Sludge formation in timber treatment with CCA preservatives. Origin and elimination

IRG/WP 3276

A Pizzi, W E Conradie, A Jansen

The exact distributions between lignin and holocellulose and retentions on wood of copper, chromium and arsenic as a function of various sets of conditions in a factorial experiment in which combinations of three temperatures of treatment, three CCA solution concentrations, four pH's of the initial CCA solution and two timber species, namely Pinus radiata and Eucalyptus grandis, are reported. Temperature and concentration appear to have an equally important effect on the preservative chemicals retentions and distribution in timber. pH, has also an effect but somewhat less marked than temperature and concentration, with the exception of the formation of sludges. Multivariable regression equations describing the amounts of Cu, Cr and As fixed on lignin and holocellulose for both pine and eucalyptus are also presented. The timber species treated also appears to have an important influence on the amounts of chemicals fixed and their distribution. Eucalyptus appears to be much less tolerant than pine to extremes of treating conditions. The influence of treating time under the most common treating conditions is also briefly discussed.


Keywords: SLUDGE FORMATION; TEMPERATURE; TREATMENT TIME; CONCENTRATION; pH; FIXATION; LIGNIN; HOLOCELLULOSE; DISTRIBUTION; DEPLETION; PINUS RADIATA; EUCALYPTUS GRANDIS

Conference: 84-05-28...06-01 Ronneby Brunn, Sweden


Download document (742 kb)
free for the members of IRG. Available if purchased.

Purchase this document