Summary
A preliminary study of a wide range of copper-chrome-arsenic formulations indicates that the most offective are in the region, CuSO4·5H2O-35 to 45 per cent; K2Cr2O7-40 per cent and above; As2O5·2H2O-25 to 15 per cent or less. Effectiveness appears to depend more on the copper content than the copper-arsenic. Observations on selective absorption and leaching suggest that the chromium fixes the arsenic preferentially to the copper. Although there appears to be no major amount of fixation of copper by arsenic, at the start of addition of arsenic to copper-chrome formulations there is a small but significant decrease in the leaching of the copper suggesting either a small amount of fixation of copper by arsenic or the formation of an insoluble complex of all three components.
Maximum fixation of arsenic was obtained when the Cr/As ratio (as salts) was 1.9 or greater. Maximum fixation of copper is not so simply defined but is round about a Cr/Cu ratio (as salts) of 1.7.
The area of maximum effectiveness is not coincident with the area of maximum fixation of both copper and arsenic but slightly displaced towards a region of higher copper where there is still maximum fixation of arsenic but some loss of copper.
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References
Fahlstrom, G. B., Gunning, P. E., Carlson, J. A. 1967. Copper-chrome-arsenate wood preservatives: a study of the influence of composition on leachability. Forest Prod. J. 17: 17–22.
Falck, R., Kamesam, S. 1931. Ein neues allgemein verwendbares Holzschutzmittel. Chem. Zeit. 55: 837–838.
Falck, R., Kamesam, S. 1933. French Patent No. 743,486.
Gunn, G. 1926. British Patent No. 273007.
Girsewald, C., Brüning, H. 1912. British Patent No. 2972.
Häger, B. 1969. Leaching tests on copper-chromium-arsenic preservatives. Forest Prod. J. 19: 21–26.
Henry, W. T., Jeroski, E. M. 1967. Relationship of arsenic concentration to the leachability of chromated copper arsenate formulations. Proc. Amer. Wood Preserv. Ass. 63: 187–192.
Kamesam, S. 1933. Process for the preservation of wood with copper and arsenic compounds. British Patent No. 404,855.
Lumsden, G. Q. 1952. A quarter century of evaluation of wood preservatives in poles and posts at the Gulfport test plot. Proc. Amer. Wood Preserv. Ass. 48: 27–47.
— 1964. Evaluation of wood preservatives in poles and posts at the Gulfport test plot. An extension to 38 years of the 1952 report covering a quarter century of testing. Proc. Amer. Wood Preserv. Ass. 60: 45–60.
Savory, J. G. 1954. Breakdown of timber by Ascomycetes and Fungi imperfectii. Ann. appl. Biol. 41: 336–347.
Smith, D. N. 1954. Field trials on preservatives used for pressure treatment. Forest Prod. Res. Bull. No. 32, London.
Smith, D. N. 1965. The evaluation of wood preservatives. Rec. Ann. Conv. Brit. Wood Preserv. Ass. 1965: 123–149.
—, 1969. Field trials on coal tar creosote and copper-chrome-arsenic preservatives. Holzforsch. 23: 185–192.
—, 1970. A possible method for the rapid evaluation of wood preservatives. Mitt. Dt. Ges. Holzforsch. 57/71: 18–22.
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Smith, D.N.R., Williams, A.I. The effect of composition on the effectiveness and fixation of copper-chrome-arsenic and copper-chrome preservatives part I: Effectiveness. Wood Science and Technology 7, 60–76 (1973). https://doi.org/10.1007/BF00353379
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DOI: https://doi.org/10.1007/BF00353379