污泥焚烧灰中磷在超临界CO2水热液中迁移转化OA北大核心CSTPCD

Based on the advantages of strong acidity,good mass transfer performance,easy separation and recovery,and regulation of supercritical CO2 hydrothermal solution,a new method is proposed for leaching phosphorus from incinerated sewage sludge ash(ISSA)with supercritical CO2 hydrothermal solution.The migration and transformation behavior of phosphorus in ISSA in supercritical CO2 hydrothermal solution is studied.The phosphorus form of ISSA and its mineral phase are investigated.The effects of pressure,reaction time and liquid-solid ratio on the migration and transformation of phosphorus in ISSA are studied.The effects of the enhanced mass transfer effect of supercritical CO2,the formation of carbonate during the reaction,and the increased reaction sites on the surface of ISSA on the migration and transformation rate of phosphorus in ISSA are analyzed.The results show that the phosphorus content of ISSA is high and the main form is non-apatite inorganic phosphorus(NAIP);the leaching rate of phosphorus from ISSA in supercritical CO2 hydrothermal solution can reach 67.5％with a pressure of 8.7 MPa,a reaction time of 60 min and a liquid-solid ratio of 20 mL/g.This method can replace the current acid leaching process in acid-base sequential extraction and improve the leaching rate of phosphorus while significantly reducing the leaching time and completely avoiding the leaching of heavy metals.This study can provide theoretical basis and data support for the development of green and efficient phosphorus recovery technology.