REC «Mekhanobr-Tekhnika» (St. Petersburg, Russia):

Mikhaylova N. V., Chief Technologist, Candidate of Engineering Sciences, mikhailova_nv@npk-mt.spb.ru
Yasinskaya A. V., Senior Engineer, yasinskaya_av@npk-mt.spb.ru

Printed circuit boards represent a special problem in the disposal of modern electronic scrap since the laminated board-to-foil structure is very durable and its recycling is characterized by a number of specific features. The traditional approach to the recycling of printed circuit boards and general electronic scrap involves a combination of physical and mechanical methods aimed to recover the minimally contaminated mixed metal concentrate using hydro- and pyrometallurgy methods for the eventual recovery of pure metals. Mechanical liberation of particles from the board and copper foil structure requires material grinding to the grain size below 1.0 mm. This process, however, generates numerous slime particles and renders many separation methods inefficient. Moreover, product metal recovery in metallurgical processing is further complicated by the presence of stable alloys. It is established that, in order to intensify the liberation in the polymer matrix of printed circuit boards, it would be practical to use of advanced crushing and grinding machines in combination with energy-efficient heating by high and ultrahigh-frequency radiation. Dry methods are the most promising (in particular, electrical separation), supported by their high efficiency and environmental advantages. It is most relevant to recover metals from polymetallic concentrates using the traditional pyrometallurgical methods, as supplemented by hydrometallurgical and electrometallurgical processes. At present, the best development strategy is to improve these methods so as to increase their selectivity and environmental safety. Due to the possible future tightening of the environmental requirements for the methods applied, it is also urgent to develop alternative «green» metal recovery technologies.
The work was performed with the financial aid of the Ministry of Science and Higher Education under Grant Agreement No. 14.585.21.0007, RFMEFI 58516X0007.

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