Hostname: page-component-78c5997874-fbnjt Total loading time: 0 Render date: 2024-11-03T05:23:50.958Z Has data issue: false hasContentIssue false
  • English
  • Français

377. Corrosion by commercial sodium hypochlorites and its inhibition

Published online by Cambridge University Press:  01 June 2009

G. H. Botham  and
G. A. Dummett
G. H. Botham
Affiliation:
A.P.V. Laboratories, London
G. A. Dummett
Affiliation:
A.P.V. Laboratories, London
Get access Rights & Permissions [Opens in a new window]

Extract

Commercial sodium hypochlorites, whether containing KMnO4 or not, are shown to be corrosive at 150 p.p.m. available chlorine and 40° C. to metals such as aluminium, tinned copper, nickel silver and cast stainless steel (18 Cr, 8 Cu, 3 Mo) which are used in dairy equipment. Hypochlorites containing KMnO4 when aged are potentially dangerous to wrought 18/8 stainless steel. The attack is by pitting and therefore especially dangerous to all the metals investigated, and, in general, increases with increase of time of exposure and temperature.

Decay of sodium hypochlorite solutions results in conversion of NaOCl to NaCl and NaC103, which reaction is shown to follow a simple equation fairly closely in various storage conditions.

Attack on metals by sodium hypochlorite can be efficiently inhibited by addition of sodium silicate, which has a specific action in addition to the effect exerted by increase of alkalinity. NaOH and Na2CO3 additions to the same pH are not so effective and increase attack on aluminium.

Increase of pH from 9 to 10·5 by addition of Na2CO3 or sodium silicate reduces bactericidal efficiency of hypochlorites to the same extent.

Type
Original Articles
Information
Journal of Dairy Research , Volume 16 , Issue 1 , January 1949 , pp. 23 - 38
Copyright
Copyright © Proprietors of Journal of Dairy Research 1949

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

(1)Quam, G. N. (1930). Food Industr. 2, 121.Google Scholar
(2)Hunziker, O. et al. (1929). J. Dairy Sci. 12, 252.CrossRefGoogle Scholar
(3)Guertler, A. et al. (1930). Molkereiztg. Nos. 72, 77, 78, 80, 81, 83.Google Scholar
(4)Haller, H. S., Grant, F. M. & Babcock, C. J. (1941). Tech Bull. U.S. Dep. Agric. 756.Google Scholar
(5)Moore, C. M. (1944). J. Milk Tech. 7, 291.CrossRefGoogle Scholar
(6)Evans, U. R. (1927). J. Soc. chem. Ind., Lond., 46, 3547.CrossRefGoogle Scholar
(7)McKay, R. J. & Worthington, R.Corrosion Resistance of Metals and Alloys, p. 63. Reinhold.Google Scholar
(8)Seligman, R. & Williams, P. (1920). J. Inst. Met. 23, 1.Google Scholar
(9)Brennert, S. (1935). Tech. Publ. Int. Tin Res. Coun. series D, no. 2.Google Scholar
(10)Uhlig, H. H. & Morrill, M. C. (1941). Industr. Engng Chem. 33, 875.CrossRefGoogle Scholar
(11)Frese, F. G. (1938). Industr. Engng Chem. 30, 83.CrossRefGoogle Scholar
(12) Firth-Viokers, Rust, Acid and Heat Resisting Steels. Firth-Vickers.Google Scholar
(13)Charlton, D. & Levine, M. (1937) Bull. la Engng Exp. Sta. 132,Google Scholar
(14)Scales, F. M. & Kemp, M. (1939). J. Milk Tech. 2, 215.CrossRefGoogle Scholar
(15)National Institute for Research in Dairying. Report for the years 1941, 1942, 1943, p. 38.Google Scholar
(16)Bohner, H., Hauszeit, V. A. W. & Enftwerk, A. G. (1931). Aluminium, 3, 347.Google Scholar
(17)Rabald, E. (1936). Die Chem. Fabr. 9, 473.Google Scholar
(18)Seligman, R. & Williams, P. (1922). J. Inst. Met. 28, 297.Google Scholar
(19)Evans, U. R. (1945). Chem. & Ind. 106.Google Scholar
(20)Todt, F. (1934). Z. Elektrochem. 40, 538.Google Scholar
(21) Uhlig, H. H. (1939). Metals Tech. 6, (7). T.P: 1121.Google Scholar