Aluminum Remelting using Directly Solar-Heated Rotary Kilns

Abstract

To check the feasibility of solar thermal remelting of aluminum scrap a directly absorbing rotary kiln receiver-reactor was constructed for experimentation in a mini-plant scale in the DLR high flux solar furnace. Conventionally the high energy demand for heating rotary kilns is met by the combustion of fossil fuels. This procedure generates a big exhaust gas volume which is contaminated by volatiles if the technology is applied to treat waste materials. Application of concentrated solar radiation to provide the high temperature heat enables to substitute the fossil fuel. Thus smaller off-gas streams are generated and lower investment and O&M cost are expected for the off-gas purification. In this paper market and environmental issues are discussed and pre-designs both for solar pilot and industrial scale applications are presented.