The present invention relates to a method for concentrating or reclaiming metals from waste that contains metal, which is used especially for recycling catalysts containing metal, especially silver, or other waste that contains metal, especially silver and/or lead and/or tin, such as silicon wafers printed with silver, flexibly printed circuits based on nanosilver ink, and/or contacts consisting of silver nanowires and/or solders.
Silver is found among other things as a main component of most contacts on silicon wafers of photovoltaic modules or as an effective substance on catalysts which are used in the chemical industry for the production of ethylene oxide or formaldehyde. Further metals that occur in waste are lead and/or tin for example. Silver and other metals such as lead and/or tin are used for lesser-known applications such as bearings for motors, batteries, RFID tags, solders and inks for circuit boards. Hydrometallurgical recycling methods are used both for silver catalysts and also for silver contacts on silicon wafers, which recycling methods are based on nitric acid and cannot be operated without a complex and expensive gas purification system due to the development of nitrous gases. On the other hand, pyrometallurgical methods are known, which reach their economic limits due to rising energy prices however, which is also due to the decreasing silver concentration in the material is to be processed, which is the result of successful savings in silver material in production. In view of stiff competition and rising energy prices, there is a need for an improved recycling method which can be applied as flexibly as possible and which offers improved profitability.