Abstract: In order to effectively enrich phosphorus in converter slag,phosphorus enrichment was studied by TiO₂ modification,the TiO₂ modification process was discussed according to thermodynamic analysis,and the phosphorus-rich phase was separated from experimental slag by magnetic separation. It is found that CaSiTiO₅,CaTiO₃ and high phosphorus solid solution(n'C₂S-C₃P) form by a continuous reaction of n2CaO·SiO₂-3CaO·P₂O₅(nC₂S-C₃P for short,n>n') solid solution precipitated in the slag and TiO₂at 1623 K. The early precipitated solid solution(nC₂S-C₃P) decreases with the increasing TiO₂ content,even disappears. If the addition of TiO₂ increases or is excess in the slag,the high phosphorus solid solution(n'C₂S-C₃P) that forms by the above mentioned reaction will continue to react with TiO₂ to produce CaSiTiO₅ and CaTiO₃,and then phosphorus content in the phosphorus-rich phase increases.Through magnetic separation under a magnetic flied intensity of 350 mT,the amount of collected non-magnetic substance in the slag modified by TiO₂ increases by 23.84% compared with the original slag,the distribution ratio of P₂O₅ enlarges from 0.96 to 2.92,the amount of separated non-magnetic substance is 65.43% of the total of the modified slag,74.46% of phosphorus in the modified slag is entered into collected non-magnetic substance,and thereby most phosphorus is recycled.