Chemie Ingenieur Technik, Vol.92, No.4, 395-404, 2020
Recycling of Phosphorus by Co-processing Sewage Sludge Ash in Phosphoric Acid Production
The approach of recycling phosphorus from sewage sludge ash by co-processing in conventional phosphoric acid production was investigated. Lab-scale experiments with real ashes and simulated industrial conditions showed that mixing of ash and phosphate rock prior to processing resulted in several disadvantages. As a solution the novel concept of return acid extraction is presented, which overcomes some of the identified shortcomings of direct mixing.