X‐ray fluorescence analysis of Co, Ni, Pd, Ag, and Au in the scrapped printed‐circuit‐board ash

Abstract

A method for the quantitative analysis of Co, Ni, Pd, Ag, and Au in the scrapped printed-circuit-board ash by X-ray fluorescence (XRF) spectrometry using loose powder was developed. The printed-circuit-board samples were converted to ash pyrolytically in porcelain crucibles by sequential heating using a gas burner and electric furnace, and then were ground with a ball mill. The calibrating standards were prepared by adding the appropriate amounts of NiO powder and aqueous standard solutions containing Co, Pd, Ag, and Au to the base mixtures of Al 2 O 3 (5.0 mass%), SiO 2 (49 mass%), CaCO 3 (11 mass%), Fe 2 O 3 (3.3 mass%), and CuO (30 mass%) as a matrix. Then, 10 g of the resulting mixtures were dried and homogenized for 90 min with a V-type mixing machine. Specimens for XRF analysis were prepared from the so-called loosepowder method in which powder samples were compacted into a hole (12.0-mm diameter and 5.0-mm height) in an acrylic plate and covered with a 6-mm thickness of polypropylene film. Matrix effects were corrected using the intensity value of Compton scattering for PdKa, AgKa, and AuLb 2 , and that of background scattering at 35.8 (2θ) for CoKa and NiKa. The detection limits corresponding to three times the standard deviation of the blank intensity were 2.5-45 mg g À1 . The proposed method was validated against the pressed-powder-pellet method by comparing the calibration curves. Moreover, the concentrations of Co, Ni, Pd, and Ag determined using the proposed XRF method were approximately the same as those resulting from an atomic-absorption-spectrometric analysis.

Development of undersized (12.5 mm diameter) low‐dilution glass beads for X‐ray fluorescence determination of 34 components in 200 mg of igneous rock for applications with geochemical and archeological silicic samples

“…The synthetic standards are useful for the measurement of various samples because the calibration curves can be designed by composition ranges, plot numbers, and the intervals appropriate to specific samples, e.g. rock, pottery, fly ash, sewage, and printed‐circuit‐board ash . In the present study, we designed these three factors as follows.…”

Preparation of cadmium-containing brown rice grains as calibration standards for X-ray fluorescence analysis of cadmium in rice grains

“…The difference in the slopes of the calibration curves between the brown rice grain and the white rice grain may be attributed to the absorption effects, which were caused by the differences in elemental compositions and/or bulk densities between brown and white rice grains. To correct the absorption effects, scattered X‐ray intensities were used as internal standards because their intensities are inversely proportional to the mass absorption coefficients of samples . The intensities of Cd Kα were corrected with the intensities of the Rh Kα‐Compton scatter line.…”

Dismantling of Printed Circuit Boards Enabling Electronic Components Sorting and Their Subsequent Treatment Open Improved Elemental Sustainability Opportunities

“…Another technique that is complementary to LIBS is X-ray fluorescence (XRF). It is expected that XRF could be powerful, although the existing studies use XRF to characterize PCBs but not specifically for sorting ECs [119][120][121][122][123][124][125][126]. A single measurement can yield information about the presence of more than 40 elements in the periodic table.…”