NEX QC—CCA Wood Treatment

Scope

The measurement of chromated copper arsenate (CCA) treated wood and wood treatment solutions is demonstrated.

Background

Wood treatments are used to protect lumber from fungi, insects, UV damage and general wear. In recent years, the US EPA has asked for voluntary compliance to restrict the use of CCA due to concerns about chromium and arsenic leaching into soils. Lumber treated with CCA is used in a limited number of situations, such as in roofing shingles, permanent building foundations, and certain commercial applications. When treating wood, the proper balance of treatment solution must be monitored to ensure the highest quality while minimizing waste and excess cost due to treatment usage or product rejection. Chromium, copper and arsenic levels are monitored in solution prior to treatment, and then in the wood to ensure proper retention. A quick, simple, reliable means of analysis is required throughout the quality control process. XRF is an ideal tool for such analysis.

Model: NEX QC

Calibration – CCA in wood

An empirical calibration was built using a set of assayed wood standards.

Calibration plot CrO₃ in wood

Calibration plot CuO in wood

Calibration plot As₂O₅ in wood

Repeatability – CCA in wood

To demonstrate repeatability (precision), the low and high samples were chosen from the set of calibration standards. Each sample was measured in static position.

Calibration – CCA in solution

An empirical calibration was built using a set of assayed solution standards.

Calibration plot CrO₃ in solution

Calibration plot CuO in solution

Calibration plot As₂O₅ in solution

Repeatability – CCA in solution

To demonstrate repeatability (precision), the low and high samples were chosen from the set of calibration standards. Each sample was measured in static position.

Retention report

To measure a wood sample, enter the density of the wood. The measurement calculates concentrations of Cr₂O₃, CuO and As₂O₅ and also outputs balance and retention values.

Conclusion

The typical results detailed here show exceptional performance for the fast and simple measurement of CCA in wood and solution. The Rigaku NEX QC is an excellent tool along the QC process in producing treated lumber, giving the production process an affordable means of optimizing quality while minimizing costs and helping to minimize product rejection and waste.