Determination of organohalogen compounds and organic carbon as sum parameter in electronic waste

Abstract

Metal-containing devices in electronic waste such as printed circuit boards can be recycled for the recovery of noble metals such as gold, silver, platinum or palladium using a thermal process. In this process the plastics are burned and more than 90% of the noble metals are transfered into a copper matrix. Finally the pure metals are refined by electrolysis. Because of the content of brominated flame retardants and chlorinated polymers in the plastics, formation of halogenated dibenzo-p-dioxins and dibenzofurans cannot be excluded. The use of modern filter techniques minimizes the emission of these substances. As a precaution the electronic waste is controlled for its content of organohalogen compounds and organic carbon. This work describes an analytical method for the determination of the sum of organohalogen compounds and organic carbon in electronic waste. The investigation of different charges of electronic waste in the fraction of particle size<0.1 mm show concentrations for the sum of organobromine compounds in the range of 0.2–4.8% originating from brominated flame retardants in the plastics. The total content of organochlorine compounds is <0.01–0.13%, showing that chlorinated plastics were efficiently removed before the thermal process. The content of organic carbon is between 13 and 27%. Because of the portion of fine particle size in relation to the total sample amount, the results have to be multiplied by a factor of about 0.25 to 0.3.