Integrated approach for economic PV waste recycling

Abstract

Cadmium, selenium, tellurium, gallium, molybdenum, indium and silicon are some of the major elements used in these photo voltaic cells. We know about the future limits in the availability of these elements. So recycling is required as the most advisable end-of-life strategy and to save the raw materials from production wastes now. On the other hand statutory prescriptions, as e.g. the German "Kreislaufivirtschaftsgesetz" (law encouraging closed-loop economy) are asking for a maximum quota of recycling - and a minimum use of resources (e.g. energy, raw materials). We report a method for extracting and reclaiming metals from scrap of CIS, CIGS or CdTe systems and associated photovoltaic manufacturing waste. We also discuss the application of our method to new PV systems, such as substrates other than glass (aluminum or stainless steel foil sheets), and other semiconductors such as GaAs. It is well known that the rare metals combined typically only represent 1 % of the mass of a photovoltaic panel, their value is significant. So for example on crystalline silicon silver is found. The current value for silver (6th of June 2011) was 1171 USD per kilogram Our procedure is another building block for a comprehensive recycling, because it saves chemicals and there is less waste water generated. We understand that loss of metals, particularly silver and aluminium for our case is another impact of lack of good recycling procedures of photo voltaic panels. We can demetalhe coated and patterned silicon wafers, as well as broken solar cells or production scrap, by using a very simple method to minimize waste and to simultaneously produce marketable products. For thin film photo voltaic waste we finished piloting our new universal recycling procedure. We obtained a very high level quality of glass, usable demonstrably for float glass production.