Phosphate-Containing Waste Ash Process for Producing Mineral Fertiliser

Keywords: Phosphate recycling, nutrient recovery, thermo-chemical process, sewage sludge, waste biomass, ash.

Availability of phosphate is critical for food security. Europe’s high dependency on imports from a limited number of supply sources has lead to numerous initiatives for closing the phosphate loop. In response, Outotec proposes to produce a renewable phosphate concentrate by combusting or gasifying relevant waste flows such as farmyard manure, sewage sludge and animal by-products.

State-of-the-art incinerators yield renewable energy and ash with a phosphate concentration comparable to rock phosphate concentrate. Depending on the feedstock, this ash may be processed to phosphate fertilisers by the conventional acid route or by alternative technology options known as Ash Dec ^® process and presented in this paper.

Ludwig Hermann, Outotec GmbH, Ludwig-Erhard-Strasse 21, D-61440 Oberursel, Germany.

11 pages, 4 figures, 1 table, 5 references.