Metal recovery by ion-exchange resins from municipal incinerated bottom ash

Abstract

Municipal waste incineration plants produce large amounts of bottom ashes, being higher year over year. In order to follow the circular economy scheme proposed by the EU, a recovery step is required to valorise the high added-value elements present in these ashes, such as copper (Cu), zinc (Zn) or even gold (Au). For this reason, the aim of this work is to recover these metal ions by means of ion-exchange resins at different pHs. Thus, different acid and base solutions were used to lixiviate bottom ashes from a municipal waste incineration plant in Barcelona (Spain) and two different ionexchange resins (Purolite S940 and AuRIX 100) were tested to obtain the maximum Cu, Zn and Au recovery. Results indicate that it was possible to obtain Cu and Zn extraction percentages around 99 % at pH 5, whereas Au was extracted about 62.5 % at pH 9, after 24 h.