Study on Effect of Basicity and P₂O₅ Content on the Crystallization Behavior of CaO-SiO₂-Al₂O₃-La₂O₃-CeO₂ Slag System AITranslate

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Chinese Library Classification Number:TF845.6[冶金工程]

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In order to more selectively enrich rare earths in rare earth-containing slags,melting-cooling ex-periments were carried out on the CaO-SiO₂-Al₂O₃-La₂O₃-CeO₂ slag system.The influence law of basicity(CaO/SiO₂ mass ratio)and P₂O₅ content(mass fraction)on the crystallization behavior of the slag system was studied by XRD,SEM-EDS,EPMA and other methods.The results show that when the P₂O₅ content remains constant,as the basicity increases from 0.86 to 1.20,the precipitated phase in the slag system transforms from a single RE-rich phase to a coexistence of two phases:the RE-rich phase and gehlenite phase(Ca2Al2SiO7).However,at a basicity of 1.20,10%P₂O₅ has an inhibitory effect on the precipitation of the Ca2Al2SiO7 phase.In addition,the area fraction and grain size of the RE-rich phase increase with the increase of basicity,and its RE content does not change much.When the basicity remains constant,as the mass fraction of P₂O₅ increases from 0 to 10%,the area fraction and average crystal size of the RE-rich phase increase,but its RE content relatively decreases.Considering the purity of the crystalline phase and the degree of rare earth enrichment comprehensively,adding 5%~10%P₂O₅ at lower alkalinity(R≤1.00)is more conducive to the enrichment and subsequent separation and extraction of rare earths in CaO-SiO₂-Al₂O₃-La₂O₃-CeO₂ slag system.