Chemical extraction of phosphorus (P) from incinerated sewage sludge ash (ISSA) is adversely influenced by co-dissolution of metals and metalloids. This study investigated P recovery and leaching of Zn, Cu, Pb, As and Ni from ISSA using inorganic acids (sulphuric acid and nitric acid), organic acids (oxalic acid and citric acid), and chelating agents (ethylenediaminetetraacetic acid (EDTA) and ethylene diamine tetramethylene phosphonate (EDTMP)). The aim of this study was to optimize a leaching process to recover P-leachate with high purity for P fertilizer production. The results show that both organic and inorganic acids extract P-containing phases but organic acids leach more trace elements, particularly Cu, Zn, Pb and As. Sulphuric acid was the most efficient for P recovery and achieved 94% of total extraction under the optimal conditions, which were 2-h reaction with 0.2 mol/L H₂SO₄ at a liquid-to-solid ratio of 20:1. EDTA extracted only 20% of the available P, but the leachates were contaminated with high levels of trace elements under optimum conditions (3-h reaction with EDTA at 0.02 mol/L, pH 2, and liquid-to-solid ratio of 20:1). Therefore, EDTA was considered an appropriate pre-treatment agent for reducing the total metal/metalloid content in ISSA, which produced negligible changes in the structure of ISSA and reduced contamination during subsequent P extraction using sulphuric acid.

从焚化的污水污泥灰（ISSA）中化学提取磷（P）受金属和准金属共溶解的不利影响。本研究使用无机酸（硫酸和硝酸），有机酸（草酸和柠檬酸）和螯合剂（乙二胺四乙酸（EDTA）和乙二胺四亚甲基膦酸酯（EDTMP））。这项研究的目的是优化浸出工艺，以回收高纯度的磷浸出液，以生产磷肥。结果表明，有机酸和无机酸均可萃取含P相，而有机酸则可浸出更多的痕量元素，特别是Cu，Zn，Pb和As。硫酸是磷回收的最有效方法，在最佳条件下，可达到总提取量的94％，₂ SO ₄的液固比为20：1。EDTA仅提取了20％的有效磷，但在最佳条件下（与0.02 mol / L的EDTA，pH为2的EDTA进行3小时反应，液固比为20： 1）。因此，EDTA被认为是用于减少ISSA中金属/准金属总含量的合适预处理剂，该预处理剂可在ISSA结构中产生微不足道的变化，并在随后的使用硫酸萃取P的过程中减少污染。