Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

Screening for Ceramic and Leaded Contaminants in Glass Recycling Streams Using Handheld X-Ray Fluorescence (HHXRF) Analyzers

440 views

Published on

Screening of Ceramic and Leaded Contaminants in Glass Streams via Handheld X-Ray Fluorescence (HHXRF) Analyzers

Dillon McDowell
and Alex Thurston

Abstract

Material recovery facilities (MRFs) typically use magnetic and optical sorting systems to separate glass cullet from recycled glass. However, these systems are not effective at screening glass ceramic and leaded constituents from cullet streams. These
contaminants lower the value of glass cullet to glass manufacturers, as they represent manufacturing and safety concerns. Handheld X-ray fluorescence (HHXRF) analyzers are widely used in various recycling and manufacturing settings to quickly provide chemical composition on a variety of elements, even to the range of 1–10 ppm. We compare HHXRF analysis of prepared glass samples to laboratory assayed glass standards used by MRFs and glass manufacturers. Our results show that HHXRF can detect even small quantities (<100 ppm) of ceramic elements in glass and glass cullet streams in situ. Our results also show HHXRF detection of leaded contaminants and coloring
streams. We also demonstrate that the same technique can be applied to in-line monitoring systems to analyze material streams for the same constituents.

Published in: Technology
  • DOWNLOAD FULL BOOKS, INTO AVAILABLE FORMAT ......................................................................................................................... ......................................................................................................................... 1.DOWNLOAD FULL. PDF EBOOK here { https://tinyurl.com/y8nn3gmc } ......................................................................................................................... 1.DOWNLOAD FULL. EPUB Ebook here { https://tinyurl.com/y8nn3gmc } ......................................................................................................................... 1.DOWNLOAD FULL. doc Ebook here { https://tinyurl.com/y8nn3gmc } ......................................................................................................................... 1.DOWNLOAD FULL. PDF EBOOK here { https://tinyurl.com/y8nn3gmc } ......................................................................................................................... 1.DOWNLOAD FULL. EPUB Ebook here { https://tinyurl.com/y8nn3gmc } ......................................................................................................................... 1.DOWNLOAD FULL. doc Ebook here { https://tinyurl.com/y8nn3gmc } ......................................................................................................................... ......................................................................................................................... ......................................................................................................................... .............. Browse by Genre Available eBooks ......................................................................................................................... Art, Biography, Business, Chick Lit, Children's, Christian, Classics, Comics, Contemporary, Cookbooks, Crime, Ebooks, Fantasy, Fiction, Graphic Novels, Historical Fiction, History, Horror, Humor And Comedy, Manga, Memoir, Music, Mystery, Non Fiction, Paranormal, Philosophy, Poetry, Psychology, Religion, Romance, Science, Science Fiction, Self Help, Suspense, Spirituality, Sports, Thriller, Travel, Young Adult,
       Reply 
    Are you sure you want to  Yes  No
    Your message goes here

Screening for Ceramic and Leaded Contaminants in Glass Recycling Streams Using Handheld X-Ray Fluorescence (HHXRF) Analyzers

  1. 1. Screening for Ceramic and Leaded Contaminants in Glass Recycling Streams Using Handheld X-Ray Fluorescence (HHXRF) Analyzers Dillon McDowell and Alex Thurston ECNDT 2018
  2. 2. Overview ¡ The glass recycling industry and recycling process – Dealing with contamination – Ceramic glass issues ¡ Brief introduction to XRF ¡ Experiment overview – CRM analysis – Glass cullet analysis ¡ In-line system overview
  3. 3. Glass Recycling ¡ The majority of recycling concerns glass containers (bottles, jars, etc.) – Primarily, soda glass ¡ Glass is recovered, sorted, and cleaned to be turned into furnace-ready cullet ¡ Soda glass can be completely recycled without any loss of quality ¡ On average, newly produced glass containers consist of ~33% recycled content ¡ Material recovery facilities (MRFs) may process as much as 20+ tons of cullet per hour ¡ Material quality is key to hitting efficiency targets and reducing process cost Solution Recycling, 11-1-2017, <http://www.solutionrecycle.org/why-recycle/>
  4. 4. Contamination and Ceramic Glass ¡ A variety of techniques that handle different types of contamination – Magnetic sorting (metallic contamination) – Vacuum suction and vibrating screens (light materials — paper, plastic, etc.) – Visual/infrared sorting (opaque materials — stones, gravel, etc.) ¡ Some materials are difficult to separate through automated techniques – Other glass types (borosilicate, leaded crystal) – Ceramic glasses ¡ Ceramic glasses are increasingly common in a variety of products – Cookware – Manufactured goods – Electronics (smartphone screens) ¡ Ceramic glass has many of the same physical properties as recyclable glass (weight, density, appearance, etc.) ¡ However, it also has… – Different chemistry (unique ceramic elements) – A higher melting point (doesn’t fully melt in a furnace)
  5. 5. Ceramic Glass Issues ¡ Increases the downtime of furnaces and/or may irreparably damage them ¡ Large risk to cutting systems – Water-cooled scissors may be damaged attempting to cut into ceramic glass ¡ The final product is rendered defective and unusable by impurities – Glass products with ceramic may crack or shatter (sometimes explosively) G. Bonifazi, “Imaging spectroscopy based strategies for ceramic glass contaminants removal in glass recycling”, Waste Management, vol. 26, pp. 627-639, June, 2005. Monofrax services, 1-8-2017, <http://monofrax.com/services/>
  6. 6. X-ray Fluorescence Spectroscopy ¡ First demonstrated in 1912 ¡ First handheld systems appeared in the late 1990s ¡ Exciting a sample with X-rays generates a fluorescence response unique to the elements in the sample ¡ Measuring that response provides compositional information ¡ Used for various commercial applications – Metals/alloys – Soil/geologic samples – Consumer products
  7. 7. Instrumentation ¡ Olympus Vanta™ handheld XRF analyzer – Model: VCR (rhodium (Rh) anode, silicon drift detector (SDD) system) – 8 mm excitation point (down to 3 mm with collimation) ¡ Used “Soil” method as basis for testing – Compton normalization technique – Typically used to test SiO2-based samples – Offers various excitation conditions (beams) for a variety of elements ¡ Testing performed using the Vanta portable Work Station – Enables consistent sample presentation – Closed-beam system while in the Work Station
  8. 8. Experiment ¡ Gauge the effectiveness of HHXRF in identifying various elements – Ceramic identifiers: titanium (Ti), zirconium (Zr), strontium (Sr), and zinc (Zn) – Additional identifiers: iron (Fe), copper (Cu), and lead (Pb) ¡ Stage 1: Certified material – Test certified glass samples (NIST 610, NIST 612) – Establish a baseline calibration ¡ Stage 2: Test recovered ceramic glass samples – Use the calibration from the previous stage – Sample composition also verified through lab testing (ICP) – Focus on effects of sample size and analysis time
  9. 9. Stage 1 — Certified Materials ¡ Samples chosen for variety ¡ Initial readings used to established calibration factors; the samples were retested using corrections ¡ Each sample was tested for 30 seconds in beams 1 and 2 (60 seconds total per test) ¡ Values shown are the averages of 10 repeat tests ¡ Samples are quite thin (~3 mm), so multiples were used to minimize thickness biasing for initial calibration ¡ Overall, very consistent response from HHXRF NIST 610 Element Assay (ppm) +/- 2σ XRF (ppm) +/- 2σ Ti* 437 30 496.8 84.8 Zr[8] 440 2 445.4 16 Zn* 433 4 428 12 Pb 426 1 427 12 Cu 415 29 443 10 Fe 458 9 447.4 18 Sr 515 0.5 437.6 15.2 NIST 612 Element Assay (ppm) +/- 2σ XRF (ppm) +/- 2σ Ti* 50.1 0.8 122.75 58 Zr[8] 36 1.3 46.8 4 Zn[9] 40 5 36.8 4 Pb 38.6 0.2 41.6 4 Cu* 35 3.3 36 2 Fe 51 2 43.6 6 Sr 78.4 0.2 83.2 4
  10. 10. Stage 2 — Recovered Glass Ceramic Samples ¡ Samples were provided from a major producer/recycler of glass and glass ceramic products ¡ Samples were independently assayed by supplier using ICP-MS ¡ Samples consisted of: – #1: Heavy ceramic glass (high Zr, Sr, and Ti) – #2: Leaded crystal glass (high Pb) – #3: Light ceramic glass (high Sr) ¡ In addition, a certified pure quartz (SiO2) sample was tested to ensure that no false positives were reported by the analyzer ¡ Samples were tested using only 1 beam at various test times to test the effect of long vs. short analysis for sorting purposes
  11. 11. Sample 1 — Heavy Ceramic Glass Sample 1 — Glass Ceramic (High Zr, Sr, Ti) XRF Concentrations Element ICP Result 30 Sec +/- 2σ 10 Sec +/- 2σ 3 Sec +/- 2σ Ti 2705 71041.6 1884.4 71647.4 3297.2 71326.8 6047.6 Zr 11105 24020 1656 23403.8 2754.4 23627 5140.4 Zn 3856 6890.2 158 6910.2 275.6 6993.2 512.4 Pb - 208.8 27.6 208 48 221.8 89.2 Cu - 188 28.4 198 50 192.6 92.4 Fe 314 - - - - - - Sr 77034 >10% 9415.2 >10% 15659.6 >10% 29120.4
  12. 12. Sample 2 — Leaded Crystal Sample 2 — Leaded Crystal Glass (High Pb) XRF Concentrations Element ICP Result 30 Sec +/- 2σ 10 Sec +/- 2σ 3 Sec +/- 2σ Ti 118 - - - - - - Zr 222 - - - - - - Zn - 94.5 45.5 125 80 - - Pb 205069 >10% 19880.4 >10% 35518 >10% 68998.4 Cu - - - - - - - Fe 287 411 77.6 393 135.2 541 260 Sr 161 - - - - - -
  13. 13. Sample 3 — Light Ceramic Glass Sample 3—Light Glass Ceramic (Low Sr) XRF Concentrations Element ICP Result 30 Sec +/- 2σ 10 Sec +/- 2σ 3 Sec +/- 2σ Ti - - - - - - - Zr - 155.4 10 154.6 17.6 156.6 32.4 Zn - 46.4 4 49.4 6 45.4 11.2 Pb - - - - - - - Cu - - - - - - - Fe 70 23.8 6 21.4 10 31.5 20 Sr 1099 1695.8 57.2 1698.2 98.8 1712.6 184
  14. 14. Small Fragment Testing ¡ Broke off a small fragment of each sample (~1 mm diameter) and repeated stage 2 ¡ Goal was to simulate the smallest fragment that may be present in a cullet stream – Can also mimic possible inclusions that may appear in final container products ¡ Results largely qualitative but demonstrate detection capabilities of ceramic elements
  15. 15. In-Line XRF Systems ¡ The technique shown here has already been scaled to an in-line system: the X-STREAM™ XRF analyzer ¡ Used currently for both scrap and glass sorting ¡ Uses multiple source/detector arrays instead of a single source/detector (like in HHXRF) ¡ Goal is qualitative analysis: – Identify the presence/absence of ceramic elements – Remove ceramics from a cullet stream using an air blast ¡ Can process as much as 28 tons/hour
  16. 16. Summary ¡ The nature of ceramic contamination is localized fragments with a high concentration of ceramic elements (Zr, Zn, Sr, and Ba) ¡ HHXRF can effectively screen ceramic elements – Accurate quantization, while achievable, requires more sample preparation and testing time – Sorting/screening can be done effectively through qualitative testing using XRF ¡ HHXRF can identify even small fragments of ceramic material – Maintain consistent detection of common ceramic tracers ¡ Technique can be scaled to in-line systems – Qualitative sorting based on fluorescent signal from ceramic elements
  17. 17. Olympus is a registered trademark, and Vanta and X-STREAM are trademarks of Olympus Corporation.

×