Phosphate rock is the primary raw material source for phosphate production, but unfortunately is mineable phosphate rock a limited non-renewable resource. Large amounts of phosphorus end up in manures and in urban waste, mainly in sewage sludge and slaughterhouse waste. Today are EU countries re-circulating phosphorus by distributing 48% of the sludge back to farmland, as can be seen in figure 1. The positive aspect is that phosphorus is re-circulated, but it’s not problem free. Sewage sludge can still contain viruses, heavy metals, and other substances that could be harmful to human health. Today 27% of the phosphorus is being transported to land fills or „other“, which are routes that rarely recover any phosphorus. 25% of the sludge is incinerated and the ash is mainly transported to land fills. The Ash2Phos process can in a near future transform the sludge ash to a raw material for phosphorus extraction and thereby be a part of a circular solution for phosphorus management.
Ash from mono-incinerated sewage sludge has a high concentration of phosphorus (7-10%), iron, and aluminium (5-10%), but also contains unwanted heavy metals such as cadmium. The high content of metal creates an obstacle for possible applications for the phosphate rich ash.
In the Ash2Phos process, sludge ash is treated in a wet chemical process for the recovery of phosphorus, aluminium, and iron as clean commercial products, and at the same time are the unwanted heavy metals separated for disposal.
The Ash2Phos process comes in two designs, the MAP or DCP. The commercial products from the MAP process are:
The commercial products from the DCP process are:
A new factory is planned based on the patented Ash2phos technology.