.

No Drawing. Application filed January 11, 1927. Serial No. 160,525.

This invention relates to the pickling and hyde onthe condfil sate of acetaldehyde with cleaning of metals, and particularly to the anil 1 n,.. among other'condensation products pickling of iron or steel, to remove scale Tn'ay be mentioned the condensation product therefrom, although the invention is of more of heptaldehyde with anilin, of formaldeor less general application to the cleaning or h'yde with anilin or with o-toluidine, or furpi'ckling of metals such as iron or steel for fural' with diethyharnineor with diphenylthe removal of oxides or scale therefrom. guan'idine, etc. l

The pickling or cleaning of iron or steel ""The'acid pickling baths with which the is commonly effected by means of acid pickagents mentioned are used may be acid baths ling or cleaning baths which dissolve the Such as are commonly employed for pickling scale or oxide from the metal. The pickling or cleaning iron and steel, containing for baths commonly employed are acid baths example, about 10% of sulfuric acid. Such which often attack the metal as well as the baths are gradually impoverished by the acetaldehyde, butyraldehyde, hep t a l lehyd:e, practice. For example, the pickling can be scale. This action on the metal is undesirable action of the acid in removing the scale or and objectionable, involving not only excesrust and their content of ferrous sulfate in sive. consumption of acids, but also corrosion creases until the bath becomes too weak or or dissolving of metal and tending to give a too concentrated in ferrous sulfate for furrough or pitted surface. ther use. Instead of usin sulfuric acid The present invention provides an imbaths, other acid baths can e used, includproved bath for pickling or cleaning metals ing acid sulfate baths. and also an improved process of pickling or The amountof the condensation product cleaning the metal in which the acid pickling added to the bath for carrying out the pickbath has incorporated therein a small amount ling or cleaning operation can be varied. In f g pgganic general, only a small amount of the condenamine WlWe. sation product is required, for example, a ruaet ound that the addition of a small small fraction of one per cent. In the case amount of a suitable condensation product of the condensation product of aldol and of an aldehyde with an amine prevents or alpha-naphthylamine, for example, about retards or inhibits the attack of the acid two pounds of the condensation product can pickling bath on the metal without interbe employed for each ton of 60 degree acid fering with the removal of scale or oxide by used in the pickling bath. A similar or somethe acid bath and leaves the surface of the What increased amount of the condensation cleaned metal in. better condition. product of aldol wit-h diphenylguanidine can The agents which are added to the cleanbe similarly used. The condensation product ing or pickling bath, according to the present employed should be one which is stable and invention, include various products of ami v IMF yes. tent in the acid bath. these ma e mentioned condensation prod- The carrying out of the pickling or clean- :uct s of various"aldehydsfsuch as aldol, ing operation may be the same as in ordinary furfural, benzaldehyde, etc. with amines. carried out continuously by passing the mai Certain condensation products'of aldol with terial to be pickled, such as wire or sheets,

amines are particularly advantageous, such through a number of baths in a regulated the condensation product of ald ol with manner; or by immersing the article to be l phwpli thylamfnband with certain guaiipickled in the pickling bath for a suitable idines such as diphenylguanidine and certain period of time. The temperature of the bath 7 other di-substituted guanid'ine's. Cond'ensa can be varied, ordinarily being around 150 tion products of guanidines with other aldeto 180 F. The pickling bath may be re-- hydes can also be used, as well as condensation plenished by the addition of further amounts products of other amines with aldehydes. of acid until the iron sulfate reaches too great For example, the condensation products of a concentration.

anilin with acetaldehyde, including the con- The addition of the condensation product densates produced both in presence and in to the bath prevents or retards or inhibits absence of acid, can be used, or the product the action of the acid bath on the metal withformed by the further action gf formaldeout interfering with the removal of scale or 1 Examiner.

condens tion does not decompose to any objectionable exoxide. The formation of hydrogen by the action of the acid bath on the metal is also reduced and the evolution of acid mist or fumes also greatly reduced. There is also a saving in the acid as Well as a protection of the metal. The reduced amount of action of the acid on the metal and the reduction in .amount of hydrogen produced correspondtection of the metal from attack, etc., which materially improve the pickling and cleaning operation.

I claim:

1. The method of cleaning or pickling metals which comprises subjecting the same to a non-oxidizing mineral acid pickling or cleaning bath and inhibiting the chemical action of the acid on the metal without interfering with the removal of scale or oxide, and therecondensation product of an aldehyde with an amine.

2. The method of cleaning or pickling metals which comprises subjecting the same to a non-oxidizing mineral acid pickling or cleaning bath and inhibiting the chemical action of the acid on the metal without interfering with the removal of scale or oxide, and thereby reducing the formation of hydrogen and the production of acid fumes and effecting an economy in the acid consumed, by incorporating in the acid bath a small amount of a condensation product of aldol with an amine.

3. The method of cleaning or pickling metals which comprises subjecting the same to a non-oxidizing mineral acid pickling or cleaning bath and inhibiting the chemical action of the acid on the metal without interfering with the removal of scale or oxide, and thereby reducing the formation of hydrogen and the production of acid fumes and effecting an economy in the acid consumed, by incorporating in the acid bath a small amount of a condensation product of aldol with alphanaphthylamine.

4. The method of pickling or cleaning iron or steel which comprises subjecting the same to an acid pickling bath containing sulfuric acid and inhibiting the chemical action of the acid on the metal without interferin with the removal of scale or oxide, and t ereby 5. The method of pickling or cleaning iron or steel which comprises subjecting the same to an acid pickling bath containing sulfuric acid and inhibiting the chemicaI action of the acid on the metal without interfering with the removal of scale or oxide, and thereby reducing the formation of hydrogen and the production of acid fumes and effecting an economy in the acid consumed, by incorporating in the acid bath a small fraction of one percent of a condensation product of aldol with an amine.

6. The method of picklin or cleaning iron or steel which comprises su jecting the same to an acid pickling bath containing sulfuric acid and inhibiting the chemical action of the acid on the metal without interfering with the removal of scale or oxide, and thereby reducing the formation of hydrogen and the production of acid fumes and effecting an economy in the acid consumed, by incorporating in the acid bath a small fraction of one percent of a condensation product of aldol with alpha napththylamine.

7. A non-oxidizing mineral acid bath for pickling or cleaning metals which contains a small amount of a condensation product of an aldehyde with an amine.

8. A non-oxidizing mineral acid bath forpickling or cleaning metals which contains a fraction of one percent of the condensation product of aldol with an amine.

9. A bath for cleaning or pickling metals which contains sulfuric acid and a small amount of a condensation product of an aldehyde with an amine.

10. A bath for cleaning or pickling iron or steel which contains sulfuric acid and a fraction of one percent of a condensation product of aldol with alphanaphthylamine.

11. A bath for cleaning or pickling metals which contains sulfuric acid and a condensation product of aldol with alphanaphthylamine.

12. A non-oxidizing mineral acid bath for pickling or cleaning metals which contains a condensation product of aldol with an amine.

13. A non-oxidizing mineral acid bath for pickling or cleaning metals which contains a condensation product of aldol with alphanaphthylamine.

In testimony whereof I afiix my signature.

GEORGE D. CHAMBERLAIN.