Understanding phosphorus phases in sewage sludge ashes: A wet-process investigation coupled with automated mineralogy analysis

Two different P-recovery routines have been investigated. Target phase groups (phosphates) have successfully been digested. Understanding phosphate setup in terms of composition, particle sizes and phase association is vital for an efficient P-extraction from SSA. P-recovery is not straightforward, but rather a series of steps in order to address different P-phase types. SSA is a complex secondary resource, which needs to be understood prior to P-extraction.