Copper stabilization in ACQ-D treated wood: retention, temperature and species effects

The rates of stabilization or fixation of copper in ACQ-treated wood were compared for different post treatment conditioning temperatures (22 degrees C and 50 degrees C), solution concentrations (0.4-2.3%) and wood species. In some species, sapwood/heartwood differences were evaluated. The rate and extent of copper stabilization were estimated from changes in concentration of expressed solution at different times after treatment. The quality of the stabilization reaction was evaluated based on leaching performance of the wood after conditioning. Copper stabilized much faster at lower ACQ retentions and when conditioned at 50 degrees C compared to high retentions and stabilization at 22 degrees C. High retention treatments held without drying at 22 degrees C could require five weeks or more for the copper to stabilize in the wood. Generally species effects were minor for the species evaluated, except for Douglas-fir in which copper reacted more quickly than in other species.