Resource recovery from municipal solid waste ash

Ashes from municipal solid waste incineration (MSWI) may be a cumbersome waste to handle. Some ash fractions contain organic pollutants, such as dioxins, as well as heavy metals. Additionally, some of the metals have a high value and are considered as critical to the industry. Recovery of e.g. copper and zinc from MSWI ashes will not only recover valuable metals that would otherwise be land filled, but also reduce the toxicity of the ash and thereby make it less cumbersome to handle. Such processes are presently being investigated by the Industrial Materials Recycling group at Chalmers University of Technology. The processes are primarily based on acid leaching of the ash combined with selective solvent extraction. The work on recovery process development is supported by investigations of the chemical speciation of metals, i.e. identification of metal compounds, in ashes by, e.g. synchrotron based X-ray absorption spectroscopy (XAS). The presentation will give an introduction to the validation of an optimized leaching process for MSWI and speciation results for Cu and Zn, as well as discuss the promising results that have been obtained using the suggested recovery processes for these metals