Sorting Technologies for CCA Treated Wood
Objective To design and implement an automated system to effectively sort CCA treated wood from other wood types at facilities such as C&D facilities
Automated System Designed using x-ray fluorescence technology or Designed using laser induced breakdown spectroscopy technology
Motivation CCA treated wood => ~ 6 % of all wood waste at C&D facilities Amounts of CCA treated wood at C&D facilities increasing At 6 % level, cannot be used as mulch or burned to generate fuel
Sorting Studies Chemical stain method X-ray fluorescence (XRF) laboratory results field results from pilot studies X-ray fluorescence (XRF) Laser Induced Breakdown Spectroscopy (LIBS)
Training and monitoring Automated System X-ray fluorescence Laser induced breakdown spectroscopy Training and monitoring chemical stains
Chemical Stains Chrome Azurol S PAN Indicator Rubeanic Acid
Performance on whole wood 0.25 pcf 0.6 pcf 2.5 pcf
Current Practical Applications Sorting Small Quantities of Treated from Untreated Wood Screening Fuel Quality Training Tool
Wood Encountered at C&D Facilities
Design for Shelter
Cost Estimate - Shelter Trident $9,600 - $11,500
Update on Building Tasks & Timeline Current Contacts
Timeline Get Building Contractor Under Contract 1 Wk 2 Wk 1 Wk 3 D 4-6 Wks Building Contractor Develops Design Drawing Team Reviews Design ? Wks Building Contractor Seals Building Design Apply for Permit Building Fabrication Concrete Slab Erect Building
Building Contractors Contacted Trident -- Met with on June 7 Estimate: $9,600 - $11,500 Anderson and Ellis Construction Job too small Bob Howard Construction Contacted John F. Swift, Inc.
Concrete Contractors Contacted Fred Derr Concrete Prestige Concrete John F. Swift
Initial Detector Mounting Design
Conveyor Design #1 Movable holding arm Wood Piece Table
Top View Wood Piece Table Movable holding arm 3/4 “ to 2”
Cross-Sectional View Movable holding arm Wood Piece Conveyor Surface X-rays Detector mounting Movable holding arm Wood Piece Conveyor Surface
Cost Estimates – Conveyor American Conveyor, Miami $11,038 Powerscreen, Lakeland $24,500
Conveyor Design #2 Holding arm Wood Table X-ray
Top View Wood Table
XRF Based on emission of x-rays Characteristic x-ray emitted by the element is read by the instrument
Model 400 No special training required Analyzer User friendly Printout or output easy to read and understand Analyzer Head
XRF Instruments Low maintenance, few consumables, easy cleaning No repetitive calibration necessary (6 mo. to 2 yrs.) Life span of 10 years
XRF Instrument Cost range from $20,000 - $100,000 Detector replacement cost of $1,800 - $2,400 (life span of 5 years) Licensing may be required Sensor protected by a small beryllium window ($100 for replacement)
Results of XRF Studies Arsenic is the best indicator metal, although all three metals can be analyzed for Optimum count time of 2 seconds, would be even less for on-line analysis 1,800 ft/hr for detection of 1-ft board (2 s) 3,600 ft/hr for detection of 1-ft board (1 s) Detection of CCA for Model 400 is possible at 1 inch distance with a plastic shield
X-Ray Technology Analysis Time < 2 seconds Best Metal for Analysis, As Largest Separation Between Sample and Detector is 1 inch
XRF - Collaboration ASOMA Inc (1 inch diameter face & strip model) Jordan Valley (Hand-held unit, 3 in x 3 in face)
Laser Technology Analysis Time < 1 second Best Metal for Analysis, Cr Tolerance, 12 inches
On-line Sorting Technologies
Laser-induced Breakdown Spectroscopy (LIBS)
Sample Configuration of LIBS Probe
Experiments with LIBS Sample 1: 0.25% CCA Sample 2: 2.5% CCA Sample 3: Weathered CCA Sample 4: Weathered Utility Pole Sample 5: New untreated Sample 6: Weathered untreated
LIBS Spectrum of CCA-treated Wood
LIBS-based Sorting
Questions?