사용 후 태양광 셀로부터 Ultrasonic wave 활용 실리콘 및 유가금속 회수

Abstract

Due to the recent rapid industrial development, renewable energy is attracting attention due to the issue of resource depletion and environmental pollution. As interest in new and renewable energy increases, the use of representative eco-friendly energy solar energy is also increasing. As the usage of solar power increases, the amount of waste solar modules with a life expectancy of about 20 to 30 years is expected to increase. According to a report to the IEA, about 76 million tons of waste solar modules are expected to be generated by 2050. The solar module is composed of Si, Ag, Cu, Pb, and Al, of which Pb is expected to cause a lot of environmental pollution when the solar module is buried or incinerated after using it as a harmful component. In this regard, Europe has made it mandatory to collect and recycle waste solar panels since 2012, and in Korea, the EPR system has been implemented since 2023, designating solar modules as essential recycling items, and the need for solar module recycling technology is increasing. Particularly, although Pb included in solar cells among solar modules has a great influence on environmental pollution, technology for recovering solar cells is still insufficient. Conventionally, a stirring process based on acid leaching is used as a process for recycling solar cells. The stirring process makes it difficult to remove impurities from the surface of a photovoltaic cell, so it is judged that a method to remove impurities more finely is needed. This research recovered silicon from solar cells after use using an acid solution and ultrasonic cavitation effect and recovered valuable metals through precipitation, pH control, and reduction reaction from leachate after recovering silicon. Silicon recovery process was experimented with acid solution concentration, reaction temperature, reaction time, and ultrasonic strength as variables, and finally, the purity of silicon recovered was 99.58 % and the recovery rate was 99.94 %, and the purity of silver recovered was 99.72 % and 92.3 %. In addition, Cu and Pb were recovered together and the integrated purity was detected as 96.09 %, and the recovery rate was calculated as Cu 94.63 % and Pb 91.04 %.