摘要
Phosphogypsum is a solid waste sourced from the wet-process phosphoric acid industry,which causes severe environmental damages.Its utilization was limited by its high decomposition temperature and high energy consumption.Herein,an Fe-P slag,which is a solid waste that mainly comprises iron phosphide(FeP)and diiron phosphide(Fe_(2)P),can dramatically decrease the decomposition temperature of phosphogypsum.It was found that the Fe-P slag and CaSO_(4) can react as shown in the following reaction equation:2Fe_(1.5)P+3CaSO_(4)+6CO_(2)→Ca_(3)(PO_(4))_(2)+Fe_(3)O_(4)+3SO_(2)+6CO.Its reaction mechanism was further determined using the thermodynamic method.It was found that CaS was the key intermediate for this reaction.The CaSO_(4) conversion for this method can reach approximately 97%under the optimized roasting conditions:the molar ratio between Fe_(1.5) P and CaSO_(4) of 2:3,roasting temperature of 900℃,a roasting time of 8 h.
基金
financially supported by the National Natural Science Foundation of China (22108185, 51702027)
the Fundamental Research Funds for the Central University in China(20826041B4126)
project of Sichuan Chengdu Science and Technology Bureau (2019-YF05-02170-SN)
