Determination of 10 Metal Elements in Waste Printed Circuit Boards by Wavelength Dispersive X-Ray Fluorescence Spectrometry with Powder Tablet

The methods for determination of metal elements in waste printed circuit boards (WPCBs) required sample digestion, which was complex and time-consuming, while X-ray fluorescence spectrometry didn’t require sample digestion, but its quantification was inaccurate due to the lack of similar matrix standard samples. Based on this, geological standard materials with similar elemental composition to WPCBs were used as the substrate, and calibration curves were drawn with a series of calibration samples which prepared by adding epoxy resin and copper powder at different ratios into the above substrate. The study mentioned by the title was proposed. WPCBs was ground, passed through a 200 mesh (0.074 mm) sieve, and dried at 105 ℃. 5 g of the above sample was taken into a stainless steel mold, and boric acid was added to border. A circular discs with a diameter of 40 mm was made by a tablet machine with the pressure of 200 kPa and holding time of 20 s, and 10 metal elements, including silver, barium, chromium, copper, iron, manganese, nickel, lead, silicon, and titanium, were determined by wavelength dispersive X-ray fluorescence spectrometry (WD-XRF). As shown by the results, linear relationships between values of the mass fraction and the response intensity of the elements were kept in definite ranges. This method was used to analyze other calibration samples, and the absolute values of the relative error of the determined values were less than 20%. This method was used to analyze two actual WPCBs samples, the determination results of silicon were basically consistent with those by potassium fluorosilicate volumetric method, and the determination results of other elements were consistent with those by inductively coupled plasma atomic emission spectrometry (ICP-AES).