Recovery of Phosphorus from Dephosphorization Slag Produced by Duplex High Phosphorus Hot Metal Refining

摘要

Phosphate rock is a vital nonrenewable resource. In order to find new source of phosphorus, the recov ery of phosphorus from dephosphorization slag produced by duplex steelmaking process (De-P slag in De-P_De-C steelmaking process) was investigated in the present paper. It was demonstrated that the P rich phase in dephosphorization slag is difficult to recover effectively by magnetic separation as the rea son of P enriched phase inlay in the Fe enriched phase in the slag. The relationship between P recovery ratio and magnetic intensity and slag particle size were also obtained. A series of slag modification exper iments were designed to investigate the recovery of phosphorus from high P_2O_5 content dephosphoriza tion slag produced by duplex high phosphorus hot metal refining. It was found that the addition of SiO_2, Al_2O_3 and TiO_2 has a positive influence on the P recovery ratio. However, the P recovery ratio and the con centration of P_2O_5 in unmagnetized slag showed a reciprocal relationship with increasing SiO_2 and Al_2O_3 content. The P recovery ratio was little affected by the addition of Fe_tO and MnO. Furthermore, the P recovery ratio increased under the stirring condition. 74% and 87% P were recovered in the unmagnetized phases with adding 10% SiO_2 and Al_2O_3, respectively. The results demonstrated that most of the phos phorus in the slag could be recovered through slag modification and magnetic separation.