Skip to main content

Recovery of high purity phosphate from sewage sludge ash

Recovery of high purity phosphate from sewage sludge ash

Phosphate rock is within the 20 critical raw materials of high economic importance and supply risk defined by the European Commission. Sewage sludge ash (SSA) often contains 5-10% phosphate, however, recovery phosphate from the SSA is a challenging task due to its extremely complex nature. A reactive crystallization process was designed and optimized for separating high purity phosphorus (P) in the form of CaClH2PO4·H2O crystals from SSA. The experimental results showed that high purity crystals (Al and Fe impurities ~0.021 wt%) can be produced from the SSA with a high P-yield (≥ 61.2 %, based on the P in SSA).

                                 

 

 

 

 Sewage sludge ash (SSA) 

 

 

 

 

CaClH2PO4·H2O crystals recovered from the SSA

Recent publications:

Y. Liu and H. Qu, Design and optimization of a reactive crystallization process for high purity phosphorus recovery from sewage sludge ash, Journal of Environmental Chemical Engineering, Vol. 4 (2016), 2155-2162.

Y. Liu, H. Qu and B.-G. Rong, Conceptual reactive crystallization process design for separation and purification of phosphorus from complex sludge ash, Computer-Aided Chemical Engineering, Vol. 38 (2016), 667-672.

 For more information please contact Associate Professor Haiyan Qu