Solar aluminum recycling in a directly heated rotary kiln

Abstract

South Africa currently is experiencing an electricity constraint due to economic growth and lack of investment in generation capacity, resulting in power blackouts in 2008. With increased electricity prices, the economic sustainability of energy intensive industries is threatened. The aluminum smelting industry is a significant consumer of electricity. The consumption of electricity and the amount of emissions in the process of aluminum recycling can be reduced by the application of solar thermal technologies. A process concept for the solar thermal recycling of aluminum waste material was developed. The process takes place in a rotary kiln heated by concentrated solar radiation. A directly absorbing rotary kiln receiver-reactor was tested on a lab-scale in the DLR high flux solar furnace. In this paper the design of the rotary kiln in the solar furnace is presented. A concept for a pilot-scale rotary kiln operated on a solar tower is shown.